link-rel-parser.php

<?
error_reporting(0);
/*
Copied from https://github.com/indieweb/link-rel-parser-php/blob/master/src/IndieWeb/link_rel_parser.php
Copyright 2015 Aaron Parecki

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
 
http_rels, head_http_rels by Tantek Çelik http://tantek.com/
license: http://creativecommons.org/publicdomain/zero/1.0/
*/

// in $h: HTTP headers as a string
// returns: array of rel values as indices to arrays of URLs
function http_rels($h) {
  $h = preg_replace("/(\r\n|\r)/", "\n", $h);
  $h = explode("\n", preg_replace("/(\n)[ \t]+/", " ", $h));
  $rels = array();
  foreach ($h as $f) {
    if (!strncmp($f, 'X-Pingback: ', 12)) {
      // convert to a link header and have common code handle it
      $f = 'Link: <' . trim(substr($f, 12)) . '>; rel="pingback"';
    }
    if (!strncmp($f, 'Link: ', 6)) {
      $links = explode(', ', trim(substr($f, 6)));
      foreach ($links as $link) {
        $hrefandrel = explode('; ', $link);
        $href = trim($hrefandrel[0], '<>');
        $relarray = '';
        foreach ($hrefandrel as $p) {
          if (!strncmp($p, 'rel=', 4)) {
            $relarray = explode(' ', trim(substr($p, 4), '"\''));
            break;
          }
        }
        if ($relarray !== '') { // ignore Link: headers without rel
          foreach ($relarray as $rel) {
            $rel = strtolower(trim($rel));
            if ($rel != '') {
              if (!array_key_exists($rel, $rels)) {
                $rels[$rel] = array();
              }
              if (!in_array($href, $rels[$rel])) {
                $rels[$rel][] = $href;
              }
            }
          }
        }
      }
    }
  }
  return $rels;
}
// in $url: URL to get HTTP HEAD Link (and effective/x-extended) rels
// returns: array of
//        "status"=> HTTP status code,
//        "type"=> HTTP Content-Type
//        "rels" array with http_rels return value
function head_http_rels($url) {
	$c = curl_init();
	curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($c, CURLOPT_URL, $url);
	curl_setopt($c, CURLOPT_CONNECTTIMEOUT, 20);
	curl_setopt($c, CURLOPT_TIMEOUT, 30);
	curl_setopt($c, CURLOPT_USERAGENT, 'head_http_rels function');
	curl_setopt($c, CURLOPT_FOLLOWLOCATION, 1);
  curl_setopt($c, CURLOPT_SSL_VERIFYPEER , false );
  curl_setopt($c, CURLOPT_SSL_VERIFYHOST , false );
  curl_setopt($c, CURLOPT_HEADER, true);
  curl_setopt($c, CURLOPT_NOBODY, true);
  $h = curl_exec($c);
	$i = curl_getinfo($c);
  curl_close($c);
  unset($c);
  $r = array();
  $r['status'] = $i['http_code'];
  $r['type'] = $i['content_type'];
  $r['rels'] = http_rels($h);
  return $r;
}
?>