comparison modules/node/node.api.php @ 0:ff03f76ab3fe

initial version

+<?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
+ * implementing modules.
+ *
+ * This hook should only 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.
+ *
+ * @param $nodes
+ *   An array of the nodes being loaded, keyed by nid.
+ *
+ * For a detailed usage example, see node_example.module.
+ *
+ * @ingroup node_api_hooks
+ */
+function hook_load($nodes) {
+  $result = db_query('SELECT nid, foo FROM {mytable} WHERE nid IN (:nids)', array(':nids' => array_keys($nodes)));
+  foreach ($result as $record) {
+    $nodes[$record->nid]->foo = $record->foo;
+  }
+}
+
+/**
+ * Respond to updates to a node.
+ *
+ * This hook is invoked only on the module that defines the node's content type
+ * (use hook_node_update() to act on all node updates).
+ *
+ * This hook is invoked from node_save() after the node is updated in the
+ * node table in the database, before field_attach_update() is called, and
+ * before hook_node_update() is invoked.
+ *
+ * @param $node
+ *   The node that is being updated.
+ *
+ * @ingroup node_api_hooks
+ */
+function hook_update($node) {
+  db_update('mytable')
+    ->fields(array('extra' => $node->extra))
+    ->condition('nid', $node->nid)
+    ->execute();
+}
+
+/**
+ * Perform node validation before a node is created or updated.
+ *
+ * This hook is invoked only on the module that defines the node's content type
+ * (use hook_node_validate() to act on all node validations).
+ *
+ * This hook is invoked from node_validate(), after a user has finished
+ * editing the node and is previewing or submitting it. It is invoked at the end
+ * of all the standard validation steps, and before hook_node_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.
+ *
+ * @param $node
+ *   The node being validated.
+ * @param $form
+ *   The form being used to edit the node.
+ * @param $form_state
+ *   The form state array.
+ *
+ * @ingroup node_api_hooks
+ */
+function hook_validate($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.'));
+    }
+  }
+}
+
+/**
+ * Display a node.
+ *
+ * This hook is invoked only on the module that defines the node's content type
+ * (use hook_node_view() to act on all node views).
+ *
+ * This hook is invoked during node viewing after the node is fully loaded, so
+ * that the node type module can define a custom method for display, or add to
+ * the default display.
+ *
+ * @param $node
+ *   The node to be displayed, as returned by node_load().
+ * @param $view_mode
+ *   View mode, e.g. 'full', 'teaser', ...
+ * @return
+ *   The passed $node parameter should be modified as necessary and returned so
+ *   it can be properly presented. Nodes are prepared for display by assembling
+ *   a structured array, formatted as in the Form API, in $node->content. As
+ *   with Form API arrays, the #weight property can be used to control the
+ *   relative positions of added elements. After this hook is invoked,
+ *   node_view() calls field_attach_view() to add field views to $node->content,
+ *   and then invokes hook_node_view() and hook_node_view_alter(), so if you
+ *   want to affect the final view of the node, you might consider implementing
+ *   one of these hooks instead.
+ *
+ * @ingroup node_api_hooks
+ */
+function hook_view($node, $view_mode) {
+  if ($view_mode == 'full' && node_is_page($node)) {
+    $breadcrumb = array();
+    $breadcrumb[] = l(t('Home'), NULL);
+    $breadcrumb[] = l(t('Example'), 'example');
+    $breadcrumb[] = l($node->field1, 'example/' . $node->field1);
+    drupal_set_breadcrumb($breadcrumb);
+  }
+
+  $node->content['myfield'] = array(
+    '#markup' => theme('mymodule_myfield', $node->myfield),
+    '#weight' => 1,
+  );
+
+  return $node;
+}
+
+/**
+ * @} End of "addtogroup hooks".
+ */