Allow for different file backends

I don't want to index the result of file_create_url().

A better option is to follow Drupal 7's version and we should either re-implement the Drupal 6 version, or wrap the druapl 6 version with anither function that also calls drupal_alter()

looks like on the right track, but this change should use the new function too:

-        $document->url = file_create_url($file->filepath);
+        $document->url = $file->url;

updated patch to latest head version, as it wouldn't apply anymore. Going to do some testing now, so we can get this into the module. I hope this is the goal?

Ok. I made a few modifications, predominately to support multisite functionality.

• The biggest change is probably around my modifications for url storage. The patches above were using relative urls for convenience, but this means that multisite implementations by default send everyone to whichever site is originating the search rather than the originating site of the file. To keep it more inline with the node implementations and allow multisite implementations to work correctly, I've made the url absolute. I left the ability for a module to override the behavior if desired.
• I corrected the spelling of seperate to separate
• I protected for a few php warnings from member variables not being set (primarily description)
• I simplified the admin theming to remove the "hack" portion of things. It was pretty theme dependent and - while making the interface cleaner - didn't seem to be something that needed to be done for all sites. The resulting interface has a tad bit more spacing, but in general looks virtually identical
• I modified the result processing so that it returns to using the solr-saved url for the link (since this value needs to be absolute for multisite implementations) and the node url from solr for the node link (since it's available) rather than the node/ link

It'd be good now to get another set of eyes back on this (neclimdul?) to see if what I've done here still works for your use cases in production.

A quick pass looks reasonable - some minor comments:

 function apachesolr_attachments_get_indexable_files($node) {
-  $files = array();
+  $files['drupal'] = array();
 
   if(!empty($node->files)) {
-    $files = $node->files;
+    $files['drupal'] = $node->files;
   }
 
   $fields = apachesolr_attachments_get_cck_file_fields();
   foreach ($fields as $field) {
     if(!empty($node->$field)) {
-      $files = array_merge($files, $node->$field);
+      $files['drupal'] = array_merge($files['drupal'], $node->$field);
     }
   }
+
+  // Allow other modules to attach files to be indexed.
+  foreach (module_implements('apachesolr_attachments_files') as $module) {
+    $files[$module] = module_invoke($module, 'apachesolr_attachments_files', $node);
+  }
+

It might make more sense for this to be an alter hook?

In any case, I'd rather see $files['upload'] and $files['filefield'] than $files['drupal']

Here's a version simply switching the file types.
The only issue I can see with this is that a later hook (apachesolr_attachments_url) is based off of the file type. So, if you wanted to do the same thing to filefield elements and upload module elements, you'd now need 2 separate hooks. I think that's reasonable.

If this isn't sufficient, I can roll another version switching to drupal_alter.

Instead of 'file_type' maybe we should call this 'module' or or 'file_module'? It's not the file type at all.

Updated from file_type to file_module and modified existing text to be more logical.

One significant concern. For the update function:

+    'initial' => 'drupal',

needs to be 'upload'? But some will actually be 'filefield'?

Some minor nits:

This doxygen needs better formatting:

 /**
+ * Get the indexing mode for the attachments of a given node.
+ *
+ * @param $node
+ * A node object.
+ * @return
+ * Index mode
+ */

this code comment is unneeded:

+  $form['#theme'] = 'apachesolr_attachments_content_type_settings'; // reset form theme.

?

I am currently using 7.x-1.2. Is there any hope of this patch working for me?