lib/pubsubhubbub/subscriber.php

   1 <?php
   2
   3 // a PHP client library for pubsubhubbub
   4 // as defined at http://code.google.com/p/pubsubhubbub/
   5 // written by Josh Fraser | joshfraser.com | josh@eventvue.com
   6 // Released under Apache License 2.0
   7
   8 class Subscriber {
   9
  10     // put your google key here
  11     // required if you want to use the google feed API to lookup RSS feeds
  12     protected $google_key = "";
  13
  14     protected $hub_url;
  15     protected $callback_url;
  16     protected $credentials;
  17     // accepted values are "async" and "sync"
  18     protected $verify = "async";
  19     protected $verify_token;
  20     protected $lease_seconds;
  21
  22     // create a new Subscriber (credentials added for SuperFeedr support)
  23     public function __construct($hub_url, $callback_url, $credentials = false) {
  24
  25         if (!isset($hub_url))
  26             throw new Exception('Please specify a hub url');
  27
  28         if (!preg_match("|^https?://|i",$hub_url))
  29             throw new Exception('The specified hub url does not appear to be valid: '.$hub_url);
  30
  31         if (!isset($callback_url))
  32             throw new Exception('Please specify a callback');
  33
  34         $this->hub_url = $hub_url;
  35         $this->callback_url = $callback_url;
  36         $this->credentials = $credentials;
  37     }
  38
  39     // $use_regexp lets you choose whether to use google AJAX feed api (faster, but cached) or a regexp to read from site
  40     public function find_feed($url, $http_function = false) {
  41         // using google feed API
  42         $url = "http://ajax.googleapis.com/ajax/services/feed/lookup?key={$this->google_key}&v=1.0&q=".urlencode($url);
  43         // fetch the content
  44         if ($http_function)
  45             $response = $http_function($url);
  46         else
  47             $response = $this->http($url);
  48
  49         $result = json_decode($response, true);
  50         $rss_url = $result['responseData']['url'];
  51         return $rss_url;
  52     }
  53
  54     public function subscribe($topic_url, $http_function = false) {
  55         return $this->change_subscription("subscribe", $topic_url, $http_function = false);
  56     }
  57
  58     public function unsubscribe($topic_url, $http_function = false) {
  59         return $this->change_subscription("unsubscribe", $topic_url, $http_function = false);
  60     }
  61
  62     // helper function since sub/unsub are handled the same way
  63     private function change_subscription($mode, $topic_url, $http_function = false) {
  64         if (!isset($topic_url))
  65             throw new Exception('Please specify a topic url');
  66
  67          // lightweight check that we're actually working w/ a valid url
  68          if (!preg_match("|^https?://|i",$topic_url))
  69             throw new Exception('The specified topic url does not appear to be valid: '.$topic_url);
  70
  71         // set the mode subscribe/unsubscribe
  72         $post_string = "hub.mode=".$mode;
  73         $post_string .= "&hub.callback=".urlencode($this->callback_url);
  74         $post_string .= "&hub.verify=".$this->verify;
  75         $post_string .= "&hub.verify_token=".$this->verify_token;
  76         $post_string .= "&hub.lease_seconds=".$this->lease_seconds;
  77
  78         // append the topic url parameters
  79         $post_string .= "&hub.topic=".urlencode($topic_url);
  80
  81         // make the http post request and return true/false
  82         // easy to over-write to use your own http function
  83         if ($http_function)
  84             return $http_function($this->hub_url,$post_string);
  85         else
  86             return $this->http($this->hub_url,$post_string);
  87     }
  88
  89     // default http function that uses curl to post to the hub endpoint
  90     private function http($url, $post_string) {
  91
  92         // add any additional curl options here
  93         $options = array(CURLOPT_URL => $url,
  94                          CURLOPT_USERAGENT => "PubSubHubbub-Subscriber-PHP/1.0",
  95                          CURLOPT_RETURNTRANSFER => true);
  96
  97         if ($post_string) {
  98             $options[CURLOPT_POST] = true;
  99             $options[CURLOPT_POSTFIELDS] = $post_string;
 100         }
 101
 102         if ($this->credentials)
 103             $options[CURLOPT_USERPWD] = $this->credentials;
 104
 105         $ch = curl_init();
 106         curl_setopt_array($ch, $options);
 107
 108         $response = curl_exec($ch);
 109         $info = curl_getinfo($ch);
 110
 111         // all good -- anything in the 200 range
 112         if (substr($info['http_code'],0,1) == "2") {
 113             return $response;
 114         }
 115         return false;
 116     }
 117 }
 118
 119
 120 ?>