Updated: RSS Autodiscovery with PHP

// April 4th, 2008 // Technology

Found an excellent function made by Keith Devens for autodiscovery of RSS feeds on a website.

The only issue I had with it was that a lot of news sites these days publish more than one RSS feed, so I updated the code to return an array of feeds instead of only the first one + I made it fetch the body of the page instead of supplying it in the call.

This is what I got:


function getRSSLocation($location = false){

$html = file_get_contents($location);
$feeds = array();

if(!$html or !$location){
return false;
}else{
#search through the HTML, save all tags
# and store each link's attributes in an associative array
preg_match_all('/ /si', $html, $matches);
$links = $matches[1];
$final_links = array();
$link_count = count($links);
for($n=0; $n<$link_count; $n++){
$attributes = preg_split('/\s+/s', $links[$n]);
foreach($attributes as $attribute){
$att = preg_split('/\s*=\s*/s', $attribute, 2);
if(isset($att[1])){
$att[1] = preg_replace('/([\'"]?)(.*)\1/', '$2', $att[1]);
$final_link[strtolower($att[0])] = $att[1];
}
}
$final_links[$n] = $final_link;
}
#now figure out which one points to the RSS file
for($n=0; $n<$link_count; $n++){
if(strtolower($final_links[$n]['rel']) == 'alternate'){
if(strtolower($final_links[$n]['type']) == 'application/rss+xml'){
$href = $final_links[$n]['href'];
}
if(!$href and strtolower($final_links[$n]['type']) == 'text/xml'){
#kludge to make the first version of this still work
$href = $final_links[$n]['href'];
}
if($href){
if(strstr($href, "http://") !== false){ #if it's absolute
$full_url = $href;
}else{ #otherwise, 'absolutize' it
$url_parts = parse_url($location);
#only made it work for http:// links. Any problem with this?
$full_url = "http://$url_parts[host]";
if(isset($url_parts['port'])){
$full_url .= ":$url_parts[port]";
}
if($href{0} != '/'){ #it's a relative link on the domain
$full_url .= dirname($url_parts['path']);
if(substr($full_url, -1) != '/'){
#if the last character isn't a '/', add it
$full_url .= '/';
}
}
$full_url .= $href;
}
if(!in_array($full_url, $feeds))
$feeds[] = $full_url;
}
}
}
return $feeds;
}
}


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