Help with ajax callback and drupal_process_form - ajax

Question

I have a form that is added through the nodeapi displayed only on view mode. Users can select an item from a select menu and their choice will automatically get saved to the database with a hook_menu callback on change. If the user has javascript disabled, it'll submit normally with the form api. This is all working fine, but now for security reasons I want to submit the ajax version via the form api too. My form_name_submit is simple like:
function mymodule_test_form_submit($form, &$form_state) {
global $user;
db_query("INSERT INTO {mymodule} (nid, uid, status, created) VALUES (%d, %d, %d, " . time() . ")", $form['#parameters'][2], $user->uid, $form_state['values']['mymodule_status']);
}
My ajax:
$('.mysubmit').css('display', 'none');
$('.myclass').change(function() {
$.ajax({
type: 'POST',
url: Drupal.settings.basePath + 'mymodule/set/' + $nid + '/' + $('.myclass').val(),
dataType: 'json',
data: { 'ajax' : true, 'form_build_id' : $('#mymodule-form input[name=form_build_id]').val() }
});
});
And my callback function:
function mymodule_set($nid, $status) {
$form_build_id = $_POST['form_build_id'];
$form_state = array('storage' => NULL, 'submitted' => FALSE);
$form = form_get_cache($form_build_id, $form_state);
$args = $form['#parameters'];
$form_id = array_shift($args);
$form['#post'] = $_POST;
$form['#redirect'] = FALSE;
$form['#programmed'] = FALSE;
$form_state['post'] = $_POST;
drupal_process_form($form_id, $form, $form_state);
}
Originally my callback function was about the same as my submit function, but now I'm trying to use the submit function with ajax as well. Is this the right way to use drupal_process_form? The form is grabbed from the cache, it get's validated and submitted if no errors? I'm using some code from this tutorial to apply to my situation: http://drupal.org/node/331941 There doesn't seem to be any examples of what I'm trying to do. I also have $form['#cache'] = TRUE; in my form function.
How does drupal_process_form compare the submitted values with the original form to check for integrity? Am I supposed to add my values to the form_state since the form state will be empty with ajax. Been stuck on this for a few days, hopefully someone has experience with this.
Thanks.

Answer 1

I had to do somenthing similar to you in the past and read the same tutorial you posted, unfortunately there isn't much information avalaible about this and it was headache for me to make it work. I don't remember well the details but I was taking a look to the code I wrote and here are a couple of suggestions that may work for you:
Do not submit the form using your own jQuery code, instead use the new "#ahah" property of form elements that can be used for calling your callback in the onchange of the select http://api.drupal.org/api/drupal/developer--topics--forms_api_reference.html/6#ahah
IF you are doing this in a node form, adding the #ahah property in a form alter may not work, I remember having seen an issue about this that wasn't solved at that moment. if this is the case, use this code for attaching the ahah binding, you'll not need "efect", "method" or "progress" since you just want to submit the form, not to change anything about it:
function YOURMODULE_form_alter(&$form, $form_state, $form_id) {
if ('YOURCONTENTTYPE_node_form' == $form_id) {
//the only way I could make it work for exisiting fields is adding the binding "manually"
$ahah_binding = array(
'url' => url('YOURCALLBACKPATH'),
'event' => 'change',
'wrapper' => 'FIELD-wrapper',
'selector' => '#FIELD',
'effect' => 'fade',
'method' => 'replace',
'progress' => array('type' => 'throbber'),
);
drupal_add_js('misc/jquery.form.js');
drupal_add_js('misc/ahah.js');
drupal_add_js(array('ahah' => array('FIELDd' => $ahah_binding)), 'setting');
//force the form to be cached
$form['#cache'] = TRUE;
}
}
Here is my callback function, note that it has some modifications from the tutorial you posted:
function YOURMODULE_js() {
// The form is generated in an include file which we need to include manually.
include_once 'modules/node/node.pages.inc';
// We're starting in step #3, preparing for #4.
//I have to add the 'rebuild' element, if not an empty node was created
$form_state = array('storage' => NULL, 'submitted' => FALSE, 'rebuild' => TRUE);
$form_build_id = $_POST['form_build_id'];
// Step #4.
$form = form_get_cache($form_build_id, $form_state);
// Preparing for #5.
$args = $form['#parameters'];
$form_id = array_shift($args);
$form_state['post'] = $form['#post'] = $_POST;
$form['#programmed'] = $form['#redirect'] = FALSE;
// if you want to do any modification to the form values, this is the place
// Step #5.
drupal_process_form($form_id, $form, $form_state);
// Step #6 and #7 and #8.
$form = drupal_rebuild_form($form_id, $form_state, $args, $form_build_id);
// Final rendering callback.
drupal_json(array('status' => TRUE, 'data' => $output));
}
As I said before there are details that I have forgot but maybe this will help you.
Good Luck.