form.inc 118 KB
Newer Older
1
<?php
2 3
// $Id$

4
/**
5 6 7 8 9 10
 * @defgroup forms Form builder functions
 * @{
 * Functions that build an abstract representation of a HTML form.
 *
 * All modules should declare their form builder functions to be in this
 * group and each builder function should reference its validate and submit
11
 * functions using \@see. Conversely, validate and submit functions should
12
 * reference the form builder function using \@see. For examples, of this see
13
 * system_modules_uninstall() or user_pass(), the latter of which has the
14 15 16 17 18 19 20 21 22 23 24
 * following in its doxygen documentation:
 *
 * \@ingroup forms
 * \@see user_pass_validate().
 * \@see user_pass_submit().
 *
 * @} End of "defgroup forms".
 */

/**
 * @defgroup form_api Form generation
25
 * @{
26
 * Functions to enable the processing and display of HTML forms.
27
 *
28 29 30 31
 * Drupal uses these functions to achieve consistency in its form processing and
 * presentation, while simplifying code and reducing the amount of HTML that
 * must be explicitly generated by modules.
 *
32
 * The drupal_get_form() function handles retrieving and processing an HTML
33
 * form for modules automatically. For example:
34
 *
35
 * @code
36 37
 *   // Display the user registration form.
 *   $output = drupal_get_form('user_register_form');
38
 * @endcode
39 40
 *
 * Forms can also be built and submitted programmatically without any user input
41
 * using the drupal_form_submit() function.
42 43
 *
 * For information on the format of the structured arrays used to define forms,
44
 * and more detailed explanations of the Form API workflow, see the
45 46
 * @link http://api.drupal.org/api/file/developer/topics/forms_api_reference.html reference @endlink
 * and the @link http://api.drupal.org/api/file/developer/topics/forms_api.html quickstart guide. @endlink
47 48 49
 */

/**
50
 * Wrapper for drupal_build_form() for use when $form_state is not needed.
51 52
 *
 * @param $form_id
53 54 55 56 57 58
 *   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 $form_id values to the
 *   proper form constructor function. Examples may be found in node_forms(),
 *   search_forms(), and user_forms().
59
 * @param ...
60
 *   Any additional arguments are passed on to the functions called by
61 62 63
 *   drupal_get_form(), including the unique form constructor function. For
 *   example, the node_edit form requires that a node object is passed in here
 *   when it is called.
64
 * @return
65
 *   The form array.
66 67
 *
 * @see drupal_build_form()
68 69
 */
function drupal_get_form($form_id) {
70
  $form_state = array();
71 72

  $args = func_get_args();
73 74
  // Remove $form_id from the arguments.
  array_shift($args);
75
  $form_state['build_info']['args'] = $args;
76 77 78 79 80

  return drupal_build_form($form_id, $form_state);
}

/**
81
 * Build and process a form based on a form id.
82 83 84
 *
 * The form may also be retrieved from the cache if the form was built in a
 * previous page-load. The form is then passed on for processing, validation
85
 * and submission if there is proper input.
86 87 88 89 90 91 92 93 94 95
 *
 * @param $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 $form_id values to the
 *   proper form constructor function. Examples may be found in node_forms(),
 *   search_forms(), and user_forms().
 * @param &$form_state
 *   An array which stores information about the form. This is passed as a
96
 *   reference so that the caller can use it to examine what in the form changed
97 98 99
 *   when the form submission process is complete.
 *   The following parameters may be set in $form_state to affect how the form
 *   is rendered:
100 101 102 103 104 105 106
 *   - build_info: A keyed array of build information that is necessary to
 *     rebuild the form from cache when the original context may no longer be
 *     available:
 *     - args: An array of arguments to pass to the form builder.
 *     - file: An optional include file that contains the form and is
 *       automatically loaded by form_get_cache(). Defaults to the current menu
 *       router item's 'file' definition, if existent.
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121
 *   - storage: An array that may be used to store information related to the
 *     processed data in the form, which can be accessed and used within the
 *     same page request, but also persist across multiple steps in a multi-step
 *     form.
 *   - rebuild: Normally, after the entire form processing is completed and
 *     submit handlers ran, a form is considered to be done and
 *     drupal_redirect_form() will redirect the user to a new page using a GET
 *     request (so a browser refresh does not re-submit the form). However, if
 *     'rebuild' has been set to TRUE, then a new copy of the form is
 *     immediately built and sent to the browser; instead of a redirect. This is
 *     used for multi-step forms, such as wizards and confirmation forms. Also,
 *     if a form validation handler has set 'rebuild' to TRUE and a validation
 *     error occurred, then the form is rebuilt prior to being returned,
 *     enabling form elements to be altered, as appropriate to the particular
 *     validation error.
122 123 124 125 126 127 128 129
 *   - input: An array of input that corresponds to $_POST or $_GET, depending
 *     on the 'method' chosen (see below).
 *   - method: The HTTP form method to use for finding the input for this form.
 *     May be 'post' or 'get'. Defaults to 'post'. Note that 'get' method
 *     forms do not use form ids so are always considered to be submitted, which
 *     can have unexpected effects. The 'get' method should only be used on
 *     forms that do not change data, as that is exclusively the domain of post.
 *   - no_redirect: If set to TRUE the form will NOT perform a drupal_goto(),
130 131 132 133 134
 *     even if 'redirect' is set.
 *   - cache: If set to TRUE the original, unprocessed form structure will be
 *     cached, which allows to rebuild the entire form from cache.
 *   - no_cache: If set to TRUE the form will NOT be cached, even if 'cache' is
 *     set.
135 136 137 138 139 140 141 142 143
 *   - always_process: If TRUE and the method is GET, a form_id is not
 *     necessary. This should only be used on RESTful GET forms that do NOT
 *     write data, as this could lead to security issues. It is useful so that
 *     searches do not need to have a form_id in their query arguments to
 *     trigger the search.
 *   - must_validate: Ordinarily, a form is only validated once but there are
 *     times when a form is resubmitted internally and should be validated
 *     again. Setting this to TRUE will force that to happen. This is most
 *     likely to occur during AHAH or AJAX operations.
144 145 146 147
 *   - wrapper_callback: Modules that wish to pre-populate certain forms with
 *     common elements, such as back/next/save buttons in multi-step form
 *     wizards, may define a form builder function name that returns a form
 *     structure, which is passed on to the actual form builder function.
148 149 150 151
 *     Such implementations may either define the 'wrapper_callback' via
 *     hook_forms() or have to invoke drupal_build_form() (instead of
 *     drupal_get_form()) on their own in a custom menu callback to prepare
 *     $form_state accordingly.
152 153 154
 *   Further $form_state properties controlling the redirection behavior after
 *   form submission may be found in drupal_redirect_form().
 *
155 156
 * @return
 *   The rendered form or NULL, depending upon the $form_state flags that were set.
157 158
 *
 * @see drupal_redirect_form()
159 160 161 162 163 164 165 166 167
 */
function drupal_build_form($form_id, &$form_state) {
  // Ensure some defaults; if already set they will not be overridden.
  $form_state += form_state_defaults();

  if (!isset($form_state['input'])) {
    $form_state['input'] = $form_state['method'] == 'get' ? $_GET : $_POST;
  }

168
  $cacheable = FALSE;
169 170 171 172 173 174 175

  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']);
176 177
  }
  else {
178
    // If the incoming input contains a form_build_id, we'll check the
179 180 181 182
    // 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.
183 184
    if (isset($form_state['input']['form_id']) && $form_state['input']['form_id'] == $form_id && !empty($form_state['input']['form_build_id'])) {
      $form = form_get_cache($form_state['input']['form_build_id'], $form_state);
185 186
    }

187 188 189 190
    // 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)) {
191 192
      // Record the filepath of the include file containing the original form,
      // so the form builder callbacks can be loaded when the form is being
193
      // rebuilt from cache on a different path (such as 'system/ajax').
194 195
      // @see form_get_cache()
      // menu_get_item() is not available at installation time.
196
      if (!isset($form_state['build_info']['file']) && !defined('MAINTENANCE_MODE')) {
197 198
        $item = menu_get_item();
        if (!empty($item['file'])) {
199
          $form_state['build_info']['file'] = $item['file'];
200 201 202
        }
      }

203 204 205 206
      $form = drupal_retrieve_form($form_id, $form_state);
      $form_build_id = 'form-' . md5(uniqid(mt_rand(), TRUE));
      $form['#build_id'] = $form_build_id;

207 208 209 210 211
      // Fix the form method, if it is 'get' in $form_state, but not in $form.
      if ($form_state['method'] == 'get' && !isset($form['#method'])) {
        $form['#method'] = 'get';
      }

212
      drupal_prepare_form($form_id, $form, $form_state);
213
      // Store a copy of the unprocessed form for caching and indicate that it
214
      // is cacheable in case $form_state['cache'] is set.
215 216
      $original_form = $form;
      $cacheable = TRUE;
217
    }
218

219 220 221 222 223 224
    // 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);
225

226 227 228 229 230
    // After processing the form, the form builder or a #process callback may
    // have set $form_state['cache'] to indicate that the original form and the
    // $form_state shall be cached. But the form may only be cached if the
    // special 'no_cache' property is not set to TRUE.
    if ($cacheable && !empty($form_state['cache']) && empty($form_state['no_cache'])) {
231
      form_set_cache($form_build_id, $original_form, $form_state);
232
    }
233 234 235 236 237 238 239 240 241
  }

  // 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.
  //
242 243 244 245
  // If $form_state['rebuild'] has been set and the form has been submitted, we
  // know that we're in a 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 $form_state in addition to any other variables passed
246
  // into drupal_get_form().
247
  if ($form_state['rebuild'] && $form_state['submitted'] && !form_get_errors()) {
248
    $form = drupal_rebuild_form($form_id, $form_state);
249
  }
250

251 252
  // Don't override #theme if someone already set it.
  if (!isset($form['#theme'])) {
253
    drupal_theme_initialize();
254 255 256 257 258
    $registry = theme_get_registry();
    if (isset($registry[$form_id])) {
      $form['#theme'] = $form_id;
    }
  }
259

260
  return $form;
261
}
262

263 264 265 266 267
/**
 * Retrieve default values for the $form_state array.
 */
function form_state_defaults() {
  return array(
268
    'args' => array(),
269 270
    'rebuild' => FALSE,
    'redirect' => NULL,
271
    'build_info' => array(),
272
    'storage' => array(),
273 274
    'submitted' => FALSE,
    'programmed' => FALSE,
275 276
    'cache'=> FALSE,
    'method' => 'post',
277
    'groups' => array(),
278 279 280
  );
}

281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311
/**
 * Retrieves a form, caches it and processes it with an empty $_POST.
 *
 * This function clears $_POST and passes the empty $_POST to the form_builder.
 * To preserve some parts from $_POST, pass them in $form_state.
 *
 * If your AHAH callback simulates the pressing of a button, then your AHAH
 * callback will need to do the same as what drupal_get_form would do when the
 * button is pressed: get the form from the cache, run drupal_process_form over
 * it and then if it needs rebuild, run drupal_rebuild_form over it. Then send
 * back a part of the returned form.
 * $form_state['clicked_button']['#array_parents'] will help you to find which
 * part.
 *
 * @param $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().
 * @param $form_state
 *   A keyed array containing the current state of the form. Most
 *   important is the $form_state['storage'] collection.
 * @param $form_build_id
 *   If the AHAH callback calling this function only alters part of the form,
 *   then pass in the existing form_build_id so we can re-cache with the same
 *   csid.
 * @return
 *   The newly built form.
 */
312 313
function drupal_rebuild_form($form_id, &$form_state, $form_build_id = NULL) {
  $form = drupal_retrieve_form($form_id, $form_state);
314 315 316

  if (!isset($form_build_id)) {
    // We need a new build_id for the new version of the form.
317
    $form_build_id = 'form-' . md5(mt_rand());
318 319 320 321
  }
  $form['#build_id'] = $form_build_id;
  drupal_prepare_form($form_id, $form, $form_state);

322
  if (empty($form_state['no_cache'])) {
323 324 325 326 327
    // We cache the form structure so it can be retrieved later for validation.
    // If $form_state['storage'] is populated, we also cache it so that it can
    // be used to resume complex multi-step processes.
    form_set_cache($form_build_id, $form, $form_state);
  }
328 329 330 331

  // Clear out all post data, as we don't want the previous step's
  // data to pollute this one and trigger validate/submit handling,
  // then process the form for rendering.
332 333
  $form_state['input'] = array();

334 335 336 337
  // Also clear out all group associations as these might be different
  // when rerendering the form.
  $form_state['groups'] = array();

338 339 340
  // Do not call drupal_process_form(), since it would prevent the rebuilt form
  // to submit.
  $form = form_builder($form_id, $form, $form_state);
341 342 343
  return $form;
}

344 345 346 347
/**
 * Fetch a form from cache.
 */
function form_get_cache($form_build_id, &$form_state) {
348
  if ($cached = cache_get('form_' . $form_build_id, 'cache_form')) {
349
    $form = $cached->data;
350

351 352
    global $user;
    if ((isset($form['#cache_token']) && drupal_valid_token($form['#cache_token'])) || (!isset($form['#cache_token']) && !$user->uid)) {
353 354 355 356 357 358 359 360 361 362
      if ($cached = cache_get('form_state_' . $form_build_id, 'cache_form')) {
        // Re-populate $form_state for subsequent rebuilds.
        $form_state['build_info'] = $cached->data['build_info'];
        $form_state['storage'] = $cached->data['storage'];

        // If the original form is contained in an include file, load the file.
        // @see drupal_build_form()
        if (!empty($form_state['build_info']['file']) && file_exists($form_state['build_info']['file'])) {
          require_once DRUPAL_ROOT . '/' . $form_state['build_info']['file'];
        }
363 364
      }
      return $form;
365 366 367 368 369
    }
  }
}

/**
370
 * Store a form in the cache.
371 372
 */
function form_set_cache($form_build_id, $form, $form_state) {
373 374
  // 6 hours cache life time for forms should be plenty.
  $expire = 21600;
375 376 377 378
  global $user;
  if ($user->uid) {
    $form['#cache_token'] = drupal_get_token();
  }
379
  cache_set('form_' . $form_build_id, $form, 'cache_form', REQUEST_TIME + $expire);
380 381 382 383 384 385
  if (!empty($form_state['build_info']) || !empty($form_state['storage'])) {
    $data = array(
      'build_info' => $form_state['build_info'],
      'storage' => $form_state['storage'],
    );
    cache_set('form_state_' . $form_build_id, $data, 'cache_form', REQUEST_TIME + $expire);
386 387 388
  }
}

389
/**
390
 * Retrieves a form using a form_id, populates it with $form_state['values'],
391 392 393 394 395 396 397 398
 * processes it, and returns any validation errors encountered. This
 * function is the programmatic counterpart to drupal_get_form().
 *
 * @param $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
399
 *   different $form_id values to the proper form constructor function. Examples
400
 *   may be found in node_forms(), search_forms(), and user_forms().
401 402 403 404 405
 * @param $form_state
 *   A keyed array containing the current state of the form. Most
 *   important is the $form_state['values'] collection, a tree of data
 *   used to simulate the incoming $_POST information from a user's
 *   form submission.
406
 * @param ...
407
 *   Any additional arguments are passed on to the functions called by
408
 *   drupal_form_submit(), including the unique form constructor function.
409 410
 *   For example, the node_edit form requires that a node object be passed
 *   in here when it is called.
411 412
 * For example:
 *
413
 * @code
414
 * // register a new user
415 416 417 418
 * $form_state = array();
 * $form_state['values']['name'] = 'robo-user';
 * $form_state['values']['mail'] = 'robouser@example.com';
 * $form_state['values']['pass'] = 'password';
419
 * $form_state['values']['op'] = t('Create new account');
420
 * drupal_form_submit('user_register_form', $form_state);
421 422
 *
 * // Create a new node
423
 * $form_state = array();
424
 * module_load_include('inc', 'node', 'node.pages');
425
 * $node = array('type' => 'story');
426 427 428
 * $form_state['values']['title'] = 'My node';
 * $form_state['values']['body'] = 'This is the body text!';
 * $form_state['values']['name'] = 'robo-user';
429
 * $form_state['values']['op'] = t('Save');
430
 * drupal_form_submit('story_node_form', $form_state, (object)$node);
431
 * @endcode
432
 */
433
function drupal_form_submit($form_id, &$form_state) {
434
  if (!isset($form_state['build_info']['args'])) {
435 436 437
    $args = func_get_args();
    array_shift($args);
    array_shift($args);
438
    $form_state['build_info']['args'] = $args;
439
  }
Dries's avatar
Dries committed
440

441 442 443
  $form = drupal_retrieve_form($form_id, $form_state);
  $form_state['input'] = $form_state['values'];
  $form_state['programmed'] = TRUE;
444 445
  // Programmed forms are always submitted.
  $form_state['submitted'] = TRUE;
446 447
  // Merge in default values.
  $form_state += form_state_defaults();
448

449 450
  drupal_prepare_form($form_id, $form, $form_state);
  drupal_process_form($form_id, $form, $form_state);
451 452
}

453 454 455 456 457 458 459 460
/**
 * Retrieves the structured array that defines a given form.
 *
 * @param $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
461
 *   different $form_id values to the proper form constructor function.
462 463
 * @param $form_state
 *   A keyed array containing the current state of the form.
464
 * @param ...
465 466
 *   Any additional arguments needed by the unique form constructor
 *   function. Generally, these are any arguments passed into the
467
 *   drupal_get_form() or drupal_form_submit() functions after the first
468 469 470
 *   argument. If a module implements hook_forms(), it can examine
 *   these additional arguments and conditionally return different
 *   builder functions as well.
471
 */
472
function drupal_retrieve_form($form_id, &$form_state) {
473
  $forms = &drupal_static(__FUNCTION__);
474

475
  // We save two copies of the incoming arguments: one for modules to use
476
  // when mapping form ids to constructor functions, and another to pass to
477
  // the constructor function itself.
478
  $args = $form_state['build_info']['args'];
479 480 481

  // We first check to see if there's a function named after the $form_id.
  // If there is, we simply pass the arguments on to it to get the form.
482
  if (!function_exists($form_id)) {
483
    // In cases where many form_ids need to share a central constructor function,
484
    // such as the node editing form, modules can implement hook_forms(). It
485
    // maps one or more form_ids to the correct constructor functions.
486 487 488 489 490 491 492 493 494
    //
    // We cache the results of that hook to save time, but that only works
    // for modules that know all their form_ids in advance. (A module that
    // adds a small 'rate this comment' form to each comment in a list
    // would need a unique form_id for each one, for example.)
    //
    // So, we call the hook if $forms isn't yet populated, OR if it doesn't
    // yet have an entry for the requested form_id.
    if (!isset($forms) || !isset($forms[$form_id])) {
495
      $forms = module_invoke_all('forms', $form_id, $args);
496 497 498 499 500 501 502 503
    }
    $form_definition = $forms[$form_id];
    if (isset($form_definition['callback arguments'])) {
      $args = array_merge($form_definition['callback arguments'], $args);
    }
    if (isset($form_definition['callback'])) {
      $callback = $form_definition['callback'];
    }
504 505 506 507 508
    // In case $form_state['wrapper_callback'] is not defined already, we also
    // allow hook_forms() to define one.
    if (!isset($form_state['wrapper_callback']) && isset($form_definition['wrapper_callback'])) {
      $form_state['wrapper_callback'] = $form_definition['wrapper_callback'];
    }
509
  }
510

511 512 513 514 515 516
  $form = array();
  // We need to pass $form_state by reference in order for forms to modify it,
  // since call_user_func_array() requires that referenced variables are passed
  // explicitly.
  $args = array_merge(array($form, &$form_state), $args);

517 518 519 520 521 522 523 524
  // When the passed $form_state (not using drupal_get_form()) defines a
  // 'wrapper_callback', then it requests to invoke a separate (wrapping) form
  // builder function to pre-populate the $form array with form elements, which
  // the actual form builder function ($callback) expects. This allows for
  // pre-populating a form with common elements for certain forms, such as
  // back/next/save buttons in multi-step form wizards.
  // @see drupal_build_form()
  if (isset($form_state['wrapper_callback']) && function_exists($form_state['wrapper_callback'])) {
525 526 527
    $form = call_user_func_array($form_state['wrapper_callback'], $args);
    // Put the prepopulated $form into $args.
    $args[0] = $form;
528
  }
529

530 531
  // If $callback was returned by a hook_forms() implementation, call it.
  // Otherwise, call the function named after the form id.
532
  $form = call_user_func_array(isset($callback) ? $callback : $form_id, $args);
533
  $form['#form_id'] = $form_id;
534

535
  return $form;
536 537 538
}

/**
539 540
 * Processes a form submission.
 *
541 542 543 544 545
 * This function is the heart of form API. The form gets built, validated and in
 * appropriate cases, submitted.
 *
 * @param $form_id
 *   The unique string identifying the current form.
546 547
 * @param $form
 *   An associative array containing the structure of the form.
548 549
 * @param $form_state
 *   A keyed array containing the current state of the form. This
Dries's avatar
Dries committed
550
 *   includes the current persistent storage data for the form, and
551 552 553
 *   any data passed along by earlier steps when displaying a
 *   multi-step form. Additional information, like the sanitized $_POST
 *   data, is also accumulated here.
554
 */
555 556 557
function drupal_process_form($form_id, &$form, &$form_state) {
  $form_state['values'] = array();

558 559 560 561 562 563 564 565 566 567 568 569 570
  // With $_GET, these forms are always submitted if requested.
  if ($form_state['method'] == 'get' && !empty($form_state['always_process'])) {
    if (!isset($form_state['input']['form_build_id'])) {
      $form_state['input']['form_build_id'] = $form['#build_id'];
    }
    if (!isset($form_state['input']['form_id'])) {
      $form_state['input']['form_id'] = $form_id;
    }
    if (!isset($form_state['input']['form_token']) && isset($form['#token'])) {
      $form_state['input']['form_token'] = drupal_get_token($form['#token']);
    }
  }

571
  // Build the form.
572
  $form = form_builder($form_id, $form, $form_state);
573 574 575

  // Only process the input if we have a correct form submission.
  if ($form_state['process_input']) {
576 577
    drupal_validate_form($form_id, $form, $form_state);

578
    // drupal_html_id() maintains a cache of element IDs it has seen,
579
    // so it can prevent duplicates. We want to be sure we reset that
580
    // cache when a form is processed, so scenarios that result in
581 582
    // the form being built behind the scenes and again for the
    // browser don't increment all the element IDs needlessly.
583
    drupal_static_reset('drupal_html_id');
584

585 586
    if ($form_state['submitted'] && !form_get_errors() && !$form_state['rebuild']) {
      // Execute form submit handlers.
587 588 589 590 591
      form_execute_handlers('submit', $form, $form_state);

      // We'll clear out the cached copies of the form and its stored data
      // here, as we've finished with them. The in-memory copies are still
      // here, though.
592
      if (variable_get('cache', CACHE_DISABLED) == CACHE_DISABLED && !empty($form_state['values']['form_build_id'])) {
593 594
        cache_clear_all('form_' . $form_state['values']['form_build_id'], 'cache_form');
        cache_clear_all('storage_' . $form_state['values']['form_build_id'], 'cache_form');
595 596 597
      }

      // If batches were set in the submit handlers, we process them now,
598 599
      // possibly ending execution. We make sure we do not react to the batch
      // that is already being processed (if a batch operation performs a
600
      // drupal_form_submit).
601
      if ($batch =& batch_get() && !isset($batch['current_set'])) {
602
        // The batch uses its own copies of $form and $form_state for
603
        // late execution of submit handlers and post-batch redirection.
604 605
        $batch['form'] = $form;
        $batch['form_state'] = $form_state;
606
        $batch['progressive'] = !$form_state['programmed'];
607
        batch_process();
608 609 610 611
        // Execution continues only for programmatic forms.
        // For 'regular' forms, we get redirected to the batch processing
        // page. Form redirection will be handled in _batch_finished(),
        // after the batch is processed.
612
      }
613

614 615 616
      // Set a flag to indicate the the form has been processed and executed.
      $form_state['executed'] = TRUE;

617 618
      // Redirect the form based on values in $form_state.
      drupal_redirect_form($form_state);
619 620 621 622 623 624 625 626 627 628 629 630 631 632
    }
  }
}

/**
 * Prepares a structured form array by adding required elements,
 * executing any hook_form_alter functions, and optionally inserting
 * a validation token to prevent tampering.
 *
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 * @param $form
 *   An associative array containing the structure of the form.
633 634 635
 * @param $form_state
 *   A keyed array containing the current state of the form. Passed
 *   in here so that hook_form_alter() calls can use it, as well.
636
 */
637
function drupal_prepare_form($form_id, &$form, &$form_state) {
638 639
  global $user;

640
  $form['#type'] = 'form';
641
  $form_state['programmed'] = isset($form_state['programmed']) ? $form_state['programmed'] : FALSE;
642

643 644 645 646 647 648 649 650 651
  if (isset($form['#build_id'])) {
    $form['form_build_id'] = array(
      '#type' => 'hidden',
      '#value' => $form['#build_id'],
      '#id' => $form['#build_id'],
      '#name' => 'form_build_id',
    );
  }

652 653 654 655
  // Add a token, based on either #token or form_id, to any form displayed to
  // authenticated users. This ensures that any submitted form was actually
  // requested previously by the user and protects against cross site request
  // forgeries.
656
  if (isset($form['#token'])) {
657
    if ($form['#token'] === FALSE || $user->uid == 0 || $form_state['programmed']) {
658
      unset($form['#token']);
659
    }
660
    else {
661
      $form['form_token'] = array('#type' => 'token', '#default_value' => drupal_get_token($form['#token']));
662
    }
663
  }
664
  elseif (isset($user->uid) && $user->uid && !$form_state['programmed']) {
665 666
    $form['#token'] = $form_id;
    $form['form_token'] = array(
667
      '#id' => drupal_html_id('edit-' . $form_id . '-form-token'),
668 669 670 671 672
      '#type' => 'token',
      '#default_value' => drupal_get_token($form['#token']),
    );
  }

673
  if (isset($form_id)) {
674 675 676
    $form['form_id'] = array(
      '#type' => 'hidden',
      '#value' => $form_id,
677
      '#id' => drupal_html_id("edit-$form_id"),
678
    );
679
  }
680
  if (!isset($form['#id'])) {
681
    $form['#id'] = drupal_html_id($form_id);
682
  }
683

684
  $form += element_info('form');
685
  $form += array('#tree' => FALSE, '#parents' => array());
686

Dries's avatar
Dries committed
687
  if (!isset($form['#validate'])) {
688
    if (function_exists($form_id . '_validate')) {
689
      $form['#validate'] = array($form_id . '_validate');
Dries's avatar
Dries committed
690 691 692
    }
  }

693
  if (!isset($form['#submit'])) {
694
    if (function_exists($form_id . '_submit')) {
695
      // We set submit here so that it can be altered.
696
      $form['#submit'] = array($form_id . '_submit');
Dries's avatar
Dries committed
697 698 699
    }
  }

700 701 702 703 704
  // Invoke hook_form_FORM_ID_alter() implementations.
  drupal_alter('form_' . $form_id, $form, $form_state);

  // Invoke hook_form_alter() implementations.
  drupal_alter('form', $form, $form_state, $form_id);
705 706
}

707 708

/**
709
 * Validates user-submitted form data from the $form_state using
710 711 712 713 714 715 716
 * the validate functions defined in a structured form array.
 *
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 * @param $form
 *   An associative array containing the structure of the form.
717 718 719 720 721 722 723 724 725 726
 * @param $form_state
 *   A keyed array containing the current state of the form. The current
 *   user-submitted data is stored in $form_state['values'], though
 *   form validation functions are passed an explicit copy of the
 *   values for the sake of simplicity. Validation handlers can also
 *   $form_state to pass information on to submit handlers. For example:
 *     $form_state['data_for_submision'] = $data;
 *   This technique is useful when validation requires file parsing,
 *   web service requests, or other expensive requests that should
 *   not be repeated in the submission step.
727
 */
728
function drupal_validate_form($form_id, $form, &$form_state) {
729
  $validated_forms = &drupal_static(__FUNCTION__, array());
730

731
  if (isset($validated_forms[$form_id]) && empty($form_state['must_validate'])) {
732 733
    return;
  }
734

735
  // If the session token was set by drupal_prepare_form(), ensure that it
736
  // matches the current user's session.
737
  if (isset($form['#token'])) {
738
    if (!drupal_valid_token($form_state['values']['form_token'], $form['#token'])) {
739
      // Setting this error will cause the form to fail validation.
740
      form_set_error('form_token', t('Validation error, please try again. If this error persists, please contact the site administrator.'));
741 742 743
    }
  }

744
  _form_validate($form, $form_state, $form_id);
745
  $validated_forms[$form_id] = TRUE;
746 747
}

748
/**
749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774
 * Redirects the user to a URL after a form has been processed.
 *
 * After a form was executed, the data in $form_state controls whether the form
 * is redirected. By default, we redirect to a new destination page. The path of
 * the destination page can be set in $form_state['redirect']. If that is not
 * set, the user is redirected to the current page to display a fresh,
 * unpopulated copy of the form.
 *
 * There are several triggers that may prevent a redirection though:
 * - If $form_state['redirect'] is FALSE, a form builder function or form
 *   validation/submit handler does not want a user to be redirected, which
 *   means that drupal_goto() is not invoked. For most forms, the redirection
 *   logic will be the same regardless of whether $form_state['redirect'] is
 *   undefined or FALSE. However, in case it was not defined and the current
 *   request contains a 'destination' query string, drupal_goto() will redirect
 *   to that given destination instead. Only setting $form_state['redirect'] to
 *   FALSE will prevent any redirection.
 * - If $form_state['no_redirect'] is TRUE, then the callback that originally
 *   built the form explicitly disallows any redirection, regardless of the
 *   redirection value in $form_state['redirect']. For example, ajax_get_form()
 *   defines $form_state['no_redirect'] when building a form in an AJAX
 *   callback to prevent any redirection. $form_state['no_redirect'] should NOT
 *   be altered by form builder functions or form validation/submit handlers.
 * - If $form_state['programmed'] is TRUE, the form submission was usually
 *   invoked via drupal_form_submit(), so any redirection would break the script
 *   that invoked drupal_form_submit().
775
 * - If $form_state['rebuild'] is TRUE, the form needs to be rebuilt without
776
 *   redirection.
777
 *
778 779 780 781 782
 * @param $form_state
 *   A keyed array containing the current state of the form.
 *
 * @see drupal_process_form()
 * @see drupal_build_form()
783
 */
784 785 786 787
function drupal_redirect_form($form_state) {
  // Skip redirection for form submissions invoked via drupal_form_submit().
  if (!empty($form_state['programmed'])) {
    return;
788
  }
789 790
  // Skip redirection if rebuild is activated.
  if (!empty($form_state['rebuild'])) {
791 792 793 794 795
    return;
  }
  // Skip redirection if it was explicitly disallowed.
  if (!empty($form_state['no_redirect'])) {
    return;
796
  }
797 798 799 800 801
  // Only invoke drupal_goto() if redirect value was not set to FALSE.
  if (!isset($form_state['redirect']) || $form_state['redirect'] !== FALSE) {
    if (isset($form_state['redirect'])) {
      if (is_array($form_state['redirect'])) {
        call_user_func_array('drupal_goto', $form_state['redirect']);
802 803
      }
      else {
804 805 806 807
        // This function can be called from the installer, which guarantees
        // that $redirect will always be a string, so catch that case here
        // and use the appropriate redirect function.
        $function = drupal_installation_attempted() ? 'install_goto' : 'drupal_goto';
808
        $function($form_state['redirect']);
809 810 811 812
      }
    }
    drupal_goto($_GET['q']);
  }
813 814
}

815 816 817 818 819 820 821
/**
 * Performs validation on form elements. First ensures required fields are
 * completed, #maxlength is not exceeded, and selected options were in the
 * list of options given to the user. Then calls user-defined validators.
 *
 * @param $elements
 *   An associative array containing the structure of the form.
822 823 824 825 826 827 828 829 830 831
 * @param $form_state
 *   A keyed array containing the current state of the form. The current
 *   user-submitted data is stored in $form_state['values'], though
 *   form validation functions are passed an explicit copy of the
 *   values for the sake of simplicity. Validation handlers can also
 *   $form_state to pass information on to submit handlers. For example:
 *     $form_state['data_for_submision'] = $data;
 *   This technique is useful when validation requires file parsing,
 *   web service requests, or other expensive requests that should
 *   not be repeated in the submission step.
832 833 834 835
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 */
836
function _form_validate($elements, &$form_state, $form_id = NULL) {
837 838
  // Also used in the installer, pre-database setup.
  $t = get_t();
839

840 841 842
  // Recurse through all children.
  foreach (element_children($elements) as $key) {
    if (isset($elements[$key]) && $elements[$key]) {
843
      _form_validate($elements[$key], $form_state);
844 845
    }
  }
846
  // Validate the current input.
847
  if (!isset($elements['#validated']) || !$elements['#validated']) {
848
    if (isset($elements['#needs_validation'])) {
849 850 851 852
      // Make sure a value is passed when the field is required.
      // A simple call to empty() will not cut it here as some fields, like
      // checkboxes, can return a valid value of '0'. Instead, check the
      // length if it's a string, and the item count if it's an array.
853 854 855
      // An unchecked checkbox has a #value of numeric 0, different than string
      // '0', which could be a valid value.
      if ($elements['#required'] && (!count($elements['#value']) || (is_string($elements['#value']) && strlen(trim($elements['#value'])) == 0) || $elements['#value'] === 0)) {
Dries's avatar
Dries committed
856
        form_error($elements, $t('!name field is required.', array('!name' => $elements['#title'])));
857
      }
858

859 860
      // Verify that the value is not longer than #maxlength.
      if (isset($elements['#maxlength']) && drupal_strlen($elements['#value']) > $elements['#maxlength']) {
861
        form_error($elements, $t('!name cannot be longer than %max characters but is currently %length characters long.', array('!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title'], '%max' => $elements['#maxlength'], '%length' => drupal_strlen($elements['#value']))));
862 863
      }

864
      if (isset($elements['#options']) && isset($elements['#value'])) {
865 866 867 868 869 870 871 872 873 874
        if ($elements['#type'] == 'select') {
          $options = form_options_flatten($elements['#options']);
        }
        else {
          $options = $elements['#options'];
        }
        if (is_array($elements['#value'])) {
          $value = $elements['#type'] == 'checkboxes' ? array_keys(array_filter($elements['#value'])) : $elements['#value'];
          foreach ($value as $v) {
            if (!isset($options[$v])) {
875
              form_error($elements, $t('An illegal choice has been detected. Please contact the site administrator.'));
876
              watchdog('form', 'Illegal choice %choice in !name element.', array('%choice' => $v, '!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
877
            }
878 879
          }
        }
880
        elseif (!isset($options[$elements['#value']])) {
881
          form_error($elements, $t('An illegal choice has been detected. Please contact the site administrator.'));
882
          watchdog('form', 'Illegal choice %choice in %name element.', array('%choice' => $elements['#value'], '%name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
883
        }
884 885 886
      }
    }

887
    // Call user-defined form level validators.
888 889 890 891 892 893 894
    if (isset($form_id)) {
      form_execute_handlers('validate', $elements, $form_state);
    }
    // Call any element-specific validators. These must act on the element
    // #value data.
    elseif (isset($elements['#element_validate'])) {
      foreach ($elements['#element_validate'] as $function) {
895
        if (function_exists($function))  {
896
          $function($elements, $form_state, $form_state['complete form']);
897 898 899
        }
      }
    }
900
    $elements['#validated'] = TRUE;
901 902 903
  }
}

904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920
/**
 * A helper function used to execute custom validation and submission
 * handlers for a given form. Button-specific handlers are checked
 * first. If none exist, the function falls back to form-level handlers.
 *
 * @param $type
 *   The type of handler to execute. 'validate' or 'submit' are the
 *   defaults used by Form API.
 * @param $form
 *   An associative array containing the structure of the form.
 * @param $form_state
 *   A keyed array containing the current state of the form. If the user
 *   submitted the form by clicking a button with custom handler functions
 *   defined, those handlers will be stored here.
 */
function form_execute_handlers($type, &$form, &$form_state) {
  $return = FALSE;
921 922
  if (isset($form_state[$type . '_handlers'])) {
    $handlers = $form_state[$type . '_handlers'];
923
  }
924 925
  elseif (isset($form['#' . $type])) {
    $handlers = $form['#' . $type];
926 927 928 929 930 931
  }
  else {
    $handlers = array();
  }

  foreach ($handlers as $function) {
932
    if (function_exists($function))  {
933 934
      // Check to see if a previous _submit handler has set a batch, but
      // make sure we do not react to a batch that is already being processed
935
      // (for instance if a batch operation performs a drupal_form_submit()).
936
      if ($type == 'submit' && ($batch =& batch_get()) && !isset($batch['current_set'])) {
937 938 939
        // Some previous _submit handler has set a batch. We store the call
        // in a special 'control' batch set, for execution at the correct
        // time during the batch processing workflow.
940
        $batch['sets'][] = array('form_submit' => $function);
941 942
      }
      else {
943
        $function($form, $form_state);
944 945 946 947 948 949 950
      }
      $return = TRUE;
    }
  }
  return $return;
}

951
/**
952 953 954 955 956 957 958 959 960
 * File an error against a form element.
 *
 * @param $name
 *   The name of the form element. If the #parents property of your form
 *   element is array('foo', 'bar', 'baz') then you may set an error on 'foo'
 *   or 'foo][bar][baz'. Setting an error on 'foo' sets an error for every
 *   element where the #parents array starts with 'foo'.
 * @param $message
 *   The error message to present to the user.
961 962
 * @param $reset
 *   Reset the form errors static cache.
963 964 965
 * @return
 *   Never use the return value of this function, use form_get_errors and
 *   form_get_error instead.
966
 */
967 968
function form_set_error($name = NULL, $message = '') {
  $form = &drupal_static(__FUNCTION__, array());
969 970
  if (isset($name) && !isset($form[$name])) {
    $form[$name] = $message;
971 972 973
    if ($message) {
      drupal_set_message($message, 'error');
    }
974 975 976 977
  }
  return $form;
}

978 979 980 981 982 983 984
/**
 * Clear all errors against all form elements made by form_set_error().
 */
function form_clear_error() {
  drupal_static_reset('form_set_error');
}

985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009
/**
 * Return an associative array of all errors.
 */
function form_get_errors() {
  $form = form_set_error();
  if (!empty($form)) {
    return $form;
  }
}

/**
 * Return the error message filed against the form with the specified name.
 */
function form_get_error($element) {
  $form = form_set_error();
  $key = $element['#parents'][0];
  if (isset($form[$key])) {
    return $form[$key];
  }
  $key = implode('][', $element['#parents']);
  if (isset($form[$key])) {
    return $form[$key];
  }
}

1010 1011 1012
/**
 * Flag an element as having an error.
 */
1013
function form_error(&$element, $message = '') {
1014
  form_set_error(implode('][', $element['#parents']), $message);
1015 1016 1017
}

/**
1018
 * Walk through the structured form array, adding any required
1019
 * properties to each element and mapping the incoming input
1020 1021
 * data to the proper elements. Also, execute any #process handlers
 * attached to a specific element.
1022 1023
 *
 * @param $form_id
1024 1025
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
1026 1027
 * @param $element
 *   An associative array containing the structure of the current element.
1028 1029 1030 1031 1032
 * @param $form_state
 *   A keyed array containing the current state of the form. In this
 *   context, it is used to accumulate information about which button
 *   was clicked when the form was submitted, as well as the sanitized
 *   $_POST data.
1033
 */
1034
function form_builder($form_id, $element, &$form_state) {
1035
  // Initialize as unprocessed.
1036
  $element['#processed'] = FALSE;
1037

1038
  // Use element defaults.
1039
  if (isset($element['#type']) && ($info = element_info($element['#type']))) {
1040 1041 1042 1043
    // Overlay $info onto $element, retaining preexisting keys in $element.
    $element += $info;
    $element['#defaults_loaded'] = TRUE;
  }
1044 1045 1046 1047 1048
  // Assign basic defaults common for all form elements.
  $element += array(
    '#required' => FALSE,
    '#attributes' => array(),
  );
1049 1050 1051

  // Special handling if we're on the top level form element.
  if (isset($element['#type']) && $element['#type'] == 'form') {
1052
    if (!empty($element['#https']) && variable_get('https', FALSE) &&
1053
        !url_is_external($element['#action'])) {
1054 1055 1056 1057 1058 1059
      global $base_root;

      // Not an external URL so ensure that it is secure.
      $element['#action'] = str_replace('http://', 'https://', $base_root) . $element['#action'];
    }

1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
    // Store a complete copy of the form in form_state prior to building the form.
    $form_state['complete form'] = $element;
    // Set a flag if we have a correct form submission. This is always TRUE for
    // programmed forms coming from drupal_form_submit(), or if the form_id coming
    // from the POST data is set and matches the current form_id.
    if ($form_state['programmed'] || (!empty($form_state['input']) && (isset($form_state['input']['form_id']) && ($form_state['input']['form_id'] == $form_id)))) {
      $form_state['process_input'] = TRUE;
    }
    else {
      $form_state['process_input'] = FALSE;
1070
    }
1071 1072
  }

1073
  if (!isset($element['#id'])) {
1074
    $element['#id'] = drupal_html_id('edit-' . implode('-', $element['#parents']));
1075
  }
1076 1077 1078
  // Handle input elements.
  if (!empty($element['#input'])) {
    _form_builder_handle_input_element($form_id, $element, $form_state);
1079
  }
1080 1081
  // Allow for elements to expand to multiple elements, e.g., radios,
  // checkboxes and files.
1082 1083
  if (isset($element['#process']) && !$element['#processed']) {
    foreach ($element['#process'] as $process) {
1084
      if (function_exists($process)) {
1085
        $element = $process($element, $form_state, $form_state['complete form']);
1086 1087
      }
    }
1088
    $element['#processed'] = TRUE;
1089
  }
1090

1091
  // We start off assuming all form elements are in the correct order.
1092
  $element['#sorted'] = TRUE;
1093

1094
  // Recurse through all child elements.
1095
  $count = 0;
1096
  foreach (element_children($element) as $key) {
1097
    // Don't squash an existing tree value.
1098 1099
    if (!isset($element[$key]['#tree'])) {
      $element[$key]['#tree'] = $element['#tree'];
1100
    }
1101

1102
    // Deny access to child elements if parent is denied.
1103 1104
    if (isset($element['#access']) && !$element['#access']) {
      $element[$key]['#access'] = FALSE;
1105 1106
    }

1107
    // Don't squash existing parents value.
1108
    if (!isset($element[$key]['#parents'])) {
1109 1110
      // Check to see if a tree of child elements is present. If so,
      // continue down the tree if required.
1111
      $element[$key]['#parents'] = $element[$key]['#tree'] && $element['#tree'] ? array_merge($element['#parents'], array($key)) : array($key);
1112
    }
1113 1114 1115 1116
    // Ensure #array_parents follows the actual form structure.
    $array_parents = isset($element['#array_parents']) ? $element['#array_parents'] : array();
    $array_parents[] = $key;
    $element[$key]['#array_parents'] = $array_parents;
1117

1118
    // Assign a decimal placeholder weight to preserve original array order.
1119 1120
    if (!isset($element[$key]['#weight'])) {
      $element[$key]['#weight'] = $count/1000;
1121