Notes on Mysql Master/Slave

Here’s a good link from or friend Paul Moen on how to promote a slave to a master.

http://www.pythian.com/blogs/300/mysql-recipes-promoting-a-slave-to-master-or-changing-masters

The basic idea hear, is to simply tell the slave to no longer pay attention to the master… and things should work as is.

Kind of obvious really.

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WordPressMU Customized Signup Wizard for Las Vegas Half Marathon Running Group

At Konamoxt we just started a test campaign to have new users signup for our service and get free online coaching to run the Las Vegas Half Marathon. If you’re a runner and a blogger, this is a great chance to get some great free coaching from a certified running coach… and to have a great time at a pretty nice Half Marathon race. The Las Vegas Half Marathon, and Marathon is really a well run race in a great location.

Anyway, since this is my development blog, you might ask, why am I posting this here? Is it just a shameless promotion of the event? Well… kinda… I mean I would like you to sign up and have a great time running the Half Marathon.

But you also might find it of interest how we did this sign up process.

First of all early on when we deployed WordPressMU we wanted to customize the signup process. And we wanted a different look and feel, have it integrated more into our default website design, etc. We did this through hacking the core wordpressmu files. Our main signup process still does this. But we’ve never really liked it.

For our Las Vegas Half Marathon promotion. We wanted an improved look and feel. In fact part of what we wanted was the ability to have a custom sign up process integrated into some of our “professional blogs” that included event specific signup fields. For example, for something like this, there may be additional terms of service. Since we are offering free online coaching, we needed the system to present an additional Online Coaching Training Waiver.

Users that sign up for this running group, get custom themes only available to them. These new blogging themes are specifically designed to highlight that the event is in Las Vegas and that the users are training together to run a Las Vegas Half Marathon together… etc. We’ve included a bunch of integrated header images of the sights and icons of Las Vegas. We’ve added widgets that automatically include a countdown to the race, and links to other team members. All of these are straight forward in WordPressMU when you develop a custom theme.

But having a custom signup process isn’t something we’ve seen alot of… and we really wanted to streamline the signup process.

Here are a list of improvements to the signup process we wanted in no particular order:

• Single Step Signup – Which is to say, we understand why the WordPressMU team decided to have multiple email roundtrips to verify that the user is a real person and not a robot… but for our user base this process was causing a lot of users to get stuck in the signup process. It’s one thing to ask dedicated bloggers to step through the process. But we want runners of all skills and interest levels, and we don’t want to scare them off with a complicated signup process.
• Integrated Captcha
• Terms of Service/Privacy Policy checkbox
• Online Training Waiver checkbox
• User Name for new users
• User settable password for new users – We’ve gotten complaints from many users that they don’t like the autogenerated passwords, and they couldn’t figure out how to change their password. So like other services we wanted to allow the new users signing up for this free online coaching to set their own password.
• User settable blog domain – but default to same name as user name
• User Profile information – Since we’re looking for runners to signup who are taking on a Half Marathon, we want the new blogs to come stocked with a better about page and first post than the standard boring ones that come with WordPressMU… we do this by asking the runners who are signing up for the Half Marathon to tell us about their running history. How many Half Marathons have they run? What is the Personal Best for the Half Marathon? What are their goals for the Half Marathon? What other activities are they interested in? We store all of this as user meta data, and we format it into an automatically generated post and about page.
• Theme Selection – Since we added a custom theme exclusive to the runners who sign up for the Half Marathon, we let them select from preview images of the custom theme. If their an existing user we let them choose their existing theme, but new users are stongly encouraged to pick one of the Las Vegas Half Marathon themes.
• Blog title and description

Ok, so those are the features we wanted how did we do this?

Well, first of all, we wrote most of this code as if it was a plugin for wordpressmu. However in the end we ended up moving it to be scoped just to the custom theme we developed for the running coach who’s offering the training. Our plan is to eventually move this to a more generalized process.

The bulk of the code is pretty object oriented PHP. We developed a wizard class, that takes wizard page objects. Each page of the wizard is responsible for rendering it’s html, and then doing a preprocessing check and eventually a processing phase. Of course we use prototype.js and script.licio.us for a bunch of the Javascript heavy lifting. The actual wizard behavior comes from some open source code that uses scriptalicious effects to move around the “pages”.

We essentially call the wordpress mu functions for blog signup and post creation just like the standard wp-signup.php pages do. I guess the point is, instead of trying to change wp-signup.php we realized that the right thing was to treat the functions in wp-admin and files like registration.php as an API that we would call into. Once we made this leap, it becomes pretty straightforward to build a custom signup process that gets past all of the ‘features’ of the standard wordpressmu signup.

Anyway, check it out… if you’re a runner, then for sure check it out and signup for the free coach and run training advice.

Crazy Globals Bug in Recent Posts Widget

I’ve just discovered and fixed a small problem in the “Recent Posts” widget.

Basically this widget creates a second “loop” and will side effect several of the post globals (like $id and $post). The result will effect any downstream plugin that thinks it can count on these globals being available. This can also manifest in any theme (like Tarski) that has post related template calls AFTER the side bar widget.

I’ve fixed this problem but saving $post in a local variable and then resetting it after the loop call. I also call setup_postdata() to restore the other globals.

I just checked the latest version of widgets.php from “http://svn.wp-plugins.org/widgets/trunk/” and it still has this issue in it.

Here’s the new function…

function widget_recent_entries($args) {
    // This global $post is side effected by the call to $r->the_post()
    // and so in order to protect any uses of $post after our widget is
    // instantiated, we will save the value of the global and restore
    // it at the end of our function.
    global $post;
    $save_global_post = $post;

	extract($args);
	$title = __('Recent Posts', 'widgets');
	$r = new WP_Query('showposts=10');
	if ($r->have_posts()) :
?>
		<?php echo $before_widget; ?>
			<?php echo $before_title . $title . $after_title; ?>
			<ul>
			<?php  while ($r->have_posts()) : $r->the_post(); ?>
			<li><a href="<?php the_permalink() ?>"><?php if ( get_the_title() ) the_title(); else the_ID(); ?> </a></li>
			<?php endwhile; ?>
			</ul>
		<?php echo $after_widget; ?>
<?php
	endif;
    $post = $save_global_post; // restore the global that was side effected by $r->the_post()
    setup_postdata($post); // and restore the other globals that we also side effected when $r->the_post() called setup_postdata()
}

Common Themes Directory for Multiple Instances of WordPress?

I have multiple installs of WordPress and WordPressMU running in the same system, and I want them to share a common Themes. I’ve been diligently updating the same theme in multiple directories… and frankly it sucks. Then I came across this forum post and was blown away!

So, I’ve implemented a plugin that allows you to set an absolute or relative path to a common themes directory.

Installation: Download the code from the link below. Rename the file to common-themes.php and place it in your plugins directory. Activate it.

Download: You can get a copy of the code here.

Usage: Set options in “Options->Theme Root Options”. Enjoy.

Improved WordPress to WordPress Importer

I’ve been playing around with importing WordPress blogs from one instance to another, and I’ve been frustrated by some of the default features of the built in WordPress to WordPress importer.

So, I’ve implemented a new version of the importer that has the following features:

• Attachments – This importer will download and “insert” the actual image files of an attachment record. So for example, if you’ve uploaded images to your WordPress blog, then they will be listed as attachments. The normal importer will store these records but no do anything with the actual image. So you basically end up with dead links. Not anymore. Now if the image is an attachment, the importer will attempt to download it and insert it into the new blog. All of this downloading happens on your server, so you don’t actually have the files download to your client machine.
• Links – Links to your own blog are remapped. This is particularly important for image links to attachments (obviously) or else the attachment feature described above would be pretty whacked! But it also applies to cross links between your own blog posts. Seems like an obvious feature right? I thought so. This also applies to internal ping backs.
• Spam Comments – For some reason the default importer decides to import comments tagged as spam. I guess I can imagine a few cases where this might make sense… but nah… I don’t think so. So this importer will discard any comments marked as spam.

Installation: Download the code from the link below. Rename the file to zappo_wordpress.php and place it in your wp-admin/import directory.

Download: You can get a copy of the code here.

Usage: Same as any other importer, go to Manage->Import. Enjoy.

By the way, I really only tested this on WordPressMu, but there isn’t anything about it that I would expect to fail on standalone WordPress. Feel free to report bugs if you see issues.

Hey Zappo – This thing is really chatty, what gives? Do you think you could make it not print out so much noise? – You

No. But you can. Enjoy! – Me

Latest wpmu-topposts plugin

Version 0.42.4 of wpmu-topposts plugin now available…

Lots of changes:

• Added support for top_blogs(), same calling convention as top_posts() but returns
  top blogs based on total hits to the blog for all posts on the blog.
• Added a couple new arguments to top_posts() include a new max_per_blog which if set
  to 1 will limit the posts to 1 per blog.
• Added days_back argument which will limit the stats to a certain number of days
  into the past.
• Added many new formatting arguments to make it easyer to use the get_*_html functions
  and get the formating you want.
• Fixed a couple bugs that would cause cache corruption (removed a call to
  update_post_caches() which was definitley corrupting the post cache)
• Also correctly call switch_to_blog() in the get_*_html functions so that the
  blog template tags actually work properly.

Definitely my favorite new feature is the max_per_blog since it uses cool nested queries in SQL. yummy!

Here are some usage examples:

This will give you top posts in an ORDERED list, with hits included surrounded by square brackets.

zap_top_posts_html('before_list=<ol>&
           after_list=</ol>&max_per_blog=-1&
           before_hits=[&after_hits=]');

This will give you top blogs in an UNORDERED list, without hits included.

zap_get_top_blogs_html('include_hits=0');

As always, get the latest code here…

New Version of Sub-directory Plugin… now acts more like WordPress

I’ve updated the subdir-mu-plugins Plugin to behave a little bit more like WordPress’s plugins and a little less like WordPress MU’s plugins. The latest version (0.42.2) can be found here.

Here’s a little background:

WordPress single instance will only load files that have the “Plugin Name:” directive. This is partly related to the fact that WordPress supports disabling plugins through a user interface. WordPressMU supports this feature as well for the plugins placed in the “wp-content/plugins” directory. But these plugins are enabled and disabled on a blog by blog basis. For those plugins in “wp-conten/mu-plugins” it will load all PHP files. So for example, if a plugin has extra support PHP files that aren’t safe to load all the time (but can be loaded at the right time by the plugin for example) these types of plugins don’t work well in WordPressMU.

My original version of this subdirectory plugin was intended to mimic the original WordPressMU behavior of loading all php files. Well, this seemed like a good idea at the time, but really the point of this plugin was to allow you to use more WordPress (non-MU) designed plugins… those that lived in subdirectories. And well, many of those plugins also depend on WordPress’s behavior of not loading PHP files that don’t contain the “Plugin Name:” directive. So I’ve decided this original behavior wasn’t the best idea.

The new version will scan subdirectories and attempt to read the plugin-info from all PHP files and only load those PHP files who have a “Plugin Name” directive.

I’ve now changed the behavior of this subdirectory loading plugin to behave a little more like WordPress. Namely it will only load files from subdirectories that have a “Plugin Name” directive.

The Case of the Disappearing TinyMCE

I’ve been having off and on problems with my TinyMCE rich text editor disappearing from WordPress… At first it seemed very random, sometimes it was there sometimes it wasn’t. Then it seemed like the problem went away, as in TinyMCE didn’t go away, and then the problem came back, as in TinyMCE was nowhere to be found.

Well, this weekend I finally figured out at least one thing that would cause this problem to happen.

Apparently one of my plugins was outputting an extra couple lines of non-php at the end of the file. Although this seems like a perfectly innocuous thing it causes big trouble for TinyMCE specifically the gzip support built in to the wordpress/tinyMCE integration.

So imagine this…

<?php
/***************************************
* Example of PHP that does nothing, except
* break TinyMCE.
*
* Notice that after the 'end php tag' there are
* two blank lines.
****************************************/
?>
 
 

These two extra lines will break TinyMCE. I haven’t found a minimal reproduce case yet, but I am sure this is related to the call to ob_start(“ob_gzhandler”); This sort of makes sense in that ob_start() is a relatively sensitive function insofaras you can’t call echo or other functions that output to the main output stream from within a callback function, but we’re not really doing that. I suspect there is some kind of a bug in ob_start() or in the ob_gzhandler handler that doesn’t like these kind of non-PHP outputs in the middle of a PHP stream.

Another case I found which creates this same behavior is…

<?php
/***************************************
* Example of PHP that does nothing, except
* break TinyMCE
*
* Notice that a single space outside of the
* php context.
****************************************/

?> <?php

?>

Anyway, if you see your TinyMCE disappearing on you, then it may be that you have a plugin with a couple extra blank lines at the end of the file outside the context of the PHP script processor.

Creative Common License Chosen

I have decided to utilize the “Creative Commons Attribution-Noncommercial-Share Alike 3.0 License” for all code released on this blog. I will be updating all the source shortly to reflect this change.

This work is licensed under a:

Creative Commons Attribution – Noncommercial – Share Alike 3.0 License.

My reasoning behind this choice is as follows:

• I intend for these posts to be informative and educational. They are not intended to be fully functioning implementations. They are intended to represent reusable ideas. Therefore, you shouldn’t need more than this license to learn from what I’m presenting here.
• If you are planning on using this as is, then I would like you to give me the appropriate level of credit. And if you see me on the street, please introduce yourself and say “Thanks Man!”
• If you are planning on using this code as is for commercial purposes, then, well, please contact me. I make my living as a technologist, and if you’re making money off my hard work, then I want some control over that. That being said, I don’t mind teaching you what I’ve learned, and so please feel free to read my code, learn from it, and go about your business as you see fit.

Thanks.

Update to WPMU- Top Posts Plugin

Note, I’ve updated the code to 0.42.1 with the following changes…

• Small bug fix to ‘maybe_create_table’ behavior. Namely, we used to try to load it if this function wasn’t available, and now we simply check that the function is available.

• Added blog_id to the posts returned by get_top_posts. This can be useful in forming correct permalinks to your blog posts.

• Added function zap_setup_post_globals() which in some cases will setup the globals for other wordpressmu templates to work, but this doesn’t always reliably work

You can get the latest code here.