Views Exposed Filter Form Submit handler

Question

I have a Views with an exposed filter block and put the block on the front page.

I use the following code to add a custom submit handler.

function mymodule_form_alter(&$form, &$form_state, $form_id) {
  if($form_id == 'views_exposed_form' )
  {
    array_unshift($form['#submit'], 'manage_custom_filters');
  }
}

function manage_custom_filters($form, &$form_state) {
 dpm($form['#id']);  // output views name
}

Here is the question, whenever i load the front page, the manage_custom_filters get called, i suppose it will be called only when i submit the exposed filter form?

I did the same thing for node form submit, it does not behave like the views exposed filter form. manage_custom_filters only get called when i submit the form.

Is this the correct behavior of views exposed filter form?

How do i differentiate the manage_custom_filters is get called by 'on load' or submit action?

Answer 1

The views exposed form will be submitted every time you view it. If you check the render_exposed_form() you can see they are setting the $form_state['always_process'] => TRUE, this means that the form will be submitted always while processing it. And this is understanable because submitting the exposed form and passing the argument in $GET are the same in view.

Answer 2

As stated above, the form is submitted as soon as you load a page. You have a couple of workarounds here:

1. If you are using Ajax, you could add a custom JavaScript function only fired on submit (so when you load the page it won't occur). Something like this:

   Drupal.behaviors.mymoduleAjaxView = {
     attach: function(context, settings) {
       this.form.submit = customFunction();
       function customFunction() {
           alert('Fired when form is submitted'); 
       }
   }};
   

2. If you don't wish / have to use JavaScript, you could check for a field in your form that, on page load has no value (is empty) but when submitted by a human has a value. E.g.

   function manage_custom_filters($form, &$form_state) {
       if(!empty($form_state['values']['field_name_here']) {
         // Form was human submitted.
       }
   }
   

Compare $form_state when the page loads and when you submit the form, to spot this. I know that probably this is not the ideal way, but it has worked for me.