Validating node creation / edit form

Question

I'm using form_alter to play with the node form for a specific content type. This content type has many different fields and I'm also using Field Collection module to organize all these fields & logic, if that makes any difference.

Apparently, there are some incompatibilities between the Field Collection & Field Dependencies modules so I thought I might be able to build a similar field dependency functionality with my own module.

I've created a validation function for the form. My problem is that I'm trying to access $form_state values that users insert in the form in order to validate these values but I think I'm doing something totally wrong here:

function _mymodule_my_validation_function($form, &$form_state){
    $short_field_name = $form_state['values']['long_field_name'];
    if (empty($short_field_name) || $$short_field_name == '') {
        form_set_error('error','That field cannot be empty!');
    }
}

Unfortunately this validation script doesn't work. To be more exact, I

dpm($form_state);

in my form_alter and $form_state doesn't even contain 'values' (shouldn't it be present but empty?).

Is there a different best practice for validation node form fields instead of dealing with the $form_state['values'] array?

Also, I need to be able to see the values submitted by users each time the node form is submitted. Currently, I dpm($form) in my form_alter function and everything is returned on the node/%/edit page as expected. But how can I catch submitted values on the node/% page after submitting the node form??

Update: When I call dpm($form_state) within my validation function I get what I need if the form doesn't validate (as we still are on the same node edit page). But how can I receive the (new/changed) values that users entered in the form fields in case the form is submitted successfully and user is directed to content list page?

Answer 1

For custom forms
The preferred way is to call hook_form_validate for hook_form but you can use $form['#validate'][] = 'custom_validate_function' to call validate function

function hook_form(&$form,&$form_state,$form_id) {

$form = array();

// write your custom fields here..........
return $form;

}

function hook_form_validate($form, &$form_state) {
 $short_field_name = $form_state['values']['long_field_name']['und'][0]['value'];
    if (empty($short_field_name) || $short_field_name == '') {
        form_set_error('long_field_name','That field cannot be empty!');
    }

}

For built in forms by creating content type

function hook_form_alter($form, &$form_state, $form_id) {
  if ($form_id == 'your_form_id') {
    $form_state['#validate'][] = 'form_1_validate';
    $form_state['#submit'][] = 'form_1_submit';
  }
}

function form_1_validate($form, &$form_state) {

$short_field_name = $form_state['values']['long_field_name']['und'][0]['value'];
    if (empty($short_field_name) || $short_field_name == '') {
        form_set_error('long_field_name','That field cannot be empty!');

}
}

function form_1_submit($form, &$form_state) {

//To get the user selected or user submitted values you should look into code below
$field_name_values = $form_state['values']['field_name'];



}