WordPress Toolbar v 2.2 : Custom toolbar url, Support for WPMU and bug fixes

download-wordpress-plugin

WordPress toolbar plugin provide a facebook, digg style toolbar for all outgoing links from your blog posts. The toolbar url defaults to http://yourblog/wp-content/plugins/wordpress-toolbar/toolbar.php. However with version 2.2, blog admin can customize toolbar url to http://yourblog/wordpress-toolbar/ through the admin panel. A lot of other enhancements have been added like cross-plugin compatibility and support for WPMU hosted blogs. Check full feature list below.

What’s New?
Listed below is list of new features and bug fixes released with v 2.2:

  1. Support for customizing toolbar url through admin panel
  2. Support for WPMU hosted blogs
  3. Support for removing “Get this Plugin” widget from the toolbar through admin panel
  4. Security fix for possible XSS attack. Fix done by passing encoded hash string instead of plain text parameters. Also added various security checks on toolbar page to avoid possible XSS attacks.
  5. Bug fix where plugin didn’t work as expected because of cross plugin compatibility issues. Fix done by replacing server side toolbar logic with client side (using jquery) logic.
  6. Bug fix to show sociable share icons and tinyurl share link only for single posts and pages
  7. Bug fix for unrecognizable code in the toolbar when the encoding of hosted blog is different from utf-8. Fix done by using hosted blog settings instead of hardcoded utf-8.

Also core plugin code has been restructured (OOPS oriented now) so that maintainability and support becomes easier and quicker.

Steps to customize the default toolbar URL
Enable WordPress Toolbar v 2.2 plugin. Assuming you want to change default toolbar url from /wp-content/plugins/wordpress-toolbar/toolbar.php to /wordpress-toolbar, follow these steps:

  1. Enable apache mod_rewrite
  2. Add AllowOverride All in your blog virtual host config file and restart apache
  3. Add following apache rewrite rule by editing your blog .htaccess file
    RewriteRule ^wordpress-toolbar$ wp-content/plugins/wordpress-toolbar/toolbar.php
    RewriteRule ^wordpress-toolbar/$ wp-content/plugins/wordpress-toolbar/toolbar.php
  4. If you have blogs hosted using WPMU, add following apache rewrite rules in .htaccess file
    RewriteRule ^wordpress-toolbar$ wp-content/plugins/wordpress-toolbar/toolbar.php
    RewriteRule ^wordpress-toolbar/$ wp-content/plugins/wordpress-toolbar/toolbar.php
    RewriteRule ^([0-9a-zA-Z-]+)/wordpress-toolbar$ $1/wp-content/plugins/wordpress-toolbar/toolbar.php
    RewriteRule ^([0-9a-zA-Z-]+)/wordpress-toolbar/$ $1/wp-content/plugins/wordpress-toolbar/toolbar.php
  5. Manually check if rewrite rules are working. Open your custom toolbar url and you should see a result similar to this http://abhinavsingh.com/blog/wordpress-toolbar
  6. If for some reasons you DO NOT see “Working! Though required parameters are missing.” on toolbar page, it means rewrite rules didn’t worked as expected. Before you proceed with the setup, you SHOULD fix rewrite rules
  7. Go to wordpress admin and click "Wordpress Toolbar" under Settings tab
  8. Update your new custom toolbar url as shown: wordpress-toolbar-v-2.2-custom-toolbar-url-demo
  9. Clear cache and verify your toolbar

Enjoy and kindly let me know if you have issues installing plugin on your host.

Writing your first facebook chat bot in PHP using Jaxl library

Today facebook officially announced availability of it’s chat through jabber/xmpp clients. This is a big win for XMPP, with almost 400 million new probable users adding into XMPP club. In this post, I will demonstrate how to connect to facebook chat servers using Jaxl client library in PHP. It can further be used to make custom chat bots for facebook.

Creating your first facebook chat bot:
Follow the steps to successfully run a facebook chat bot:

  1. Download Jaxl or checkout latest from trunk
    svn checkout http://jaxl.googlecode.com/svn/trunk/ jaxl-read-only
  2. Edit the configuration file config.ini.php as follows:
      // Set an enviornment
      $env = "prod";
    
      $key = array("prod"=>array("user"=>"facebook_username",
                                 "pass"=>"facebook_password",
                                 "host"=>"chat.facebook.com",
                                 "port"=>5222,
                                 "domain"=>"chat.facebook.com"
                                ),
  3. Run from command line:
    [email protected]:/jaxl$ sudo php index.php
    OSType: Linux, Registering shutdown for SIGINT and SIGTERM
    OpenSSL: Enabled for CLI
    Attempting DIGEST-MD5 Authentication...
    Starting Session...
    Requesting Feature List...
    Requesting Roster List...
    Setting Status...
    Done
    

Try to send a message to your running chat bot and you shall receive a default message back from the bot saying “Hi, Thanks for your message”.

See further sample codes and explaination on how to build a full fledged gaming chat bots under xmpp category.

MEMQ : Fast queue implementation using Memcached and PHP only

Memcached is a scalable caching solution developed by Danga interactive. One can do a lot of cool things using memcached including spam control, online-offline detection of users, building scalable web services. In this post, I will demonstrate and explain how to implement fast scalable queues in PHP.

MEMQ: Overview
Every queue is uniquely identified by it’s name. Let’s consider a queue named “foo” and see how MEMQ will implement it inside memcached:

  • Two keys namely, foo_head and foo_tail contains meta information about the queue
  • While queuing, item is saved in key foo_1234, where 1234 is the current value of key foo_tail
  • While de-queuing, item saved in key foo_123 is returned, where 123 is the current value of key foo_head
  • Value of keys foo_head and foo_tail start with 1 and gets incremented on every pop and push operation respectively
  • Value of key foo_head NEVER exceeds value of foo_tail. When value of two meta keys is same, queue is considered empty.

MEMQ: Code
Get the source code from GitHub:
http://github.com/abhinavsingh/memq

<?php

	define('MEMQ_POOL', 'localhost:11211');
	define('MEMQ_TTL', 0);

	class MEMQ {

		private static $mem = NULL;

		private function __construct() {}

		private function __clone() {}

		private static function getInstance() {
			if(!self::$mem) self::init();
			return self::$mem;
		}

		private static function init() {
			$mem = new Memcached;
			$servers = explode(",", MEMQ_POOL);
			foreach($servers as $server) {
				list($host, $port) = explode(":", $server);
				$mem->addServer($host, $port);
			}
			self::$mem = $mem;
		}

		public static function is_empty($queue) {
			$mem = self::getInstance();
			$head = $mem->get($queue."_head");
			$tail = $mem->get($queue."_tail");

			if($head >= $tail || $head === FALSE || $tail === FALSE)
				return TRUE;
			else
				return FALSE;
		}

		public static function dequeue($queue, $after_id=FALSE, $till_id=FALSE) {
			$mem = self::getInstance();

			if($after_id === FALSE && $till_id === FALSE) {
				$tail = $mem->get($queue."_tail");
				if(($id = $mem->increment($queue."_head")) === FALSE)
					return FALSE;

				if($id <= $tail) {
					return $mem->get($queue."_".($id-1));
				}
				else {
					$mem->decrement($queue."_head");
					return FALSE;
				}
			}
			else if($after_id !== FALSE && $till_id === FALSE) {
				$till_id = $mem->get($queue."_tail");
			}

			$item_keys = array();
			for($i=$after_id+1; $i<=$till_id; $i++)
				$item_keys[] = $queue."_".$i;
			$null = NULL;

			return $mem->getMulti($item_keys, $null, Memcached::GET_PRESERVE_ORDER);
		}

		public static function enqueue($queue, $item) {
			$mem = self::getInstance();

			$id = $mem->increment($queue."_tail");
			if($id === FALSE) {
				if($mem->add($queue."_tail", 1, MEMQ_TTL) === FALSE) {
					$id = $mem->increment($queue."_tail");
					if($id === FALSE)
						return FALSE;
				}
				else {
					$id = 1;
					$mem->add($queue."_head", $id, MEMQ_TTL);
				}
			}

			if($mem->add($queue."_".$id, $item, MEMQ_TTL) === FALSE)
				return FALSE;

			return $id;
		}

	}

?>

MEMQ: Usage
The class file provide 3 methods which can be utilized for implementing queues:

  1. MEMQ::is_empty – Returns TRUE if a queue is empty, otherwise FALSE
  2. MEMQ::enqueue – Queue up the passed item
  3. MEMQ::dequeue – De-queue an item from the queue

Specifically MEMQ::dequeue can run in two modes depending upon the parameters passed, as defined below:

  1. $queue: This is MUST for dequeue to work. If other optional parameters are not passed, top item from the queue is returned back
  2. $after_id: If this parameter is also passed along, all items from $after_id till the end of the queue are returned
  3. $till_id: If this paramater is also passed along with $after_id, dequeue acts like a popRange function

Whenever optional parameters are passed, MEMQ do not remove the returned items from the queue.

MEMQ: Is it working?
Add following line of code at the end of the above class file and hit the class file from your browser. You will get back inserted item id as response on the browser:

var_dump(MEMQ::enqueue($_GET['q'], time()));

Lets see how cache keys looks like in memcached:

[email protected]:~$ telnet localhost 11211
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

get foo_head
VALUE foo_head 1 1
1
END

get foo_tail
VALUE foo_tail 1 1
2
END

get foo_1
VALUE foo_1 1 10
1265540583
END

get foo_2
VALUE foo_2 1 10
1265540585
END

MEMQ: Benchmark
Below are the benchmarking results for varying load:

  1. Queuing performance: 697.18 req/sec (n=1000, c=100) and 258.64 req/sec (n=5000, c=500)
  2. Dequeue performance: 641.27 req/sec (n=1000, c=100) and 242.87 req/sec (n=5000, c=500)

MEMQ: Why and other alternatives
There are several open source alternatives which provide a lot more scalability. However, MEMQ was written because my application doesn’t expect a load in order of 10,000 hits/sec. Listed below are a few open source alternatives for applications expecting high load:

  1. ActiveMQ: A reliable and fast solution under apache foundation
  2. RabbitMQ: Another reliable solution based on AMQP solution
  3. Memcacheq: A mash-up of two very stable stacks namely memcached and berkleyDB. However, it’s installation is a bit tricky.

MEMQ: Mantra and Customization
At the base MEMQ implementation can be visualized as follows:

There is a race between two keys in memcached (foo_head and foo_tail). Both are incremented on every dequeue and queue operation respectively. However, foo_tail is strong enough and never allows foo_head to exceed. When value of keys foo_tail and foo_head are equal, queue is considered empty.

The above code file still doesn’t include utility methods like MEMQ::total_items etc. However, writing such methods should be pretty easy depending upon your application needs. Also depending upon your application requirement, you should also take care of overflowing integer values.