<?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: When defining a node type, hook_node_info()

 *   returns a 'base' component. Node-type-specific hooks are named

 *   base_hookname() instead of mymodule_hookname() (in a module called

 *   'mymodule' for example). Only the node type's corresponding implementation

 *   is invoked. For example, poll_node_info() in poll.module defines the base

 *   for the 'poll' node type as 'poll'. So when a poll node is created,

 *   hook_insert() is invoked on poll_insert() only.

 *   Hooks that are node-type-specific are noted below.

 * - 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);

  }

  $grants['example_author'] = array($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) {