Prefill contact form

I added the two lines and entered the line below on a page to prefill the contact subject (Drupal 5.2).

TESTLINK
< a href="http://XX.XX.XX.XX/xxxxxxxxxxx/?q=contact?subject=testvalue" > TESTLINK< /a >

(without the spaces in the tags)

Unfortunately this does not work (page not found). What else do I have to consider?

Thanks in advance
jeckl

This can lead to problems when upgrading your installation (you would need to add the new line to the contact.module file every time you replaced it with a newer version).

Instead, Drupal provides you with 'hooks' that you can use to tie into the core functionality without editing the core files. In this case, the hook you want is called 'hook_form_alter', and it allows you, unsurprisingly, to alter forms. The function looks like this:

function hook_form_alter($form_id, &$form) {
   // some stuff here, check the api for the full function, but it doesn't actually matter for what we're doing
}

What you want to do is make a module, and add an implementation of hook_form_alter to it. So you create a new directory in sites/all/modules, called, say, 'contact_subject'. Inside that directory make two new files called contact_subject.module and contact_subject.info. Fill out the info file with the name, group, and description of your module (you can copy existing modules for the structure of this file.)

Then, for contact_subject.module, add this code:

<?php
/**
 * Implementation of hook_form_alter
 *
 */
  function contact_subject_form_alter($form_id, &$form) {

    if ($form_id == 'contact_mail_page' && !empty($_GET['subject'])) {
      $form['subject']['#value'] = $_GET['subject'];
    }    
  }
?>

The only part of the code that changes is that you use the form_id to tell the hook which form you want to alter. Every time Drupal displays a form, it asks all active modules if they have an implementation of hook_form_alter, and then runs through all of them. In this case, your function just checks to see if the contact form is being displayed, and if a subject is being passed in the URL. If they are, it pre-fills the topic.

(If you don't know the ID of the form you want to alter, you can just activate a dummy module with form_alter printing the ID on every form:

<?php
function dummy_form_alter($form_id, &$form) {
  $form['id-display'] = array('#value' => $form_id, '#weight' => -10);
}
?>

)

With the code split out into its own module, you can update Drupal freely, without overwriting your changes.

The snippet of code above can be simplified:

//... (this is inside contact.module)...
function contact_mail_page() {
    //...
    $form['subject'] = array('#type' => 'textfield',
      '#title' => t('Subject'),
      '#maxlength' => 255,
      '#required' => TRUE,
      '#default_value' => $_REQUEST['subject'],  // this should be added
    );
    //...
    }
}

Use the Contact Forms module. You can put your subject in the URL that points to the contact page, and it'll be inserted in the Subject field.

I got the same functionality working under D7, with the following lines in the template.php file of my custom theme:

function mytheme_form_alter(&$form, $form_state, $form_id) {
   if ($form_id == 'contact-personal-form' && !empty($_GET['subject'])) {
      $form['subject']['#default_value'] = $_GET['subject'];
    }
}

Thanks for the suggestions!