Contributions API

drupal_get_form

Definition

drupal_get_form($form_id)
6/includes/form.inc, line 68

Description

Retrieves a form from a constructor function, or from the cache if the form was built in a previous page-load. The form is then passesed on for processing, after and rendered for display if necessary.

Parameters

$form_id The unique string identifying the desired form. If a function with that name exists, it is called to build the form array. Modules that need to generate the same form (or very similar forms) using different $form_ids can implement hook_forms(), which maps different $form_id values to the proper form constructor function. Examples may be found in node_forms(), search_forms(), and user_forms().

... Any additional arguments are passed on to the functions called by drupal_get_form(), including the unique form constructor function. For example, the node_edit form requires that a node object be passed in here when it is called.

Return value

The rendered form.

Related topics

Name	Description
Form generation	Functions to enable the processing and display of HTML forms.

Code

<?php
function drupal_get_form($form_id) {
  $form_state = array('storage' => NULL, 'submitted' => FALSE);

  $args = func_get_args();
  $cacheable = FALSE;

  if (isset($_SESSION['batch_form_state'])) {
    // We've been redirected here after a batch processing : the form has
    // already been processed, so we grab the post-process $form_state value
    // and move on to form display. See _batch_finished() function.
    $form_state = $_SESSION['batch_form_state'];
    unset($_SESSION['batch_form_state']);
  }
  else {
    // If the incoming $_POST contains a form_build_id, we'll check the
    // cache for a copy of the form in question. If it's there, we don't
    // have to rebuild the form to proceed. In addition, if there is stored
    // form_state data from a previous step, we'll retrieve it so it can
    // be passed on to the form processing code.
    if (isset($_POST['form_id']) && $_POST['form_id'] == $form_id && !empty($_POST['form_build_id'])) {
      $form = form_get_cache($_POST['form_build_id'], $form_state);
    }

    // If the previous bit of code didn't result in a populated $form
    // object, we're hitting the form for the first time and we need
    // to build it from scratch.
    if (!isset($form)) {
      $form_state['post'] = $_POST;
      // Use a copy of the function's arguments for manipulation
      $args_temp = $args;
      $args_temp[0] = &$form_state;
      array_unshift($args_temp, $form_id);

      $form = call_user_func_array('drupal_retrieve_form', $args_temp);
      $form_build_id = 'form-'. md5(uniqid(mt_rand(), true));
      $form['#build_id'] = $form_build_id;
      drupal_prepare_form($form_id, $form, $form_state);
      // Store a copy of the unprocessed form for caching and indicate that it
      // is cacheable if #cache will be set.
      $original_form = $form;
      $cacheable = TRUE;
      unset($form_state['post']);
    }
    $form['#post'] = $_POST;

    // Now that we know we have a form, we'll process it (validating,
    // submitting, and handling the results returned by its submission
    // handlers. Submit handlers accumulate data in the form_state by
    // altering the $form_state variable, which is passed into them by
    // reference.
    drupal_process_form($form_id, $form, $form_state);
    if ($cacheable && !empty($form['#cache'])) {
      // Caching is done past drupal_process_form so #process callbacks can
      // set #cache. By not sending the form state, we avoid storing
      // $form_state['storage'].
      form_set_cache($form_build_id, $original_form, NULL);
    }
  }

  // Most simple, single-step forms will be finished by this point --
  // drupal_process_form() usually redirects to another page (or to
  // a 'fresh' copy of the form) once processing is complete. If one
  // of the form's handlers has set $form_state['redirect'] to FALSE,
  // the form will simply be re-rendered with the values still in its
  // fields.
  //
  // If $form_state['storage'] or $form_state['rebuild'] have been
  // set by any submit or validate handlers, however, we know that
  // we're in a complex multi-part process of some sort and the form's
  // workflow is NOT complete. We need to construct a fresh copy of
  // the form, passing in the latest $form_state in addition to any
  // other variables passed into drupal_get_form().

  if (!empty($form_state['rebuild']) || !empty($form_state['storage'])) {
    $form = drupal_rebuild_form($form_id, $form_state, $args);
  }

  // If we haven't redirected to a new location by now, we want to
  // render whatever form array is currently in hand.
  return drupal_render_form($form_id, $form);
}
?>