External module link checker, just a point in the right direction

Sure! Thanks for taking up this cause (sorry for being so long responding).

The best way to find what fields a node has is to use the content_fields() function. This will return a list of all fields that a node currently uses. Then you can iterate through the list and find which fields are links.

$fields = content_fields(NULL, $node->type);
foreach ($fields) {
  if ($fields->type == 'link') {
    // Do something
  }
}

Note: totally untested code. Hope this helps.

Subscribing

Looks very exciting! Any progress? or maybe even canceled plans to create this module?

Looks good :)

You mention on the project page that you'd like to merge with link, but I'm still not sure this would be a good idea. Right now you're leveraging modr8 to handling listing of invalid links, which is a smart move to reduce the amount of code your module needs to provide. However, if this were part of link.module, I'm sure people wouldn't want to have to use modr8 just to see what links are dead. Then we get into adding a lot of functionality into link.module to remove the dependency, and then people want link click-through tracking because link.module now does more than just a CCK field... you can kind of see where this is going. Adding any features besides a CCK field means ultimately adding all the features of a complete links package, which is what I want to avoid.

I absolutely don't want to discourage the creation of a CCK-based links package however. I'd love if a solution were available so that people could stop posting the requests here :) If there's anything I can do to help facilitate your module short of implementing it directly in link, just let me know.

One happy medium might be adding a link status to the link fields, defaulting it to "good" (or even the expected status code). The 3rd-party module would be responsible for maintaining the check-queue and updating the status as required.

This might permit the link module to expose link status via Views (thus deferring the how-to-handle-broken-links question to administrators), and any display formatter - link.module or otherwise - could handle display according to status.

Oh, a way to check for duplicates seems to be pretty popular as well. Awesome to see this!

I'm not sure we can sneak by with just adding a 2 database columns. Look at the links package, which contains 3 tables:

  $schema['links'] = array(
    'fields' => array(
      'lid' => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
      'url_md5' => array('type' => 'char', 'length' => 32, 'not null' => TRUE, 'default' => ''),
      'url' => array('type' => 'text', 'not null' => TRUE, 'default' => ''),
      'link_title' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => ''),
      'last_click_time' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
    ),
  );
  $schema['links_node'] = array(
    'fields' => array(
      'lid' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'nid' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'link_title' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => ''),
      'weight' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0, 'size'=>'tiny'),
      'clicks' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'module' => array('type' => 'varchar', 'length' => 60, 'not null' => TRUE, 'default' => ''),
    ),
  );
  $schema['links_monitor'] = array(
    'fields' => array(
      'lid' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'check_interval' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'last_check' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'fail_count' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'alternate_monitor_url' => array('type' => 'text', 'not null' => FALSE),
      'redirect_propose_url' => array('type' => 'text', 'not null' => FALSE),
      'redirect_saved_url' => array('type' => 'text', 'not null' => FALSE),
      'change_threshold' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'change_flag' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0, 'size'=>'tiny'),
      'change_last_data' => array('type' => 'text', 'not null' => FALSE),
    ),

Nearly immediately after mentioning adding a column to link module, Prodigy jumped in to say that we could add another feature (or database column) for unique checking. This is the sort of feature creep that I'd like to avoid.

If we did add these columns, we'd probably denormalize these tables of course, meaning that the columns needed would be:

last checked
status code
fail_count (threshold unpublishing)
clicks (needed for click counting)
url_md5 (needed for duplicate checking)
last_click_time (recent clicks? not sure what links package really needs this one for)

So now adding a link field (with all the features people commonly request) takes 9 database columns. The above 6 plus the 3 it already uses (url, title, attributes). I don't know I want to go down that path.

There's no need to make assumptions about table structure, just ask content.module what tables link uses:

  $fields = content_fields();
  foreach ($fields as $field) {
    $db_info = content_database_info($field);
  }

As for modr8, yes you're right. It's not actually a dependency.

Hmm, yeah that's a bit troublesome. I can't really think of a way to shorten that key down any. Because link data can be spread across multiple database tables, this is a bit of a tricky situation.

As a (slightly wild) attempt, maybe you could use an md5 hash to identify links, then give them individual lids (pretty much like links package). Then build out a second table that contains the nid, vid, field_name, and delta information. Interestingly, if you take this approach, you could essentially piggy-back off the functionality of the links package (which already has URL checking and click through tracking).

If you do use an md5 hash to build a table of unique links, be sure that you run the URL through link_cleanup_url() first, so that the http:// and such gets appended and duplicate links are reduced.

Hi,

On a digg-like website, any idea how to make a list of the websites to which I send visitors ?

http://drupal.org/node/295425

Thanks.