WordPress REST API returns error when updating quoted JSON data

My particular situation involved updating a user via REST API with a custom registered user meta.  The meta updates correctly the first time, and any time there is a change. However an error is thrown if the user update includes the unchanged user meta (i.e. I’m updating the user’s first name, but my solution includes all fields with each update). The user meta value was a quoted JSON object, but this also applies to other serialized values. This also occurs with custom meta for other types besides users, like posts or comments.

The server returns a 500 HTTP status, with the following response:

{“code”:”rest_meta_database_error”,”message”:”Could not update meta value in database.”,”data”:{“key”:”my_custom_meta_key”,”status”:500}}

Credit for identifying this bug goes to Corey Salzano. Corey’s solution is to first pull the data, and if there’s no change, omit it in the update request. I didn’t want to add another request to the server, so I came up with a server-side solution. It is provided below with no guarantees!

Note that you will have to change the hook update_user_metadata  and $meta_type  and $serialized_meta_keys  for your particular situation.

WordPress 3.7.1 Update Causing Errors

upgrade_wordpressUpgrading to WordPress 3.7.1 broke a lot of backend (admin, wp-admin) pages. I got 404 Missing and sometimes 500 Internal Server Errors for themes.php, and options.php. No quick fixes were working…

Upgrading PHP from 5.3 to 5.4 solved all issues.

WordPress.org states that the minimum PHP version required is version 5.2.4 or greater. I was using 5.2.11 and upgraded to 5.3.15. Good luck!

WP E-Commerce Using Incorrect Timezone

I noticed incorrect dates in the sales log, as well as incorrect expiration calculations for coupons… Not great things. WP E-Commerce appears to ignore the WordPress settings and use the server settings via PHP.

Quick fix solution, credit goes to Babelscribe.com

Set the server timezone by adding this to the header file of your theme:

<?php date_default_timezone_set ('Pacific/Auckland' ); ?>

Time zones are detailed here:


I just added it to the top of the theme’s function.php, seems more appropriate than any header template. Obviously you must adjust the argument for your timezone.

This instantly fixed and updated dates displayed everywhere in WP E-Commerce.

Creating a WP e-Commerce plugin: Settings Page API (fix)

Recently I’ve been developing a WordPress plugin to extend WP e-Commerce, a free storefront plugin. I used to use osCommerce, a robust PHP solution for shopping carts and heavily customized it. I was looking at this implementation of osCommerce (a great effort) as a WordPress plugin, but it was like reinventing the wheel–not worth it. WP e-Commerce is a native WordPress plugin, works well, has a huge user base and is (mostly) easy to extend.

The WP e-Commerce developers are kind enough to provide documentation for developers of plugins. Their page on “Settings Page API” describes the process of adding a tab to the WPEC settings page. While mostly straightforward there are two points that tripped me up:

  1. The  class WPSC_Settings_Tab_PLUGIN_SLUG extends WPSC_Settings_Tab needs to be inside the plugin tab function being described. This issue was mostly a result of my own dimness…
  2. This one seems to be a typo. The action hook tying in your plugin tab function as described is: However while using this action hook, my plugin settings tab was not accessible directly, only through an AJAX call after the settings page was already loaded. Also, I was using the optional  public function callback_submit_options()  to handle the form submission myself, and this was non-functional! Using the following hook fixed all this and resulted in a settings tab that functioned identically to the default tabs:

add_action( 'wpsc_register_settings_tabs', 'my_plugin_settings_tabs');  

It’s this the main query?

The main query in a WordPress site is the query based on the URL being accessed. When you access this post’s single page, the URL indicates the main query is the text you are reading right now. The “Recent Posts” widget on the sidebar is generated from a query, but not the main query.

There are a few methods to test for the “main query”. As of WordPress 3.3, there is a new way:


Examples: Using pre_get_posts hook | Using posts_where hook

There’s the old way (which is the basis for the above method):

In situations where I wanted to alter the content of a post (in the loop) if it was the main query, the above methods didn’t work reliably. I attempted to hook into the pre_get_posts action and set a global variable, which I would then test in the content filter function. I reasoned that the variable would be set to true before the loop, and then set to false if another query was called after that. The results however were always false.

My solution was to set a global variable with the post ID in a wp_head action, then test that against the post ID while in the loop (every time the_content filter is called.) Code below…

Now it’s quite possible this is not the most direct, efficient or reliable method. I welcome your comments if you have suggestions or concerns.


Displaying Custom Post Types by Term

It’s documented, it’s used, but it wasn’t obvious to me. After hunting around, I finally found what I needed in the first place I looked: the WordPress Codex.

This is the wp_query argument needed to display posts assigned a particular term:

Using the term ID as a cat ID wasn’t working. I came across the above here, and used it in two simple loops to display the custom posts under category headers.

Want to display posts in a nested hierarchy? This goal led me to what is probably a cleaner solution. The following code is adapted from Hierarchical Category List with Post Titles, and blended with the code above.

It’s in action here under Sites

Conditional Display of Widgets in WordPress

Many times I’ve needed to display or hide a widget based on some condition. Usually that condition is which page is being served. That’s easy enough with my own widgets by wrapping the output in an if statement employing a built-in WordPress Conditional Tag. The same can of course be done by directly editing 3rd-party widgets/plugins.

What if you need to change the behavior of a 3rd-party widget, but don’t want to alter it’s code? There’s a great plugin called Widget Logic that can help you do just that. The only caveat is that it directly runs code that you input. That opens up a security hole by executing code stored in the database. Not always a show stopper, but when developing for clients I try to play it safe.

Almost all the code and comments below are borrowed directly from the Widget Logic plugin. I’ve greatly simplified it to effect only the widget(s) and condition(s) hard coded. Also I removed the filtering function, as I was only using this to hide or show a widget. If you want to alter the output of a widget, it’s a pretty simple copy and paste from the original plugin to the second function.

Find the unique widget ID by inspecting the source of a page displaying the widget, like:

Insert the ID into the space specified. Next add in some conditional tags in the space specified like: