Initial Drupal 7 upgrade

Peter, thanks for all your work on this.

Can we keep the regex cleanup to this issue, so that it's in 6 & 7 branches? #538172: Refactor regex for better validation and to allow for special chars in urls

Also:

+    // We don't have an API to create new networks yet, so for now, we only
+    // call hook_follow_networks_alter().

If I'm not mistaken, there is a hook for adding new networks that I believe is called hook_follow_networks().

Also, looking at your follow_build_url_regex function made me think it would make sense to move away from the simple array structure of hook_follow_networks to something more like this:

/**
 * Implementation of hook_follow_networks().
 *
 * @return
 *   An array of networks.
 */
function follow_follow_networks() {
  $items = array();

  $items['facebook'] = array(
    'title' => 'Facebook',
    'domain' => 'facebook.com',
  );
  $items['virb'] = array(
    'title' => 'Virb',
    'domain' => 'virb.com',
  );

  ...

  return $items;
}

That would allow you to pass the array to your regex validator and get the domain for each that way, without having to hard code all that garbage into the function itself, and also greater flexibility in the future for custom title callbacks and such.

Not sure if domain should be kept 'domain' or maybe it should be 'url', or 'base_url' or 'base'.

Thoughts?

@q0rban - the way it's written now, hook_follow_networks() only lets you add, not remove or alter. Using drupal_alter as in this patch lets other contrib module add change or remove any of the network based on the default list provided by follow.module - I think this is a more useful API to expose.

Yes, but your comment said 'there is no way to create new networks', I was just clarifying that there is a way to create new networks. There is already an issue about adding the drupal_alter as well: #555636: Allow altering of networks

Thanks! :)