How can I get the title of a form element in Drupal? - drupal

Question

For example, in the registration form, there is "Username" and the text field for it which has the input type="text" name="name" ....
I need to know how can I get the title from the input field's name.
I'm expecting a function like:
$title = get_title_for_element('name');
Result:
assert($title == 'Username'); // is true
Is there something like this in Drupal?
Thanks.

Answer 1

You have the form and the form state variables available to your validation function. You should use form_set_error() to set the error.
There is no function that I am aware of which will map from the values array to the form array. But it is not dificult to work it out. Understanding the form data structure is one of the key skills you need when building drupal.
In this case the form in question is generated (in a roundabout way) by user_edit_form, you can see the data structure in there.
$form['account']['name'] is the username field. and the array key for the title is '#title' as it will be in most cases for form elements.

Answer 2

You can do it in two different ways as I see it. Let's create a module called mycustomvalidation.module (remember to create the mycustomvalidation.info file also).
Note: The code below has not been tested, so you might have to do some minor adjustments. This is Drupal 6.x code by the way.
1) Using hook_user()
What you need is a custom module containing your own implementation of hook_user() http://api.drupal.org/api/function/hook_user/6.
<?php
function mycustomvalidation_user($op, &$edit, &$account, $category = NULL) {
if ($op == 'validate') {
// Checking for an empty 'profile_fullname' field here, but you should adjust it to your needs.
if ($edit['profile_fullname'] != '') {
form_set_error('profile_fullname', t("Field 'Fullname' must not be empty."));
}
}
}
?>
2) Using form_alter() and a custom validation function
Personally, I would go for this option because I find it cleaner and more "correct". We're adding a custom validation function to our profile field here.
<?php
function mycustomvalidation_form_alter(&$form, $form_state, $form_id) {
// Check if we are loading 'user_register' or 'user_edit' forms.
if ($form_id == 'user_register' || $form_id == 'user_edit') {
// Add a custom validation function to the element.
$form['User information']['profile_fullname']['#element_validate'] = array('mycustomvalidation_profile_fullname_validate');
}
}
function mycustomvalidation_profile_fullname_validate($field) {
// Checking for an empty 'profile_fullname' field here, but you should adjust it to your needs.
if ($field['#value'] != '') {
form_set_error('profile_fullname', t("Field %title must not be empty.", array('%title' => $field['#title']));
}
}
?>