node_example.module in Examples for Developers 6

This is an example outlining how a module can be used to define a new node type.

(Note that custom node types are most often created with CCK in recent versions of Drupal.)

Our example node type will allow users to specify a "color" and a "quantity" for their nodes; some kind of rudimentary inventory-tracking system, perhaps? To store this extra information, we need an auxiliary database table as defined in node_example_schema().

File

node_example/node_example.module

<?php

/**
 * @file
 * This is an example outlining how a module can be used to define a new
 * node type.
 *
 * (Note that custom node types are most often created with CCK in recent
 * versions of Drupal.)
 *
 * Our example node type will allow users to specify a "color" and a "quantity"
 * for their nodes; some kind of rudimentary inventory-tracking system, perhaps?
 * To store this extra information, we need an auxiliary database table as
 * defined in node_example_schema().
 */

/**
 * @defgroup node_example Example: Node
 * @ingroup examples
 * @{
 * Creating a new content type in a module. (drupal 6)
 *
 * This is an example outlining how a module can be used to define a new
 * node type.
 *
 * (Note that custom node types are most often created with CCK in recent
 * versions of Drupal.)
 *
 * Our example node type will allow users to specify a "color" and a "quantity"
 * for their nodes; some kind of rudimentary inventory-tracking system, perhaps?
 * To store this extra information, we need an auxiliary database table as
 * defined in node_example_schema().
 *
 * This example is part of the Examples for Developers Project which you can download
 * and experiment with here: http://drupal.org/project/examples
 */

/**
 * Implementation of hook_menu().
 */
function node_example_menu() {
  $items['examples/node_example'] = array(
    'title' => 'Node Example',
    'page callback' => 'node_example_info',
    'access callback' => TRUE,
  );
  return $items;
}

/**
 * Explain how the module demonstrates a new node type.node_example.test
 */
function node_example_info() {
  return t('The node example defines a new node type, "Example node type 1", which can be created at !link.', array(
    '!link' => l(t('node/add/example-node-type-1'), 'node/add/example-node-type-1'),
  ));
}

/**
 * Implementation of hook_node_info().
 *
 * This is a required node hook. This function describes the nodes provided by
 * this module.
 *
 * The required attributes are:
 * - "name" provides a human readable name for the node,
 * - "module" tells Drupal how the module's functions map to hooks (i.e. if the
 *   module is node_example_foo then node_example_foo_insert will be called
 *   when inserting the node).
 * - "description" provides a brief description of the node type, which is
 *   shown when a user accesses the "Create content" page for that node type.
 *
 * The other optional, attributes:
 * - "has_title" boolean that indicates whether or not this node type has a
 *   title field.
 * - "title_label": the label for the title field of this content type.
 * - "has_body": boolean that indicates whether or not this node type has a
 *   body field.
 * - "body_label": the label for the body field of this content type.
 * - "min_word_count": the minimum number of words for the body field to be
 *   considered valid for this content type.
 *
 * The key in this example, "example_node_type_1", is the "machine name" of the
 * node type and is stored in {node}.type. The node's type value cannot be
 * changed through the admin interface.
 *
 */
function node_example_node_info() {
  return array(
    'example_node_type_1' => array(
      'name' => t('Example node type 1'),
      'module' => 'node_example',
      'description' => t("An example node type with a few fields."),
      'has_title' => TRUE,
      'title_label' => t('Example Node Type 1 Title'),
      'has_body' => TRUE,
      'body_label' => t('Example Node Type 1 Body'),
    ),
  );
}

/**
 * Implementation of hook_access().
 *
 * Node modules may implement node_access() to determine the operations
 * users may perform on nodes. This example uses a very common access pattern.
 */
function node_example_access($op, $node, $account) {
  if ($op == 'create') {
    return user_access('create example content', $account);
  }
  if ($op == 'update') {
    if (user_access('edit any example content', $account) || user_access('edit own example content', $account) && $account->uid == $node->uid) {
      return TRUE;
    }
  }
  if ($op == 'delete') {
    if (user_access('delete any example content', $account) || user_access('delete own example content', $account) && $account->uid == $node->uid) {
      return TRUE;
    }
  }
}

/**
 * Implementation of hook_perm().
 *
 * Since we are limiting the ability to create new nodes to certain users,
 * we need to define what those permissions are here. We also define a permission
 * to allow users to edit the nodes they created.
 */
function node_example_perm() {
  return array(
    'create example content',
    'delete own example content',
    'delete any example content',
    'edit own example content',
    'edit any example content',
  );
}

/**
 * Implementation of hook_form().
 *
 * Now it's time to describe the form for collecting the information
 * specific to this node type. This hook requires us to return an array with
 * a sub array containing information for each element in the form.
 */
function node_example_form(&$node, $form_state) {

  // The site admin can decide if this node type has a title and body, and how
  // the fields should be labeled. We need to load these settings so we can
  // build the node form correctly.
  $type = node_get_types('type', $node);
  if ($type->has_title) {
    $form['title'] = array(
      '#type' => 'textfield',
      '#title' => check_plain($type->title_label),
      '#required' => TRUE,
      '#default_value' => $node->title,
      '#weight' => -5,
    );
  }
  if ($type->has_body) {

    // In Drupal 6, we use node_body_field() to get the body and filter
    // elements. This replaces the old textarea + filter_form() method of
    // setting this up. It will also ensure the teaser splitter gets set up
    // properly.
    $form['body_field'] = node_body_field($node, $type->body_label, $type->min_word_count);
  }

  // Now we define the form elements specific to our node type.
  $form['color'] = array(
    '#type' => 'textfield',
    '#title' => t('Color'),
    '#default_value' => isset($node->color) ? $node->color : '',
  );
  $form['quantity'] = array(
    '#type' => 'textfield',
    '#title' => t('Quantity'),
    '#default_value' => isset($node->quantity) ? $node->quantity : 0,
    '#size' => 10,
    '#maxlength' => 10,
  );
  return $form;
}

/**
 * Implementation of hook_validate().
 *
 * Our "quantity" field requires a number to be entered. This hook lets
 * us ensure that the user entered an appropriate value before we try
 * inserting anything into the database.
 *
 * Errors should be signaled with form_set_error().
 */
function node_example_validate($node, &$form) {
  if ($node->quantity) {
    if (!is_numeric($node->quantity)) {
      form_set_error('quantity', t('The quantity must be a number.'));
    }
  }
}

/**
 * Implementation of hook_insert().
 *
 * As a new node is being inserted into the database, we need to do our own
 * database inserts.
 */
function node_example_insert($node) {
  db_query("INSERT INTO {node_example} (vid, nid, color, quantity) VALUES (%d, %d, '%s', %d)", $node->vid, $node->nid, $node->color, $node->quantity);
}

/**
 * Implementation of hook_update().
 *
 * As an existing node is being updated in the database, we need to do our own
 * database updates.
 */
function node_example_update($node) {

  // if this is a new node or we're adding a new revision,
  if ($node->revision) {
    node_example_insert($node);
  }
  else {
    db_query("UPDATE {node_example} SET color = '%s', quantity = %d WHERE vid = %d", $node->color, $node->quantity, $node->vid);
  }
}

/**
 * Implementation of hook_nodeapi().
 *
 * When a node revision is deleted, we need to remove the corresponding record
 * from our table. The only way to handle revision deletion is by implementing
 * hook_nodeapi().
 */
function node_example_nodeapi(&$node, $op, $teaser, $page) {
  switch ($op) {
    case 'delete revision':

      // Notice that we're matching a single revision based on the node's vid.
      db_query('DELETE FROM {node_example} WHERE vid = %d', $node->vid);
      break;
  }
}

/**
 * Implementation of hook_delete().
 *
 * When a node is deleted, we need to remove all related records from our table.
 */
function node_example_delete($node) {

  // Notice that we're matching all revision, by using the node's nid.
  db_query('DELETE FROM {node_example} WHERE nid = %d', $node->nid);
}

/**
 * Implementation of hook_load().
 *
 * Now that we've defined how to manage the node data in the database, we
 * need to tell Drupal how to get the node back out. This hook is called
 * every time a node is loaded, and allows us to do some loading of our own.
 */
function node_example_load($node) {
  $additions = db_fetch_object(db_query('SELECT color, quantity FROM {node_example} WHERE vid = %d', $node->vid));
  return $additions;
}

/**
 * Implementation of hook_view().
 *
 * This is a typical implementation that simply runs the node text through
 * the output filters.
 */
function node_example_view($node, $teaser = FALSE, $page = FALSE) {
  $node = node_prepare($node, $teaser);
  $node->content['myfield'] = array(
    '#value' => theme('node_example_order_info', $node),
    '#weight' => 1,
  );
  return $node;
}

/**
 * Implementation of hook_theme().
 *
 * This lets us tell Drupal about our theme functions and their arguments.
 */
function node_example_theme() {
  return array(
    'node_example_order_info' => array(
      'arguments' => array(
        'node',
      ),
    ),
  );
}

/**
 * A custom theme function.
 *
 * By using this function to format our node-specific information, themes
 * can override this presentation if they wish. We also wrap the default
 * presentation in a CSS class that is prefixed by the module name. This
 * way, style sheets can modify the output without requiring theme code.
 */
function theme_node_example_order_info($node) {
  $output = '<div class="node_example_order_info">';
  $output .= t('The order is for %quantity %color items.', array(
    '%quantity' => check_plain($node->quantity),
    '%color' => check_plain($node->color),
  ));
  $output .= '</div>';
  return $output;
}

/**
 * @} End of "defgroup node_example".
 */

Functions

Name	Description
node_example_access	Implementation of hook_access().
node_example_delete	Implementation of hook_delete().
node_example_form	Implementation of hook_form().
node_example_info	Explain how the module demonstrates a new node type.node_example.test
node_example_insert	Implementation of hook_insert().
node_example_load	Implementation of hook_load().
node_example_menu	Implementation of hook_menu().
node_example_nodeapi	Implementation of hook_nodeapi().
node_example_node_info	Implementation of hook_node_info().
node_example_perm	Implementation of hook_perm().
node_example_theme	Implementation of hook_theme().
node_example_update	Implementation of hook_update().
node_example_validate	Implementation of hook_validate().
node_example_view	Implementation of hook_view().
theme_node_example_order_info	A custom theme function.