juust ~ php oddities

a social spider

juust | 24/01/2009

I was reading about the BloGee project and some other stuff and then I thought “how much trouble would it be writing a Wordpress plugin to do some basic ’social spidering’”. BloGee is about a micro-content format and that’s a bit out of my scope.

I want a simple ’social’ spider for Wordpress so I am going to take some functions of simpleTags and add them to the Wordpress xml-rpc server methods, to get some basic functionality I can call upon through the xml-rpc endpoint.

I don’t know if I mentioned that, adding methods to Wordpress XML-RPC differs from the straight forward use of Incutio because Wordpress uses its own filter/hook system, the actual IXR_Server instance is made and managed by Wordpress itself.

I hence don’t use the

class PeekAtYouServer extends IXR_Server {

style class instancing, in stead I make a class where I hook the function I would normally hand to the IXR_Server as callback into wordpress by adding method/callback to the ‘xmlrpc_methods’ filter array.

class PeekAtYouServer {
function PeekAtYouServer() {
// add callbacks as methods to the array (filter) xmlrpc_methods
add_filter('xmlrpc_methods', array(&$this, 'filterXmlrpcMethods'));
}
/**
* Here I connect the methodName pay.PeekAtYou to a custom function
*
* This is the array that is added (as pair) to the xmlrpc_methods filter
**/
function filterXmlrpcMethods(&$methods) {
$methods['pay.PeekAtYou'] = array(&$this, 'onXmlRpcpayPeekAtYou');
return $methods;
}
/**
* the custom function used as callback for pay.PeekAtYou
**/
function onXmlRpcpayPeekAtYou($args) {
global $wpdb;
//grab posts
$sql = "SELECT ID, post_title FROM " . $wpdb->posts . " WHERE post_status = 'publish'";
$posts = $wpdb->get_results($sql);
//cycle through all posts and grab the IDs
$result = array();
if (!empty($posts)) {
foreach ($posts as $post) $this->postids[] = $post->ID;
//I got all the ids in an array,
//now I grab the tags (query is from the simpleTags plugin)
$this->getTagsFromCurrentPosts();
} else {
return new IXR_Error(404, 'no posts for the selected criterium.');
}
return $this->tags_currentposts;
}
/**
* Get tags from current post views
* (SimpleTags plugin)
* @return boolean
*/
function getTagsFromCurrentPosts() {
if ( is_array($this->postids) && count($this->postids) > 0 ) {
// Generate SQL from post id
$postlist = implode( "', '", $this->postids);
global $wpdb;
$results = $wpdb->get_results("
SELECT t.name AS name, t.term_id AS term_id, tt.count AS count
FROM {$wpdb->term_relationships} AS tr
INNER JOIN {$wpdb->term_taxonomy} AS tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
INNER JOIN {$wpdb->terms} AS t ON (tt.term_id = t.term_id)
WHERE tt.taxonomy = 'post_tag'
AND ( tr.object_id IN ('{$postlist}') )
GROUP BY t.term_id
ORDER BY tt.count DESC");
$this->tags_currentposts = $results;
unset($results, $key);
}
return true;
}
}

I saved the file as PeekAtYouServer.class.php.

Now I need a simple file for Wordpress to ’spot the plugin’, so I can activate it and make the class instance, that adds the custom method and callback function.

/*
Plugin Name: PeekAtYou XMLRPC Server
Plugin URI: http://www.juust.org/
Description: Adds Social Spidering to your blog
Author: juust
Author URI: http://www.juust.org/
License: GPL
Version: 1.1
*/
require_once 'PeekAtYouServer.class.php';
$PeekAtYouServer = new PeekAtYouServer();

I save that as PeekAtYouServer.php and upload the lot to a directory /wp-plugins/pay-xmlrpc-server.

In the Plugin screen (wp 2.5) I can activate the plugin, and then make a call to the xmlrpc-endpoint of the blog using pay.PeekAtYou as methodName.