example_field.php in Content Construction Kit (CCK) 6

These hooks are defined by field modules, modules that define a new kind of field for insertion in a content type.

Field hooks are typically called by content.module using _content_field_invoke().

Widget module hooks are also defined here; the two go hand-in-hand, often in the same module (though they are independent).

Widget hooks are typically called by content.module when it creates the field form elements in the node form using hook_form_alter().

File

examples/example_field.php

<?php

/**
 * @file
 * These hooks are defined by field modules, modules that define a new kind
 * of field for insertion in a content type.
 *
 * Field hooks are typically called by content.module using _content_field_invoke().
 *
 * Widget module hooks are also defined here; the two go hand-in-hand, often in
 * the same module (though they are independent).
 *
 * Widget hooks are typically called by content.module when it creates the field
 * form elements in the node form using hook_form_alter().
 */

/**
 * @addtogroup install
 * @{
 */

/**
 * Implementation of hook_content_notify().
 *
 * This hook should be implemented inside hook_install(), hook_uninstall(),
 * hook_enable() and hook_disable(), and is used to notify the content
 * module when a field module is added or removed so it can respond
 * appropriately. One use of this hook is to allow the content module
 * to remove fields and field data created by this module when the
 * module is uninstalled.
 *
 * The recommended location for these hooks is in the module's .install file.
 */

/**
 * Implementation of hook_install().
 */
function text_install() {
  content_notify('install', 'text');
}

/**
 * Implementation of hook_uninstall().
 */
function text_uninstall() {
  content_notify('uninstall', 'text');
}

/**
 * Implementation of hook_enable().
 *
 * Notify content module when this module is enabled.
 */
function text_enable() {
  content_notify('enable', 'text');
}

/**
 * Implementation of hook_disable().
 *
 * Notify content module when this module is disabled.
 */
function text_disable() {
  content_notify('disable', 'text');
}

/**
 * @} End of "addtogroup install".
 */

/**
 * @addtogroup hooks
 * @{
 */

/**
 * Implementation of hook_theme().
 */
function text_theme() {
  return array(
    'text_textarea' => array(
      'arguments' => array(
        'element' => NULL,
      ),
    ),
    'text_textfield' => array(
      'arguments' => array(
        'element' => NULL,
      ),
    ),
  );
}

/**
 * Implementation of hook_field_info().
 *
 * Here we indicate that the content module will use its default
 * handling for the view of this field.
 *
 * Callbacks can be omitted if default handing is used.
 * They're included here just so this module can be used
 * as an example for custom modules that might do things
 * differently.
 *
 * If your module will provide its own Views tables or arguments,
 * change CONTENT_CALLBACK_DEFAULT to CONTENT_CALLBACK_CUSTOM.
 *
 * IMPORTANT! - field and widget names will be truncated to 32 characters in
 * the database and in internal arrays, like content_fields().
 */
function text_field_info() {
  return array(
    'text' => array(
      'label' => t('Text'),
      'callbacks' => array(
        'tables' => CONTENT_CALLBACK_DEFAULT,
        'arguments' => CONTENT_CALLBACK_DEFAULT,
      ),
    ),
  );
}

/**
 * Implementation of hook_field_settings().
 *
 * Handle the settings for a field.
 *
 * @param $op
 *   The operation to be performed. Possible values:
 *   - "form": Display the field settings form.
 *   - "validate": Check the field settings form for errors.
 *   - "save": Declare which fields to save back to the database.
 *   - "database columns": Declare the columns that content.module should create
 *     and manage on behalf of the field. If the field module wishes to handle
 *     its own database storage, this should be omitted.
 *   - "filters": Declare the Views filters available for the field.
 *     (this is used in CCK's default Views tables definition)
 *     They always apply to the first column listed in the "database columns"
 *     array.
 * @param $field
 *   The field on which the operation is to be performed.
 * @return
 *   This varies depending on the operation.
 *   - "form": an array of form elements to add to
 *     the settings page.
 *   - "validate": no return value. Use form_set_error().
 *   - "save": an array of names of form elements to
 *     be saved in the database.
 *   - "database columns": an array keyed by column name, with arrays of column
 *     information as values. This column information must include "type", the
 *     MySQL data type of the column, and may also include a "sortable" parameter
 *     to indicate to views.module that the column contains ordered information.
 *     TODO : Details of other information that can be passed to the database layer can
 *     be found in the API for the Schema API.
 *   - "filters": an array of 'filters' definitions as expected by views.module
 *     (see Views Documentation).
 *     When providing several filters, it is recommended to use the 'name'
 *     attribute in order to let the user distinguish between them. If no 'name'
 *     is specified for a filter, the key of the filter will be used instead.
 */
function text_field_settings($op, $field) {
  switch ($op) {
    case 'form':
      $form = array();
      $options = array(
        0 => t('Plain text'),
        1 => t('Filtered text (user selects input format)'),
      );
      $form['text_processing'] = array(
        '#type' => 'radios',
        '#title' => t('Text processing'),
        '#default_value' => is_numeric($field['text_processing']) ? $field['text_processing'] : 0,
        '#options' => $options,
      );
      $form['max_length'] = array(
        '#type' => 'textfield',
        '#title' => t('Maximum length'),
        '#default_value' => is_numeric($field['max_length']) ? $field['max_length'] : '',
        '#required' => FALSE,
        '#description' => t('The maximum length of the field in characters. Leave blank for an unlimited size.'),
      );
      $form['allowed_values'] = array(
        '#type' => 'textarea',
        '#title' => t('Allowed values list'),
        '#default_value' => !empty($field['allowed_values']) ? $field['allowed_values'] : '',
        '#required' => FALSE,
        '#rows' => 10,
        '#description' => t('The possible values this field can contain. Enter one value per line, in the format key|label. The key is the value that will be stored in the database and it must match the field storage type, %type. The label is optional and the key will be used as the label if no label is specified.', array(
          '%type' => $field['type'],
        )),
      );
      $form['advanced_options'] = array(
        '#type' => 'fieldset',
        '#title' => t('PHP code'),
        '#collapsible' => TRUE,
        '#collapsed' => TRUE,
      );
      $form['advanced_options']['allowed_values_php'] = array(
        '#type' => 'textarea',
        '#title' => t('Code'),
        '#default_value' => !empty($field['allowed_values_php']) ? $field['allowed_values_php'] : '',
        '#rows' => 6,
        '#description' => t('Advanced usage only: PHP code that returns a keyed array of allowed values. Should not include &lt;?php ?&gt; delimiters. If this field is filled out, the array returned by this code will override the allowed values list above.'),
      );
      return $form;
    case 'save':
      return array(
        'text_processing',
        'max_length',
        'allowed_values',
        'allowed_values_php',
      );
    case 'database columns':
      if (empty($field['max_length']) || $field['max_length'] > 255) {
        $columns['value'] = array(
          'type' => 'text',
          'size' => 'big',
          'not null' => FALSE,
          'sortable' => TRUE,
        );
      }
      else {
        $columns['value'] = array(
          'type' => 'varchar',
          'length' => $field['max_length'],
          'not null' => FALSE,
          'sortable' => TRUE,
        );
      }
      if (!empty($field['text_processing'])) {
        $columns['format'] = array(
          'type' => 'int',
          'unsigned' => TRUE,
          'not null' => FALSE,
        );
      }
      return $columns;
    case 'filters':
      $allowed_values = content_allowed_values($field);
      if (count($allowed_values)) {
        return array(
          'default' => array(
            'list' => $allowed_values,
            'list-type' => 'list',
            'operator' => 'views_handler_operator_or',
            'value-type' => 'array',
          ),
        );
      }
      else {
        return array(
          'like' => array(
            'operator' => 'views_handler_operator_like',
            'handler' => 'views_handler_filter_like',
          ),
        );
      }
      break;
  }
}

/**
 * Implementation of hook_field().
 *
 * Define the behavior of a field type.
 *
 * @param $op
 *   What kind of action is being performed. Possible values:
 *   - "load": The node is about to be loaded from the database. This hook
 *     should be used to load the field.
 *   - "validate": The user has just finished editing the node and is
 *     trying to preview or submit it. This hook can be used to check or
 *     even modify the node. Errors should be set with form_set_error().
 *   - "presave": The user has just finished editing the node and the node has
 *     passed validation. This hook can be used to modify the node.
 *   - "insert": The node is being created (inserted in the database).
 *   - "update": The node is being updated.
 *   - "delete": The node is being deleted.
 * @param &$node
 *   The node the action is being performed on. This argument is passed by
 *   reference for performance only; do not modify it.
 * @param $field
 *   The field the action is being performed on.
 * @param &$node_field
 *   The contents of the field in this node. Changes to this variable will
 *   be saved back to the node object.
 * @return
 *   This varies depending on the operation.
 *   - The "load" operation should return an object containing extra values
 *     to be merged into the node object.
 *   - The "insert", "update", "delete", "validate", and "presave" operations
 *     have no return value.
 *
 * In most cases, only "validate" operations is relevant ; the rest
 * have default implementations in content_field() that usually suffice.
 */
function text_field($op, &$node, $field, &$items, $teaser, $page) {
  switch ($op) {
    case 'validate':
      $allowed_values = content_allowed_values($field);
      if (is_array($items)) {
        foreach ($items as $delta => $item) {
          $error_field = $field['field_name'] . '][' . $delta . '][value';
          if ($item['value'] != '') {
            if (count($allowed_values) && !array_key_exists($item['value'], $allowed_values)) {
              form_set_error($error_field, t('Illegal value for %name.', array(
                '%name' => t($field['widget']['label']),
              )));
            }
          }
        }
      }
      if (!empty($field['max_length'])) {
        foreach ($items as $delta => $data) {
          $error_field = $field['field_name'] . '][' . $delta . '][value';
          if (strlen($data['value']) > $field['max_length']) {
            form_set_error($error_field, t('%label is longer than %max characters.', array(
              '%label' => $field['widget']['label'],
              '%max' => $field['max_length'],
            )));
          }
        }
      }
      break;
  }
}

/**
 * Implementation of hook_content_is_empty().
 *
 * NEW REQUIRED HOOK!
 *
 * This function tells the content module whether or not to consider
 * the $item to be empty. This is used by the content module
 * to remove empty, non-required values before saving them.
 */
function text_content_is_empty($item, $field) {
  if (empty($item['value'])) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Implementation of hook_field_formatter_info().
 *
 * The default behavior of formatters is that they will create
 * a theme for a single field value.
 *
 * Setting 'multiple values' to CONTENT_HANDLE_FIELD will create
 * a formatter that will receive all the values of a field so you
 * can, for instance, plot all the values on a map or in a graph.
 *
 * The 'view' operation (handled by the Content module) constructs the
 * $node in a way that you can use drupal_render() to display the
 * formatted output for an individual field.
 *
 * i.e. print drupal_render($node->field_foo);
 *
 * The code now supports both single value formatters, which theme an
 * individual item value as has been done in previous version of CCK,
 * and multiple value formatters, which theme all values for the field
 * in a single theme. The multiple value formatters could be used, for
 * instance, to plot field values on a single map or display them
 * in a graph. Single value formatters are the default, multiple value
 * formatters can be designated as such in formatter_info().
 *
 * The node array will look like:
 *
 *  'Single value' formatter :
 *   $node->content['field_foo'] = array(
 *     '#type' => 'content_field_view',
 *     '#title' => 'label'
 *     '#field_name' => 'field_name',
 *     '#node' => $node,
 *     'items' =>
 *       0 => array(
 *         '#theme' => $theme,
 *         '#field_name' => 'field_name',
 *         '#type_name' => $node->type,
 *         '#formatter' => $formatter_name,
 *         '#item' => $items[0],
 *       ),
 *       1 => array(
 *         '#theme' => $theme,
 *         '#field_name' => 'field_name',
 *         '#type_name' => $node->type,
 *         '#formatter' => $formatter_name,
 *         '#item' => $items[1],
 *       ),
 *     ),
 *   );
 *  'Multiple value' formatter :
 *   $node->content['field_foo'] = array(
 *     '#type' => 'content_field_view',
 *     '#title' => 'label'
 *     '#field_name' => 'field_name',
 *     '#node' => $node,
 *     'items' => array(
 *       '#theme' => $theme,
 *       '#field_name' => 'field_name',
 *       '#type_name' => $node->type,
 *       '#formatter' => $formatter_name,
 *       0 => array(
 *         '#item' => $items[0],
 *       ),
 *       1 => array(
 *         '#item' => $items[1],
 *       ),
 *     ),
 *   );
 */
function text_field_formatter_info() {
  return array(
    'default' => array(
      'label' => t('Default'),
      'field types' => array(
        'text',
      ),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
    'plain' => array(
      'label' => t('Plain text'),
      'field types' => array(
        'text',
      ),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
    'trimmed' => array(
      'label' => t('Trimmed'),
      'field types' => array(
        'text',
      ),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
  );
}

/**
 * Implementation of hook_field_formatter().
 *
 * Prepare an individual item for viewing in a browser.
 *
 * @param $field
 *   The field the action is being performed on.
 * @param $item
 *   An array, keyed by column, of the data stored for this item in this field.
 * @param $formatter
 *   The name of the formatter being used to display the field.
 * @param $node
 *   The node object, for context. Will be NULL in some cases.
 *   Warning : when displaying field retrieved by Views, $node will not
 *   be a "full-fledged" node object, but an object containg the data returned
 *   by the Views query (at least nid, vid, changed)
 * @return
 *   An HTML string containing the formatted item.
 *
 * In a multiple-value field scenario, this function will be called once per
 * value currently stored in the field. This function is also used as the handler
 * for viewing a field in a views.module tabular listing.
 *
 * It is important that this function at the minimum perform security
 * transformations such as running check_plain() or check_markup().
 */
function text_field_formatter($field, $item, $formatter, $node) {
  if (!isset($item['value'])) {
    return '';
  }
  $allowed_values = content_allowed_values($field);
  if (!empty($allowed_values) && isset($allowed_values[$item['value']])) {
    return $allowed_values[$item['value']];
  }
  switch ($formatter) {
    case 'plain':
      $text = strip_tags($item['value']);
      break;
    case 'trimmed':
      $text = node_teaser($item['value'], $field['text_processing'] ? $item['format'] : NULL);
      break;
    case 'default':
      $text = $item['value'];
  }

  // TODO : undefined index text_processing / format on node preview
  if ($field['text_processing']) {
    return check_markup($text, $item['format'], is_null($node) || $node->build_mode == NODE_BUILD_PREVIEW);
  }
  else {
    return check_plain($text);
  }
}

/**
 * Implementation of hook_widget_info().
 *
 * Here we indicate that the content module will handle
 * the default value and multiple values for these widgets.
 *
 * Callbacks can be omitted if default handing is used.
 * They're included here just so this module can be used
 * as an example for custom modules that might do things
 * differently.
 *
 * IMPORTANT! - field and widget names will be truncated to 32 characters in
 * the database and in internal arrays, like content_fields().
 */
function text_widget_info() {
  return array(
    'text_textfield' => array(
      'label' => t('Text field'),
      'field types' => array(
        'text',
      ),
      'multiple values' => CONTENT_HANDLE_CORE,
      'callbacks' => array(
        'default value' => CONTENT_CALLBACK_DEFAULT,
      ),
    ),
    'text_textarea' => array(
      'label' => t('Text area'),
      'field types' => array(
        'text',
      ),
      'multiple values' => CONTENT_HANDLE_CORE,
      'callbacks' => array(
        'default value' => CONTENT_CALLBACK_DEFAULT,
      ),
    ),
  );
}

/**
 * Implementation of FAPI hook_elements().
 *
 * Any FAPI callbacks needed for individual widgets can be declared here,
 * and the element will be passed to those callbacks for processing.
 *
 * Drupal will automatically theme the element using a theme with
 * the same name as the hook_elements key.
 *
 * Autocomplete_path is not used by text_widget but other widgets can use it
 * (see nodereference and userreference).
 */
function text_elements() {
  return array(
    'text_textfield' => array(
      '#input' => TRUE,
      '#columns' => array(
        'value',
      ),
      '#delta' => 0,
      '#process' => array(
        'text_textfield_process',
      ),
      '#autocomplete_path' => FALSE,
    ),
    'text_textarea' => array(
      '#input' => TRUE,
      '#columns' => array(
        'value',
        'format',
      ),
      '#delta' => 0,
      '#process' => array(
        'text_textarea_process',
      ),
      '#filter_value' => FILTER_FORMAT_DEFAULT,
    ),
  );
}

/**
 * Implementation of hook_widget_settings().
 *
 * Handle the parameters for a widget.
 *
 * @param $op
 *   The operation to be performed. Possible values:
 *   - "form": Display the widget settings form.
 *   - "validate": Check the widget settings form for errors.
 *   - "save": Declare which pieces of information to save back to the database.
 * @param $widget
 *   The widget on which the operation is to be performed.
 * @return
 *   This varies depending on the operation.
 *   - "form": an array of form elements to add to the settings page.
 *   - "validate": no return value. Use form_set_error().
 *   - "save": an array of names of form elements to be saved in the database.
 */
function text_widget_settings($op, $widget) {
  switch ($op) {
    case 'form':
      $form = array();
      if ($widget['type'] == 'text_textfield') {
        $form['rows'] = array(
          '#type' => 'hidden',
          '#value' => 1,
        );
      }
      else {
        $form['rows'] = array(
          '#type' => 'textfield',
          '#title' => t('Rows'),
          '#default_value' => is_numeric($widget['rows']) ? $widget['rows'] : 5,
          '#required' => TRUE,
        );
      }
      return $form;
    case 'validate':
      if (!is_numeric($widget['rows']) || intval($widget['rows']) != $widget['rows'] || $widget['rows'] <= 0) {
        form_set_error('rows', t('"Rows" must be a positive integer.'));
      }
      break;
    case 'save':
      return array(
        'rows',
      );
  }
}

/**
 * Implementation of hook_widget().
 *
 * Attach a single form element to the form. It will be built out and
 * validated in the callback(s) listed in hook_elements. We build it
 * out in the callbacks rather than here in hook_widget so it can be
 * plugged into any module that can provide it with valid
 * $field information.
 *
 * Content module will set the weight, field name and delta values
 * for each form element. This is a change from earlier CCK versions
 * where the widget managed its own multiple values.
 *
 * If there are multiple values for this field, the content module will
 * call this function as many times as needed.
 *
 * @param $form
 *   the entire form array, $form['#node'] holds node information
 * @param $form_state
 *   the form_state, $form_state['values'][$field['field_name']]
 *   holds the field's form values.
 * @param $field
 *   the field array
 * @param $items
 *   array of default values for this field
 * @param $delta
 *   the order of this item in the array of subelements (0, 1, 2, etc)
 *
 * @return
 *   the form item for a single element for this field
 */
function text_widget(&$form, &$form_state, $field, $items, $delta = 0) {
  $element = array(
    '#type' => $field['widget']['type'],
    '#default_value' => isset($items[$delta]) ? $items[$delta] : '',
  );
  return $element;
}

/**
 * Process an individual element.
 *
 * Build the form element. When creating a form using FAPI #process,
 * note that $element['#value'] is already set.
 *
 * The $fields array is in $form['#field_info'][$element['#field_name']].
 */
function text_textfield_process($element, $edit, $form_state, $form) {
  $field = $form['#field_info'][$element['#field_name']];
  $field_key = $element['#columns'][0];
  $delta = $element['#delta'];
  $element[$field_key] = array(
    '#type' => 'textfield',
    '#title' => t($field['widget']['label']),
    '#description' => t($field['widget']['description']),
    '#required' => $element['#required'],
    '#default_value' => isset($element['#value'][$field_key]) ? $element['#value'][$field_key] : NULL,
    '#autocomplete_path' => $element['#autocomplete_path'],
  );
  if (!empty($field['text_processing'])) {
    $filter_key = $element['#columns'][1];
    $format = isset($element['#value'][$filter_key]) ? $element['#value'][$filter_key] : FILTER_FORMAT_DEFAULT;
    $parents = array_merge($element['#parents'], array(
      $filter_key,
    ));
    $element[$filter_key] = filter_form($format, 1, $parents);
  }
  return $element;
}

/**
 * Process an individual element.
 *
 * Build the form element. When creating a form using FAPI #process,
 * note that $element['#value'] is already set.
 *
 * The $fields array is in $form['#field_info'][$element['#field_name']].
 */
function text_textarea_process($element, $edit, $form_state, $form) {
  $field = $form['#field_info'][$element['#field_name']];
  $field_key = $element['#columns'][0];
  $element[$field_key] = array(
    '#type' => 'textarea',
    '#title' => t($field['widget']['label']),
    '#description' => t($field['widget']['description']),
    '#required' => $element['#required'],
    '#default_value' => isset($element['#value'][$field_key]) ? $element['#value'][$field_key] : NULL,
    '#rows' => !empty($field['widget']['rows']) ? $field['widget']['rows'] : 10,
    '#weight' => 0,
  );
  if (!empty($field['text_processing'])) {
    $filter_key = $element['#columns'][1];
    $format = isset($element['#value'][$filter_key]) ? $element['#value'][$filter_key] : FILTER_FORMAT_DEFAULT;
    $parents = array_merge($element['#parents'], array(
      $filter_key,
    ));
    $element[$filter_key] = filter_form($format, 1, $parents);
  }
  return $element;
}

/**
 * FAPI theme for an individual text elements.
 *
 * The textfield or textarea is already rendered by the
 * textfield or textarea themes and the html output
 * lives in $element['#children']. Override this theme to
 * make custom changes to the output.
 *
 * $element['#field_name'] contains the field name
 * $element['#delta]  is the position of this element in the group
 */
function theme_text_textfield($element) {
  return $element['#children'];
}
function theme_text_textarea($element) {
  return $element['#children'];
}

/**
 * @} End of "addtogroup hooks".
 */

Functions

Name	Description
text_content_is_empty	Implementation of hook_content_is_empty().
text_disable	Implementation of hook_disable().
text_elements	Implementation of FAPI hook_elements().
text_enable	Implementation of hook_enable().
text_field	Implementation of hook_field().
text_field_formatter	Implementation of hook_field_formatter().
text_field_formatter_info	Implementation of hook_field_formatter_info().
text_field_info	Implementation of hook_field_info().
text_field_settings	Implementation of hook_field_settings().
text_install	Implementation of hook_install().
text_textarea_process	Process an individual element.
text_textfield_process	Process an individual element.
text_theme	Implementation of hook_theme().
text_uninstall	Implementation of hook_uninstall().
text_widget	Implementation of hook_widget().
text_widget_info	Implementation of hook_widget_info().
text_widget_settings	Implementation of hook_widget_settings().
theme_text_textarea
theme_text_textfield	FAPI theme for an individual text elements.