trackback/lib.php

   1 <?php
   2         /*
   3          Trackback plugin for Elgg
   4          Initial author: Marcus Povey <marcus@dushka.co.uk>
   5         */
   6
   7         /** Initialise the trackback code & hook into framework */
   8         function trackback_init() {
   9
  10                 global $function, $CFG, $metatags;
  11
  12                 // Register javascript
  13                 $metatags .= "<script type=\"text/javascript\" src=\"{$CFG->wwwroot}mod/trackback/trackback.js\"><!-- trackback js --></script>";
  14
  15                 $function['weblog:post:links'][] = $CFG->dirroot . "mod/trackback/lib/weblog_post_links.php"; // Add trackback link.
  16                 $function['display:content:toolbar'][] = $CFG->dirroot . "mod/trackback/lib/weblog_post_trackback.php"; // Add trackback options to post
  17
  18                 listen_for_event("weblog_post","publish","trackback_parsefortrackbacks");
  19         }
  20
  21         function trackback_pagesetup() {
  22         }
  23
  24
  25         /**
  26          * Truncate some text to a given number of words.
  27          * This function truncates some text to a given number of words.
  28          */
  29         function trackback_TruncateToWords($text, $maxwords)
  30         {
  31                 $output = "";
  32                 $cnt = 0;
  33
  34                 for ($n = 0; $n < strlen($text); $n++)
  35                 {
  36                         if ($text[$n]==" ")
  37                                 $cnt++;
  38
  39                         if ($cnt>$maxwords)
  40                                 return $output;
  41
  42                         $output .= $text[$n];
  43                 }
  44
  45                 return $output;
  46          }
  47
  48         /**
  49          * This function sends some data as a post request to a server url.
  50          */
  51         function trackback_PostSend($server, $query, $contenttype = "application/x-www-form-urlencoded") {
  52
  53                 if (trim($server) == "")
  54                         return FALSE;
  55
  56                 // Construct data
  57                 $data_o = $query;
  58                 $serverdetails = parse_url($server);
  59
  60                 $host = $serverdetails['host'];
  61                 $port = 80;
  62
  63                 if ($serverdetails['scheme'] == "https") {
  64                         $host = "ssl://" . $host;
  65                         $port = 443;
  66                 }
  67
  68                 if (($serverdetails['port']!="") && ($serverdetails['port']!=$port)) $port = $serverdetails['port'];
  69
  70                 // Open socket
  71                 $socket = @fsockopen($host, $port,$errno, $errstr);
  72
  73                 if ($socket==FALSE)
  74                         return FALSE;
  75
  76                 // Construct URI to query
  77                 if (isset($serverdetails['query'])) {
  78                         $uri = $serverdetails['path'] . "?" . $serverdetails['query'];
  79                 } else {
  80                         $uri = $serverdetails['path'];
  81                 }
  82
  83                 // Construct query
  84                 $header_o = "POST " . $uri. " HTTP/1.0\r\n";
  85                 $header_o .= "Host: ".$serverdetails['host']."\r\n";
  86                 $header_o .= "Content-Length: " . strlen($data_o) . "\r\n";
  87                 $header_o .= "Content-type: $contenttype\r\n";
  88                 $header_o .= "User-Agent: Elgg trackback pinger\r\n";
  89                 $header_o .= "Connection: close\r\n";
  90
  91                 // Construct buffer
  92                 $buff = $header_o . "\n" . $data_o;
  93
  94                 // Write query
  95                 fputs($socket, $buff, strlen($buff));
  96
  97                 // Read response
  98                 $blob = "";
  99                 while (!feof($socket)) {
 100                         $blob .= fgets($socket);
 101                 }
 102
 103                 // Close socket
 104                 fclose($socket);
 105
 106                 // Parse out session variables
 107                 $blobs = explode("\r\n\r\n", $blob);
 108                 $headers = $blobs[0];
 109                 $body = $blobs[1];
 110
 111                 $r_data = $body;
 112
 113                 // Sanity check data
 114                 if (strlen(trim($r_data))==0)
 115                         return FALSE;
 116
 117                 return $r_data;
 118         }
 119
 120
 121         function trackback_Ok()
 122         {
 123 ?>
 124 <response>
 125 <error>0</error>
 126 </response>
 127 <?php
 128         }
 129
 130         function trackback_Error($message)
 131         {
 132 ?>
 133 <response>
 134 <error>1</error>
 135 <message><?php echo $message; ?></message>
 136 </response>
 137 <?php
 138                 die();
 139         }
 140
 141         /**
 142          * Send a trackback ping to a url.
 143          * @returns false on error
 144          */
 145         function trackback_sendtrackbackping($post, $url)
 146         {
 147                 global $CFG;
 148
 149                 $url = trim($url);
 150
 151                 // Pull user details
 152                 $username = urlencode(user_info("username", $post->weblog));
 153                 $blog_name = urlencode(user_info("name",$post->weblog));
 154
 155                 $words = trackback_TruncateToWords(
 156                                                 htmlentities(
 157                                                         strip_tags(
 158                                                                 stripslashes($post->body)
 159                                                         )
 160                                                 )
 161                                                 ,70
 162                                 );
 163
 164                 $title = urlencode(strip_tags(stripslashes($post->title)));
 165                 $excerpt = urlencode(
 166                         trim(
 167                                 $words . "...",
 168                                 "\r\n\t \0."
 169                         )
 170                 );
 171                 $src = urlencode($CFG->wwwroot . $username . "/weblog/" . $post->ident . ".html");
 172
 173                 $query = "title=$title&url=$src&excerpt=$excerpt&blog_name=$blog_name";
 174
 175                 $result = trackback_PostSend($url, $query);
 176                 if (($result != FALSE) && (strpos($result, "<error>0")!==FALSE) )
 177                         return true;
 178
 179                 return false;
 180         }
 181
 182         /**
 183          * Mine the post for links and see if we can find trackbacks.
 184          */
 185         function trackback_parsefortrackbacks($object_type, $event, $object)
 186         {
 187                 global $messages;
 188
 189                 if ($event=="publish")
 190                 {
 191                         // Check options for trackbacks
 192                         $SendTrackbacks = trim(optional_param('sendtrackbacks',''));
 193                         $giventrackbacks = trim(optional_param('trackbackurls',''), " \r\n,");
 194
 195                         $TrackbackUrls = array();
 196
 197                         // Have we been provided a trackback urls?
 198                         if ($giventrackbacks!="")
 199                                 $TrackbackUrls = explode(",", $giventrackbacks);
 200
 201                         // Do we need to search for trackbacks
 202                         if ($SendTrackbacks!="")
 203                         {
 204                                 // Find trackback pings
 205
 206                                 // Find urls in post
 207                                 $rtn = preg_match_all("*href=\"([^\"]+)\"*", $object->body, $urlarray);
 208                                 //$rtn = preg_match_all("/href=\"(.*)\"/imsU", $object->body, $urlarray);
 209
 210                                 if ($rtn>0) {
 211
 212                                         foreach ($urlarray[1] as $url)
 213                                         {
 214                                                 // Fetch permalink
 215                                                 $url = trim($url);
 216
 217                                                 // attempt to fetch url
 218                                                 $page = file_get_contents($url);
 219
 220                                                 // find trackback containing the permalink
 221                                                 preg_match_all("/<rdf\:RDF(.*)<\/rdf\:RDF>/imsU", $page, $matches);
 222
 223                                                 foreach ($matches[1] as $rdf)
 224                                                 {
 225                                                         if (strpos($rdf, $url)!==FALSE)
 226                                                         {
 227                                                                 // Found the correct trackback link
 228                                                                 $a = strpos($rdf, "trackback:ping=");
 229                                                                 $a+=16;
 230
 231                                                                 $b = strpos($rdf, "\"", $a);
 232
 233                                                                 if (($a!==FALSE) && ($b!==FALSE))
 234                                                                 {
 235                                                                         $TrackbackUrls[] = substr($rdf, $a, $b - $a);
 236                                                                 }
 237
 238                                                         }
 239                                                 }
 240
 241                                         }
 242                                 }
 243                         }
 244
 245                         // Ok, now send trackbacks to each url we have been given or harvested.
 246                         foreach (array_unique($TrackbackUrls) as $url)
 247                         {
 248                                 if (!trackback_sendtrackbackping($object, $url))
 249                                         $messages[] = "Could not send trackback to $url";
 250                                 else
 251                                         $messages[] = "Trackback sent to $url";
 252                         }
 253
 254                 }
 255
 256                 return $object;
 257         }
 258
 259
 260
 261 ?>