Invalid argument supplied for foreach() in wp-capabilities.php: Case Cracked! [en]

[fr] Le problème avec wp-capabilities.php qui fait qu'on peut se retrouver "exfermé" (enfermé dehors) de son blog WordPress (typiquement en cas de changement de serveur) semble avoir sa source dans le contenu du champ wp_user_roles dans la table wp_options. En particulier, pour la version française, "Abonné" est un rôle d'utilisateur, et en cas de problèmes d'encodage MySQL, le caractère accentué sera corrompu, causant ainsi l'erreur.

Il suffit de remplacer le caractère fautif dans PhpMyAdmin, et on retrouve l'accès à son blog. Bon, reste ensuite à régler les questions d'encodage... mais c'est déjà ça!

Finally. At last. Endlich. Enfin.

Once more, while trying to transfer a WordPress installation from one server to another, I found myself facing the dreaded problem which locks me out of my WordPress install with a rather cryptic message:

Warning: Invalid argument supplied for foreach() in /home/user/wp/wp-includes/capabilities.php on line 31

(Your lineage may vary.)

What happens is that WordPress cannot read user roles, and therefore, even though your password is accepted, you get a message telling you that you’re not welcome in the wp-admin section:

Vous n’avez pas les droits suffisants pour accéder à cette page.

Or, in English:

You do not have sufficient permissions to access this page.

A quick search on the WordPress forums told me that I was [not alone in my fight with wp-capabilities.php](, but that many problems had not been resolved, and more importantly, that suggested solutions often did not work for everyone.

I’ve bumped into this problem a couple of times before, and I knew that it was linked to encoding problems in the database. (I’ve had my share of encoding problems: [once](, [twice](, [thrice]( — “once” being on of the most-visited posts on this blog, by the way, proof if needed that [I’m not alone with mysql encoding issues]( either.)

I’ll leave the detailed resolution of how to avoid/cure the MySQL problems later (adding
mysql_query("SET NAMES 'utf8'");
to wp-db.php as detailed in [this thread](, and as [zedrdave]( had already previously told me to do — should have listened! — should prevent them). So anyway, adding that line to my *working* WordPress install showed me that the problem was not so much in the database dumping process than in the way WordPress itself interacted with the database, because the dreaded wp-capabilities.php problem suddenly appeared on the original blog.

Now, this is where I got lucky. Browsing quickly through the first dozen or so of [forum threads about wp-capability.php problems](, [this response]( caught my eye. It indicated that the source of the problem was the content of the wp_user_roles field (your prefix may vary). In this case, it had been split on more than one line.

I headed for the database, looked at the field, and didn’t see anything abnormal about it at first. All on one line, no weird characters… just before giving up, I moved the horizontal scrollbar to the end of the line, and there — **Eurêka!** I saw it.


“Contributor”, in French, is “abonné”, with an accent. Accent which got horribly mangled by the MySQL problems which I’ll strive to resolve shorty. Mangled character which caused the foreach() loop to break in wp-capabilities.php, which caused the capabilities to not be loaded, which caused me to be locked out of my blog.

So, in summary: if you’re locked out of your blog and get a warning/error about wp-capabilities and some invalid foreach() loop thingy, head for PhpMyAdmin, and look carefully through the wp_user_roles field in the wp_options table. If it’s split over two or more lines, or contains funky characters, you have probably found the source of your problem.

Good luck!

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Batch Categories 0.9 [en]

Batch Categories for WordPress has been fixed and enhanced. If you have major category jobs to do, it can probably help you. Feedback and testers welcome.

[fr] Batch Categories pour WordPress a été corrigé et fonctionne à  présent. Le compagnon idéal si vous desirez changer les catégories de nombreux billets en même temps.

Batch Categories 0.9 is out! It’s the ideal companion for large-scale post-import messy category work. List all posts belonging to a category or matching a keyword, and edit their categories, easily visible at a glace with a collection of sexy drop-down lists. What’s new since the the first draft?

  • It now works, and does not “eat” categories without a warning. (Pretty nice of it, huh?)
  • It tells you what it did — which categories it added to which posts, and which ones it removed.
  • Add a whole bunch of posts to a category with one click.
  • Remove a whole bunch of posts from a category with one click.
  • Ensures that all the categories for a post are always listed, whatever the setting for the limit number of drop-down lists.
  • This is what it can look like.

You can still access it as a plugin or edit the Edit navigation menu, as described in my post introducing Batch Categories. If you’re in a hurry, just drop the PHP file into your wp-admin directory and send your browser straight on it.

Next steps?

  • Gather feedback from courageous testers (please don’t blame me if you haven’t backed up your post2cat table and things go wrong) for chasing the last bugs, improving interface and functionality.
  • Redo the code which generates the drop-down lists to take advantage of the category cache, and avoid flooding the database with useless queries.
  • Allow more subtle selection of posts: combinations of categories (AND/OR/NOT), categories without their subcategories…
  • Anything else you would want…?

Update 24.07.04: BB made me notice that “All” and “None” didn’t make much sense in the drop-down which allows one to select the categories to display. Replaced them in v. 0.91 by “Any category”.

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Life and Trials of a Multilingual Weblog [en]

Here is an explanation of how I set up WordPress to manage my bilingual weblog. I give all the code I used to do it, and announce some of the things I’d like to implement. A “Multilingual blogging” TopicExchange channel is now open.

[fr] J'explique ici quelles sont les modifications que j'ai faites à WordPress pour gérer le bilinguisme de mon weblog -- code php et css à l'appui. Je mentionne également quelques innovations que j'ai en tête pour rendre ce weblog plus sympathique à mes lecteurs monolingues (ce résumé en est une!) Un canal pour le weblogging multilingue a été ouvert sur TopicExchange, et vous y trouverez peut-être d'autres écrits sur le même sujet. Utilisez-le (en envoyant un trackback) si vous écrivez des billets sur le multinguisme dans les weblogs!

My weblog is bilingual, and has been since November 2000. Already then, I knew that I wouldn’t be capable of producing a site which duplicates every entry in two languages.

I think this would defeat the whole idea of weblogging: lowering the “publication barrier”. I feel like writing something, I quickly type it out, press “Publish”, and there we are. Imposing upon myself to translate everything just pushes it back up again. I have seen people try this, but I have never seen somebody keep it up for anything nearing four years (this weblog is turning four on July 13).

This weblog is therefore happily bilingual, as I am — sometimes in English, sometimes in French. This post is about how I have adapted the blogging tools I use to my bilingualism, and more importantly, how I can accommodate my monolingual readers so that they also feel comfortable here.

First thing to note: although weblogging tools are now ready to be used by people speaking a variety of languages (thanks to a process named “localization”), they remain monolingual. Language is determined at weblog-level.

With Movable Type, I used categories to emulate post-level language awareness. This wasn’t satisfying at all: I ended up with to monstrous categories, Français and English, which didn’t help keep rebuild times down.

With WordPress, the solution is far more satisfying: I store the language information as Post Meta, or “custom field”. No more category exploitation for something they shouldn’t be used for.

Before I really got started doing the exciting stuff, I made a quick change to the WordPress admin interface. If I was going to be adding a “language” custom field to each and every post of mine, I didn’t want to be doing it with the (imho) rather clumsy “Custom Fields” form.

In edit.php, just after the categorydiv fieldset, I inserted the following:

<fieldset id="languagediv">
      <legend>< ?php _e('Language') ?></legend>
	  <div><input type="text" name="language" size="7"
                     tabindex="2" value="en" id="language" /></div>

(You’ll probably have to move around your tabindex values so that the tabbing order makes sense to you.)

I also tweaked the wp-admin.css file a bit to keep it looking reasonably pretty, adding the rule below:

#languagediv {
	height: 3.5em;
	width: 5em;

and adding #languagediv everywhere I could see #poststatusdiv, so that they obeyed the same rules.

In this way, I have a small text field to edit to set the language. I pre-set it to “en”, and have just to change it to “fr” if I am writing in French.

We just need to add a little piece of code in the form processing script, post.php, just after the line that says add_meta($post_ID):

 // add language
	$_POST['metakeyselect'] = 'language';
        $_POST['metavalue'] = $_POST['language'];

The first thing I do with this language information is styling posts differently depending on the language. I do this by adding a lang attribute to my post <div>:

<div class="post" lang="<?php $post_language=get_post_custom_values("language"); $the_language=$post_language['0']; print($the_language); ?>">

In the CSS, I add these rules: {
  content: " [fr] ";
  font-weight: normal;
} {
  content: " [en] ";
  font-weight: normal;
background-color: #FAECE7;

I also make sure the language of the date matches the language of the post. For this, I added a new function, the_time_lg(), to my-hacks.php. I then use the following code to print the date: <?php the_time_lg($the_language); ?>.

Can more be done? Yes! I know I have readers who are not bilingual in the two languages I use. I know that at times I write a lot in one language and less in another, and my “monolingual” readers can get frustrated about this. During a between-session conversation at BlogTalk, I suddenly had an idea: I would provide an “other language” excerpt for each of my posts.

I’ve been writing excerpts for each of my posts for the last six months now, and it’s not something that raises the publishing barrier for me. Quickly writing a sentence or two about my post in the “other language” is something I can easily do, and it will at least give my readers an indication about what is said in the posts they can’t understand. This is the first post I’m trying this with.

So, as I did for language above, I added another “custom field” to my admin interface (in edit-form.php). Actually, I didn’t stop there. I also added the field for the excerpt to the “simple controls” posting page that I use (set that in Options > Writing), and another field for keywords, which I also store for each post as meta data. Use at your convenience:

<fieldset style="clear:both">
<legend><a href=""
title="<?php _e('Help with excerpts') ?>"><?php _e('Excerpt') ?></a></legend>
<div><textarea rows="1" cols="40" name="excerpt" tabindex="5" id="excerpt">
<?php echo $excerpt ?></textarea></div>
<fieldset style="clear:both">
<legend><?php _e('Other Language Excerpt') ?></legend>
<div><textarea rows="1" cols="40" name="other-excerpt"
tabindex="6" id="other-excerpt"></textarea></div>
<fieldset style="clear:both">
<legend><?php _e('Keywords') ?></legend>
<div><textarea rows="1" cols="40" name="keywords" tabindex="7" id="keywords">
<?php echo $keywords ?></textarea></div>
<!-- I moved around some tabindex values too -->

I inserted these fields just below the “content” fieldset, and styled the #keywords and #other-excerpt textarea fields in exactly the same way as #excerpt. Practical translation: open wp-admin.css, search for “excerpt”, and modify the rules so that they look like this:

#excerpt, #keywords, #other-excerpt {
	height: 1.8em;
	width: 98%;

instead of simply this:

#excerpt {
	height: 1.8em;
	width: 98%;

I’m sure by now you’re curious about what my posting screen looks like!

To make sure the data in these fields is processed, we need to add the following code to post.php (as we did for the “language” field above):

// add keywords
	$_POST['metakeyselect'] = 'keywords';
        $_POST['metavalue'] = $_POST['keywords'];
   // add other excerpt
	$_POST['metakeyselect'] = 'other-excerpt';
        $_POST['metavalue'] = $_POST['other-excerpt'];

Displaying the “other language excerpt” is done in this simple-but-not-too-elegant way:


    <div class="other-excerpt" lang="<?php print($the_other_language); ?>">
    <?php print($the_other_excerpt); ?>

accompanied by the following CSS:

background-color: #FAECE7;
background-color: #FFF;
div.other-excerpt:before {
  content: " [" attr(lang) "] ";
  font-weight: normal;

Now that we’ve got the basics covered, what else can be done? Well, I’ve got some ideas. Mainly, I’d like visitors to be able to add “en” or “fr” at the end of any url to my weblog, and that would automatically filter out all the content which is not in that language — maybe using the trick Daniel describes? In addition to that, it would also change the language of what I call the “page furniture” — titles, footer, and even (let’s by ambitious) category names. Adding language sensitivity to trackbacks and comments could also be interesting.

A last thing I’ll mention in the multilingual department for this weblog is my styling of outgoing links if they are written in a language which is not my post language, using the hreflang attribute. It’s easy, and you should do it too!

Suw (who has just resumed blogging in Welsh) and I have just set up a “Multilingual blogging” channel on TopicExchange — please trackback it if you write about blogging in more than one language!

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Batch Category Editing For WordPress [en]

I put together an admin screen for WordPress today which allows changing multiple categories of multiple posts at the same time. Code available, no guarantees.

[fr] J'ai codé une extension à  WordPress qui permet d'éditer les catégories de nombreux billets en un coup. L'écran liste par exemple tous les billets d'une catégorie, accompagnés d'un certain nombre de selects. On effectue les modifications que l'on désire et on soumet le formulaire entier en une fois.

Update 13.07: A more recent version is out!

I had planned to give you a write-up of the beginning of my WordPress experience today. Unfortunately, I decided to clean up my categories somewhat before I did that, and I managed to badly mess things up.

The result is that I spent most of my day writing a Batch Categories admin screen to help me clean things up. It was something I had planned to do, and I suppose it will also be useful to other people.

If you want to play around: copy the code above into a file named batch-categories.php in your wp-admin directory. I highly recommend that you back up your wp_post2cat table before you get going. This script works for me, but hasn’t been tested much, and comes with no guarantees. It is not optimised either, so depending on how many posts and categories you list, the screen can very well take over half a minute to load!

There are still a few functionalities I want to add, in particular: assigning all listed posts to a category in one go (or removing them).

If you want pretty integration with the other screens of the Edit menu, you’ll have to tweak the navigation bar in edit.php, edit-comments.php, and moderation.php.

Update 24.06.04: I’ve uploaded a screenshot of the admin screen so you can see what it could look like.

Update II 24.06.04: Instead of hacking the Edit menu bars, you can also access the Batch Categories screen from the Plugins page: create a file called batch-access.php (e.g.) in your plugins directory. (Beware not to leave any whitespace after the ?>, though, or you’ll get errors. Promised, zips and more detailed documentation will follow.

Update 04.07.04: I tried using the script this morning, and it seems nastily broken (removed all categories for some posts). Use with caution, and get back to me if ever you hack it or modify it, I’m interested! I’ll look into this once I get back home from Vienna.

Update 12.07.04: The script now works as it should! Thanks to Ben and MooKitty for helping me nail the big nasty bug which was driving me bonkers! Two improvements I’m working on right now: making the code more efficient by using the category cache, and adding a “add all listed posts to category X” option.

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