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<?php

/**

 * @file

 * Hooks provided by the Node module.

 */

/**

 * @defgroup node_api_hooks Node API Hooks

 * @{

 * Functions to define and modify content types.

 *

 * Each content type is maintained by a primary module, which is either

 * node.module (for content types created in the user interface) or the module

 * that implements hook_node_info() to define the content type.

 *

 * During node operations (create, update, view, delete, etc.), there are

 * several sets of hooks that get invoked to allow modules to modify the base

 * node operation:

 * - Node-type-specific hooks: These hooks are only invoked on the primary

 *   module, using the "base" return component of hook_node_info() as the

 *   function prefix.  For example, poll.module defines the base for the Poll

 *   content type as "poll", so during creation of a poll node, hook_insert() is

 *   only invoked by calling poll_insert().

 * - All-module hooks: This set of hooks is invoked on all implementing modules,

 *   to allow other modules to modify what the primary node module is doing. For

 *   example, hook_node_insert() is invoked on all modules when creating a poll

 *   node.

 * - Field hooks: Hooks related to the fields attached to the node. These are

 *   invoked from the field operations functions described below, and can be

 *   either field-type-specific or all-module hooks.

 * - Entity hooks: Generic hooks for "entity" operations. These are always

 *   invoked on all modules.

 *

 * Here is a list of the node and entity hooks that are invoked, field

 * operations, and other steps that take place during node operations:

 * - Creating a new node (calling node_save() on a new node):

 *   - field_attach_presave()

 *   - hook_node_presave() (all)

 *   - hook_entity_presave() (all)

 *   - Node and revision records are written to the database

 *   - hook_insert() (node-type-specific)

 *   - field_attach_insert()

 *   - hook_node_insert() (all)

 *   - hook_entity_insert() (all)

 *   - hook_node_access_records() (all)

 *   - hook_node_access_records_alter() (all)

 * - Updating an existing node (calling node_save() on an existing node):

 *   - field_attach_presave()

 *   - hook_node_presave() (all)

 *   - hook_entity_presave() (all)

 *   - Node and revision records are written to the database

 *   - hook_update() (node-type-specific)

 *   - field_attach_update()

 *   - hook_node_update() (all)

 *   - hook_entity_update() (all)

 *   - hook_node_access_records() (all)

 *   - hook_node_access_records_alter() (all)

 * - Loading a node (calling node_load(), node_load_multiple() or entity_load()

 *   with $entity_type of 'node'):

 *   - Node and revision information is read from database.

 *   - hook_load() (node-type-specific)

 *   - field_attach_load_revision() and field_attach_load()

 *   - hook_entity_load() (all)

 *   - hook_node_load() (all)

 * - Viewing a single node (calling node_view() - note that the input to

 *   node_view() is a loaded node, so the Loading steps above are already done):

 *   - hook_view() (node-type-specific)

 *   - field_attach_prepare_view()

 *   - hook_entity_prepare_view() (all)

 *   - field_attach_view()

 *   - hook_node_view() (all)

 *   - hook_entity_view() (all)

 *   - hook_node_view_alter() (all)

 *   - hook_entity_view_alter() (all)

 * - Viewing multiple nodes (calling node_view_multiple() - note that the input

 *   to node_view_multiple() is a set of loaded nodes, so the Loading steps

 *   above are already done):

 *   - field_attach_prepare_view()

 *   - hook_entity_prepare_view() (all)

 *   - hook_view() (node-type-specific)

 *   - field_attach_view()

 *   - hook_node_view() (all)

 *   - hook_entity_view() (all)

 *   - hook_node_view_alter() (all)

 *   - hook_entity_view_alter() (all)

 * - Deleting a node (calling node_delete() or node_delete_multiple()):

 *   - Node is loaded (see Loading section above)

 *   - hook_delete() (node-type-specific)

 *   - hook_node_delete() (all)

 *   - hook_entity_delete() (all)

 *   - field_attach_delete()

 *   - Node and revision information are deleted from database

 * - Deleting a node revision (calling node_revision_delete()):

 *   - Node is loaded (see Loading section above)

 *   - Revision information is deleted from database

 *   - hook_node_revision_delete() (all)

 *   - field_attach_delete_revision()

 * - Preparing a node for editing (calling node_form() - note that if it is an

 *   existing node, it will already be loaded; see the Loading section above):

 *   - hook_prepare() (node-type-specific)

 *   - hook_node_prepare() (all)

 *   - hook_form() (node-type-specific)

 *   - field_attach_form()

 * - Validating a node during editing form submit (calling

 *   node_form_validate()):

 *   - hook_validate() (node-type-specific)

 *   - hook_node_validate() (all)

 *   - field_attach_form_validate()

 * - Searching (calling node_search_execute()):

 *   - hook_ranking() (all)

 *   - Query is executed to find matching nodes

 *   - Resulting node is loaded (see Loading section above)

 *   - Resulting node is prepared for viewing (see Viewing a single node above)

 *   - comment_node_update_index() is called.

 *   - hook_node_search_result() (all)

 * - Search indexing (calling node_update_index()):

 *   - Node is loaded (see Loading section above)

 *   - Node is prepared for viewing (see Viewing a single node above)

 *   - hook_node_update_index() (all)

 * @}

 */

/**

 * @addtogroup hooks

 * @{

 */

/**

 * Inform the node access system what permissions the user has.

 *

 * This hook is for implementation by node access modules. In this hook,

 * the module grants a user different "grant IDs" within one or more

 * "realms". In hook_node_access_records(), the realms and grant IDs are

 * associated with permission to view, edit, and delete individual nodes.

 *

 * The realms and grant IDs can be arbitrarily defined by your node access

 * module; it is common to use role IDs as grant IDs, but that is not required.

 * Your module could instead maintain its own list of users, where each list has

 * an ID. In that case, the return value of this hook would be an array of the

 * list IDs that this user is a member of.

 *

 * A node access module may implement as many realms as necessary to properly

 * define the access privileges for the nodes. Note that the system makes no

 * distinction between published and unpublished nodes. It is the module's

 * responsibility to provide appropriate realms to limit access to unpublished

 * content.

 *

 * Node access records are stored in the {node_access} table and define which

 * grants are required to access a node. There is a special case for the view

 * operation -- a record with node ID 0 corresponds to a "view all" grant for

 * the realm and grant ID of that record. If there are no node access modules

 * enabled, the core node module adds a node ID 0 record for realm 'all'. Node

 * access modules can also grant "view all" permission on their custom realms;

 * for example, a module could create a record in {node_access} with:

 * @code

 * $record = array(

 *   'nid' => 0,

 *   'gid' => 888,

 *   'realm' => 'example_realm',

 *   'grant_view' => 1,

 *   'grant_update' => 0,

 *   'grant_delete' => 0,

 * );

 * drupal_write_record('node_access', $record);

 * @endcode

 * And then in its hook_node_grants() implementation, it would need to return:

 * @code

 * if ($op == 'view') {

 *   $grants['example_realm'] = array(888);

 * }

 * @endcode

 * If you decide to do this, be aware that the node_access_rebuild() function

 * will erase any node ID 0 entry when it is called, so you will need to make

 * sure to restore your {node_access} record after node_access_rebuild() is

 * called.

 *

 * @see node_access_view_all_nodes()

 * @see node_access_rebuild()

 *

 * @param $account

 *   The user object whose grants are requested.

 * @param $op

 *   The node operation to be performed, such as 'view', 'update', or 'delete'.

 *

 * @return

 *   An array whose keys are "realms" of grants, and whose values are arrays of

 *   the grant IDs within this realm that this user is being granted.

 *

 * For a detailed example, see node_access_example.module.

 *

 * @ingroup node_access

 */

function hook_node_grants($account, $op) {

  if (user_access('access private content', $account)) {

    $grants['example'] = array(1);

  }

  $grants['example_owner'] = array($account->uid);

  return $grants;

}

/**

 * Set permissions for a node to be written to the database.

 *

 * When a node is saved, a module implementing hook_node_access_records() will

 * be asked if it is interested in the access permissions for a node. If it is

 * interested, it must respond with an array of permissions arrays for that

 * node.

 *

 * Node access grants apply regardless of the published or unpublished status

 * of the node. Implementations must make sure not to grant access to

 * unpublished nodes if they don't want to change the standard access control

 * behavior. Your module may need to create a separate access realm to handle

 * access to unpublished nodes.

 *

 * Note that the grant values in the return value from your hook must be

 * integers and not boolean TRUE and FALSE.

 *

 * Each permissions item in the array is an array with the following elements:

 * - 'realm': The name of a realm that the module has defined in

 *   hook_node_grants().

 * - 'gid': A 'grant ID' from hook_node_grants().

 * - 'grant_view': If set to 1 a user that has been identified as a member

 *   of this gid within this realm can view this node. This should usually be

 *   set to $node->status. Failure to do so may expose unpublished content

 *   to some users.

 * - 'grant_update': If set to 1 a user that has been identified as a member

 *   of this gid within this realm can edit this node.

 * - 'grant_delete': If set to 1 a user that has been identified as a member

 *   of this gid within this realm can delete this node.

 * - 'priority': If multiple modules seek to set permissions on a node, the

 *   realms that have the highest priority will win out, and realms with a lower

 *   priority will not be written. If there is any doubt, it is best to

 *   leave this 0.

 *

 *

 * When an implementation is interested in a node but want to deny access to

 * everyone, it may return a "deny all" grant:

 *

 * @code

 * $grants[] = array(

 *   'realm' => 'all',

 *   'gid' => 0,

 *   'grant_view' => 0,

 *   'grant_update' => 0,

 *   'grant_delete' => 0,

 *   'priority' => 1,

 * );

 * @endcode

 *

 * Setting the priority should cancel out other grants. In the case of a

 * conflict between modules, it is safer to use hook_node_access_records_alter()

 * to return only the deny grant.

 *

 * Note: a deny all grant is not written to the database; denies are implicit.

 *

 * @see node_access_write_grants()

 *

 * @param $node

 *   The node that has just been saved.

 *

 * @return

 *   An array of grants as defined above.

 *

 * @see hook_node_access_records_alter()

 * @ingroup node_access

 */

function hook_node_access_records($node) {

  // We only care about the node if it has been marked private. If not, it is

  // treated just like any other node and we completely ignore it.

  if ($node->private) {

    $grants = array();

    // Only published nodes should be viewable to all users. If we allow access

    // blindly here, then all users could view an unpublished node.

    if ($node->status) {

      $grants[] = array(

        'realm' => 'example',

        'gid' => 1,

        'grant_view' => 1,

        'grant_update' => 0,

        'grant_delete' => 0,

        'priority' => 0,

      );

    }

    // For the example_author array, the GID is equivalent to a UID, which

    // means there are many groups of just 1 user.

    // Note that an author can always view his or her nodes, even if they

    // have status unpublished.

    $grants[] = array(

      'realm' => 'example_author',

      'gid' => $node->uid,

      'grant_view' => 1,

      'grant_update' => 1,

      'grant_delete' => 1,

      'priority' => 0,

    );

    return $grants;

  }

}

/**

 * Alter permissions for a node before it is written to the database.

 *

 * Node access modules establish rules for user access to content. Node access

 * records are stored in the {node_access} table and define which permissions

 * are required to access a node. This hook is invoked after node access modules

 * returned their requirements via hook_node_access_records(); doing so allows

 * modules to modify the $grants array by reference before it is stored, so

 * custom or advanced business logic can be applied.

 *

 * @see hook_node_access_records()

 *

 * Upon viewing, editing or deleting a node, hook_node_grants() builds a

 * permissions array that is compared against the stored access records. The

 * user must have one or more matching permissions in order to complete the

 * requested operation.

 *

 * A module may deny all access to a node by setting $grants to an empty array.

 *

 * @see hook_node_grants()

 * @see hook_node_grants_alter()

 *

 * @param $grants

 *   The $grants array returned by hook_node_access_records().

 * @param $node

 *   The node for which the grants were acquired.

 *

 * The preferred use of this hook is in a module that bridges multiple node

 * access modules with a configurable behavior, as shown in the example with the

 * 'is_preview' field.

 *

 * @ingroup node_access

 */

function hook_node_access_records_alter(&$grants, $node) {

  // Our module allows editors to mark specific articles with the 'is_preview'

  // field. If the node being saved has a TRUE value for that field, then only

  // our grants are retained, and other grants are removed. Doing so ensures

  // that our rules are enforced no matter what priority other grants are given.

  if ($node->is_preview) {

    // Our module grants are set in $grants['example'].

    $temp = $grants['example'];

    // Now remove all module grants but our own.

    $grants = array('example' => $temp);

  }

}

/**

 * Alter user access rules when trying to view, edit or delete a node.

 *

 * Node access modules establish rules for user access to content.

 * hook_node_grants() defines permissions for a user to view, edit or delete

 * nodes by building a $grants array that indicates the permissions assigned to

 * the user by each node access module. This hook is called to allow modules to

 * modify the $grants array by reference, so the interaction of multiple node

 * access modules can be altered or advanced business logic can be applied.

 *

 * @see hook_node_grants()

 *

 * The resulting grants are then checked against the records stored in the

 * {node_access} table to determine if the operation may be completed.

 *

 * A module may deny all access to a user by setting $grants to an empty array.

 *

 * @see hook_node_access_records()

 * @see hook_node_access_records_alter()

 *

 * @param $grants

 *   The $grants array returned by hook_node_grants().

 * @param $account

 *   The user account requesting access to content.

 * @param $op

 *   The operation being performed, 'view', 'update' or 'delete'.

 *

 * Developers may use this hook to either add additional grants to a user or to

 * remove existing grants. These rules are typically based on either the

 * permissions assigned to a user role, or specific attributes of a user

 * account.

 *

 * @ingroup node_access

 */

function hook_node_grants_alter(&$grants, $account, $op) {

  // Our sample module never allows certain roles to edit or delete

  // content. Since some other node access modules might allow this

  // permission, we expressly remove it by returning an empty $grants

  // array for roles specified in our variable setting.

  // Get our list of banned roles.

  $restricted = variable_get('example_restricted_roles', array());

  if ($op != 'view' && !empty($restricted)) {

    // Now check the roles for this account against the restrictions.

    foreach ($restricted as $role_id) {

      if (isset($account->roles[$role_id])) {

        $grants = array();

      }

    }

  }

}

/**

 * Add mass node operations.

 *

 * This hook enables modules to inject custom operations into the mass

 * operations dropdown found at admin/content, by associating a callback

 * function with the operation, which is called when the form is submitted. The

 * callback function receives one initial argument, which is an array of the

 * checked nodes.

 *

 * @return

 *   An array of operations. Each operation is an associative array that may

 *   contain the following key-value pairs:

 *   - label: (required) The label for the operation, displayed in the dropdown

 *     menu.

 *   - callback: (required) The function to call for the operation.

 *   - callback arguments: (optional) An array of additional arguments to pass

 *     to the callback function.

 */

function hook_node_operations() {

  $operations = array(

    'publish' => array(

      'label' => t('Publish selected content'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('status' => NODE_PUBLISHED)),

    ),

    'unpublish' => array(

      'label' => t('Unpublish selected content'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('status' => NODE_NOT_PUBLISHED)),

    ),

    'promote' => array(

      'label' => t('Promote selected content to front page'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('status' => NODE_PUBLISHED, 'promote' => NODE_PROMOTED)),

    ),

    'demote' => array(

      'label' => t('Demote selected content from front page'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('promote' => NODE_NOT_PROMOTED)),

    ),

    'sticky' => array(

      'label' => t('Make selected content sticky'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('status' => NODE_PUBLISHED, 'sticky' => NODE_STICKY)),

    ),

    'unsticky' => array(

      'label' => t('Make selected content not sticky'),

      'callback' => 'node_mass_update',

      'callback arguments' => array('updates' => array('sticky' => NODE_NOT_STICKY)),

    ),

    'delete' => array(

      'label' => t('Delete selected content'),

      'callback' => NULL,

    ),

  );

  return $operations;

}

/**

 * Respond to node deletion.

 *

 * This hook is invoked from node_delete_multiple() after the type-specific

 * hook_delete() has been invoked, but before hook_entity_delete and

 * field_attach_delete() are called, and before the node is removed from the

 * node table in the database.

 *

 * @param $node

 *   The node that is being deleted.

 *

 * @ingroup node_api_hooks

 */

function hook_node_delete($node) {

  db_delete('mytable')

    ->condition('nid', $node->nid)

    ->execute();

}

/**

 * Respond to deletion of a node revision.

 *

 * This hook is invoked from node_revision_delete() after the revision has been

 * removed from the node_revision table, and before

 * field_attach_delete_revision() is called.

 *

 * @param $node

 *   The node revision (node object) that is being deleted.

 *

 * @ingroup node_api_hooks

 */

function hook_node_revision_delete($node) {

  db_delete('mytable')

    ->condition('vid', $node->vid)

    ->execute();

}

/**

 * Respond to creation of a new node.

 *

 * This hook is invoked from node_save() after the database query that will

 * insert the node into the node table is scheduled for execution, after the

 * type-specific hook_insert() is invoked, and after field_attach_insert() is

 * called.

 *

 * Note that when this hook is invoked, the changes have not yet been written to

 * the database, because a database transaction is still in progress. The

 * transaction is not finalized until the save operation is entirely completed

 * and node_save() goes out of scope. You should not rely on data in the

 * database at this time as it is not updated yet. You should also note that any

 * write/update database queries executed from this hook are also not committed

 * immediately. Check node_save() and db_transaction() for more info.

 *

 * @param $node

 *   The node that is being created.

 *

 * @ingroup node_api_hooks

 */

function hook_node_insert($node) {

  db_insert('mytable')

    ->fields(array(

      'nid' => $node->nid,

      'extra' => $node->extra,

    ))

    ->execute();

}

/**

 * Act on arbitrary nodes being loaded from the database.

 *

 * This hook should be used to add information that is not in the node or node

 * revisions table, not to replace information that is in these tables (which

 * could interfere with the entity cache). For performance reasons, information

 * for all available nodes should be loaded in a single query where possible.

 *

 * This hook is invoked during node loading, which is handled by entity_load(),

 * via classes NodeController and DrupalDefaultEntityController. After the node

 * information is read from the database or the entity cache, hook_load() is

 * invoked on the node's content type module, then field_attach_load_revision()

 * or field_attach_load() is called, then hook_entity_load() is invoked on all

 * implementing modules, and finally hook_node_load() is invoked on all

 * implementing modules.

 *

 * @param $nodes

 *   An array of the nodes being loaded, keyed by nid.

 * @param $types

 *   An array containing the node types present in $nodes. Allows for an early

 *   return for modules that only support certain node types. However, if your

 *   module defines a content type, you can use hook_load() to respond to

 *   loading of just that content type.

 *

 * For a detailed usage example, see nodeapi_example.module.

 *

 * @ingroup node_api_hooks

 */

function hook_node_load($nodes, $types) {

  // Decide whether any of $types are relevant to our purposes.

  if (count(array_intersect($types_we_want_to_process, $types))) {

    // Gather our extra data for each of these nodes.

    $result = db_query('SELECT nid, foo FROM {mytable} WHERE nid IN(:nids)', array(':nids' => array_keys($nodes)));

    // Add our extra data to the node objects.

    foreach ($result as $record) {

      $nodes[$record->nid]->foo = $record->foo;

    }

  }

}

/**

 * Control access to a node.

 *

 * Modules may implement this hook if they want to have a say in whether or not

 * a given user has access to perform a given operation on a node.

 *

 * The administrative account (user ID #1) always passes any access check, so

 * this hook is not called in that case. Users with the "bypass node access"

 * permission may always view and edit content through the administrative

 * interface.

 *

 * Note that not all modules will want to influence access on all node types. If

 * your module does not want to actively grant or block access, return

 * NODE_ACCESS_IGNORE or simply return nothing. Blindly returning FALSE will

 * break other node access modules.

 *

 * Also note that this function isn't called for node listings (e.g., RSS feeds,

 * the default home page at path 'node', a recent content block, etc.) See

 * @link node_access Node access rights @endlink for a full explanation.

 *

 * @param $node

 *   Either a node object or the machine name of the content type on which to

 *   perform the access check.

 * @param $op

 *   The operation to be performed. Possible values:

 *   - "create"

 *   - "delete"

 *   - "update"

 *   - "view"

 * @param $account

 *   The user object to perform the access check operation on.

 *

 * @return

 *   - NODE_ACCESS_ALLOW: if the operation is to be allowed.

 *   - NODE_ACCESS_DENY: if the operation is to be denied.

 *   - NODE_ACCESS_IGNORE: to not affect this operation at all.

 *

 * @ingroup node_access

 */

function hook_node_access($node, $op, $account) {

  $type = is_string($node) ? $node : $node->type;

  if (in_array($type, node_permissions_get_configured_types())) {

    if ($op == 'create' && user_access('create ' . $type . ' content', $account)) {

      return NODE_ACCESS_ALLOW;

    }

    if ($op == 'update') {

      if (user_access('edit any ' . $type . ' content', $account) || (user_access('edit own ' . $type . ' content', $account) && ($account->uid == $node->uid))) {

        return NODE_ACCESS_ALLOW;

      }

    }

    if ($op == 'delete') {

      if (user_access('delete any ' . $type . ' content', $account) || (user_access('delete own ' . $type . ' content', $account) && ($account->uid == $node->uid))) {

        return NODE_ACCESS_ALLOW;

      }

    }

  }

  // Returning nothing from this function would have the same effect.

  return NODE_ACCESS_IGNORE;

}

/**

 * Act on a node object about to be shown on the add/edit form.

 *

 * This hook is invoked from node_object_prepare() after the type-specific

 * hook_prepare() is invoked.

 *

 * @param $node

 *   The node that is about to be shown on the add/edit form.

 *

 * @ingroup node_api_hooks

 */

function hook_node_prepare($node) {

  if (!isset($node->comment)) {

    $node->comment = variable_get("comment_$node->type", COMMENT_NODE_OPEN);

  }

}

/**

 * Act on a node being displayed as a search result.

 *

 * This hook is invoked from node_search_execute(), after node_load() and

 * node_view() have been called.

 *

 * @param $node

 *   The node being displayed in a search result.

 *

 * @return array

 *   Extra information to be displayed with search result. This information

 *   should be presented as an associative array. It will be concatenated with

 *   the post information (last updated, author) in the default search result

 *   theming.

 *

 * @see template_preprocess_search_result()

 * @see search-result.tpl.php

 *

 * @ingroup node_api_hooks

 */

function hook_node_search_result($node) {

  $comments = db_query('SELECT comment_count FROM {node_comment_statistics} WHERE nid = :nid', array('nid' => $node->nid))->fetchField();

  return array('comment' => format_plural($comments, '1 comment', '@count comments'));

}

/**

 * Act on a node being inserted or updated.

 *

 * This hook is invoked from node_save() before the node is saved to the

 * database.

 *

 * @param $node

 *   The node that is being inserted or updated.

 *

 * @ingroup node_api_hooks

 */

function hook_node_presave($node) {

  if ($node->nid && $node->moderate) {

    // Reset votes when node is updated:

    $node->score = 0;

    $node->users = '';

    $node->votes = 0;

  }

}

/**

 * Respond to updates to a node.

 *

 * This hook is invoked from node_save() after the database query that will

 * update node in the node table is scheduled for execution, after the

 * type-specific hook_update() is invoked, and after field_attach_update() is

 * called.

 *

 * Note that when this hook is invoked, the changes have not yet been written to

 * the database, because a database transaction is still in progress. The

 * transaction is not finalized until the save operation is entirely completed

 * and node_save() goes out of scope. You should not rely on data in the

 * database at this time as it is not updated yet. You should also note that any

 * write/update database queries executed from this hook are also not committed

 * immediately. Check node_save() and db_transaction() for more info.

 *

 * @param $node

 *   The node that is being updated.

 *

 * @ingroup node_api_hooks

 */

function hook_node_update($node) {

  db_update('mytable')

    ->fields(array('extra' => $node->extra))

    ->condition('nid', $node->nid)

    ->execute();

}

/**

 * Act on a node being indexed for searching.

 *

 * This hook is invoked during search indexing, after node_load(), and after the

 * result of node_view() is added as $node->rendered to the node object.

 *

 * @param $node

 *   The node being indexed.

 *

 * @return string

 *   Additional node information to be indexed.

 *

 * @ingroup node_api_hooks

 */

function hook_node_update_index($node) {

  $text = '';

  $comments = db_query('SELECT subject, comment, format FROM {comment} WHERE nid = :nid AND status = :status', array(':nid' => $node->nid, ':status' => COMMENT_PUBLISHED));

  foreach ($comments as $comment) {

    $text .= '<h2>' . check_plain($comment->subject) . '</h2>' . check_markup($comment->comment, $comment->format, '', TRUE);

  }

  return $text;

}

/**

 * Perform node validation before a node is created or updated.

 *

 * This hook is invoked from node_validate(), after a user has has finished

 * editing the node and is previewing or submitting it. It is invoked at the

 * end of all the standard validation steps, and after the type-specific

 * hook_validate() is invoked.

 *

 * To indicate a validation error, use form_set_error().

 *

 * Note: Changes made to the $node object within your hook implementation will

 * have no effect.  The preferred method to change a node's content is to use

 * hook_node_presave() instead. If it is really necessary to change the node at

 * the validate stage, you can use form_set_value().

 *

 * @param $node

 *   The node being validated.

 * @param $form

 *   The form being used to edit the node.

 * @param $form_state

 *   The form state array.

 *

 * @ingroup node_api_hooks

 */

function hook_node_validate($node, $form, &$form_state) {

  if (isset($node->end) && isset($node->start)) {

    if ($node->start > $node->end) {

      form_set_error('time', t('An event may not end before it starts.'));

    }

  }

}

/**

 * Act on a node after validated form values have been copied to it.

 *

 * This hook is invoked when a node form is submitted with either the "Save" or

 * "Preview" button, after form values have been copied to the form state's node

 * object, but before the node is saved or previewed. It is a chance for modules

 * to adjust the node's properties from what they are simply after a copy from

 * $form_state['values']. This hook is intended for adjusting non-field-related

 * properties. See hook_field_attach_submit() for customizing field-related

 * properties.

 *

 * @param $node

 *   The node object being updated in response to a form submission.

 * @param $form

 *   The form being used to edit the node.

 * @param $form_state

 *   The form state array.

 *

 * @ingroup node_api_hooks

 */

function hook_node_submit($node, $form, &$form_state) {

  // Decompose the selected menu parent option into 'menu_name' and 'plid', if

  // the form used the default parent selection widget.

  if (!empty($form_state['values']['menu']['parent'])) {

    list($node->menu['menu_name'], $node->menu['plid']) = explode(':', $form_state['values']['menu']['parent']);

  }

}

/**

 * Act on a node that is being assembled before rendering.

 *

 * The module may add elements to $node->content prior to rendering. This hook

 * will be called after hook_view(). The structure of $node->content is a

 * renderable array as expected by drupal_render().

 *

 * When $view_mode is 'rss', modules can also add extra RSS elements and

 * namespaces to $node->rss_elements and $node->rss_namespaces respectively for

 * the RSS item generated for this node.

 * For details on how this is used, see node_feed().

 *

 * @see blog_node_view()

 * @see forum_node_view()

 * @see comment_node_view()

 *

 * @param $node

 *   The node that is being assembled for rendering.

 * @param $view_mode

 *   The $view_mode parameter from node_view().

 * @param $langcode

 *   The language code used for rendering.

 *

 * @see hook_entity_view()

 *

 * @ingroup node_api_hooks

 */

function hook_node_view($node, $view_mode, $langcode) {

  $node->content['my_additional_field'] = array(

    '#markup' => $additional_field,

    '#weight' => 10,

    '#theme' => 'mymodule_my_additional_field',

  );

}

/**

 * Alter the results of node_view().

 *

 * This hook is called after the content has been assembled in a structured

 * array and may be used for doing processing which requires that the complete

 * node content structure has been built.

 *

 * If the module wishes to act on the rendered HTML of the node rather than the

 * structured content array, it may use this hook to add a #post_render

 * callback.  Alternatively, it could also implement hook_preprocess_node(). See

 * drupal_render() and theme() documentation respectively for details.

 *

 * @param $build

 *   A renderable array representing the node content.

 *

 * @see node_view()

 * @see hook_entity_view_alter()

 *

 * @ingroup node_api_hooks

 */

function hook_node_view_alter(&$build) {

  if ($build['#view_mode'] == 'full' && isset($build['an_additional_field'])) {

    // Change its weight.

    $build['an_additional_field']['#weight'] = -10;

  }

  // Add a #post_render callback to act on the rendered HTML of the node.

  $build['#post_render'][] = 'my_module_node_post_render';

}

/**

 * Define module-provided node types.

 *

 * This hook allows a module to define one or more of its own node types. For

 * example, the blog module uses it to define a blog node-type named "Blog

 * entry." The name and attributes of each desired node type are specified in an

 * array returned by the hook.

 *

 * Only module-provided node types should be defined through this hook. User-

 * provided (or 'custom') node types should be defined only in the 'node_type'

 * database table, and should be maintained by using the node_type_save() and

 * node_type_delete() functions.

 *

 * @return

 *   An array of information defining the module's node types. The array

 *   contains a sub-array for each node type, with the machine-readable type

 *   name as the key. Each sub-array has up to 10 attributes. Possible

 *   attributes:

 *   - name: (required) The human-readable name of the node type.

 *   - base: (required) The base string used to construct callbacks

 *     corresponding to this node type (for example, if base is defined as

 *     example_foo, then example_foo_insert will be called when inserting a node

 *     of that type). This string is usually the name of the module, but not

 *     always.

 *   - description: (required) A brief description of the node type.

 *   - help: (optional) Help information shown to the user when creating a node

 *     of this type.

 *   - has_title: (optional) A Boolean indicating whether or not this node type

 *     has a title field.

 *   - title_label: (optional) The label for the title field of this content

 *     type.

 *   - locked: (optional) A Boolean indicating whether the administrator can

 *     change the machine name of this type. FALSE = changeable (not locked),

 *     TRUE = unchangeable (locked).

 *

 * The machine name of a node type should contain only letters, numbers, and

 * underscores. Underscores will be converted into hyphens for the purpose of

 * constructing URLs.

 *

 * All attributes of a node type that are defined through this hook (except for

 * 'locked') can be edited by a site administrator. This includes the

 * machine-readable name of a node type, if 'locked' is set to FALSE.

 *

 * @ingroup node_api_hooks

 */

function hook_node_info() {

  return array(

    'blog' => array(

      'name' => t('Blog entry'),

      'base' => 'blog',

      'description' => t('Use for multi-user blogs. Every user gets a personal blog.'),

    )

  );

}

/**

 * Provide additional methods of scoring for core search results for nodes.

 *

 * A node's search score is used to rank it among other nodes matched by the

 * search, with the highest-ranked nodes appearing first in the search listing.

 *

 * For example, a module allowing users to vote on content could expose an

 * option to allow search results' rankings to be influenced by the average

 * voting score of a node.

 *

 * All scoring mechanisms are provided as options to site administrators, and

 * may be tweaked based on individual sites or disabled altogether if they do

 * not make sense. Individual scoring mechanisms, if enabled, are assigned a

 * weight from 1 to 10. The weight represents the factor of magnification of

 * the ranking mechanism, with higher-weighted ranking mechanisms having more

 * influence. In order for the weight system to work, each scoring mechanism

 * must return a value between 0 and 1 for every node. That value is then

 * multiplied by the administrator-assigned weight for the ranking mechanism,

 * and then the weighted scores from all ranking mechanisms are added, which

 * brings about the same result as a weighted average.

 *

 * @return

 *   An associative array of ranking data. The keys should be strings,

 *   corresponding to the internal name of the ranking mechanism, such as

 *   'recent', or 'comments'. The values should be arrays themselves, with the

 *   following keys available:

 *   - title: (required) The human readable name of the ranking mechanism.

 *   - join: (optional) The part of a query string to join to any additional

 *     necessary table. This is not necessary if the table required is already

 *     joined to by the base query, such as for the {node} table. Other tables

 *     should use the full table name as an alias to avoid naming collisions.

 *   - score: (required) The part of a query string to calculate the score for

 *     the ranking mechanism based on values in the database. This does not need

 *     to be wrapped in parentheses, as it will be done automatically; it also

 *     does not need to take the weighted system into account, as it will be

 *     done automatically. It does, however, need to calculate a decimal between

 *     0 and 1; be careful not to cast the entire score to an integer by

 *     inadvertently introducing a variable argument.

 *   - arguments: (optional) If any arguments are required for the score, they

 *     can be specified in an array here.

 *

 * @ingroup node_api_hooks

 */

function hook_ranking() {

  // If voting is disabled, we can avoid returning the array, no hard feelings.

  if (variable_get('vote_node_enabled', TRUE)) {

    return array(

      'vote_average' => array(

        'title' => t('Average vote'),

        // Note that we use i.sid, the search index's search item id, rather than

        // n.nid.

        'join' => 'LEFT JOIN {vote_node_data} vote_node_data ON vote_node_data.nid = i.sid',

        // The highest possible score should be 1, and the lowest possible score,

        // always 0, should be 0.

        'score' => 'vote_node_data.average / CAST(%f AS DECIMAL)',

        // Pass in the highest possible voting score as a decimal argument.

        'arguments' => array(variable_get('vote_score_max', 5)),

      ),

    );

  }

}

/**

 * Respond to node type creation.

 *

 * This hook is invoked from node_type_save() after the node type is added to

 * the database.

 *

 * @param $info

 *   The node type object that is being created.

 */

function hook_node_type_insert($info) {

  drupal_set_message(t('You have just created a content type with a machine name %type.', array('%type' => $info->type)));

}

/**

 * Respond to node type updates.

 *

 * This hook is invoked from node_type_save() after the node type is updated in

 * the database.

 *

 * @param $info

 *   The node type object that is being updated.

 */

function hook_node_type_update($info) {

  if (!empty($info->old_type) && $info->old_type != $info->type) {

    $setting = variable_get('comment_' . $info->old_type, COMMENT_NODE_OPEN);

    variable_del('comment_' . $info->old_type);

    variable_set('comment_' . $info->type, $setting);

  }

}

/**

 * Respond to node type deletion.

 *

 * This hook is invoked from node_type_delete() after the node type is removed

 * from the database.

 *

 * @param $info

 *   The node type object that is being deleted.

 */

function hook_node_type_delete($info) {

  variable_del('comment_' . $info->type);

}

/**

 * Respond to node deletion.

 *

 * This hook is invoked only on the module that defines the node's content type

 * (use hook_node_delete() to respond to all node deletions).

 *

 * This hook is invoked from node_delete_multiple() after the node has been

 * removed from the node table in the database, before hook_node_delete() is

 * invoked, and before field_attach_delete() is called.

 *

 * @param $node

 *   The node that is being deleted.

 *

 * @ingroup node_api_hooks

 */

function hook_delete($node) {

  db_delete('mytable')

    ->condition('nid', $node->nid)

    ->execute();

}

/**

 * Act on a node object about to be shown on the add/edit form.

 *

 * This hook is invoked only on the module that defines the node's content type

 * (use hook_node_prepare() to act on all node preparations).

 *

 * This hook is invoked from node_object_prepare() before the general

 * hook_node_prepare() is invoked.

 *

 * @param $node

 *   The node that is about to be shown on the add/edit form.

 *

 * @ingroup node_api_hooks

 */

function hook_prepare($node) {

  if ($file = file_check_upload($field_name)) {

    $file = file_save_upload($field_name, _image_filename($file->filename, NULL, TRUE));

    if ($file) {

      if (!image_get_info($file->uri)) {

        form_set_error($field_name, t('Uploaded file is not a valid image'));

        return;

      }

    }

    else {

      return;

    }

    $node->images['_original'] = $file->uri;

    _image_build_derivatives($node, TRUE);

    $node->new_file = TRUE;

  }

}

/**

 * Display a node editing form.

 *

 * This hook, implemented by node modules, is called to retrieve the form

 * that is displayed to create or edit a node. This form is displayed at path

 * node/add/[node type] or node/[node ID]/edit.

 *

 * The submit and preview buttons, administrative and display controls, and

 * sections added by other modules (such as path settings, menu settings,

 * comment settings, and fields managed by the Field UI module) are

 * displayed automatically by the node module. This hook just needs to

 * return the node title and form editing fields specific to the node type.

 *

 * @param $node

 *   The node being added or edited.

 * @param $form_state

 *   The form state array.

 *

 * @return

 *   An array containing the title and any custom form elements to be displayed

 *   in the node editing form.

 *

 * @ingroup node_api_hooks

 */

function hook_form($node, &$form_state) {

  $type = node_type_get_type($node);

  $form['title'] = array(

    '#type' => 'textfield',

    '#title' => check_plain($type->title_label),

    '#default_value' => !empty($node->title) ? $node->title : '',

    '#required' => TRUE, '#weight' => -5

  );

  $form['field1'] = array(

    '#type' => 'textfield',

    '#title' => t('Custom field'),

    '#default_value' => $node->field1,

    '#maxlength' => 127,

  );

  $form['selectbox'] = array(

    '#type' => 'select',

    '#title' => t('Select box'),

    '#default_value' => $node->selectbox,

    '#options' => array(

      1 => 'Option A',

      2 => 'Option B',

      3 => 'Option C',

    ),

    '#description' => t('Choose an option.'),

  );

  return $form;

}

/**

 * Respond to creation of a new node.

 *

 * This hook is invoked only on the module that defines the node's content type

 * (use hook_node_insert() to act on all node insertions).

 *

 * This hook is invoked from node_save() after the node is inserted into the

 * node table in the database, before field_attach_insert() is called, and

 * before hook_node_insert() is invoked.

 *

 * @param $node

 *   The node that is being created.

 *

 * @ingroup node_api_hooks

 */

function hook_insert($node) {

  db_insert('mytable')

    ->fields(array(

      'nid' => $node->nid,

      'extra' => $node->extra,

    ))

    ->execute();

}

/**

 * Act on nodes being loaded from the database.

 *

 * This hook is invoked only on the module that defines the node's content type

 * (use hook_node_load() to respond to all node loads).

 *

 * This hook is invoked during node loading, which is handled by entity_load(),

 * via classes NodeController and DrupalDefaultEntityController. After the node

 * information is read from the database or the entity cache, hook_load() is

 * invoked on the node's content type module, then field_attach_node_revision()

 * or field_attach_load() is called, then hook_entity_load() is invoked on all

 * implementing modules, and finally hook_node_load() is invoked on all