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   1  <?php
   2  
   3  /**
   4   * @file
   5   * These are the hooks that are invoked by the Drupal core.
   6   *
   7   * Core hooks are typically called in all modules at once using
   8   * module_invoke_all().
   9   */
  10  
  11  /**
  12   * @addtogroup hooks
  13   * @{
  14   */
  15  
  16  /**
  17   * Declare information about one or more Drupal actions.
  18   *
  19   * Any module can define any number of Drupal actions. The trigger module is an
  20   * example of a module that uses actions. An action consists of two or three
  21   * parts: (1) an action definition (returned by this hook), (2) a function which
  22   * does the action (which by convention is named module + '_' + description of
  23   * what the function does + '_action'), and an optional form definition
  24   * function that defines a configuration form (which has the name of the action
  25   * with '_form' appended to it.)
  26   *
  27   * @return
  28   *  - An array of action descriptions. Each action description is an associative
  29   *    array, where the key of the item is the action's function, and the
  30   *    following key-value pairs:
  31   *     - 'type': (required) the type is determined by what object the action
  32   *       acts on. Possible choices are node, user, comment, and system. Or
  33   *       whatever your own custom type is.  So, for the nodequeue module, the
  34   *       type might be set to 'nodequeue' if the action would be performed on a
  35   *       nodequeue.
  36   *     - 'description': (required) The human-readable name of the action.
  37   *     - 'configurable': (required) If FALSE, then the action doesn't require
  38   *       any extra configuration.  If TRUE, then you should define a form
  39   *       function with the same name as the key, but with '_form' appended to
  40   *       it (i.e., the form for 'node_assign_owner_action' is
  41   *       'node_assign_owner_action_form'.)
  42   *       This function will take the $context as the only parameter, and is
  43   *       paired with the usual _submit function, and possibly a _validate
  44   *       function.
  45   *     - 'hooks': (required) An array of all of the operations this action is
  46   *       appropriate for, keyed by hook name.  The trigger module uses this to
  47   *       filter out inappropriate actions when presenting the interface for
  48   *       assigning actions to events.  If you are writing actions in your own
  49   *       modules and you simply want to declare support for all possible hooks,
  50   *       you can set 'hooks' => array('any' => TRUE).  Common hooks are 'user',
  51   *       'nodeapi', 'comment', or 'taxonomy'. Any hook that has been described
  52   *       to Drupal in hook_hook_info() will work is a possiblity.
  53   *     - 'behavior': (optional) Human-readable array of behavior descriptions.
  54   *       The only one we have now is 'changes node property'.  You will almost
  55   *       certainly never have to return this in your own implementations of this
  56   *       hook.
  57   *
  58   * The function that is called when the action is triggered is passed two
  59   * parameters - an object of the same type as the 'type' value of the
  60   * hook_action_info array, and a context variable that contains the context
  61   * under which the action is currently running, sent as an array.  For example,
  62   * the actions module sets the 'hook' and 'op' keys of the context array (so,
  63   * 'hook' may be 'nodeapi' and 'op' may be 'insert').
  64   */
  65  function hook_action_info() {
  66    return array(
  67      'comment_unpublish_action' => array(
  68        'description' => t('Unpublish comment'),
  69        'type' => 'comment',
  70        'configurable' => FALSE,
  71        'hooks' => array(
  72          'comment' => array('insert', 'update'),
  73        )
  74      ),
  75      'comment_unpublish_by_keyword_action' => array(
  76        'description' => t('Unpublish comment containing keyword(s)'),
  77        'type' => 'comment',
  78        'configurable' => TRUE,
  79        'hooks' => array(
  80          'comment' => array('insert', 'update'),
  81        )
  82      )
  83    );
  84  }
  85  
  86  /**
  87   * Execute code after an action is deleted.
  88   *
  89   * @param $aid
  90   *   The action ID.
  91   */
  92  function hook_actions_delete($aid) {
  93    db_query("DELETE FROM {actions_assignments} WHERE aid = '%s'", $aid);
  94  }
  95  
  96  /**
  97   * Alter the actions declared by another module.
  98   *
  99   * Called by actions_list() to allow modules to alter the return
 100   * values from implementations of hook_action_info().
 101   *
 102   * @see trigger_example_action_info_alter().
 103   */
 104  function hook_action_info_alter(&$actions) {
 105    $actions['node_unpublish_action']['description'] = t('Unpublish and remove from public view.');
 106  }
 107  
 108  /**
 109   * Declare a block or set of blocks.
 110   *
 111   * Any module can declare a block (or blocks) to be displayed by implementing
 112   * hook_block(), which also allows you to specify any custom configuration
 113   * settings, and how to display the block.
 114   *
 115   * In hook_block(), each block your module provides is given a unique
 116   * identifier referred to as "delta" (the array key in the return value for the
 117   * 'list' operation). Delta values only need to be unique within your module,
 118   * and they are used in the following ways:
 119   * - Passed into the other hook_block() operations as an argument to
 120   *   identify the block being configured or viewed.
 121   * - Used to construct the default HTML ID of "block-MODULE-DELTA" applied to
 122   *   each block when it is rendered (which can then be used for CSS styling or
 123   *   JavaScript programming).
 124   * - Used to define a theming template suggestion of block__MODULE__DELTA, for
 125   *   advanced theming possibilities.
 126   * The values of delta can be strings or numbers, but because of the uses above
 127   * it is preferable to use descriptive strings whenever possible, and only use a
 128   * numeric identifier if you have to (for instance if your module allows users
 129   * to create several similar blocks that you identify within your module code
 130   * with numeric IDs).
 131   *
 132   * @param $op
 133   *   What kind of information to retrieve about the block or blocks.
 134   *   Possible values:
 135   *   - 'list': A list of all blocks defined by the module.
 136   *   - 'configure': Configuration form for the block.
 137   *   - 'save': Save the configuration options.
 138   *   - 'view': Process the block when enabled in a region in order to view its
 139   *     contents.
 140   * @param $delta
 141   *   Which block to return (not applicable if $op is 'list'). See above for more
 142   *   information about delta values.
 143   * @param $edit
 144   *   If $op is 'save', the submitted form data from the configuration form.
 145   * @return
 146   *   - If $op is 'list': An array of block descriptions. Each block description
 147   *     is an associative array, with the following key-value pairs:
 148   *     - 'info': (required) The human-readable name of the block. This is used
 149   *       to identify the block on administration screens, and is not displayed
 150   *       to non-administrative users.
 151   *     - 'cache': A bitmask of flags describing how the block should behave with
 152   *       respect to block caching. The following shortcut bitmasks are provided
 153   *       as constants in block.module:
 154   *       - BLOCK_CACHE_PER_ROLE (default): The block can change depending on the
 155   *         roles the user viewing the page belongs to.
 156   *       - BLOCK_CACHE_PER_USER: The block can change depending on the user
 157   *         viewing the page. This setting can be resource-consuming for sites
 158   *         with large number of users, and should only be used when
 159   *         BLOCK_CACHE_PER_ROLE is not sufficient.
 160   *       - BLOCK_CACHE_PER_PAGE: The block can change depending on the page
 161   *         being viewed.
 162   *       - BLOCK_CACHE_GLOBAL: The block is the same for every user on every
 163   *         page where it is visible.
 164   *       - BLOCK_NO_CACHE: The block should not get cached.
 165   *     - 'weight': (optional) Initial value for the ordering weight of this
 166   *       block. Most modules do not provide an initial value, and any value
 167   *       provided can be modified by a user on the block configuration screen.
 168   *     - 'status': (optional) Initial value for block enabled status. (1 =
 169   *       enabled, 0 = disabled). Most modules do not provide an initial value,
 170   *       and any value provided can be modified by a user on the block
 171   *       configuration screen.
 172   *     - 'region': (optional) Initial value for theme region within which this
 173   *       block is set. Most modules do not provide an initial value, and
 174   *       any value provided can be modified by a user on the block configuration
 175   *       screen. Note: If you set a region that isn't available in the currently
 176   *       enabled theme, the block will be disabled.
 177   *     - 'visibility': (optional) Initial value for the visibility flag, which
 178   *       tells how to interpret the 'pages' value. Possible values are:
 179   *       - 0: Show on all pages except listed pages. 'pages' lists the paths
 180   *         where the block should not be shown.
 181   *       - 1: Show only on listed pages. 'pages' lists the paths where the block
 182   *         should be shown.
 183   *       - 2: Use custom PHP code to determine visibility. 'pages' gives the PHP
 184   *         code to use.
 185   *       Most modules do not provide an initial value for 'visibility' or
 186   *       'pages', and any value provided can be modified by a user on the block
 187   *       configuration screen.
 188   *     - 'pages': (optional) See 'visibility' above.
 189   *   - If $op is 'configure': optionally return the configuration form.
 190   *   - If $op is 'save': return nothing; save the configuration values.
 191   *   - If $op is 'view': return an array which must define a 'subject' element
 192   *     (the localized block title) and a 'content' element (the block body)
 193   *     defining the block indexed by $delta. If the "content" element
 194   *     is empty, no block will be displayed even if "subject" is present.
 195   *
 196   * For a detailed usage example, see block_example.module.
 197   */
 198  function hook_block($op = 'list', $delta = 0, $edit = array()) {
 199    if ($op == 'list') {
 200      $blocks[0] = array('info' => t('Mymodule block #1 shows ...'),
 201        'weight' => 0, 'status' => 1, 'region' => 'left');
 202        // BLOCK_CACHE_PER_ROLE will be assumed for block 0.
 203  
 204      $blocks[1] = array('info' => t('Mymodule block #2 describes ...'),
 205        'cache' => BLOCK_CACHE_PER_ROLE | BLOCK_CACHE_PER_PAGE);
 206  
 207      return $blocks;
 208    }
 209    else if ($op == 'configure' && $delta == 0) {
 210      $form['items'] = array(
 211        '#type' => 'select',
 212        '#title' => t('Number of items'),
 213        '#default_value' => variable_get('mymodule_block_items', 0),
 214        '#options' => array('1', '2', '3'),
 215      );
 216      return $form;
 217    }
 218    else if ($op == 'save' && $delta == 0) {
 219      variable_set('mymodule_block_items', $edit['items']);
 220    }
 221    else if ($op == 'view') {
 222      switch($delta) {
 223        case 0:
 224          // Your module will need to define this function to render the block.
 225          $block = array('subject' => t('Title of block #1'),
 226            'content' => mymodule_display_block_1());
 227          break;
 228        case 1:
 229          // Your module will need to define this function to render the block.
 230          $block = array('subject' => t('Title of block #2'),
 231            'content' => mymodule_display_block_2());
 232          break;
 233      }
 234      return $block;
 235    }
 236  }
 237  
 238  /**
 239   * Respond to comment actions.
 240   *
 241   * This hook allows modules to extend the comments system by responding when
 242   * certain actions take place.
 243   *
 244   * @param $a1
 245   *   Argument; meaning is dependent on the action being performed.
 246   *   - For "validate", "update", and "insert": an array of form values
 247   *     submitted by the user.
 248   *   - For all other operations, the comment the action is being performed on.
 249   * @param $op
 250   *   The action being performed. Possible values:
 251   *   - "insert": The comment is being inserted.
 252   *   - "update": The comment is being updated.
 253   *   - "view": The comment is being viewed. This hook can be used to add
 254   *     additional data to the comment before theming.
 255   *   - "validate": The user has just finished editing the comment and is
 256   *     trying to preview or submit it. This hook can be used to check
 257   *     the comment. Errors should be set with form_set_error().
 258   *   - "publish": The comment is being published by the moderator.
 259   *   - "unpublish": The comment is being unpublished by the moderator.
 260   *   - "delete": The comment is being deleted by the moderator.
 261   */
 262  function hook_comment(&$a1, $op) {
 263    if ($op == 'insert' || $op == 'update') {
 264      $nid = $a1['nid'];
 265    }
 266  
 267    cache_clear_all_like(drupal_url(array('id' => $nid)));
 268  }
 269  
 270  /**
 271   * Perform periodic actions.
 272   *
 273   * Modules that require to schedule some commands to be executed at regular
 274   * intervals can implement hook_cron(). The engine will then call the hook
 275   * at the appropriate intervals defined by the administrator. This interface
 276   * is particularly handy to implement timers or to automate certain tasks.
 277   * Database maintenance, recalculation of settings or parameters, and
 278   * automatic mailings are good candidates for cron tasks.
 279   *
 280   * @return
 281   *   None.
 282   *
 283   * This hook will only be called if cron.php is run (e.g. by crontab).
 284   */
 285  function hook_cron() {
 286    $result = db_query('SELECT * FROM {site} WHERE checked = 0 OR checked
 287      + refresh < %d', time());
 288  
 289    while ($site = db_fetch_array($result)) {
 290      cloud_update($site);
 291    }
 292  }
 293  
 294  /**
 295   * Expose a list of triggers (events) that users can assign actions to.
 296   *
 297   * @see hook_action_info(), which allows your module to define actions.
 298   *
 299   * Note: Implementing this hook doesn't actually make any action functions run.
 300   * It just lets the trigger module set up an admin page that will let a site
 301   * administrator assign actions to hooks. To make this work, module needs to:
 302   * - Detect that the event has happened
 303   * - Figure out which actions have been associated with the event. Currently,
 304   *   the best way to do that is to call _trigger_get_hook_aids(), whose inputs
 305   *   are the name of the hook and the name of the operation, as defined in your
 306   *   hook_hook_info() return value)
 307   * - Call the associated action functions using the actions_do() function.
 308   *
 309   * @return
 310   *  A nested array:
 311   *    - The outermost array key must be the name of your module.
 312   *      - The next key represents the name of the hook that triggers the
 313   *        events, but for custom and contributed modules, it actually must
 314   *        be the name of your module.
 315   *        - The next key is the name of the operation within the hook. The
 316   *          array values at this level are arrays; currently, the only
 317   *          recognized key in that array is 'runs when', whose array value gives
 318   *          a translated description of the hook.
 319   */
 320  function hook_hook_info() {
 321    return array(
 322      'comment' => array(
 323        'comment' => array(
 324          'insert' => array(
 325            'runs when' => t('After saving a new comment'),
 326          ),
 327          'update' => array(
 328            'runs when' => t('After saving an updated comment'),
 329          ),
 330          'delete' => array(
 331            'runs when' => t('After deleting a comment')
 332          ),
 333          'view' => array(
 334            'runs when' => t('When a comment is being viewed by an authenticated user')
 335          ),
 336        ),
 337      ),
 338    );
 339  }
 340  
 341  /**
 342   * Alter the data being saved to the {menu_router} table after hook_menu is invoked.
 343   *
 344   * This hook is invoked by menu_router_build(). The menu definitions are passed
 345   * in by reference.  Each element of the $items array is one item returned
 346   * by a module from hook_menu.  Additional items may be added, or existing items
 347   * altered.
 348   *
 349   * @param $items
 350   *   Associative array of menu router definitions returned from hook_menu().
 351   * @return
 352   *   None.
 353   */
 354  function hook_menu_alter(&$items) {
 355    // Example - disable the page at node/add
 356    $items['node/add']['access callback'] = FALSE;
 357  }
 358  
 359  /**
 360   * Alter the data being saved to the {menu_links} table by menu_link_save().
 361   *
 362   * @param $item
 363   *   Associative array defining a menu link as passed into menu_link_save().
 364   * @param $menu
 365   *   Associative array containg the menu router returned from menu_router_build().
 366   * @return
 367   *   None.
 368   */
 369  function hook_menu_link_alter(&$item, $menu) {
 370    // Example 1 - make all new admin links hidden (a.k.a disabled).
 371    if (strpos($item['link_path'], 'admin') === 0 && empty($item['mlid'])) {
 372      $item['hidden'] = 1;
 373    }
 374    // Example 2  - flag a link to be altered by hook_translated_menu_link_alter()
 375    if ($item['link_path'] == 'devel/cache/clear') {
 376      $item['options']['alter'] = TRUE;
 377    }
 378  }
 379  
 380  /**
 381   * Alter a menu link after it's translated, but before it's rendered.
 382   *
 383   * This hook may be used, for example, to add a page-specific query string.
 384   * For performance reasons, only links that have $item['options']['alter'] == TRUE
 385   * will be passed into this hook.  The $item['options']['alter'] flag should
 386   * generally be set using hook_menu_link_alter().
 387   *
 388   * @param $item
 389   *   Associative array defining a menu link after _menu_link_translate()
 390   * @param $map
 391   *   Associative array containing the menu $map (path parts and/or objects).
 392   * @return
 393   *   None.
 394   */
 395  function hook_translated_menu_link_alter(&$item, $map) {
 396    if ($item['href'] == 'devel/cache/clear') {
 397      $item['localized_options']['query'] = drupal_get_destination();
 398    }
 399  }
 400  
 401  /**
 402   * Rewrite database queries, usually for access control.
 403   *
 404   * Add JOIN and WHERE statements to queries and decide whether the primary_field
 405   * shall be made DISTINCT. For node objects, primary field is always called nid.
 406   * For taxonomy terms, it is tid and for vocabularies it is vid. For comments,
 407   * it is cid. Primary table is the table where the primary object (node, file,
 408   * term_node etc.) is.
 409   *
 410   * You shall return an associative array. Possible keys are 'join', 'where' and
 411   * 'distinct'. The value of 'distinct' shall be 1 if you want that the
 412   * primary_field made DISTINCT.
 413   *
 414   * @param $query
 415   *   Query to be rewritten.
 416   * @param $primary_table
 417   *   Name or alias of the table which has the primary key field for this query.
 418   *   Typical table names would be: {blocks}, {comments}, {forum}, {node},
 419   *   {menu}, {term_data} or {vocabulary}. However, it is more common for
 420   *   $primary_table to contain the usual table alias: b, c, f, n, m, t or v.
 421   * @param $primary_field
 422   *   Name of the primary field.
 423   * @param $args
 424   *   Array of additional arguments.
 425   * @return
 426   *   An array of join statements, where statements, distinct decision.
 427   */
 428  function hook_db_rewrite_sql($query, $primary_table, $primary_field, $args) {
 429    switch ($primary_field) {
 430      case 'nid':
 431        // this query deals with node objects
 432        $return = array();
 433        if ($primary_table != 'n') {
 434          $return['join'] = "LEFT JOIN {node} n ON $primary_table.nid = n.nid";
 435        }
 436        $return['where'] = 'created >' . mktime(0, 0, 0, 1, 1, 2005);
 437        return $return;
 438        break;
 439      case 'tid':
 440        // this query deals with taxonomy objects
 441        break;
 442      case 'vid':
 443        // this query deals with vocabulary objects
 444        break;
 445    }
 446  }
 447  
 448  /**
 449   * Allows modules to declare their own Forms API element types and specify their
 450   * default values.
 451   *
 452   * This hook allows modules to declare their own form element types and to
 453   * specify their default values. The values returned by this hook will be
 454   * merged with the elements returned by hook_form() implementations and so
 455   * can return defaults for any Form APIs keys in addition to those explicitly
 456   * mentioned below.
 457   *
 458   * Each of the form element types defined by this hook is assumed to have
 459   * a matching theme function, e.g. theme_elementtype(), which should be
 460   * registered with hook_theme() as normal.
 461   *
 462   * For more information about custom element types see the explanation at
 463   * @link http://drupal.org/node/169815 http://drupal.org/node/169815 @endlink .
 464   *
 465   * @return
 466   *  An associative array describing the element types being defined. The array
 467   *  contains a sub-array for each element type, with the machine-readable type
 468   *  name as the key. Each sub-array has a number of possible attributes:
 469   *  - "#input": boolean indicating whether or not this element carries a value
 470   *    (even if it's hidden).
 471   *  - "#process": array of callback functions taking $element, $edit,
 472   *    $form_state, and $complete_form.
 473   *  - "#after_build": array of callback functions taking $element and $form_state.
 474   *  - "#validate": array of callback functions taking $form and $form_state.
 475   *  - "#element_validate": array of callback functions taking $element and
 476   *    $form_state.
 477   *  - "#pre_render": array of callback functions taking $element and $form_state.
 478   *  - "#post_render": array of callback functions taking $element and $form_state.
 479   *  - "#submit": array of callback functions taking $form and $form_state.
 480   */
 481  function hook_elements() {
 482    $type['filter_format'] = array('#input' => TRUE);
 483    return $type;
 484  }
 485  
 486  /**
 487   * Perform cleanup tasks.
 488   *
 489   * This hook is run at the end of each page request. It is often used for
 490   * page logging and printing out debugging information.
 491   *
 492   * Only use this hook if your code must run even for cached page views.
 493   * If you have code which must run once on all non cached pages, use
 494   * hook_init instead. Thats the usual case. If you implement this hook
 495   * and see an error like 'Call to undefined function', it is likely that
 496   * you are depending on the presence of a module which has not been loaded yet.
 497   * It is not loaded because Drupal is still in bootstrap mode.
 498   *
 499   * @param $destination
 500   *   If this hook is invoked as part of a drupal_goto() call, then this argument
 501   *   will be a fully-qualified URL that is the destination of the redirect.
 502   *   Modules may use this to react appropriately; for example, nothing should
 503   *   be output in this case, because PHP will then throw a "headers cannot be
 504   *   modified" error when attempting the redirection.
 505   * @return
 506   *   None.
 507   */
 508  function hook_exit($destination = NULL) {
 509    db_query('UPDATE {counter} SET hits = hits + 1 WHERE type = 1');
 510  }
 511  
 512  /**
 513   * Control access to private file downloads and specify HTTP headers.
 514   *
 515   * This hook allows modules enforce permissions on file downloads when the
 516   * private file download method is selected. Modules can also provide headers
 517   * to specify information like the file's name or MIME type.
 518   *
 519   * @param $filepath
 520   *   String of the file's path.
 521   * @return
 522   *   If the user does not have permission to access the file, return -1. If the
 523   *   user has permission, return an array with the appropriate headers. If the file
 524   *   is not controlled by the current module, the return value should be NULL.
 525   */
 526  function hook_file_download($filepath) {
 527    if ($filemime = db_result(db_query("SELECT filemime FROM {fileupload} WHERE filepath = '%s'", file_create_path($filepath)))) {
 528      if (user_access('access content')) {
 529        return array('Content-type:' . $filemime);
 530      }
 531      else {
 532        return -1;
 533      }
 534    }
 535  }
 536  
 537  /**
 538   * Define content filters.
 539   *
 540   * Content in Drupal is passed through all enabled filters before it is
 541   * output. This lets a module modify content to the site administrator's
 542   * liking.
 543   *
 544   * This hook contains all that is needed for having a module provide filtering
 545   * functionality.
 546   *
 547   * Depending on $op, different tasks are performed.
 548   *
 549   * A module can contain as many filters as it wants. The 'list' operation tells
 550   * the filter system which filters are available. Every filter has a numerical
 551   * 'delta' which is used to refer to it in every operation.
 552   *
 553   * Filtering is a two-step process. First, the content is 'prepared' by calling
 554   * the 'prepare' operation for every filter. The purpose of 'prepare' is to
 555   * escape HTML-like structures. For example, imagine a filter which allows the
 556   * user to paste entire chunks of programming code without requiring manual
 557   * escaping of special HTML characters like @< or @&. If the programming code
 558   * were left untouched, then other filters could think it was HTML and change
 559   * it. For most filters however, the prepare-step is not necessary, and they can
 560   * just return the input without changes.
 561   *
 562   * Filters should not use the 'prepare' step for anything other than escaping,
 563   * because that would short-circuits the control the user has over the order
 564   * in which filters are applied.
 565   *
 566   * The second step is the actual processing step. The result from the
 567   * prepare-step gets passed to all the filters again, this time with the
 568   * 'process' operation. It's here that filters should perform actual changing of
 569   * the content: transforming URLs into hyperlinks, converting smileys into
 570   * images, etc.
 571   *
 572   * An important aspect of the filtering system are 'input formats'. Every input
 573   * format is an entire filter setup: which filters to enable, in what order
 574   * and with what settings. Filters that provide settings should usually store
 575   * these settings per format.
 576   *
 577   * If the filter's behaviour depends on an extensive list and/or external data
 578   * (e.g. a list of smileys, a list of glossary terms) then filters are allowed
 579   * to provide a separate, global configuration page rather than provide settings
 580   * per format. In that case, there should be a link from the format-specific
 581   * settings to the separate settings page.
 582   *
 583   * For performance reasons content is only filtered once; the result is stored
 584   * in the cache table and retrieved the next time the piece of content is
 585   * displayed. If a filter's output is dynamic it can override the cache
 586   * mechanism, but obviously this feature should be used with caution: having one
 587   * 'no cache' filter in a particular input format disables caching for the
 588   * entire format, not just for one filter.
 589   *
 590   * Beware of the filter cache when developing your module: it is advised to set
 591   * your filter to 'no cache' while developing, but be sure to remove it again
 592   * if it's not needed. You can clear the cache by running the SQL query 'DELETE
 593   * FROM cache_filter';
 594   *
 595   * @param $op
 596   *  Which filtering operation to perform. Possible values:
 597   *   - list: provide a list of available filters.
 598   *     Returns an associative array of filter names with numerical keys.
 599   *     These keys are used for subsequent operations and passed back through
 600   *     the $delta parameter.
 601   *   - no cache: Return true if caching should be disabled for this filter.
 602   *   - description: Return a short description of what this filter does.
 603   *   - prepare: Return the prepared version of the content in $text.
 604   *   - process: Return the processed version of the content in $text.
 605   *   - settings: Return HTML form controls for the filter's settings. These
 606   *     settings are stored with variable_set() when the form is submitted.
 607   *     Remember to use the $format identifier in the variable and control names
 608   *     to store settings per input format (e.g. "mymodule_setting_$format").
 609   * @param $delta
 610   *   Which of the module's filters to use (applies to every operation except
 611   *   'list'). Modules that only contain one filter can ignore this parameter.
 612   * @param $format
 613   *   Which input format the filter is being used in (applies to 'prepare',
 614   *   'process' and 'settings').
 615   * @param $text
 616   *   The content to filter (applies to 'prepare' and 'process').
 617   * @param $cache_id
 618   *   The cache id of the content.
 619   * @return
 620   *   The return value depends on $op. The filter hook is designed so that a
 621   *   module can return $text for operations it does not use/need.
 622   *
 623   * For a detailed usage example, see filter_example.module. For an example of
 624   * using multiple filters in one module, see filter_filter() and
 625   * filter_filter_tips().
 626   */
 627  function hook_filter($op, $delta = 0, $format = -1, $text = '', $cache_id = 0) {
 628    switch ($op) {
 629      case 'list':
 630        return array(0 => t('Code filter'));
 631  
 632      case 'description':
 633        return t('Allows users to post code verbatim using &lt;code&gt; and &lt;?php ?&gt; tags.');
 634  
 635      case 'prepare':
 636        // Note: we use [ and ] to replace < > during the filtering process.
 637        // For more information, see "Temporary placeholders and
 638        // delimiters" at http://drupal.org/node/209715.
 639        $text = preg_replace('@<code>(.+?)</code>@se', "'[codefilter-code]' . codefilter_escape('\\1') . '[/codefilter-code]'", $text);
 640        $text = preg_replace('@<(\?(php)?|%)(.+?)(\?|%)>@se', "'[codefilter-php]' . codefilter_escape('\\3') . '[/codefilter-php]'", $text);
 641        return $text;
 642  
 643      case "process":
 644        $text = preg_replace('@[codefilter-code](.+?)[/codefilter-code]@se', "codefilter_process_code('$1')", $text);
 645        $text = preg_replace('@[codefilter-php](.+?)[/codefilter-php]@se', "codefilter_process_php('$1')", $text);
 646        return $text;
 647  
 648      default:
 649        return $text;
 650    }
 651  }
 652  
 653  /**
 654   * Provide tips for using filters.
 655   *
 656   * A module's tips should be informative and to the point. Short tips are
 657   * preferably one-liners.
 658   *
 659   * @param $delta
 660   *   Which of this module's filters to use. Modules which only implement one
 661   *   filter can ignore this parameter.
 662   * @param $format
 663   *   Which format we are providing tips for.
 664   * @param $long
 665   *   If set to true, long tips are requested, otherwise short tips are needed.
 666   * @return
 667   *   The text of the filter tip.
 668   *
 669   *
 670   */
 671  function hook_filter_tips($delta, $format, $long = FALSE) {
 672    if ($long) {
 673      return t('To post pieces of code, surround them with &lt;code&gt;...&lt;/code&gt; tags. For PHP code, you can use &lt;?php ... ?&gt;, which will also colour it based on syntax.');
 674    }
 675    else {
 676      return t('You may post code using &lt;code&gt;...&lt;/code&gt; (generic) or &lt;?php ... ?&gt; (highlighted PHP) tags.');
 677    }
 678  }
 679  
 680  /**
 681   * Insert closing HTML.
 682   *
 683   * This hook enables modules to insert HTML just before the \</body\> closing
 684   * tag of web pages. This is useful for adding JavaScript code to the footer
 685   * and for outputting debug information. It is not possible to add JavaScript
 686   * to the header at this point, and developers wishing to do so should use
 687   * hook_init() instead.
 688   *
 689   * @param $main
 690   *   Whether the current page is the front page of the site.
 691   * @return
 692   *   The HTML to be inserted.
 693   */
 694  function hook_footer($main = 0) {
 695    if (variable_get('dev_query', 0)) {
 696      return '<div style="clear:both;">'. devel_query_table() .'</div>';
 697    }
 698  }
 699  
 700  /**
 701   * Performs alterations to existing database schemas.
 702   *
 703   * When a module modifies the database structure of another module (by
 704   * changing, adding or removing fields, keys or indexes), it should
 705   * implement hook_schema_alter() to update the default $schema to take
 706   * its changes into account.
 707   *
 708   * See hook_schema() for details on the schema definition structure.
 709   *
 710   * @param $schema
 711   *   Nested array describing the schemas for all modules.
 712   * @return
 713   *   None.
 714   */
 715  function hook_schema_alter(&$schema) {
 716    // Add field to existing schema.
 717    $schema['users']['fields']['timezone_id'] = array(
 718      'type' => 'int',
 719      'not null' => TRUE,
 720      'default' => 0,
 721      'description' => 'Per-user timezone configuration.',
 722    );
 723  }
 724  
 725  /**
 726   * Perform alterations before a form is rendered.
 727   *
 728   * One popular use of this hook is to add form elements to the node form. When
 729   * altering a node form, the node object retrieved at from $form['#node'].
 730   *
 731   * Note that instead of hook_form_alter(), which is called for all forms, you
 732   * can also use hook_form_FORM_ID_alter() to alter a specific form.
 733   *
 734   * @param $form
 735   *   Nested array of form elements that comprise the form. The arguments
 736   *   that drupal_get_form() was originally called with are available in the
 737   *   array $form['#parameters'].
 738   * @param $form_state
 739   *   A keyed array containing the current state of the form.
 740   * @param $form_id
 741   *   String representing the name of the form itself. Typically this is the
 742   *   name of the function that generated the form.
 743   */
 744  function hook_form_alter(&$form, &$form_state, $form_id) {
 745    if (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] .'_node_form' == $form_id) {
 746      $path = isset($form['#node']->path) ? $form['#node']->path : NULL;
 747      $form['path'] = array(
 748        '#type' => 'fieldset',
 749        '#title' => t('URL path settings'),
 750        '#collapsible' => TRUE,
 751        '#collapsed' => empty($path),
 752        '#access' => user_access('create url aliases'),
 753        '#weight' => 30,
 754      );
 755      $form['path']['path'] = array(
 756        '#type' => 'textfield',
 757        '#default_value' => $path,
 758        '#maxlength' => 128,
 759        '#collapsible' => TRUE,
 760        '#collapsed' => TRUE,
 761        '#description' => t('Optionally specify an alternative URL by which this node can be accessed. For example, type "about" when writing an about page. Use a relative path and don\'t add a trailing slash or the URL alias won\'t work.'),
 762      );
 763      if ($path) {
 764        $form['path']['pid'] = array(
 765          '#type' => 'value',
 766          '#value' => db_result(db_query("SELECT pid FROM {url_alias} WHERE dst = '%s' AND language = '%s'", $path, $form['#node']->language))
 767        );
 768      }
 769    }
 770  }
 771  
 772  /**
 773   * Provide a form-specific alteration instead of the global hook_form_alter().
 774   *
 775   * Modules can implement hook_form_FORM_ID_alter() to modify a specific form,
 776   * rather than implementing hook_form_alter() and checking the form ID, or
 777   * using long switch statements to alter multiple forms.
 778   *
 779   * Note that this hook fires before hook_form_alter(). Therefore all
 780   * implementations of hook_form_FORM_ID_alter() will run before all
 781   * implementations of hook_form_alter(), regardless of the module order.
 782   *
 783   * @param $form
 784   *   Nested array of form elements that comprise the form. The arguments
 785   *   that drupal_get_form() was originally called with are available in the
 786   *   array $form['#parameters'].
 787   * @param $form_state
 788   *   A keyed array containing the current state of the form.
 789   *
 790   * @see hook_form_alter()
 791   * @see drupal_prepare_form()
 792   */
 793  function hook_form_FORM_ID_alter(&$form, &$form_state) {
 794    // Modification for the form with the given form ID goes here. For example, if
 795    // FORM_ID is "user_register" this code would run only on the user
 796    // registration form.
 797  
 798    // Add a checkbox to registration form about agreeing to terms of use.
 799    $form['terms_of_use'] = array(
 800      '#type' => 'checkbox',
 801      '#title' => t("I agree with the website's terms and conditions."),
 802      '#required' => TRUE,
 803    );
 804  }
 805  
 806  /**
 807   * Map form_ids to builder functions.
 808   *
 809   * This hook allows modules to build multiple forms from a single form "factory"
 810   * function but each form will have a different form id for submission,
 811   * validation, theming or alteration by other modules.
 812   *
 813   * The callback arguments will be passed as parameters to the function. Callers
 814   * of drupal_get_form() are also able to pass in parameters. These will be
 815   * appended after those specified by hook_forms().
 816   *
 817   * See node_forms() for an actual example of how multiple forms share a common
 818   * building function.
 819   *
 820   * @param $form_id
 821   *   The unique string identifying the desired form.
 822   * @param $args
 823   *   An array containing the original arguments provided to drupal_get_form().
 824   * @return
 825   *   An array keyed by form id with callbacks and optional, callback arguments.
 826   */
 827  function hook_forms($form_id, $args) {
 828    $forms['mymodule_first_form'] = array(
 829      'callback' => 'mymodule_form_builder',
 830      'callback arguments' => array('some parameter'),
 831    );
 832    $forms['mymodule_second_form'] = array(
 833      'callback' => 'mymodule_form_builder',
 834    );
 835    return $forms;
 836  }
 837  
 838  /**
 839   * Provide online user help.
 840   *
 841   * By implementing hook_help(), a module can make documentation
 842   * available to the user for the module as a whole, or for specific paths.
 843   * Help for developers should usually be provided via function
 844   * header comments in the code, or in special API example files.
 845   *
 846   * For a detailed usage example, see page_example.module.
 847   *
 848   * @param $path
 849   *   The router menu path, as defined in hook_menu(), for the help that
 850   *   is being requested; e.g., 'admin/node' or 'user/edit'. If the router path
 851   *   includes a % wildcard, then this will appear in $path; for example,
 852   *   node pages would have $path equal to 'node/%' or 'node/%/view'. Your hook
 853   *   implementation may also be called with special descriptors after a
 854   *   "#" sign. Some examples:
 855   *   - admin/help#modulename
 856   *     The main module help text, displayed on the admin/help/modulename
 857   *     page and linked to from the admin/help page.
 858   *   - user/help#modulename
 859   *     The help for a distributed authorization module (if applicable).
 860   * @param $arg
 861   *   An array that corresponds to the return value of the arg() function, for
 862   *   modules that want to provide help that is specific to certain values
 863   *   of wildcards in $path. For example, you could provide help for the path
 864   *   'user/1' by looking for the path 'user/%' and $arg[1] == '1'. This
 865   *   array should always be used rather than directly invoking arg(), because
 866   *   your hook implementation may be called for other purposes besides building
 867   *   the current page's help. Note that depending on which module is invoking
 868   *   hook_help, $arg may contain only empty strings. Regardless, $arg[0] to
 869   *   $arg[11] will always be set.
 870   * @return
 871   *   A localized string containing the help text.
 872   */
 873  function hook_help($path, $arg) {
 874    switch ($path) {
 875      // Main module help for the block module
 876      case 'admin/help#block':
 877        return '<p>' . t('Blocks are boxes of content rendered into an area, or region, of a web page. The default theme Garland, for example, implements the regions "left sidebar", "right sidebar", "content", "header", and "footer", and a block may appear in any one of these areas. The <a href="@blocks">blocks administration page</a> provides a drag-and-drop interface for assigning a block to a region, and for controlling the order of blocks within regions.', array('@blocks' => url('admin/structure/block'))) . '</p>';
 878  
 879      // Help for another path in the block module
 880      case 'admin/build/block':
 881        return '<p>' . t('This page provides a drag-and-drop interface for assigning a block to a region, and for controlling the order of blocks within regions. Since not all themes implement the same regions, or display regions in the same way, blocks are positioned on a per-theme basis. Remember that your changes will not be saved until you click the <em>Save blocks</em> button at the bottom of the page.') . '</p>';
 882    }
 883  }
 884  
 885  /**
 886   * Outputs a cached page.
 887   *
 888   * By implementing page_cache_fastpath(), a special cache handler can skip
 889   * most of the bootstrap process, including the database connection.
 890   * This function is invoked during DRUPAL_BOOTSTRAP_EARLY_PAGE_CACHE.
 891   *
 892   * @return
 893   *   TRUE if a page was output successfully.
 894   *
 895   * @see _drupal_bootstrap()
 896   */
 897  function page_cache_fastpath() {
 898    $page = mycache_fetch($base_root . request_uri(), 'cache_page');
 899    if (!empty($page)) {
 900      drupal_page_header();
 901      print $page;
 902      return TRUE;
 903    }
 904  }
 905  
 906  /**
 907   * Perform setup tasks. See also, hook_init.
 908   *
 909   * This hook is run at the beginning of the page request. It is typically
 910   * used to set up global parameters which are needed later in the request.
 911   *
 912   * Only use this hook if your code must run even for cached page views.This hook
 913   * is called before modules or most include files are loaded into memory.
 914   * It happens while Drupal is still in bootstrap mode.
 915   *
 916   * @return
 917   *   None.
 918   */
 919  function hook_boot() {
 920    // we need user_access() in the shutdown function. make sure it gets loaded
 921    drupal_load('module', 'user');
 922    register_shutdown_function('devel_shutdown');
 923  }
 924  
 925  /**
 926   * Perform setup tasks. See also, hook_boot.
 927   *
 928   * This hook is run at the beginning of the page request. It is typically
 929   * used to set up global parameters which are needed later in the request.
 930   * when this hook is called, all modules are already loaded in memory.
 931   *
 932   * For example, this hook is a typical place for modules to add CSS or JS
 933   * that should be present on every page. This hook is not run on cached
 934   * pages - though CSS or JS added this way will be present on a cached page.
 935   *
 936   * @return
 937   *   None.
 938   */
 939  function hook_init() {
 940    drupal_add_css(drupal_get_path('module', 'book') .'/book.css');
 941  }
 942  
 943  /**
 944   * Define internal Drupal links.
 945   *
 946   * This hook enables modules to add links to many parts of Drupal. Links
 947   * may be added in nodes or in the navigation block, for example.
 948   *
 949   * The returned array should be a keyed array of link entries. Each link can
 950   * be in one of two formats.
 951   *
 952   * The first format will use the l() function to render the link:
 953   *   - attributes: Optional. See l() for usage.
 954   *   - fragment: Optional. See l() for usage.
 955   *   - href: Required. The URL of the link.
 956   *   - html: Optional. See l() for usage.
 957   *   - query: Optional. See l() for usage.
 958   *   - title: Required. The name of the link.
 959   *
 960   * The second format can be used for non-links. Leaving out the href index will
 961   * select this format:
 962   *   - title: Required. The text or HTML code to display.
 963   *   - attributes: Optional. An associative array of HTML attributes to apply to the span tag.
 964   *   - html: Optional. If not set to true, check_plain() will be run on the title before it is displayed.
 965   *
 966   * @param $type
 967   *   An identifier declaring what kind of link is being requested.
 968   *   Possible values:
 969   *   - comment: Links to be placed below a comment being viewed.
 970   *   - node: Links to be placed below a node being viewed.
 971   * @param $object
 972   *   A node object or a comment object according to the $type.
 973   * @param $teaser
 974   *   In case of node link: a 0/1 flag depending on whether the node is
 975   *   displayed with its teaser or its full form.
 976   * @return
 977   *   An array of the requested links.
 978   *
 979   */
 980  function hook_link($type, $object, $teaser = FALSE) {
 981    $links = array();
 982  
 983    if ($type == 'node' && isset($object->parent)) {
 984      if (!$teaser) {
 985        if (book_access('create', $object)) {
 986          $links['book_add_child'] = array(
 987            'title' => t('add child page'),
 988            'href' => "node/add/book/parent/$object->nid",
 989          );
 990        }
 991        if (user_access('see printer-friendly version')) {
 992          $links['book_printer'] = array(
 993            'title' => t('printer-friendly version'),
 994            'href' => 'book/export/html/'. $object->nid,
 995            'attributes' => array('title' => t('Show a printer-friendly version of this book page and its sub-pages.'))
 996          );
 997        }
 998      }
 999    }
1000  
1001    $links['sample_link'] = array(
1002      'title' => t('go somewhere'),
1003      'href' => 'node/add',
1004      'query' => 'foo=bar',
1005      'fragment' => 'anchorname',
1006      'attributes' => array('title' => t('go to another page')),
1007    );
1008  
1009    // Example of a link that's not an anchor
1010    if ($type == 'video') {
1011      if (variable_get('video_playcounter', 1) && user_access('view play counter')) {
1012        $links['play_counter'] = array(
1013          'title' => format_plural($object->play_counter, '1 play', '@count plays'),
1014        );
1015      }
1016    }
1017  
1018    return $links;
1019  }
1020  
1021  /**
1022   * Perform alterations before links on a node or comment are rendered.
1023   *
1024   * One popular use of this hook is to modify/remove links from other modules.
1025   * If you want to add a link to the links section of a node or comment, use
1026   * hook_link() instead.
1027   *
1028   * @param $links
1029   *   Nested array of links for the node or comment keyed by providing module.
1030   * @param $node
1031   *   A node object.
1032   * @param $comment
1033   *   An optional comment object if the links are comment links. If not
1034   *   provided, the links are node links.
1035   *
1036   * @see hook_link()
1037   */
1038  function hook_link_alter(&$links, $node, $comment = NULL) {
1039    foreach ($links as $module => $link) {
1040      if (strstr($module, 'taxonomy_term')) {
1041        // Link back to the forum and not the taxonomy term page
1042        $links[$module]['href'] = str_replace('taxonomy/term', 'forum', $link['href']);
1043      }
1044    }
1045  }
1046  
1047  /**
1048   * Alter profile items before they are rendered.
1049   *
1050   * You may omit/add/re-sort/re-categorize, etc.
1051   *
1052   * @param $account
1053   *   A user object whose profile is being rendered. Profile items
1054   *   are stored in $account->content.
1055   */
1056  function hook_profile_alter(&$account) {
1057    foreach ($account->content AS $key => $field) {
1058      // do something
1059    }
1060  }
1061  
1062  /**
1063   * Alter any aspect of email sent by Drupal. You can use this hook to add a
1064   * common site footer to all outgoing email, add extra header fields, and/or
1065   * modify the email in any way. HTML-izing the outgoing email is one possibility.
1066   * See also drupal_mail().
1067   *
1068   * @param $message
1069   *   A structured array containing the message to be altered. Keys in this
1070   *   array include:
1071   *   - 'id'
1072   *     An id to identify the mail sent. Look at module source code or
1073   *     drupal_mail() for possible id values.
1074   *   - 'to'
1075   *     The mail address or addresses the message will be sent to. The
1076   *     formatting of this string must comply with RFC 2822.
1077   *   - 'subject'
1078   *     Subject of the e-mail to be sent. This must not contain any newline
1079   *     characters, or the mail may not be sent properly.
1080   *   - 'body'
1081   *     An array of lines containing the message to be sent. Drupal will format
1082   *     the correct line endings for you.
1083   *   - 'from'
1084   *     The address the message will be marked as being from, which is either a
1085   *     custom address or the site-wide default email address.
1086   *   - 'headers'
1087   *     Associative array containing mail headers, such as From, Sender,
1088   *     MIME-Version, Content-Type, etc.
1089   *   - 'params'
1090   *     An array of optional parameters supplied by the caller of drupal_mail()
1091   *     that is used to build the message before hook_mail_alter() is invoked.
1092   *   - language'
1093   *     The language object used to build the message before hook_mail_alter()
1094   *     is invoked.
1095   */
1096  function hook_mail_alter(&$message) {
1097    if ($message['id'] == 'modulename_messagekey') {
1098      $message['body'][] = "--\nMail sent out from " . variable_get('sitename', t('Drupal'));
1099    }
1100  }
1101  
1102  /**
1103   * Define menu items and page callbacks.
1104   *
1105   * This hook enables modules to register paths in order to define how URL
1106   * requests are handled. Paths may be registered for URL handling only, or they
1107   * can register a link to be placed in a menu (usually the Navigation menu). A
1108   * path and its associated information is commonly called a "menu router item".
1109   * This hook is rarely called (for example, when modules are enabled), and
1110   * its results are cached in the database.
1111   *
1112   * hook_menu() implementations return an associative array whose keys define
1113   * paths and whose values are an associative array of properties for each
1114   * path. (The complete list of properties is in the return value section below.)
1115   *
1116   * The definition for each path may include a page callback function, which is
1117   * invoked when the registered path is requested. If there is no other
1118   * registered path that fits the requested path better, any further path
1119   * components are passed to the callback function. For example, your module
1120   * could register path 'abc/def':
1121   * @code
1122   *   function mymodule_menu() {
1123   *     $items['abc/def'] = array(
1124   *       'page callback' => 'mymodule_abc_view',
1125   *     );
1126   *     return $items;
1127   *   }
1128   *
1129   *   function mymodule_abc_view($ghi = 0, $jkl = '') {
1130   *     // ...
1131   *   }
1132   * @endcode
1133   * When path 'abc/def' is requested, no further path components are in the
1134   * request, and no additional arguments are passed to the callback function (so
1135   * $ghi and $jkl would take the default values as defined in the function
1136   * signature). When 'abc/def/123/foo' is requested, $ghi will be '123' and
1137   * $jkl will be 'foo'. Note that this automatic passing of optional path
1138   * arguments applies only to page and theme callback functions.
1139   *
1140   * In addition to optional path arguments, the page callback and other callback
1141   * functions may specify argument lists as arrays. These argument lists may
1142   * contain both fixed/hard-coded argument values and integers that correspond
1143   * to path components. When integers are used and the callback function is
1144   * called, the corresponding path components will be substituted for the
1145   * integers. That is, the integer 0 in an argument list will be replaced with
1146   * the first path component, integer 1 with the second, and so on (path
1147   * components are numbered starting from zero). To pass an integer without it
1148   * being replaced with its respective path component, use the string value of
1149   * the integer (e.g., '1') as the argument value. This substitution feature
1150   * allows you to re-use a callback function for several different paths. For
1151   * example:
1152   * @code
1153   *   function mymodule_menu() {
1154   *     $items['abc/def'] = array(
1155   *       'page callback' => 'mymodule_abc_view',
1156   *       'page arguments' => array(1, 'foo'),
1157   *     );
1158   *     return $items;
1159   *   }
1160   * @endcode
1161   * When path 'abc/def' is requested, the page callback function will get 'def'
1162   * as the first argument and (always) 'foo' as the second argument.
1163   *
1164   * If a page callback function uses an argument list array, and its path is
1165   * requested with optional path arguments, then the list array's arguments are
1166   * passed to the callback function first, followed by the optional path
1167   * arguments. Using the above example, when path 'abc/def/bar/baz' is requested,
1168   * mymodule_abc_view() will be called with 'def', 'foo', 'bar' and 'baz' as
1169   * arguments, in that order.
1170   *
1171   * Wildcards within paths also work with integer substitution. For example,
1172   * your module could register path 'my-module/%/edit':
1173   * @code
1174   *   $items['my-module/%/edit'] = array(
1175   *     'page callback' => 'mymodule_abc_edit',
1176   *     'page arguments' => array(1),
1177   *   );
1178   * @endcode
1179   * When path 'my-module/foo/edit' is requested, integer 1 will be replaced
1180   * with 'foo' and passed to the callback function.
1181   *
1182   * Registered paths may also contain special "auto-loader" wildcard components
1183   * in the form of '%mymodule_abc', where the '%' part means that this path
1184   * component is a wildcard, and the 'mymodule_abc' part defines the prefix for a
1185   * load function, which here would be named mymodule_abc_load(). When a matching
1186   * path is requested, your load function will receive as its first argument the
1187   * path component in the position of the wildcard; load functions may also be
1188   * passed additional arguments (see "load arguments" in the return value
1189   * section below). For example, your module could register path
1190   * 'my-module/%mymodule_abc/edit':
1191   * @code
1192   *   $items['my-module/%mymodule_abc/edit'] = array(
1193   *     'page callback' => 'mymodule_abc_edit',
1194   *     'page arguments' => array(1),
1195   *   );
1196   * @endcode
1197   * When path 'my-module/123/edit' is requested, your load function
1198   * mymodule_abc_load() will be invoked with the argument '123', and should
1199   * load and return an "abc" object with internal id 123:
1200   * @code
1201   *   function mymodule_abc_load($abc_id) {
1202   *     return db_query("SELECT * FROM {mymodule_abc} WHERE abc_id = :abc_id", array(':abc_id' => $abc_id))->fetchObject();
1203   *   }
1204   * @endcode
1205   * This 'abc' object will then be passed into the page callback function
1206   * mymodule_abc_edit() to replace the integer 1 in the page arguments.
1207   *
1208   * You can also make groups of menu items to be rendered (by default) as tabs
1209   * on a page. To do that, first create one menu item of type MENU_NORMAL_ITEM,
1210   * with your chosen path, such as 'foo'. Then duplicate that menu item, using a
1211   * subdirectory path, such as 'foo/tab1', and changing the type to
1212   * MENU_DEFAULT_LOCAL_TASK to make it the default tab for the group. Then add
1213   * the additional tab items, with paths such as "foo/tab2" etc., with type
1214   * MENU_LOCAL_TASK. Example:
1215   * @code
1216   * // Make "Foo settings" appear on the admin Config page
1217   * $items['admin/config/foo'] = array(
1218   *   'title' => 'Foo settings',
1219   *   'type' => MENU_NORMAL_ITEM,
1220   *   // Page callback, etc. need to be added here.
1221   * );
1222   * // Make "Global settings" the main tab on the "Foo settings" page
1223   * $items['admin/config/foo/global'] = array(
1224   *   'title' => 'Global settings',
1225   *   'type' => MENU_DEFAULT_LOCAL_TASK,
1226   *   // Access callback, page callback, and theme callback will be inherited
1227   *   // from 'admin/config/foo', if not specified here to override.
1228   * );
1229   * // Make an additional tab called "Node settings" on "Foo settings"
1230   * $items['admin/config/foo/node'] = array(
1231   *   'title' => 'Node settings',
1232   *   'type' => MENU_LOCAL_TASK,
1233   *   // Page callback and theme callback will be inherited from
1234   *   // 'admin/config/foo', if not specified here to override.
1235   *   // Need to add access callback or access arguments.
1236   * );
1237   * @endcode
1238   *
1239   * @return
1240   *   An array of menu items. Each menu item has a key corresponding to the
1241   *   Drupal path being registered. The corresponding array value is an
1242   *   associative array that may contain the following key-value pairs:
1243   *   - "title": Required. The untranslated title of the menu item.
1244   *   - "title callback": Function to generate the title; defaults to t().
1245   *     If you require only the raw string to be output, set this to FALSE.
1246   *   - "title arguments": Arguments to send to t() or your custom callback,
1247   *     with path component substitution as described above.
1248   *   - "description": The untranslated description of the menu item.
1249   *   - "page callback": The function to call to display a web page when the user
1250   *     visits the path. If omitted, the parent menu item's callback will be used
1251   *     instead.
1252   *   - "page arguments": An array of arguments to pass to the page callback
1253   *     function, with path component substitution as described above.
1254   *   - "access callback": A function returning TRUE if the user has access
1255   *     rights to this menu item, and FALSE if not. It can also be a boolean
1256   *     constant instead of a function, and you can also use numeric values
1257   *     (will be cast to boolean). Defaults to user_access() unless a value is
1258   *     inherited from the parent menu item; only MENU_DEFAULT_LOCAL_TASK items
1259   *     can inherit access callbacks. To use the user_access() default callback,
1260   *     you must specify the permission to check as 'access arguments' (see
1261   *     below).
1262   *   - "access arguments": An array of arguments to pass to the access callback
1263   *     function, with path component substitution as described above. If the
1264   *     access callback is inherited (see above), the access arguments will be
1265   *     inherited with it, unless overridden in the child menu item.
1266   *   - "file": A file that will be included before the page callback is called;
1267   *     this allows page callback functions to be in separate files. The file
1268   *     should be relative to the implementing module's directory unless
1269   *     otherwise specified by the "file path" option. Does not apply to other
1270   *     callbacks (only page callback).
1271   *   - "file path": The path to the directory containing the file specified in
1272   *     "file". This defaults to the path to the module implementing the hook.
1273   *   - "load arguments": An array of arguments to be passed to each of the
1274   *     wildcard object loaders in the path, after the path argument itself.
1275   *     For example, if a module registers path node/%node/revisions/%/view
1276   *     with load arguments set to array(3), the '%node' in the path indicates
1277   *     that the loader function node_load() will be called with the second
1278   *     path component as the first argument. The 3 in the load arguments
1279   *     indicates that the fourth path component will also be passed to
1280   *     node_load() (numbering of path components starts at zero). So, if path
1281   *     node/12/revisions/29/view is requested, node_load(12, 29) will be called.
1282   *     There are also two "magic" values that can be used in load arguments.
1283   *     "%index" indicates the index of the wildcard path component. "%map"
1284   *     indicates the path components as an array. For example, if a module
1285   *     registers for several paths of the form 'user/%user_category/edit/*', all
1286   *     of them can use the same load function user_category_load(), by setting
1287   *     the load arguments to array('%map', '%index'). For instance, if the user
1288   *     is editing category 'foo' by requesting path 'user/32/edit/foo', the load
1289   *     function user_category_load() will be called with 32 as its first
1290   *     argument, the array ('user', 32, 'edit', 'foo') as the map argument,
1291   *     and 1 as the index argument (because %user_category is the second path
1292   *     component and numbering starts at zero). user_category_load() can then
1293   *     use these values to extract the information that 'foo' is the category
1294   *     being requested.
1295   *   - "weight": An integer that determines the relative position of items in
1296   *     the menu; higher-weighted items sink. Defaults to 0. Menu items with the
1297   *     same weight are ordered alphabetically.
1298   *   - "menu_name": Optional. Set this to a custom menu if you don't want your
1299   *     item to be placed in Navigation.
1300   *   - "tab_parent": For local task menu items, the path of the task's parent
1301   *     item; defaults to the same path without the last component (e.g., the
1302   *     default parent for 'admin/people/create' is 'admin/people').
1303   *   - "tab_root": For local task menu items, the path of the closest non-tab
1304   *     item; same default as "tab_parent".
1305   *   - "position": Position of the block ('left' or 'right') on the system
1306   *     administration page for this item.
1307   *   - "type": A bitmask of flags describing properties of the menu item.
1308   *     Many shortcut bitmasks are provided as constants in menu.inc:
1309   *     - MENU_NORMAL_ITEM: Normal menu items show up in the menu tree and can be
1310   *       moved/hidden by the administrator.
1311   *     - MENU_CALLBACK: Callbacks simply register a path so that the correct
1312   *       information is generated when the path is accessed.
1313   *     - MENU_SUGGESTED_ITEM: Modules may "suggest" menu items that the
1314   *       administrator may enable.
1315   *     - MENU_LOCAL_TASK: Local tasks are menu items that describe different
1316   *       displays of data, and are generally rendered as tabs.
1317   *     - MENU_DEFAULT_LOCAL_TASK: Every set of local tasks should provide one
1318   *       "default" task, which should display the same page as the parent item.
1319   *     If the "type" element is omitted, MENU_NORMAL_ITEM is assumed.
1320   *
1321   * For a detailed usage example, see page_example.module.
1322   * For comprehensive documentation on the menu system, see
1323   * http://drupal.org/node/102338.
1324   */
1325  function hook_menu() {
1326    $items = array();
1327  
1328    $items['blog'] = array(
1329      'title' => 'blogs',
1330      'description' => 'Listing of blogs.',
1331      'page callback' => 'blog_page',
1332      'access arguments' => array('access content'),
1333      'type' => MENU_SUGGESTED_ITEM,
1334    );
1335    $items['blog/feed'] = array(
1336      'title' => 'RSS feed',
1337      'page callback' => 'blog_feed',
1338      'access arguments' => array('access content'),
1339      'type' => MENU_CALLBACK,
1340    );
1341  
1342    return $items;
1343  }
1344  
1345  /**
1346   * Alter the information parsed from module and theme .info files
1347   *
1348   * This hook is invoked in  module_rebuild_cache() and in system_theme_data().
1349   * A module may implement this hook in order to add to or alter the data
1350   * generated by reading the .info file with drupal_parse_info_file().
1351   *
1352   * @param &$info
1353   *   The .info file contents, passed by reference so that it can be altered.
1354   * @param $file
1355   *   Full information about the module or theme, including $file->name, and
1356   *   $file->filename
1357   */
1358  function hook_system_info_alter(&$info, $file) {
1359    // Only fill this in if the .info file does not define a 'datestamp'.
1360    if (empty($info['datestamp'])) {
1361      $info['datestamp'] = filemtime($file->filename);
1362    }
1363  }
1364  
1365  /**
1366   * Alter the information about available updates for projects.
1367   *
1368   * @param $projects
1369   *   Reference to an array of information about available updates to each
1370   *   project installed on the system.
1371   *
1372   * @see update_calculate_project_data()
1373   */
1374  function hook_update_status_alter(&$projects) {
1375    $settings = variable_get('update_advanced_project_settings', array());
1376    foreach ($projects as $project => $project_info) {
1377      if (isset($settings[$project]) && isset($settings[$project]['check']) &&
1378          ($settings[$project]['check'] == 'never' ||
1379           (isset($project_info['recommended']) &&
1380            $settings[$project]['check'] === $project_info['recommended']))) {
1381        $projects[$project]['status'] = UPDATE_NOT_CHECKED;
1382        $projects[$project]['reason'] = t('Ignored from settings');
1383        if (!empty($settings[$project]['notes'])) {
1384          $projects[$project]['extra'][] = array(
1385            'class' => 'admin-note',
1386            'label' => t('Administrator note'),
1387            'data' => $settings[$project]['notes'],
1388          );
1389        }
1390      }
1391    }
1392  }
1393  
1394  /**
1395   * Alter the list of projects before fetching data and comparing versions.
1396   *
1397   * Most modules will never need to implement this hook. It is for advanced
1398   * interaction with the update status module: mere mortals need not apply.
1399   * The primary use-case for this hook is to add projects to the list, for
1400   * example, to provide update status data on disabled modules and themes. A
1401   * contributed module might want to hide projects from the list, for example,
1402   * if there is a site-specific module that doesn't have any official releases,
1403   * that module could remove itself from this list to avoid "No available
1404   * releases found" warnings on the available updates report. In rare cases, a
1405   * module might want to alter the data associated with a project already in
1406   * the list.
1407   *
1408   * @param $projects
1409   *   Reference to an array of the projects installed on the system. This
1410   *   includes all the metadata documented in the comments below for each
1411   *   project (either module or theme) that is currently enabled. The array is
1412   *   initially populated inside update_get_projects() with the help of
1413   *   _update_process_info_list(), so look there for examples of how to
1414   *   populate the array with real values.
1415   *
1416   * @see update_get_projects()
1417   * @see _update_process_info_list()
1418   */
1419  function hook_update_projects_alter(&$projects) {
1420    // Hide a site-specific module from the list.
1421    unset($projects['site_specific_module']);
1422  
1423    // Add a disabled module to the list.
1424    // The key for the array should be the machine-readable project "short name".
1425    $projects['disabled_project_name'] = array(
1426      // Machine-readable project short name (same as the array key above).
1427      'name' => 'disabled_project_name',
1428      // Array of values from the main .info file for this project.
1429      'info' => array(
1430        'name' => 'Some disabled module',
1431        'description' => 'A module not enabled on the site that you want to see in the available updates report.',
1432        'version' => '6.x-1.0',
1433        'core' => '6.x',
1434        // The maximum file change time (the "ctime" returned by the filectime()
1435        // PHP method) for all of the .info files included in this project.
1436        '_info_file_ctime' => 1243888165,
1437      ),
1438      // The date stamp when the project was released, if known. If the disabled
1439      // project was an officially packaged release from drupal.org, this will
1440      // be included in the .info file as the 'datestamp' field. This only
1441      // really matters for development snapshot releases that are regenerated,
1442      // so it can be left undefined or set to 0 in most cases.
1443      'datestamp' => 1243888185,
1444      // Any modules (or themes) included in this project. Keyed by machine-
1445      // readable "short name", value is the human-readable project name printed
1446      // in the UI.
1447      'includes' => array(
1448        'disabled_project' => 'Disabled module',
1449        'disabled_project_helper' => 'Disabled module helper module',
1450        'disabled_project_foo' => 'Disabled module foo add-on module',
1451      ),
1452      // Does this project contain a 'module', 'theme', 'disabled-module', or
1453      // 'disabled-theme'?
1454      'project_type' => 'disabled-module',
1455    );
1456  }
1457  
1458  
1459  /**
1460   * Inform the node access system what permissions the user has.
1461   *
1462   * This hook is for implementation by node access modules. In this hook,
1463   * the module grants a user different "grant IDs" within one or more
1464   * "realms". In hook_node_access_records(), the realms and grant IDs are
1465   * associated with permission to view, edit, and delete individual nodes.
1466   *
1467   * The realms and grant IDs can be arbitrarily defined by your node access
1468   * module; it is common to use role IDs as grant IDs, but that is not
1469   * required. Your module could instead maintain its own list of users, where
1470   * each list has an ID. In that case, the return value of this hook would be
1471   * an array of the list IDs that this user is a member of.
1472   *
1473   * A node access module may implement as many realms as necessary to
1474   * properly define the access privileges for the nodes.
1475   *
1476   * @param $account
1477   *   The user object whose grants are requested.
1478   * @param $op
1479   *   The node operation to be performed, such as "view", "update", or "delete".
1480   *
1481   * @return
1482   *   An array whose keys are "realms" of grants, and whose values are arrays of
1483   *   the grant IDs within this realm that this user is being granted.
1484   *
1485   * For a detailed example, see node_access_example.module.
1486   *
1487   * @ingroup node_access
1488   */
1489  function hook_node_grants($account, $op) {
1490    if (user_access('access private content', $account)) {
1491      $grants['example'] = array(1);
1492    }
1493    $grants['example_owner'] = array($account->uid);
1494    return $grants;
1495  }
1496  
1497  /**
1498   * Set permissions for a node to be written to the database.
1499   *
1500   * When a node is saved, a module implementing hook_node_access_records() will
1501   * be asked if it is interested in the access permissions for a node. If it is
1502   * interested, it must respond with an array of permissions arrays for that
1503   * node.
1504   *
1505   * Each permissions item in the array is an array with the following elements:
1506   * - 'realm': The name of a realm that the module has defined in
1507   *   hook_node_grants().
1508   * - 'gid': A 'grant ID' from hook_node_grants().
1509   * - 'grant_view': If set to TRUE a user that has been identified as a member
1510   *   of this gid within this realm can view this node.
1511   * - 'grant_update': If set to TRUE a user that has been identified as a member
1512   *   of this gid within this realm can edit this node.
1513   * - 'grant_delete': If set to TRUE a user that has been identified as a member
1514   *   of this gid within this realm can delete this node.
1515   * - 'priority': If multiple modules seek to set permissions on a node, the
1516   *   realms that have the highest priority will win out, and realms with a lower
1517   *   priority will not be written. If there is any doubt, it is best to
1518   *   leave this 0.
1519   *
1520   * @ingroup node_access
1521   */
1522  function hook_node_access_records($node) {
1523    if (node_access_example_disabling()) {
1524      return;
1525    }
1526  
1527    // We only care about the node if it's been marked private. If not, it is
1528    // treated just like any other node and we completely ignore it.
1529    if ($node->private) {
1530      $grants = array();
1531      $grants[] = array(
1532        'realm' => 'example',
1533        'gid' => 1,
1534        'grant_view' => TRUE,
1535        'grant_update' => FALSE,
1536        'grant_delete' => FALSE,
1537        'priority' => 0,
1538      );
1539  
1540      // For the example_author array, the GID is equivalent to a UID, which
1541      // means there are many many groups of just 1 user.
1542      $grants[] = array(
1543        'realm' => 'example_author',
1544        'gid' => $node->uid,
1545        'grant_view' => TRUE,
1546        'grant_update' => TRUE,
1547        'grant_delete' => TRUE,
1548        'priority' => 0,
1549      );
1550      return $grants;
1551    }
1552  }
1553  
1554  /**
1555   * Add mass node operations.
1556   *
1557   * This hook enables modules to inject custom operations into the mass operations
1558   * dropdown found at admin/content/node, by associating a callback function with
1559   * the operation, which is called when the form is submitted. The callback function
1560   * receives one initial argument, which is an array of the checked nodes.
1561   *
1562   * @return
1563   *   An array of operations. Each operation is an associative array that may
1564   *   contain the following key-value pairs:
1565   *   - "label": Required. The label for the operation, displayed in the dropdown menu.
1566   *   - "callback": Required. The function to call for the operation.
1567   *   - "callback arguments": Optional. An array of additional arguments to pass to
1568   *     the callback function.
1569   *
1570   */
1571  function hook_node_operations() {
1572    $operations = array(
1573      'approve' => array(
1574        'label' => t('Approve the selected posts'),
1575        'callback' => 'node_operations_approve',
1576      ),
1577      'promote' => array(
1578        'label' => t('Promote the selected posts'),
1579        'callback' => 'node_operations_promote',
1580      ),
1581      'sticky' => array(
1582        'label' => t('Make the selected posts sticky'),
1583        'callback' => 'node_operations_sticky',
1584      ),
1585      'demote' => array(
1586        'label' => t('Demote the selected posts'),
1587        'callback' => 'node_operations_demote',
1588      ),
1589      'unpublish' => array(
1590        'label' => t('Unpublish the selected posts'),
1591        'callback' => 'node_operations_unpublish',
1592      ),
1593      'delete' => array(
1594        'label' => t('Delete the selected posts'),
1595      ),
1596    );
1597    return $operations;
1598  }
1599  
1600  /**
1601   * Act on nodes defined by other modules.
1602   *
1603   * Despite what its name might make you think, hook_nodeapi() is not
1604   * reserved for node modules. On the contrary, it allows modules to react
1605   * to actions affecting all kinds of nodes, regardless of whether that
1606   * module defined the node.
1607   *
1608   * It is common to find hook_nodeapi() used in conjunction with
1609   * hook_form_alter(). Modules use hook_form_alter() to place additional form
1610   * elements onto the node edit form, and hook_nodeapi() is used to read and
1611   * write those values to and from the database.
1612   *
1613   * @param &$node
1614   *   The node the action is being performed on.
1615   * @param $op
1616   *   What kind of action is being performed. Possible values:
1617   *   - "alter": the $node->content array has been rendered, so the node body or
1618   *     teaser is filtered and now contains HTML. This op should only be used when
1619   *     text substitution, filtering, or other raw text operations are necessary.
1620   *   - "delete": The node is being deleted.
1621   *   - "delete revision": The revision of the node is deleted. You can delete data
1622   *     associated with that revision.
1623   *   - "insert": The node has just been created (inserted in the database).
1624   *   - "load": The node is about to be loaded from the database. This hook
1625   *     can be used to load additional data at this time.
1626   *   - "prepare": The node is about to be shown on the add/edit form.
1627   *   - "prepare translation": The node is being cloned for translation. Load
1628   *     additional data or copy values from $node->translation_source.
1629   *   - "print": Prepare a node view for printing. Used for printer-friendly
1630   *     view in book_module
1631   *   - "rss item": An RSS feed is generated. The module can return properties
1632   *     to be added to the RSS item generated for this node. See comment_nodeapi()
1633   *     and upload_nodeapi() for examples. The $node passed can also be modified
1634   *     to add or remove contents to the feed item.
1635   *   - "search result": The node is displayed as a search result. If you
1636   *     want to display extra information with the result, return it.
1637   *   - "presave": The node passed validation and is about to be saved. Modules may
1638   *      use this to make changes to the node before it is saved to the database.
1639   *   - "update": The node has just been updated in the database.
1640   *   - "update index": The node is being indexed. If you want additional
1641   *     information to be indexed which is not already visible through
1642   *     nodeapi "view", then you should return it here.
1643   *   - "validate": The user has just finished editing the node and is
1644   *     trying to preview or submit it. This hook can be used to check
1645   *     the node data. Errors should be set with form_set_error().
1646   *   - "view": The node content is being assembled before rendering. The module
1647   *     may add elements $node->content prior to rendering. This hook will be
1648   *     called after hook_view().  The format of $node->content is the same as
1649   *     used by Forms API.
1650   * @param $a3
1651   *   - For "view", passes in the $teaser parameter from node_view().
1652   *   - For "validate", passes in the $form parameter from node_validate().
1653   * @param $a4
1654   *   - For "view", passes in the $page parameter from node_view().
1655   * @return
1656   *   This varies depending on the operation.
1657   *   - The "presave", "insert", "update", "delete", "print" and "view"
1658   *     operations have no return value.
1659   *   - The "load" operation should return an array containing pairs
1660   *     of fields => values to be merged into the node object.
1661   *
1662   * If you are writing a node module, do not use this hook to perform
1663   * actions on your type of node alone. Instead, use the hooks set aside
1664   * for node modules, such as hook_insert() and hook_form(). That said, for
1665   * some operations, such as "delete revision" or "rss item" there is no
1666   * corresponding hook so even the module defining the node will need to
1667   * implement hook_nodeapi().
1668   */
1669  function hook_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
1670    switch ($op) {
1671      case 'presave':
1672        if ($node->nid && $node->moderate) {
1673          // Reset votes when node is updated:
1674          $node->score = 0;
1675          $node->users = '';
1676          $node->votes = 0;
1677        }
1678        break;
1679      case 'insert':
1680      case 'update':
1681        if ($node->moderate && user_access('access submission queue')) {
1682          drupal_set_message(t('The post is queued for approval'));
1683        }
1684        elseif ($node->moderate) {
1685          drupal_set_message(t('The post is queued for approval. The editors will decide whether it should be published.'));
1686        }
1687        break;
1688      case 'view':
1689        $node->content['my_additional_field'] = array(
1690          '#value' => theme('mymodule_my_additional_field', $additional_field),
1691          '#weight' => 10,
1692        );
1693        break;
1694    }
1695  }
1696  
1697  /**
1698   * Allow modules to modify the OpenID request parameters.
1699   *
1700   * @param $op
1701   *   The operation to be performed.
1702   *   Possible values:
1703   *   - request: Modify parameters before they are sent to the OpenID provider.
1704   * @param $request
1705   *   An associative array of parameter defaults to which to modify or append.
1706   * @return
1707   *   An associative array of parameters to be merged with the default list.
1708   *
1709   */
1710  function hook_openid($op, $request) {
1711    if ($op == 'request') {
1712      $request['openid.identity'] = 'http://myname.myopenid.com/';
1713    }
1714    return $request;
1715  }
1716  
1717  /**
1718   * Define user permissions.
1719   *
1720   * This hook can supply permissions that the module defines, so that they
1721   * can be selected on the user permissions page and used to grant or restrict
1722   * access to actions the module performs.
1723   *
1724   * Permissions are checked using user_access().
1725   *
1726   * For a detailed usage example, see page_example.module.
1727   *
1728   * @return
1729   *   An array of permission strings. The strings must not be wrapped with
1730   *   the t() function, since the string extractor takes care of
1731   *   extracting permission names defined in the perm hook for
1732   *   translation.
1733   */
1734  function hook_perm() {
1735    return array('administer my module');
1736  }
1737  
1738  /**
1739   * Ping another server.
1740   *
1741   * This hook allows a module to notify other sites of updates on your
1742   * Drupal site.
1743   *
1744   * @param $name
1745   *   The name of your Drupal site.
1746   * @param $url
1747   *   The URL of your Drupal site.
1748   * @return
1749   *   None.
1750   */
1751  function hook_ping($name = '', $url = '') {
1752    $feed = url('node/feed');
1753  
1754    $client = new xmlrpc_client('/RPC2', 'rpc.weblogs.com', 80);
1755  
1756    $message = new xmlrpcmsg('weblogUpdates.ping',
1757      array(new xmlrpcval($name), new xmlrpcval($url)));
1758  
1759    $result = $client->send($message);
1760  
1761    if (!$result || $result->faultCode()) {
1762      watchdog('error', 'failed to notify "weblogs.com" (site)');
1763    }
1764  
1765    unset($client);
1766  }
1767  
1768  /**
1769   * Define a custom search routine.
1770   *
1771   * This hook allows a module to perform searches on content it defines
1772   * (custom node types, users, or comments, for example) when a site search
1773   * is performed.
1774   *
1775   * Note that you can use form API to extend the search. You will need to use
1776   * hook_form_alter() to add any additional required form elements. You can
1777   * process their values on submission using a custom validation function.
1778   * You will need to merge any custom search values into the search keys
1779   * using a key:value syntax. This allows all search queries to have a clean
1780   * and permanent URL. See node_form_alter() for an example.
1781   *
1782   * The example given here is for node.module, which uses the indexed search
1783   * capabilities. To do this, node module also implements hook_update_index()
1784   * which is used to create and maintain the index.
1785   *
1786   * We call do_search() with the keys, the module name, and extra SQL fragments
1787   * to use when searching. See hook_update_index() for more information.
1788   *
1789   * @param $op
1790   *   A string defining which operation to perform:
1791   *   - 'admin': The hook should return a form array, containing any fieldsets
1792   *     the module wants to add to the Search settings page at
1793   *     admin/settings/search.
1794   *   - 'name': The hook should return a translated name defining the type of
1795   *     items that are searched for with this module ('content', 'users', ...).
1796   *   - 'reset': The search index is going to be rebuilt. Modules which use
1797   *     hook_update_index() should update their indexing bookkeeping so that it
1798   *     starts from scratch the next time hook_update_index() is called.
1799   *   - 'search': The hook should perform a search using the keywords in $keys.
1800   *   - 'status': If the module implements hook_update_index(), it should return
1801   *     an array containing the following keys:
1802   *     - remaining: The amount of items that still need to be indexed.
1803   *     - total: The total amount of items (both indexed and unindexed).
1804   * @param $keys
1805   *   The search keywords as entered by the user.
1806   * @return
1807   *   This varies depending on the operation.
1808   *   - 'admin': The form array for the Search settings page at
1809   *     admin/settings/search.
1810   *   - 'name': The translated string of 'Content'.
1811   *   - 'reset': None.
1812   *   - 'search': An array of search results. To use the default search result
1813   *     display, each item should have the following keys':
1814   *     - 'link': Required. The URL of the found item.
1815   *     - 'type': The type of item.
1816   *     - 'title': Required. The name of the item.
1817   *     - 'user': The author of the item.
1818   *     - 'date': A timestamp when the item was last modified.
1819   *     - 'extra': An array of optional extra information items.
1820   *     - 'snippet': An excerpt or preview to show with the result (can be
1821   *       generated with search_excerpt()).
1822   *   - 'status': An associative array with the key-value pairs:
1823   *     - 'remaining': The number of items left to index.
1824   *     - 'total': The total number of items to index.
1825   *
1826   * @ingroup search
1827   */
1828  function hook_search($op = 'search', $keys = NULL) {
1829    switch ($op) {
1830      case 'name':
1831        return t('Content');
1832  
1833      case 'reset':
1834        db_query("UPDATE {search_dataset} SET reindex = %d WHERE type = 'node'", time());
1835        return;
1836  
1837      case 'status':
1838        $total = db_result(db_query('SELECT COUNT(*) FROM {node} WHERE status = 1'));
1839        $remaining = db_result(db_query("SELECT COUNT(*) FROM {node} n LEFT JOIN {search_dataset} d ON d.type = 'node' AND d.sid = n.nid WHERE n.status = 1 AND (d.sid IS NULL OR d.reindex <> 0)"));
1840        return array('remaining' => $remaining, 'total' => $total);
1841  
1842      case 'admin':
1843        $form = array();
1844        // Output form for defining rank factor weights.
1845        $form['content_ranking'] = array(
1846          '#type' => 'fieldset',
1847          '#title' => t('Content ranking'),
1848        );
1849        $form['content_ranking']['#theme'] = 'node_search_admin';
1850        $form['content_ranking']['info'] = array(
1851          '#value' => '<em>'. t('The following numbers control which properties the content search should favor when ordering the results. Higher numbers mean more influence, zero means the property is ignored. Changing these numbers does not require the search index to be rebuilt. Changes take effect immediately.') .'</em>'
1852        );
1853  
1854        $ranking = array('node_rank_relevance' => t('Keyword relevance'),
1855                         'node_rank_recent' => t('Recently posted'));
1856        if (module_exists('comment')) {
1857          $ranking['node_rank_comments'] = t('Number of comments');
1858        }
1859        if (module_exists('statistics') && variable_get('statistics_count_content_views', 0)) {
1860          $ranking['node_rank_views'] = t('Number of views');
1861        }
1862  
1863        // Note: reversed to reflect that higher number = higher ranking.
1864        $options = drupal_map_assoc(range(0, 10));
1865        foreach ($ranking as $var => $title) {
1866          $form['content_ranking']['factors'][$var] = array(
1867            '#title' => $title,
1868            '#type' => 'select',
1869            '#options' => $options,
1870            '#default_value' => variable_get($var, 5),
1871          );
1872        }
1873        return $form;
1874  
1875      case 'search':
1876        // Build matching conditions
1877        list($join1, $where1) = _db_rewrite_sql();
1878        $arguments1 = array();
1879        $conditions1 = 'n.status = 1';
1880  
1881        if ($type = search_query_extract($keys, 'type')) {
1882          $types = array();
1883          foreach (explode(',', $type) as $t) {
1884            $types[] = "n.type = '%s'";
1885            $arguments1[] = $t;
1886          }
1887          $conditions1 .= ' AND ('. implode(' OR ', $types) .')';
1888          $keys = search_query_insert($keys, 'type');
1889        }
1890  
1891        if ($category = search_query_extract($keys, 'category')) {
1892          $categories = array();
1893          foreach (explode(',', $category) as $c) {
1894            $categories[] = "tn.tid = %d";
1895            $arguments1[] = $c;
1896          }
1897          $conditions1 .= ' AND ('. implode(' OR ', $categories) .')';
1898          $join1 .= ' INNER JOIN {term_node} tn ON n.vid = tn.vid';
1899          $keys = search_query_insert($keys, 'category');
1900        }
1901  
1902        // Build ranking expression (we try to map each parameter to a
1903        // uniform distribution in the range 0..1).
1904        $ranking = array();
1905        $arguments2 = array();
1906        $join2 = '';
1907        // Used to avoid joining on node_comment_statistics twice
1908        $stats_join = FALSE;
1909        $total = 0;
1910        if ($weight = (int)variable_get('node_rank_relevance', 5)) {
1911          // Average relevance values hover around 0.15
1912          $ranking[] = '%d * i.relevance';
1913          $arguments2[] = $weight;
1914          $total += $weight;
1915        }
1916        if ($weight = (int)variable_get('node_rank_recent', 5)) {
1917          // Exponential decay with half-life of 6 months, starting at last indexed node
1918          $ranking[] = '%d * POW(2, (GREATEST(MAX(n.created), MAX(n.changed), MAX(c.last_comment_timestamp)) - %d) * 6.43e-8)';
1919          $arguments2[] = $weight;
1920          $arguments2[] = (int)variable_get('node_cron_last', 0);
1921          $join2 .= ' LEFT JOIN {node_comment_statistics} c ON c.nid = i.sid';
1922          $stats_join = TRUE;
1923          $total += $weight;
1924        }
1925        if (module_exists('comment') && $weight = (int)variable_get('node_rank_comments', 5)) {
1926          // Inverse law that maps the highest reply count on the site to 1 and 0 to 0.
1927          $scale = variable_get('node_cron_comments_scale', 0.0);
1928          $ranking[] = '%d * (2.0 - 2.0 / (1.0 + MAX(c.comment_count) * %f))';
1929          $arguments2[] = $weight;
1930          $arguments2[] = $scale;
1931          if (!$stats_join) {
1932            $join2 .= ' LEFT JOIN {node_comment_statistics} c ON c.nid = i.sid';
1933          }
1934          $total += $weight;
1935        }
1936        if (module_exists('statistics') && variable_get('statistics_count_content_views', 0) &&
1937            $weight = (int)variable_get('node_rank_views', 5)) {
1938          // Inverse law that maps the highest view count on the site to 1 and 0 to 0.
1939          $scale = variable_get('node_cron_views_scale', 0.0);
1940          $ranking[] = '%d * (2.0 - 2.0 / (1.0 + MAX(nc.totalcount) * %f))';
1941          $arguments2[] = $weight;
1942          $arguments2[] = $scale;
1943          $join2 .= ' LEFT JOIN {node_counter} nc ON nc.nid = i.sid';
1944          $total += $weight;
1945        }
1946  
1947        // When all search factors are disabled (ie they have a weight of zero),
1948        // the default score is based only on keyword relevance and there is no need to
1949        // adjust the score of each item.
1950        if ($total == 0) {
1951          $select2 = 'i.relevance AS score';
1952          $total = 1;
1953        }
1954        else {
1955          $select2 = implode(' + ', $ranking) . ' AS score';
1956        }
1957  
1958        // Do search.
1959        $find = do_search($keys, 'node', 'INNER JOIN {node} n ON n.nid = i.sid '. $join1, $conditions1 . (empty($where1) ? '' : ' AND '. $where1), $arguments1, $select2, $join2, $arguments2);
1960  
1961        // Load results.
1962        $results = array();
1963        foreach ($find as $item) {
1964          // Build the node body.
1965          $node = node_load($item->sid);
1966          $node->build_mode = NODE_BUILD_SEARCH_RESULT;
1967          $node = node_build_content($node, FALSE, FALSE);
1968          $node->body = drupal_render($node->content);
1969  
1970          // Fetch comments for snippet.
1971          $node->body .= module_invoke('comment', 'nodeapi', $node, 'update index');
1972          // Fetch terms for snippet.
1973          $node->body .= module_invoke('taxonomy', 'nodeapi', $node, 'update index');
1974  
1975          $extra = node_invoke_nodeapi($node, 'search result');
1976          $results[] = array(
1977            'link' => url('node/'. $item->sid, array('absolute' => TRUE)),
1978            'type' => check_plain(node_get_types('name', $node)),
1979            'title' => $node->title,
1980            'user' => theme('username', $node),
1981            'date' => $node->changed,
1982            'node' => $node,
1983            'extra' => $extra,
1984            'score' => $item->score / $total,
1985            'snippet' => search_excerpt($keys, $node->body),
1986          );
1987        }
1988        return $results;
1989    }
1990  }
1991  
1992  /**
1993   * Preprocess text for the search index.
1994   *
1995   * This hook is called both for text added to the search index, as well as
1996   * the keywords users have submitted for searching.
1997   *
1998   * This is required for example to allow Japanese or Chinese text to be
1999   * searched. As these languages do not use spaces, it needs to be split into
2000   * separate words before it can be indexed. There are various external
2001   * libraries for this.
2002   *
2003   * @param $text
2004   *   The text to split. This is a single piece of plain-text that was
2005   *   extracted from between two HTML tags. Will not contain any HTML entities.
2006   * @return
2007   *   The text after processing.
2008   */
2009  function hook_search_preprocess($text) {
2010    // Do processing on $text
2011    return $text;
2012  }
2013  
2014  /**
2015   * Act on taxonomy changes.
2016   *
2017   * This hook allows modules to take action when the terms and vocabularies
2018   * in the taxonomy are modified.
2019   *
2020   * @param $op
2021   *   What is being done to $array. Possible values:
2022   *   - "delete"
2023   *   - "insert"
2024   *   - "update"
2025   * @param $type
2026   *   What manner of item $array is. Possible values:
2027   *   - "term"
2028   *   - "vocabulary"
2029   * @param $array
2030   *   The item on which $op is being performed. Possible values:
2031   *   - for vocabularies, 'insert' and 'update' ops:
2032   *     $form_values from taxonomy_form_vocabulary_submit()
2033   *   - for vocabularies, 'delete' op:
2034   *     $vocabulary from taxonomy_get_vocabulary() cast to an array
2035   *   - for terms, 'insert' and 'update' ops:
2036   *     $form_values from taxonomy_form_term_submit()
2037   *   - for terms, 'delete' op:
2038   *     $term from taxonomy_get_term() cast to an array
2039   * @return
2040   *   None.
2041   */
2042  function hook_taxonomy($op, $type, $array = NULL) {
2043    if ($type == 'vocabulary' && ($op == 'insert' || $op == 'update')) {
2044      if (variable_get('forum_nav_vocabulary', '') == ''
2045          && in_array('forum', $array['nodes'])) {
2046        // since none is already set, silently set this vocabulary as the
2047        // navigation vocabulary
2048        variable_set('forum_nav_vocabulary', $array['vid']);
2049      }
2050    }
2051  }
2052  
2053  /**
2054   * Register a module (or theme's) theme implementations.
2055   *
2056   * Modules and themes implementing this return an array of arrays. The key
2057   * to each sub-array is the internal name of the hook, and the array contains
2058   * info about the hook. Each array may contain the following items:
2059   *
2060   * - arguments: (required) An array of arguments that this theme hook uses. This
2061   *   value allows the theme layer to properly utilize templates. The
2062   *   array keys represent the name of the variable, and the value will be
2063   *   used as the default value if not specified to the theme() function.
2064   *   These arguments must be in the same order that they will be given to
2065   *   the theme() function.
2066   * - file: The file the implementation resides in. This file will be included
2067   *   prior to the theme being rendered, to make sure that the function or
2068   *   preprocess function (as needed) is actually loaded; this makes it possible
2069   *   to split theme functions out into separate files quite easily.
2070   * - path: Override the path of the file to be used. Ordinarily the module or
2071   *   theme path will be used, but if the file will not be in the default path,
2072   *   include it here. This path should be relative to the Drupal root
2073   *   directory.
2074   * - template: If specified, this theme implementation is a template, and this
2075   *   is the template file without an extension. Do not put .tpl.php
2076   *   on this file; that extension will be added automatically by the default
2077   *   rendering engine (which is PHPTemplate). If 'path', above, is specified,
2078   *   the template should also be in this path.
2079   * - function: If specified, this will be the function name to invoke for this
2080   *   implementation. If neither file nor function is specified, a default
2081   *   function name will be assumed. For example, if a module registers
2082   *   the 'node' theme hook, 'theme_node' will be assigned to its function.
2083   *   If the chameleon theme registers the node hook, it will be assigned
2084   *   'chameleon_node' as its function.
2085   * - pattern: A regular expression pattern to be used to allow this theme
2086   *   implementation to have a dynamic name. The convention is to use __ to
2087   *   differentiate the dynamic portion of the theme. For example, to allow
2088   *   forums to be themed individually, the pattern might be: 'forum__'. Then,
2089   *   when the forum is themed, call: theme(array('forum__'. $tid, 'forum'),
2090   *   $forum).
2091   * - preprocess functions: A list of functions used to preprocess this data.
2092   *   Ordinarily this won't be used; it's automatically filled in. By default,
2093   *   for a module this will be filled in as template_preprocess_HOOK. For
2094   *   a theme this will be filled in as phptemplate_preprocess and
2095   *   phptemplate_preprocess_HOOK as well as themename_preprocess and
2096   *   themename_preprocess_HOOK.
2097   * - override preprocess functions: Set to TRUE when a theme does NOT want the
2098   *   standard preprocess functions to run. This can be used to give a theme
2099   *   FULL control over how variables are set. For example, if a theme wants
2100   *   total control over how certain variables in the page.tpl.php are set,
2101   *   this can be set to true. Please keep in mind that when this is used
2102   *   by a theme, that theme becomes responsible for making sure necessary
2103   *   variables are set.
2104   * - type: (automatically derived) Where the theme hook is defined:
2105   *   'module', 'theme_engine', or 'theme'.
2106   * - theme path: (automatically derived) The directory path of the theme or
2107   *   module, so that it doesn't need to be looked up.
2108   * - theme paths: (automatically derived) An array of template suggestions where
2109   *   .tpl.php files related to this theme hook may be found.
2110   *
2111   * The following parameters are all optional.
2112   *
2113   * @param $existing
2114   *   An array of existing implementations that may be used for override
2115   *   purposes. This is primarily useful for themes that may wish to examine
2116   *   existing implementations to extract data (such as arguments) so that
2117   *   it may properly register its own, higher priority implementations.
2118   * @param $type
2119   *   What 'type' is being processed. This is primarily useful so that themes
2120   *   tell if they are the actual theme being called or a parent theme.
2121   *   May be one of:
2122   *     - module: A module is being checked for theme implementations.
2123   *     - base_theme_engine: A theme engine is being checked for a theme which is a parent of the actual theme being used.
2124   *     - theme_engine: A theme engine is being checked for the actual theme being used.
2125   *     - base_theme: A base theme is being checked for theme implementations.
2126   *     - theme: The actual theme in use is being checked.
2127   * @param $theme
2128   *   The actual name of theme that is being being checked (mostly only useful for
2129   *   theme engine).
2130   * @param $path
2131   *   The directory path of the theme or module, so that it doesn't need to be
2132   *   looked up.
2133   *
2134   * @return
2135   *   A keyed array of theme hooks.
2136   */
2137  function hook_theme($existing, $type, $theme, $path) {
2138    return array(
2139      'forum_display' => array(
2140        'arguments' => array('forums' => NULL, 'topics' => NULL, 'parents' => NULL, 'tid' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
2141      ),
2142      'forum_list' => array(
2143        'arguments' => array('forums' => NULL, 'parents' => NULL, 'tid' => NULL),
2144      ),
2145      'forum_topic_list' => array(
2146        'arguments' => array('tid' => NULL, 'topics' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
2147      ),
2148      'forum_icon' => array(
2149        'arguments' => array('new_posts' => NULL, 'num_posts' => 0, 'comment_mode' => 0, 'sticky' => 0),
2150      ),
2151      'forum_topic_navigation' => array(
2152        'arguments' => array('node' => NULL),
2153      ),
2154      'node' => array(
2155        'arguments' => array('node' => NULL, 'teaser' => FALSE, 'page' => FALSE),
2156        'template' => 'node',
2157      ),
2158      'node_filter_form' => array(
2159        'arguments' => array('form' => NULL),
2160        'file' => 'node.admin.inc',
2161      ),
2162    );
2163  }
2164  
2165  /**
2166   * Alter the theme registry information returned from hook_theme().
2167   *
2168   * The theme registry stores information about all available theme hooks,
2169   * including which callback functions those hooks will call when triggered,
2170   * what template files are exposed by these hooks, and so on.
2171   *
2172   * Note that this hook is only executed as the theme cache is re-built.
2173   * Changes here will not be visible until the next cache clear.
2174   *
2175   * The $theme_registry array is keyed by theme hook name, and contains the
2176   * information returned from hook_theme(), as well as additional properties
2177   * added by _theme_process_registry().
2178   *
2179   * For example:
2180   * @code
2181   * $theme_registry['user_profile'] = array(
2182   *   'arguments' => array(
2183   *     'account' => NULL,
2184   *   ),
2185   *   'template' => 'modules/user/user-profile',
2186   *   'file' => 'modules/user/user.pages.inc',
2187   *   'type' => 'module',
2188   *   'theme path' => 'modules/user',
2189   *   'theme paths' => array(
2190   *     0 => 'modules/user',
2191   *   ),
2192   *   'preprocess functions' => array(
2193   *     0 => 'template_preprocess',
2194   *     1 => 'template_preprocess_user_profile',
2195   *   ),
2196   * );
2197   * @endcode
2198   *
2199   * @param $theme_registry
2200   *   The entire cache of theme registry information, post-processing.
2201   *
2202   * @see hook_theme()
2203   * @see _theme_process_registry()
2204   */
2205  function hook_theme_registry_alter(&$theme_registry) {
2206    // Kill the next/previous forum topic navigation links.
2207    foreach ($theme_registry['forum_topic_navigation']['preprocess functions'] as $key => $value) {
2208      if ($value = 'template_preprocess_forum_topic_navigation') {
2209        unset($theme_registry['forum_topic_navigation']['preprocess functions'][$key]);
2210      }
2211    }
2212  }
2213  
2214  /**
2215   * Update Drupal's full-text index for this module.
2216   *
2217   * Modules can implement this hook if they want to use the full-text indexing
2218   * mechanism in Drupal.
2219   *
2220   * This hook is called every cron run if search.module is enabled. A module
2221   * should check which of its items were modified or added since the last
2222   * run. It is advised that you implement a throttling mechanism which indexes
2223   * at most 'search_cron_limit' items per run (see example below).
2224   *
2225   * You should also be aware that indexing may take too long and be aborted if
2226   * there is a PHP time limit. That's why you should update your internal
2227   * bookkeeping multiple times per run, preferably after every item that
2228   * is indexed.
2229   *
2230   * Per item that needs to be indexed, you should call search_index() with
2231   * its content as a single HTML string. The search indexer will analyse the
2232   * HTML and use it to assign higher weights to important words (such as
2233   * titles). It will also check for links that point to nodes, and use them to
2234   * boost the ranking of the target nodes.
2235   *
2236   * @ingroup search
2237   */
2238  function hook_update_index() {
2239    $last = variable_get('node_cron_last', 0);
2240    $limit = (int)variable_get('search_cron_limit', 100);
2241  
2242    $result = db_query_range('SELECT n.nid, c.last_comment_timestamp FROM {node} n LEFT JOIN {node_comment_statistics} c ON n.nid = c.nid WHERE n.status = 1 AND n.moderate = 0 AND (n.created > %d OR n.changed > %d OR c.last_comment_timestamp > %d) ORDER BY GREATEST(n.created, n.changed, c.last_comment_timestamp) ASC', $last, $last, $last, 0, $limit);
2243  
2244    while ($node = db_fetch_object($result)) {
2245      $last_comment = $node->last_comment_timestamp;
2246      $node = node_load(array('nid' => $node->nid));
2247  
2248      // We update this variable per node in case cron times out, or if the node
2249      // cannot be indexed (PHP nodes which call drupal_goto, for example).
2250      // In rare cases this can mean a node is only partially indexed, but the
2251      // chances of this happening are very small.
2252      variable_set('node_cron_last', max($last_comment, $node->changed, $node->created));
2253  
2254      // Get node output (filtered and with module-specific fields).
2255      if (node_hook($node, 'view')) {
2256        node_invoke($node, 'view', false, false);
2257      }
2258      else {
2259        $node = node_prepare($node, false);
2260      }
2261      // Allow modules to change $node->body before viewing.
2262      node_invoke_nodeapi($node, 'view', false, false);
2263  
2264      $text = '<h1>'. drupal_specialchars($node->title) .'</h1>'. $node->body;
2265  
2266      // Fetch extra data normally not visible
2267      $extra = node_invoke_nodeapi($node, 'update index');
2268      foreach ($extra as $t) {
2269        $text .= $t;
2270      }
2271  
2272      // Update index
2273      search_index($node->nid, 'node', $text);
2274    }
2275  }
2276  
2277  /**
2278   * Act on user account actions.
2279   *
2280   * This hook allows modules to react when operations are performed on user
2281   * accounts.
2282   *
2283   * @param $op
2284   *   What kind of action is being performed. Possible values (in alphabetical
2285   *   order):
2286   *   - "after_update": The user object has been updated and changed. Use this
2287   *     (probably along with 'insert') if you want to reuse some information from
2288   *     the user object.
2289   *   - "categories": A set of user information categories is requested.
2290   *   - "delete": The user account is being deleted. The module should remove its
2291   *     custom additions to the user object from the database.
2292   *   - "form": The user account edit form is about to be displayed. The module
2293   *     should present the form elements it wishes to inject into the form.
2294   *   - "insert": The user account is being added. The module should save its
2295   *     custom additions to the user object into the database and set the saved
2296   *     fields to NULL in $edit.
2297   *   - "load": The user account is being loaded. The module may respond to this
2298   *     and insert additional information into the user object.
2299   *   - "login": The user just logged in.
2300   *   - "logout": The user just logged out.
2301   *   - "register": The user account registration form is about to be displayed.
2302   *     The module should present the form elements it wishes to inject into the
2303   *     form.
2304   *   - "submit": Modify the account before it gets saved.
2305   *   - "update": The user account is being changed. The module should save its
2306   *     custom additions to the user object into the database and set the saved
2307   *     fields to NULL in $edit.
2308   *   - "validate": The user account is about to be modified. The module should
2309   *     validate its custom additions to the user object, registering errors as
2310   *     necessary.
2311   *   - "view": The user's account information is being displayed. The module
2312   *     should format its custom additions for display, and add them to the
2313   *     $account->content array.
2314   * @param &$edit
2315   *   The array of form values submitted by the user.
2316   * @param &$account
2317   *   The user object on which the operation is being performed.
2318   * @param $category
2319   *   The active category of user information being edited.
2320   *
2321   * @return
2322   *   This varies depending on the operation.
2323   *   - "categories": An array of associative arrays. These arrays have keys:
2324   *     - "name": The internal name of the category.
2325   *     - "title": The human-readable, localized name of the category.
2326   *     - "weight": An integer specifying the category's sort ordering.
2327   *     - "access callback": Name of a menu access callback function to use when
2328   *       editing this category. Defaults to using user_edit_access() if not
2329   *       specified. See hook_menu() for more information on menu access
2330   *       callbacks.
2331   *     - "access arguments": Arguments for the access callback function.
2332   *       Defaults to array(1) if not specified.
2333   *   - "delete": None.
2334   *   - "form", "register": A $form array containing the form elements to
2335   *     display.
2336   *   - "insert": None.
2337   *   - "load": None.
2338   *   - "login": None.
2339   *   - "logout": None.
2340   *   - "submit": None.
2341   *   - "update": None.
2342   *   - "validate": None.
2343   *   - "view": None.
2344   */
2345  function hook_user($op, &$edit, &$account, $category = NULL) {
2346    if ($op == 'form' && $category == 'account') {
2347      $form['comment_settings'] = array(
2348        '#type' => 'fieldset',
2349        '#title' => t('Comment settings'),
2350        '#collapsible' => TRUE,
2351        '#weight' => 4);
2352      $form['comment_settings']['signature'] = array(
2353        '#type' => 'textarea',
2354        '#title' => t('Signature'),
2355        '#default_value' => $edit['signature'],
2356        '#description' => t('Your signature will be publicly displayed at the end of your comments.'));
2357      return $form;
2358    }
2359  }
2360  
2361  /**
2362   * Add mass user operations.
2363   *
2364   * This hook enables modules to inject custom operations into the mass operations
2365   * dropdown found at admin/user/user, by associating a callback function with
2366   * the operation, which is called when the form is submitted. The callback function
2367   * receives one initial argument, which is an array of the checked users.
2368   *
2369   * @return
2370   *   An array of operations. Each operation is an associative array that may
2371   *   contain the following key-value pairs:
2372   *   - "label": Required. The label for the operation, displayed in the dropdown menu.
2373   *   - "callback": Required. The function to call for the operation.
2374   *   - "callback arguments": Optional. An array of additional arguments to pass to
2375   *     the callback function.
2376   *
2377   */
2378  function hook_user_operations() {
2379    $operations = array(
2380      'unblock' => array(
2381        'label' => t('Unblock the selected users'),
2382        'callback' => 'user_user_operations_unblock',
2383      ),
2384      'block' => array(
2385        'label' => t('Block the selected users'),
2386        'callback' => 'user_user_operations_block',
2387      ),
2388      'delete' => array(
2389        'label' => t('Delete the selected users'),
2390      ),
2391    );
2392    return $operations;
2393  }
2394  
2395  /**
2396   * Register XML-RPC callbacks.
2397   *
2398   * This hook lets a module register callback functions to be called when
2399   * particular XML-RPC methods are invoked by a client.
2400   *
2401   * @return
2402   *   An array which maps XML-RPC methods to Drupal functions. Each array
2403   *   element is either a pair of method => function or an array with four
2404   *   entries:
2405   *   - The XML-RPC method name (for example, module.function).
2406   *   - The Drupal callback function (for example, module_function).
2407   *   - The method signature is an array of XML-RPC types. The first element
2408   *     of this array is the type of return value and then you should write a
2409   *     list of the types of the parameters. XML-RPC types are the following
2410   *     (See the types at @link http://www.xmlrpc.com/spec http://www.xmlrpc.com/spec @endlink ):
2411   *       - "boolean": 0 (false) or 1 (true).
2412   *       - "double": a floating point number (for example, -12.214).
2413   *       - "int": a integer number (for example,  -12).
2414   *       - "array": an array without keys (for example, array(1, 2, 3)).
2415   *       - "struct": an associative array or an object (for example,
2416   *          array('one' => 1, 'two' => 2)).
2417   *       - "date": when you return a date, then you may either return a
2418   *          timestamp (time(), mktime() etc.) or an ISO8601 timestamp. When
2419   *          date is specified as an input parameter, then you get an object,
2420   *          which is described in the function xmlrpc_date
2421   *       - "base64": a string containing binary data, automatically
2422   *          encoded/decoded automatically.
2423   *       - "string": anything else, typically a string.
2424   *   - A descriptive help string, enclosed in a t() function for translation
2425   *     purposes.
2426   *   Both forms are shown in the example.
2427   */
2428  function hook_xmlrpc() {
2429    return array(
2430      'drupal.login' => 'drupal_login',
2431      array(
2432        'drupal.site.ping',
2433        'drupal_directory_ping',
2434        array('boolean', 'string', 'string', 'string', 'string', 'string'),
2435        t('Handling ping request'))
2436    );
2437  }
2438  
2439  /**
2440   * Log an event message
2441   *
2442   * This hook allows modules to route log events to custom destinations, such as
2443   * SMS, Email, pager, syslog, ...etc.
2444   *
2445   * @param $log_entry
2446   *   An associative array containing the following keys:
2447   *   - type: The type of message for this entry. For contributed modules, this is
2448   *     normally the module name. Do not use 'debug', use severity WATCHDOG_DEBUG instead.
2449   *   - user: The user object for the user who was logged in when the event happened.
2450   *   - request_uri: The Request URI for the page the event happened in.
2451   *   - referer: The page that referred the use to the page where the event occurred.
2452   *   - ip: The IP address where the request for the page came from.
2453   *   - timestamp: The UNIX timetamp of the date/time the event occurred
2454   *   - severity: One of the following values as defined in RFC 3164 http://www.faqs.org/rfcs/rfc3164.html
2455   *     WATCHDOG_EMERG     Emergency: system is unusable
2456   *     WATCHDOG_ALERT     Alert: action must be taken immediately
2457   *     WATCHDOG_CRITICAL  Critical: critical conditions
2458   *     WATCHDOG_ERROR     Error: error conditions
2459   *     WATCHDOG_WARNING   Warning: warning conditions
2460   *     WATCHDOG_NOTICE    Notice: normal but significant condition
2461   *     WATCHDOG_INFO      Informational: informational messages
2462   *     WATCHDOG_DEBUG     Debug: debug-level messages
2463   *   - link: an optional link provided by the module that called the watchdog() function.
2464   *   - message: The text of the message to be logged.
2465   *
2466   * @return
2467   *   None.
2468   */
2469  function hook_watchdog($log_entry) {
2470    global $base_url, $language;
2471  
2472    $severity_list = array(
2473      WATCHDOG_EMERG    => t('Emergency'),
2474      WATCHDOG_ALERT    => t('Alert'),
2475      WATCHDOG_CRITICAL => t('Critical'),
2476      WATCHDOG_ERROR    => t('Error'),
2477      WATCHDOG_WARNING  => t('Warning'),
2478      WATCHDOG_NOTICE   => t('Notice'),
2479      WATCHDOG_INFO     => t('Info'),
2480      WATCHDOG_DEBUG    => t('Debug'),
2481    );
2482  
2483    $to = 'someone@example.com';
2484    $params = array();
2485    $params['subject'] = t('[@site_name] @severity_desc: Alert from your web site', array(
2486        '@site_name' => variable_get('site_name', 'Drupal'),
2487        '@severity_desc' => $severity_list[$log_entry['severity']]
2488    ));
2489  
2490    $params['message']  = "\nSite:         @base_url";
2491    $params['message'] .= "\nSeverity:     (@severity) @severity_desc";
2492    $params['message'] .= "\nTimestamp:    @timestamp";
2493    $params['message'] .= "\nType:         @type";
2494    $params['message'] .= "\nIP Address:   @ip";
2495    $params['message'] .= "\nRequest URI:  @request_uri";
2496    $params['message'] .= "\nReferrer URI: @referer_uri";
2497    $params['message'] .= "\nUser:         (@uid) @name";
2498    $params['message'] .= "\nLink:         @link";
2499    $params['message'] .= "\nMessage:      \n\n@message";
2500  
2501    $params['message'] = t($params['message'], array(
2502      '@base_url'      => $base_url,
2503      '@severity'      => $log_entry['severity'],
2504      '@severity_desc' => $severity_list[$log_entry['severity']],
2505      '@timestamp'     => format_date($log_entry['timestamp']),
2506      '@type'          => $log_entry['type'],
2507      '@ip'            => $log_entry['ip'],
2508      '@request_uri'   => $log_entry['request_uri'],
2509      '@referer_uri'   => $log_entry['referer'],
2510      '@uid'           => $log_entry['user']->uid,
2511      '@name'          => $log_entry['user']->name,
2512      '@link'          => strip_tags($log_entry['link']),
2513      '@message'       => strip_tags($log_entry['message']),
2514    ));
2515  
2516    drupal_mail('emaillog', 'log', $to, $language, $params);
2517  }
2518  
2519  /**
2520   * Prepare a message based on parameters; called from drupal_mail().
2521   *
2522   * @param $key
2523   *   An identifier of the mail.
2524   * @param $message
2525   *  An array to be filled in. Keys in this array include:
2526   *  - 'id':
2527   *     An id to identify the mail sent. Look at module source code
2528   *     or drupal_mail() for possible id values.
2529   *  - 'to':
2530   *     The address or addresses the message will be sent to. The
2531   *     formatting of this string must comply with RFC 2822.
2532   *  - 'subject':
2533   *     Subject of the e-mail to be sent. This must not contain any
2534   *     newline characters, or the mail may not be sent properly.
2535   *     drupal_mail() sets this to an empty string when the hook is invoked.
2536   *  - 'body':
2537   *     An array of lines containing the message to be sent. Drupal will format
2538   *     the correct line endings for you. drupal_mail() sets this to an empty array
2539   *     when the hook is invoked.
2540   *  - 'from':
2541   *     The address the message will be marked as being from, which is set by
2542   *     drupal_mail() to either a custom address or the site-wide default email
2543   *     address when the hook is invoked.
2544   *  - 'headers:
2545   *     Associative array containing mail headers, such as From, Sender, MIME-Version,
2546   *     Content-Type, etc. drupal_mail() pre-fills several headers in this array.
2547   * @param $params
2548   *   An arbitrary array of parameters set by the caller to drupal_mail.
2549   */
2550  function hook_mail($key, &$message, $params) {
2551    $account = $params['account'];
2552    $context = $params['context'];
2553    $variables = array(
2554      '%site_name' => variable_get('site_name', 'Drupal'),
2555      '%username' => $account->name,
2556    );
2557    if ($context['hook'] == 'taxonomy') {
2558      $object = $params['object'];
2559      $vocabulary = taxonomy_vocabulary_load($object->vid);
2560      $variables += array(
2561        '%term_name' => $object->name,
2562        '%term_description' => $object->description,
2563        '%term_id' => $object->tid,
2564        '%vocabulary_name' => $vocabulary->name,
2565        '%vocabulary_description' => $vocabulary->description,
2566        '%vocabulary_id' => $vocabulary->vid,
2567      );
2568    }
2569  
2570    // Node-based variable translation is only available if we have a node.
2571    if (isset($params['node'])) {
2572      $node = $params['node'];
2573      $variables += array(
2574        '%uid' => $node->uid,
2575        '%node_url' => url('node/'. $node->nid, array('absolute' => TRUE)),
2576        '%node_type' => node_get_types('name', $node),
2577        '%title' => $node->title,
2578        '%teaser' => $node->teaser,
2579        '%body' => $node->body,
2580      );
2581    }
2582    $subject = strtr($context['subject'], $variables);
2583    $body = strtr($context['message'], $variables);
2584    $message['subject'] .= str_replace(array("\r", "\n"), '', $subject);
2585    $message['body'][] = drupal_html_to_text($body);
2586  }
2587  
2588  /**
2589   * Add a list of cache tables to be cleared.
2590   *
2591   * This hook allows your module to add cache table names to the list of cache
2592   * tables that will be cleared by the Clear button on the Performance page or
2593   * whenever drupal_flush_all_caches is invoked.
2594   *
2595   * @see drupal_flush_all_caches()
2596   * @see system_clear_cache_submit()
2597   *
2598   * @param None.
2599   *
2600   * @return
2601   *   An array of cache table names.
2602   */
2603  function hook_flush_caches() {
2604    return array('cache_example');
2605  }
2606  
2607  /**
2608   * Allows modules to provide an alternative path for the terms it manages.
2609   *
2610   * For vocabularies not maintained by taxonomy.module, give the maintaining
2611   * module a chance to provide a path for terms in that vocabulary.
2612   *
2613   * "Not maintained by taxonomy.module" is misleading. It means that the vocabulary
2614   * table contains a module name in the 'module' column. Any module may update this
2615   * column and will then be called to provide an alternative path for the terms
2616   * it recognizes (manages).
2617   *
2618   * This hook should be used rather than hard-coding a "taxonomy/term/xxx" path.
2619   *
2620   * @see taxonomy_term_path()
2621   *
2622   * @param $term
2623   *   A term object.
2624   * @return
2625   *   An internal Drupal path.
2626   */
2627  function hook_term_path($term) {
2628    return 'taxonomy/term/'. $term->tid;
2629  }
2630  
2631  /**
2632   * Allows modules to define their own text groups that can be translated.
2633   *
2634   * @param $op
2635   *   Type of operation. Currently, only supports 'groups'.
2636   */
2637  function hook_locale($op = 'groups') {
2638    switch ($op) {
2639      case 'groups':
2640        return array('custom' => t('Custom'));
2641    }
2642  }
2643  
2644  /**
2645   * custom_url_rewrite_outbound is not a hook, it's a function you can add to
2646   * settings.php to alter all links generated by Drupal. This function is called from url().
2647   * This function is called very frequently (100+ times per page) so performance is
2648   * critical.
2649   *
2650   * This function should change the value of $path and $options by reference.
2651   *
2652   * @param $path
2653   *   The alias of the $original_path as defined in the database.
2654   *   If there is no match in the database it'll be the same as $original_path
2655   * @param $options
2656   *   An array of link attributes such as querystring and fragment. See url().
2657   * @param $original_path
2658   *   The unaliased Drupal path that is being linked to.
2659   */
2660  function custom_url_rewrite_outbound(&$path, &$options, $original_path) {
2661    global $user;
2662  
2663    // Change all 'node' to 'article'.
2664    if (preg_match('|^node(/.*)|', $path, $matches)) {
2665      $path = 'article'. $matches[1];
2666    }
2667    // Create a path called 'e' which lands the user on her profile edit page.
2668    if ($path == 'user/'. $user->uid .'/edit') {
2669      $path = 'e';
2670    }
2671  
2672  }
2673  
2674  /**
2675   * custom_url_rewrite_inbound is not a hook, it's a function you can add to
2676   * settings.php to alter incoming requests so they map to a Drupal path.
2677   * This function is called before modules are loaded and
2678   * the menu system is initialized and it changes $_GET['q'].
2679   *
2680   * This function should change the value of $result by reference.
2681   *
2682   * @param $result
2683   *   The Drupal path based on the database. If there is no match in the database it'll be the same as $path.
2684   * @param $path
2685   *   The path to be rewritten.
2686   * @param $path_language
2687   *   An optional language code to rewrite the path into.
2688   */
2689  function custom_url_rewrite_inbound(&$result, $path, $path_language) {
2690    global $user;
2691  
2692    // Change all article/x requests to node/x
2693    if (preg_match('|^article(/.*)|', $path, $matches)) {
2694      $result = 'node'. $matches[1];
2695    }
2696    // Redirect a path called 'e' to the user's profile edit page.
2697    if ($path == 'e') {
2698      $result = 'user/'. $user->uid .'/edit';
2699    }
2700  }
2701  
2702  /**
2703   * Perform alterations on translation links.
2704   *
2705   * A translation link may need to point to a different path or use a translated
2706   * link text before going through l(), which will just handle the path aliases.
2707   *
2708   * @param $links
2709   *   Nested array of links keyed by language code.
2710   * @param $path
2711   *   The current path.
2712   * @return
2713   *   None.
2714   */
2715  function hook_translation_link_alter(&$links, $path) {
2716    global $language;
2717  
2718    if (isset($links[$language])) {
2719      foreach ($links[$language] as $link) {
2720        $link['attributes']['class'] .= ' active-language';
2721      }
2722    }
2723  }
2724  
2725  /**
2726   * @} End of "addtogroup hooks".
2727   */


Generated: Mon Jul 9 18:01:44 2012 Cross-referenced by PHPXref 0.7