Cat_breadcrumb: Better handling of "breadcrumbs only" menu items

This seems to be true. I am working on a site that will have about 10-15k categories in the long run and I think this issue will create a serious problem on that site.

KarenS also has some thoughts about this:
http://drupal.org/node/73830#comment-118099
http://drupal.org/node/73830#comment-118113

The actual issue - as I have found - is not category itself. Its kind of core.

See, to get breadcrumbs down to node level you need menu's to represent those paths (as you know). Also you've found that having that many menu's can kill drupal.

What happens is Drupal detects a change in the menu cache and tries to regenerate it. Once done, all is fine. Thing is - when you approach a few hundred cat's, it takes ages (10, 20 and possibly over 60 second) to regenerate the cache. This also happens whenever you add a new node - the whole menu cache gets regenerated.

Whats wierd, thought, is this very site (drupal.org) can breadcrumb down to node level without dying whenever a node is made. I can probably garuntee they dont use the Category module though :-)

Taxonomy_menu does it without creating menu items, so there must be a way to do it...

kiteatlas, I have been considering offering some kind of a bug bounty to Jaza for clearing up the long issue list for category_menu issues. What do you think about this? Is anyone else interested in contributing to this?

The issue list seems to suggest that lots and lots of people are trying out the module and generally liking it better than the taxonomy module. Jaza has done an incredible amount of coding for category module and it would be a shame if time or lack of support from users or other factors prevented its progression into a potential replacement for core taxonomy.

Meanwhile, I am hoping he will look into the category_pathauto and category_bulkedit modules, both of which are unfortunately quite broken and unusable.

Clarification of previous post- the intent of the proposed bounty is to fix bugs and not to evangelize category as a replacement for taxonomy:-)

Some time ago I wished to create category_breadcrumb.module, which generates bredcrumbs for nodes in category structure without using menu items. But because lack of spare time I postponed this.
There is to approaches to solving this problem:
1) Simply generate breadcrumb on each page request, setting it with drupal_set_breadcrumb().
2) Use some kind of cache as for menu items. But this may be an early "over-optimization".

Is there need for such module in short time?

@kiteatlas: Thanks for the time you spent on working through the issue queue for menu module. I think about 80% (okay, it's an arbitrary number, but probably pretty close;-)) of category_menu issues. At the moment, I am not very comfortable about asking some other developer to do this. Let's wait until Jaza finishes his SoC project.

@radev: It would be great if you could whip up a quick patch on the lines you suggested as that would help Jaza make a decision quickly.

Sorry, I mean that additional module will display breadcrumbs, NOT patched category_menu module.

In attachment there is first test version of my category_breadcrumbs.module.

For this moment there is no settings on container page (settings like 'set breadcrumbs for categories' and 'set breadcrumbs for assigned nodes' will be provided in future version).

To use this module - simply place it into subdirectory within category module (like 'modules/category/category_breadcrumb') and enable in adminster/modules.

Breadcrumbs will be generated for nodes with assigned categories.

Thanks, radev. I think this will be an useful starting point.

Heya all, if you're all interested, I've tweaked the module to show full paths, as it didn't work for me. Also it is now compatible with hidden containers.(they wont show in the breadcrumb)

It definetly needs testing, but I'll upload if I get more bugs. Lemme know if this is useful for ya. :)

This is only tested with my category_get_parents() bugfixes from
http://drupal.org/node/76921

I changed the "regular nodes" case to use category_location. This appears to work OK.

Oops! I accidentally left some debugging code in. Sorry about that.

I've taken the version posted on #16 and modified it:

1) if you also apply the patch in the following post, it should fix the 'hidden containers showing in breadcrumbs' problem

2) now the current post is always listed in the breadcrumb, but never linked

What I couldn't fix:

1) the function category_get_parents is currently broken, and does not return parents of containers. Fixing it is apparently beyond me, so I've posted an issue about it and hopefully somebody else will take care of it. Until that problem is fixed, containers will still have broken breadcrumbs. All categories will have correct breadcrumbs instead, with all parents (visible containers included) listed.

2) I don't use forums, so I have no idea if forums behave correctly or not

Here is the patch I mentioned. It makes a very small change, namely it adds in the database query the value 'hidden_cont' that can tell whether a container is hidden or not. The previous cat_breadcrumb module checked that value to see if it had to display the link or not, but since the value wasn't added to the database query in category.inc in the first place, the check always displayed the links, simply because the real value wasn't actually there. With the patch, the value is actually retrieved from the database and the module can work correctly.

The module I posted in #21 has introduced (or was it already there?) a bug, where nodes assigned to multiple categories get a multiple breadcrumb. I'm not sure on what approach to take in order to fix this; which category among the many should I choose? Any ideas?

Here is the fixed version, now the breadcrumb isn't duplicated anymore. You still need the patch in #22, or the hidden containers will show up.

The module still works in Drupal 5 (with the patch in the other issue). You'll need to create a folder called category_breadcrumb for it (I created mine as a subfolder in the contrib folder), add the .info file I'm attaching and you still need the patch in comment #22, or hidden containers will show up.

This is a great module that could save me from having to drop Categories in a site that I am working on, but I see a little problem: it shows the end piece of the breadcrumb trail twice: once as a link, then followed by the same text unlinked.

For example, I have a contained called Development, and the breadcrumb shows:

Home » Development » Development

...instead of just

Home » Development

The same happens with deeper breadcrumbs.

Any way to fix this?

In reference to #26:
the only way I've managed to reproduce this if I have a visible container or a category called 'Development' and then I have a subcategory called 'Development' of that visible container/category. This is correct behavior, since it's a subcategory with the same name. It is however very different from the bug you mention, namely the same item appearing in the breadcrumb twice. I haven't managed to reproduce the latter at all. If you can provide more info (e.g. what versions are you using, and are they the latest? what is your exact hierarchy container/category structure for the buggy item? have you applied the patch in comment #22 to get rid of hidden containers in the path?) so that I can reproduce it, I can try and fix it as soon as I have time.

I do have to point out that the module attached in comment #24 is taking into consideration what comment #17 says, namely that from a UI point of view the final bit of the breadcrumb (the one referring to the node the user is currently viewing) shouldn't be clickable, because you are already viewing that page and this could be confusing for the user. So if you use the module in #24 you'll always have the current page listed as text only at the end of the breadcrumb (this doesn't mean anything will appear twice). If you do not care for this behavior, use the module attached in #16 instead plus the patch in #22 (that will get rid of hidden containers in the breadcrumb). If I ever manage to find time, it'd be nice to add an option so that admins can choose what kind of behavior they want (i.e. add unlinked current page in the breadcrumb or not).

Following this, even though I hope I won't need it.

Assigning to self.

Let's start at HEAD and work backwards, shall we?

Instead of hardcoding content types, let's just let the user decide on the content type edit form.

Something like

Category_breadcrumb behavior:
( ) Enable by default on new nodes
( ) Disable by default on new nodes
( ) Disabled completely on this content type

Total +1 from me, this is a must and would save me a lot of trouble.

Here's a very quick hack to cheat at breadcrumbs. It works for everything that's a category. (Put it in whatever you use for a site customization module, the example is for "mysite_custom.module")

function mysite_custom_menu($may_cache) {
  if (!$may_cache) {
    if (arg(0)=='node' && is_numeric(arg(1))) {
      $node = node_load(arg(1));
      if ($path = category_location($node)) {
        $crumb = array(l('Home',''));
        foreach ($path as $c) {
          $crumb[] = l(check_plain($c->title),'node/'.$c->nid);
        }
        drupal_set_breadcrumb($crumb);
      }
    }
  }
}

Hmm, now that I think of it, using this and checking for a menu item on the way up would let us expand the menu as far as we can as well as having a breadcrumb...

Oops, what a pity the Issue queue is so long... I overlooked this, and created my own category_breadcrumb module, to match the needs of my website.

It's maybe not so much precised, doesn't do anything about category-pages, but at node level it works fine on the site, and there's no need to work elsewhere, as we're putting Categories to the navigation menu. I think that only the node-level needs to avoid the menu-entries-creation.

--- One important feature in my version: While enabled, multiple breadcrumbs may be generated for one page, to reflect the node being assigned to more categories (i.e. one complete path for each category on the node). On our site, we use two parallel Category-trees to sort contents by both What happened and Where it happened, and so the breadcrumb needs to offer "navigate back" ways to both the trees, otherwise it'll be non-reliable for the user as navigation. It's a bit tricky to pass an Item-list of breadcrumbs to the page, but works fine (if no complicated theming is used on breadcrumbs, which is not usually the case, I believe). Also node-titles are optionally added, to allow having them on all the multiple breadcrumbs.

--- My version also have admin-settings page to control the behaviour (although there's currently not much to be set).

I'm attaching the module I created, which is NOT a modification of the previous ones here. Perhaps someone might put both the versions together, otherwise it's an alternative for anyone searching quick solutions in this thread, and maybe a bit of inspiration.

OK, there's some more progress from me :-)

I further improved my version of Category_breadcrumb, including ideas and code-snippets from the versions seen earlier in this thread, aiming to put the best from both the versions together. The resulting module seems to me finished, fully working and configurable, so I hope someone review it.

Features:
--- Tested on Category 5.x-1.1, Drupal 5.1
--- Allows normal or multiple breadcrumbs on node-pages (multiple = one path per category, if there are more on the node), or just do-nothing.
--- Allows breadcrumbs on category and container-pages, if enabled.
--- Allows to add node-title to the breadcrumb (linked, plain text, or no title), which might be useful on multiple breadcrumbs.
--- Allows to specify node-types to exclude (forum and blog by default, to avoid mentioned-above problems).
--- Avoids changing another module's explicitly set breadcrumbs.
--- Checks for hidden containers in the same way as previous versions seen here (i.e. needs the patch from #22).
--- Provides full admin-settings page to control the behaviour (including explanations on the settings).

My module doesn't play with menus (that's category_menu's work, so no need to confuse things), relies as much as possible on the existing $node object (to avoid unnecessary complex function calls). The node-types-to-exclude setting is provided just as a textfield - I think that this will be changed rarely. (I'm not voting for the way suggested by bdragon (#32), as this is NOT a content-related workflow-preference, so there's no point overloading other pages with such settings, and make the site-admin pursue them over many different pages. This is just an install-setting-to-avoid-problems on Category_breadcrumb itself, and so it belongs to it's own settings-page, I believe.)

If one choose to add node-titles into breadcrumb for the sake of multiple breadcrumbs being equipped with it (which is not default), it's still a good idea to put something like this into page.tpl.php:
<?php print $breadcrumb . (strpos($breadcrumb,$title) ? '' : ' » '.$title); ?>
This ensures the title to be there also on different non-node pages, where Drupal doesn't add it.

Module is attached (remove the .txt extension, which I just needed to attach the file here - Drupal.org seems to disallow .module files as attachments!), the .info file remains unchanged from my previous post.

#38 and .info from #37 added to DRUPAL-5 and HEAD verbatim.

My implementation seems to be inside latest -dev release now, so I think this Issue deserves a "fixed" status. Feel free to re-open if there's something else left to be done about this.