1  $.ajax({
   2  	type: 'GET',
   3  	url: '/some/good/stuff.xml',
   4  	dataType: 'xml',
   5  	error: function(xhr) {
   6  		alert('Failed to parse feed');
   7  	},
   8  	success: function(xml) {
   9  		var channel = $('channel', xml).eq(0);
  10  		var items = [];
  11  		$('item', xml).each( function() {
  12  			var item = {};
  13  			item.title = $(this).find('title').eq(0).text();
  14  			item.link = $(this).find('link').eq(0).text();
  15  			item.description = $(this).find('description').eq(0).text();
  16  			item.updated = $(this).find('pubDate').eq(0).text();
  17  			item.id = $(this).find('guid').eq(0).text();
  18  			items.push(item);
  19  		});
  20  		console.dir(items);
  21  	}
  22  });

Your friend Internet Explorer

For IE 6 and better (worse?) the feed must return the right content type, so make sure the response contains this header:

   1  Content-type: text/xml

If this header is not set the jQuery Ajax error handler is called and the feed is not parsed.

This snippet shows how to parse feeds with Scala and the Rome library:

   1  import com.sun.syndication.io._
   2  import com.sun.syndication.feed.synd._
   3  import java.net.URL
   4  
   5  object FeedParser {
   6    def main(args: Array[String]): Unit = {
   7      try {
   8        val sfi = new SyndFeedInput()
   9  
  10        val urls = List("http://hbl.fi/rss.xml")
  11        
  12        urls.foreach(url => {
  13          val feed = sfi.build(new XmlReader(new URL(url)))
  14  
  15          val entries = feed.getEntries()
  16  
  17          println(feed.getTitle())
  18          println(entries.size())
  19        })
  20      } catch {
  21        case e => throw new RuntimeException(e)
  22      }
  23      
  24    }
  25  }

This snippet explains how to do conditional gets with Feedzirra 0.0.17:

   1  # First create a dummy parser, any type of parser will do
   2  f = Feedzirra::Parser::RSS.new
   3  
   4  # Set the required Feedzirra values with data from your database
   5  f.feed_url = feed_from_db.url
   6  f.etag = feed_from_db.etag
   7  f.last_modified = feed_from_db.last_modified_at
   8  
   9  # Set the last entry. This step is important. 
  10  # This allows Feedzirra to detect if a feed that doesn't support last modified and etag has been updated.
  11  last_entry = Feedzirra::Parser::RSSEntry.new
  12  
  13  # Do we have a last entry in the database? If so let Feedzirra know
  14  if feed_from_db.items.last
  15    last_entry.url = feed_from_db.items.last.link
  16  end
  17  
  18  # Without this Feedzirra will return an empty array or some other surprise
  19  f.entries << last_entry
  20  
  21  # Update the feed
  22  Feedzirra::Feed.update f

   1  atom_feed(:url => formatted_posts_url(:atom)) do |feed|
   2    feed.title(@category.name)
   3    feed.updated(@posts.first ? @posts.first.created_at : Time.now.utc)
   4  
   5    for post in @posts
   6      feed.entry(post) do |entry|
   7        entry.title(post.title)
   8        entry.content(post.body_html, :type => 'html')
   9        entry.updated post.updated_at
  10  
  11        for tag in post.tags
  12          entry.category :term => url_for(tag), :label => tag.name
  13        end
  14      end
  15    end
  16  end

This example uses the Universal Feed Parser, one of the best and fastest parsers for Python.

Feed Parser is a lot faster than feed_tools for Ruby and it’s about as fast as the ROME Java library according to my simple benchmark.

Feed Parser uses less memory and about as much of the CPU as ROME , but this wasn’t tested with a long running process, so don’t take my word for it.

   1  import time
   2  import feedparser
   3  
   4  start = time.time()
   5  
   6  feeds = [
   7  	'http://..', 
   8  	'http://'
   9  ]
  10  
  11  for url in feeds:
  12    options = {
  13      'agent'   : '..',
  14      'etag'    : '..',
  15      'modified': feedparser._parse_date('Sat, 29 Oct 1994 19:43:31 GMT'),
  16      'referrer' : '..'
  17    }
  18  
  19    feed = feedparser.parse(url, **options)
  20  
  21    print len(feed.entries)
  22    print feed.feed.title.encode('utf-8')
  23  
  24  end = time.time()
  25  
  26  print 'fetch took %0.3f s' % (end-start)