Artem Russakovskii's programming and technology blog

Having spent way more time on this problem than I really should have, I'm going to make sure everyone can actually find a solution instead of useless WordPress support threads.

The Problem

I wanted to export all the data from WordPress using its native export mechanism (located at http://YOURBLOG/wp-admin/export.php), but since the blog I was working on was pretty large (6k posts, 120k comments), I kept getting XML files that ended prematurely and for which xmllint spit out this error:

Premature end of data in tag channel

Upon closer inspection, I saw the XML file ended with a random, yet always fully closed, </item> tag, but was missing the closing </channel> and </rss> tags, as well as a whole …

One thing that's been continuously annoying me when doing WordPress development on the go is when something somewhere inside WordPress decides to send requests to external urls when I don't even have Internet connection or it's slow and flaky (tethering, slow Wi-Fi, etc). This results in random lag when loading pages, especially if I haven't opened my dev WordPress instance for a long time.

Turns out there's an easy and undocumented (other than in code) solution. To block external HTTP requests right in WordPress's core itself, open up wp-config.php and add WP_HTTP_BLOCK_EXTERNAL like so:

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define('WP_HTTP_BLOCK_EXTERNAL', true);

Whenever this variable is present, external requests will be ignored, unless you specify your own comma-separated whitelist …

Updated: February 2nd, 2011

WordPress has a great way of letting you use simple text tags called shortcodes to provide a whole bunch of functionality, including custom PHP code. In this article, I'm assuming that you already know what shortcodes do and how they operate (if you don't, head over here: Shortcode_API).

One glaring omission in the way shortcodes are set up by default is that they only get triggered in the content of your post, leaving the sidebar and comments out. I'm sure this is done for security, so that your readers can't screw something up by posting shortcodes they're not supposed to – after all, shortcodes are PHP snippets on the backend.

However, let's assume you really know what you're doing …

Updated: September 16th, 2012

Introduction

If your WordPress comment counts got messed up, whether because of a plugin (I'm talking about you, DISQUS) or you messed with your database manually and did something wrong (yup, that's what I just did), fear not – I have a solution for you.

But first, a little background.

Comment Counts In WordPress

Here's how comment counts work in WP:

• Posts live in a table called wp_posts and each has an ID.
• Comments reside in a table called wp_comments, each referring to an ID in wp_posts.
• However, to make queries faster, the comment count is also cached in the wp_posts table, rather than getting calculated on every page load.
  If this count ever gets out of sync with

…

Read the rest of this article »

Updated: July 26th, 2010

This is a quick recipe that I found pretty interesting and relatively unknown.

Everyone who uses SVN knows that most repositories are set up to allow viewing of their contents via a web browser. For example, here's the trunk of WP Plugins SVN: http://plugins.svn.wordpress.org/ and here is the current trunk version of a specific file, let's say http://plugins.svn.wordpress.org/stats/trunk/readme.txt.

The Problem

However, what if you wanted to view a specific revision of a file or directory in your browser?

Let's say I wanted revision 100,000 of http://plugins.svn.wordpress.org/stats/trunk/readme.txt

Normally, on a command line, you'd do something like

svn co http://plugins.svn.wordpress.org/stats/trunk/readme.txt stats
cd stats;
svn up -r100000 readme.txt

or simply

svn 

The Problem

If you use the Recent Comments sidebar widget in your WordPress installation, it's possible that you want to customize this widget's style.

You will quickly find, however, that as soon as you add the widget to your sidebar, it injects the following inline, hardcoded CSS into the containing page (using !important to make things worse): 

<style type="text/css">.recentcomments a{display:inline !important;padding:0 !important;margin:0 !important;}</style>

The code above comes from recent_comments_style() (found in wp-includes/default-widgets.php), which is in turn called by WP_Widget_Recent_Comments() in the same file (this is just an old-style PHP4 constructor – same as PHP5's __construct()), which is triggered when the Recent Comments widget is used:

add_action( 'wp_head', 

Updated: May 3rd, 2010

The Question

I'd like to pose this question to all WordPress developers – plugin, theme, as well as core ones:

How do you make your living?

And, for clarification, by this I mean: "what are your primary sources of income?"

Open Source

Open source is a beautiful concept but it often comes with a price tag or, rather, the inverse price tag: most of the time you are not being paid for your time (of course, there are exceptions, such as companies hiring dedicated open source developers and keeping them on their direct payroll).

Everyone has to make a living, however, and everyone has their ways.

Developers can benefit from such income sources as:

• advertising on their sites, fueled by

…

Read the rest of this article »

First of all, I'd like to thank everyone who read and gave their 2 cents about the [Wordpress Plugin Development] How To Include CSS and JavaScript Conditionally And Only When Needed By The Posts post. The article was well received and will hopefully spark some optimizations around loading styles and scripts.

Here are some discussions and mentions around the web:

• an article on Weblog Tools Collection
• a forum post on WP Tavern
• twitter retweets

Sure, there are drawbacks to this method and it does require some more processing on the backend and it's not for everyone, which is why we should always strive for an even better solution.

I stand by my point of view that, for instance, my dedicated …

Updated: January 25th, 2010

Introduction

If you follow web design at all, you probably see 5 billion top NN posts on a daily basis mentioning site and blog designs, fonts, icons, etc.

However, nobody seems to be paying attention to these little but important guys: comment forms.

If you have an appealing comment box, you are more likely to receive comments (this is based on days of scientific research that I imagined I did in my head) and your content is more likely to be re-shared, voted up, and saved.

I really do feel that way when I visit blogs, especially when an otherwise aesthetically pleasing site has a plain vanilla comment box.

Let's Go

So here we go. I have looked through hundreds …

Updated: August 30th, 2014

Introduction

In this tutorial, I am going to introduce a WordPress technique that I believe was unpublished until I raised the question a few days ago on the WordPress forums.

In short, the problem I was trying to solve was plugins unnecessarily loading their JavaScript and CSS on *every* page of the blog, even when doing so would achieve absolutely nothing and the plugin wouldn't do any work.

I briefly mentioned this approach here but Scribu decided to expand on …

Updated: September 16th, 2012

The Problem

I've had MySQL on my Windows 7 laptop for a bit (as part of wampserver), mostly for local offline WordPress development.

However, even though MySQL is relatively stable, I've been observing a vast quantity of intermittent MySQL errors, as reported by WordPress in the PHP error log (C:\wamp\logs\php_error.log). Here are some examples:

[05-Jan-2010 09:47:51] WordPress database error Error on delete of
'C:\Windows\TEMP\#sql17e0_1a2_6.MYD' (Errcode: 13) for query SELECT t.*, tt.* 
FROM wp_terms AS t INNER JOIN wp_term_taxonomy AS tt ON tt.term_id = t.term_id 
INNER JOIN wp_term_relationships AS tr ON tr.term_taxonomy_id = 
tt.term_taxonomy_id WHERE tt.taxonomy IN ('category') AND tr.object_id IN (3) 
ORDER BY t.name ASC made by 

Updated: June 10th, 2009

* Lightning Fast is a blatant exaggeration. Got you to look though, didn't it?

Introduction

Whether you are a web developer or a self-hosting business owner, the only excuse for not activating compression capabilities of your web server can be that you didn't know about it. And now that you are reading this, there is no excuse left at all.

Here is how big a single page of this blog was before compression was enabled on CSS and Javascript files (computed by YSlow):

And here it is after compression:

As you see, the difference is quite substantial – almost 30% savings.

Compressing your HTML, XML, Javascript, CSS, etc pages will mean less data transferred between the server and the …

IntenseDebate, a popular WordPress comment enhancer recently acquired by Automattic (the creator of WP), just announced plugin support. It’s a nice touch to the already useful commenting system that allows threading, easier comment moderation, reputation, voting, etc.

Let’s have a look at some of the announced plugins. Here’s what the comment block looks like with plugins enabled:

PollDaddy

This plugins allows you to add a poll to your comment. By the way, PollDaddy is also an Automattic brand.

Seesmic

Seesmic enables video comments that you can record right off your webcam.

YouTube

I think this one is self-explanatory – you can easily insert youtube videos into your comments.

Smileys

Adds smiley support.

You can activate the plugins by …

If you're like me, most of your WordPress plugins are checked out into your plugins directory from the official WordPress SVN repository or some other one. I haven't updated any of mine for about a month and wanted to sync up everything quickly (including SVN externals). Here's a short command I ran to achieve that:

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cd YOUR_BLOG_ROOT/wp-content/plugins;
find . -maxdepth 1 -type d -exec svn up {} \;

What this command does is finds the top level directories in your WordPress plugins directory, then applies the "svn update" command to each, one by one.

The result is something like

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