Buddypress.org link: http://buddypress.org/community/groups/bp-group-control/

If you have comments and/or suggestions, I regularly check these channels as well as comments on this site.

Note to anyone who downloaded the plugin before a few days ago – I had named the plugin root folder wrong. You can re-download the plugin, or simply change the name of the plugin root directory from “BP-Group-Control” to “bp-group-control.”

I learn a few interesting things from this test. First, the tester got very annoyed with the lack of instant validation on the form. Turns out there is a lot you can mess up, and it tells you what you got wrong only one at a time. This will be a priority to fix in the next version.

This user seemed to understand what “make identifying” meant in the context, which was something that I was a bit unsure about.

For the most part, the tester figured out how to do what needed to be done, creating new users, adding existing users, and setting their group identifier.

As usual, the test exposed a few bugs that had gotten through. They’re fixed now!

WordPress loads plugins in alphabetical order. So the simplest (and most janky) solution is to name your plugin something that comes after “buddypress” in the alphabet. But there are better methods that you should use instead.

For versions before BP 1.2

The goal here is to check whether Buddypress has been loaded at the point when your plugin loads, and if it has not, load it manually. The manual load will prevent the normal load from happening later, so you won’t get double what you need.

If you are using BP 1.2+

Fortunately, they made this much easier to do in BP 1.2. For my plugin, all I needed to do was:

… in order to load my classes only once Buddypress has finished loading. Probably the safest way to ensure that your plugin completely loads after Buddypress is to create a loader.php file that contains this action and loads all of your other files.

I’ve seen this question come up on a lot of forums – people want to use email addresses as usernames in Buddypress. It makes sense – emails are easy to remember. But Buddypress has made this difficult to do. Andy Peatling added the following constant to the core:

in order to deal with part of this problem. But this did not solve the problem completely. See this article for how to use this. This changed allowed users to navigate to an @-containing username’s profile, but that user could not do things like create groups or edit his profile.

It turns out there’s another step to getting this to work. You have to override wp_sanitize_redirect in wp-includes/pluggable.php and add ‘@’ to the list of OK characters, like this:

Now it should work.

Fortunately it is quite easy to change the way activity items are stored in the database. I’m going to use blog post activity items as an example, but this process is the same for just about every kind of activity item.

The first objective is to find the filter function that you want to hook into. For blog posts, look to line 385 of bp-blogs.php, inside function bp_blogs_record_post(). In general, to find these record functions, search the component core file for the string ‘record.’ This will point you to both the utility function that hands the array off to bp_activity_add(), and to the function that a specific user task initiates to record an activity.

The filter we are interested in is bp_blogs_activity_new_post, in the segment:

Now, in our plugin, or in custom.php, add the following:

Skip to the next heading if you understand filters, or don’t care!

I will take a minute to explain filters, because they are a useful but somewhat obscure concept in WordPress. Filters are like actions, in that they provide an access point into code running in the WordPress framework. Filters are different from actions in that they return a value. It helps to think of apply_filters() as being analogous to do_action(). The first argument of apply_filters() is the tag that an add_filter() action hooks into with its first argument. This is not unlike the relationship between add_action() and do_action().

The second to nth arguments in apply_filters() allow variables to be passed into your custom filter. Try and understand this diagram:

Information flow between apply_filters, add_filter, and custom filter function

Back to the task!

It would be nice if we could edit the individual components of $activity_content, but alas, it doesn’t have its own filter. That’s why some copying is necessary from the core file – but usually this code is pretty short, as you can see. It’s necessary to pass $post, $post_permalink into your filter function so that you can use these values in your activity content variable.

After returning the variable with your formatted feed, guess what, you’re done! apply_filters() will return the value of your function’s return.

Its not too hard, but a big barrier to getting it to work is keeping all of the connections straight. When you have something of this nature wrong it is hard to debug.

Lets make a button that loads a hello world via ajax. Start with whatever input fields you need, and put a wp_nonce_field() underneath. Its a good idea to put all of this inside a form with an action, because you want people to be able to use your plugin even if they can’t run Javascript for some silly reason!

Enqueue a javacript file that has something like this:

We’re doing jQuery here. Basically this hi-jacks the submit button and causes javascript to run instead of the usual post to the action page. Read up on jQuery if this code doesn’t make any sense.

But let me explain a few things about the jQuery.post(). action, _wpnonce and cookie are $_REQUEST variables that Buddypress understands – you must name these properties exactly as you see here. Additionally, their values must correspond to other values set in different places of the Ajax process. I’m going to communicate these necessary equalities in a series of rules. The first one is:

_wpnonce” in the javascript file = id of your nonce_field (the second parameter of wp_nonce_field)

Now its time to write our target php function.

Here’s the second rule:

Bind your target function to an action named after the “action” property in your Ajax Javascript, and remember to add “wp_ajax_” to the beginning

. . . And the third:

Use the first argument (the action) of your wp_nonce_field() on the Ajax initiating template/screen function as the argument for check_admin_referer()

check_ajax_referer is a security thing – you need to do this. At the end of all of this, the message should appear dynamically at the end of your form when you press the button. Keeping the equalities straight is key.

It works by removing the action that normally triggers a function that includes bp-activity-site-wide-feed.php.

This issue was the culprit in most of the incompatibilities that I encountered. Other problems centered around the deprecated bp_add_nav_item(), which seemed to sometimes work but usually didn’t call the screen function correctly.

New callback format for your screen functions

Use this instead of bp_core_add_nav_item():

bp_core_new_nav_item() takes an array as its argument, otherwise it doesn’t work.

No avatars in database

This one really threw me for a loop. I was bringing a plugin up to 1.1 compatibility, and it mysteriously could not load avatar_thumb or avatar_full from the database. It turns out that they got rid of these columns in wp_bp_groups, and now use PHP filesystem functions to load urls directly from a folder.

Loading an avatar is actually much simpler now. For example, if you want to load a group avatar url, just call:

I pulled this example from a db class that takes a BP_Groups_Group object as a paramter. Any way of getting a group id here works though. And the arbitrary 'avatar_dir' => 'group-avatars' selects the correct group avatar directory. It finds whatever folder you type in, but bp-core/bp-core-avatars.php throws on a fixed preceding path.

What exactly does this mean? It means that after we’re done, you will have something on the right of your appearance->widgets screen like:

"Groups Sidebar" is not a default widget

There’s nothing special about code that runs inside a widget.

A widget is similar to any other piece of template code, except that widget output is defined by the return value of a special function and class. When you put your custom code into the specified parts of this function, WordPress will treat that code as something that can be run and displayed in a specific widget area, depending on where you drag your widget in /wp-admin/widgets.php.

Usually you want to define a widget area in your theme file. Lets say we want to add a widget area to the groups directory page (/directories/groups/index.php) in Buddypress. First find a place where you want to put your widget area div. For my example, I’m going to make a new div in /directories/groups/index.php. You can make a new one like I’m doing, or use an existing element in the template. I’ll put my new element right about here:

This will make the area below the group search box widget friendly. Add the following lines of code underneath, like this:

see http://codex.wordpress.org/WordPress_Widgets_Api/dynamic_sidebar

Basically this is saying “if nothing has called dynamic sidebar on the element with id ‘groups-sidebar,’ execute the code that comes after this. This is how you add default sidebar content to display when users have not added any widgets

There is one more step to defining a widget area. You might want to do this in a simple plugin:

source: http://codex.wordpress.org/Function_Reference/register_sidebar

You can modify these tags, but WordPress suggests that you leave the sprintf stuff alone for the sake of consistency.

Your widget area should now show up in wp-admin/widgets.php

It should display a properly formatted widget where ever you have it located. I found this process especially useful while editing Buddypress, because it seems like the groups and members pages should really be made widget friendly.

I suggest you read the documentation in http://codex.wordpress.org/WordPress_Widgets_Api for more information – this is basically how I learned to do this.