Medieval Programming

Creating feeds in symfony is already quite easy. If you want to create feeds you can have a look at the Askeet tutorial day 11 which describes how to create a feed with sfFeedPlugin. But If you can you should use sfFeed2Plugin which is the enhanced and maintained version. What you now need to do is to create your feeds.

I am using a simple routing rule pattern

feed_whatever:
  url: /feed/:type/$whateverName/:extraInformation
  param:  { module: feed, action: $whateverAction, type: rss}

I want to support both atom and rss feeds so this is handled for all routes in the feed pre execute:

public function preExecute() {
  $type = $this->getRequestParameter('type');
  switch ($type) {
    case "atom":
      $this->feed = new sfAtom1Feed();
      break;
    case "rss":
      $this->feed = new sfRssFeed();
      break;
  }
}

Doing so enables you $whateverAction to use $this->feed and generate a polymorphic feed, which will be returned as requested either as atom or rss.

The next step is to provide easy integration of those two. For that I created a feed Helper

function link_to_feed($name, $uri, $parameters = array(), $type = "rss"){
  if ($type == "rss") {
    $feed = "rss";
    $icon = "rss";
    $name = $name." (RSS 2.0)";
  } else {
    $feed = "atom";
    $icon = "feed";
    $name = $name." (ATOM 1.0)";
  }
  $uri = "@".$uri."?type=".$feed;
  foreach($parameters as $key => $value){
    $uri .= "&".$key."=".$value;
  }
  $options = array('alt' => $name, 'title' => $name, 'align' => 'absmiddle');
  $sf_request = sfContext::getInstance()->getRequest();
  $sf_request->setParameter('tvfeeds', $sf_request->getParameter('myfeeds').
        auto_discovery_link_tag($feed,$uri,$options)."\n");
  return link_to(image_tag('icons/'.$icon, $options), $uri);
}
 
function link_to_feeds($name, $uri, $parameters = array()){
  return link_to_feed($name, $uri, $parameters, "rss")." ".
           link_to_feed($name, $uri, $parameters, "atom");
}

This easy helper will automatically create both icons and routes when invoked like this:

 echo link_to_feeds("Newest Post","feed_posts",array("extraInformation"=>"user:15"));

Note the absence of the “@” in the route name, as the final route gets constructed inside.

One important part of magic gets done when setting that request parameter. You might know that symfony has a helper which helps you creating those “link alt” tags, called auto_discovery_link_tag, which the browser reads and can put a nice feed icon into the adress bar. However it needs to get to the header section.

To do so this is a slight hack. Dave Dash came up with another solution, which I was unaware of when implementing mine. I think both are simliar in idea, but different in doing, choose which you like best or invent your own .

When using the helper I automatically put the html code of a auto_discovery_link_tag representing this normal link to the feed into a request parameter. It does not have a fancy namespace. just called myfeeds.

Then in the layout.php I just need to do:

echo $sf_request->getParameter('myfeeds');

and all prepared auto_discovery_link’s are printed there. it also does nicely nothing if there are no links inside this parameter.

If you like you can also make this a get_autlink_for_header() helper but I was to lazy doing so (unfortunatly having that myfeeds hardcoded in two files instead of just one ).

I hope I could give you some ideas, or help you out.