Feedparser - Robust RSS, Atom, and RDF feed parsing in Node.js

This module adds methods for RSS, Atom, and RDF feed parsing in node.js using Isaac Schlueter's sax parser.

Requirements

• sax
• request
• addressparser

Installation

npm install feedparser

Changes since v0.9.x

The module now exports parseString, parseFile, parseUrl, and parseStream as static functions. You no longer need to create a FeedParser instance or use the prototype methods. Due to confusion about how to implement those methods in application code, using the prototype methods is now DEPRECATED.

As a major enhancement, Feedparser is now able to properly handle XML namespaces, including those in sadistic feeds that define a non-default namespace for the main feed elements.

Old API (Deprecated)

var FeedParser = require('feedparser')
  , parser = new FeedParser()
  ;
parser.on('article', console.log);
parser.parseString(string);

New API

var feedparser = require('feedparser');
feedparser.parseString(string)
  .on('article', console.log);

Usage

parser.parseString(string, [options], [callback])

• string - the contents of the feed

parser.parseFile(filename, [options], [callback])

• filename - a local filename or remote url

parser.parseUrl(url, [options], [callback])

The first argument can be either a url or a request options object. The only required option is uri, all others are optional. See request for details about what that request options object might look like.

• url - fully qualified uri or a parsed url object from url.parse()

parser.parseStream(readableStream, [options], [callback])

• readableStream - a Readable Stream

options

• normalize - Set to false to override Feedparser's default behavior, which is to parse feeds into an object that contains the generic properties patterned after (although not identical to) the RSS 2.0 format, regardless of the feed's format.

• addmeta - Set to false to override Feedparser's default behavior, which is to add the feed's meta information to each article.

• dateformat - Optionally set a specific format for parsing of the dates (e.g. for different locales). The format is moment style.

• feedurl - The url (string) of the feed. FeedParser is very good at resolving relative urls in feeds. But some feeds use relative urls without declaring the xml:base attribute any place in the feed. This is perfectly valid, but if we are parsing the feed with the parseString, parseFile, or parseStream method, we don't know know the feed's url before we start parsing the feed and trying to resolve those relative urls. If we discover the feed's url, we will go back and resolve the relative urls we've already seen, but this takes a little time (not much). If you want to be sure we never have to re-resolve relative urls (or if FeedParser is failing to properly resolve relative urls), you should set feedurl.

Examples

var feedparser = require('feedparser')
  , fs = require('fs') // used in the examples below
  ;

Use as an EventEmitter

(For brevity in this pseudo-code, I'm not handling errors. But you need to handle errors in your code.)

function callback (article) {
  console.log('Got article: %s', JSON.stringify(article));
}

// You can give a local file path to parseFile()
feedparser.parseFile('./feed')
  .on('article', callback);

// For libxml compatibility, you can also give a URL to parseFile()
feedparser.parseFile('http://cyber.law.harvard.edu/rss/examples/rss2sample.xml')
  .on('article', callback);

// Or, you can give that URL to parseUrl()
feedparser.parseUrl('http://cyber.law.harvard.edu/rss/examples/rss2sample.xml')
  .on('article', callback);

// But you should probably be using conditional GETs and passing the results to
// parseString() or piping it right into the stream, if possible

var request = require('request');
var reqObj = {'uri': 'http://cyber.law.harvard.edu/rss/examples/rss2sample.xml',
              'headers': {'If-Modified-Since' : <your cached 'lastModified' value>,
                          'If-None-Match' : <your cached 'etag' value>}};

// parseString()
request(reqObj, function (err, response, body){
  feedparser.parseString(body)
    .on('article', callback);
});

// Stream piping
request(reqObj).pipe(feedparser.stream);

// Or you could try letting feedparser handle working with request (experimental)
feedparser.parseUrl(reqObj)
  .on('response', function (response){
    // do something like save the HTTP headers for a future request
  })
  .on('article', callback);

// Using the stream interface with a file (or string)
// A good alternative to parseFile() or parseString() when you have a large local file
feedparser.parseStream(fs.createReadStream('./feed'))
  .on('article', callback);
// Or
fs.createReadStream('./feed').pipe(feedparser.stream)
  .on('article', callback);

Events

• complete - called with meta and articles when parsing is complete
• end - called with no parameters when parsing is complete or aborted (e.g., due to error)
• error - called with error whenever there is a an error of any kind (SAXEror, Feedparser error, request error, etc.)
• meta - called with meta when it has been parsed
• article - called with a single article when each article has been parsed
• response - called with the HTTP response only when a url has been fetched via parseUrl or parseFile
• 304 - called with no parameters when when a url has been fetched with a conditional GET via parseUrl or parseFile and the remote server responds with '304 Not Modified'

Use with a callback

When the feed is finished being parsed, if you provide a callback, it gets called with three parameters: error, meta, and articles.

function callback (error, meta, articles){
  if (error) console.error(error);
  else {
    console.log('Feed info');
    console.log('%s - %s - %s', meta.title, meta.link, meta.xmlurl);
    console.log('Articles');
    articles.forEach(function (article){
      console.log('%s - %s (%s)', article.date, article.title, article.link);
    });
  }
}

feedparser.parseFile('./feed', callback);

// To use the stream interface with a callback, you *MUST* use parseStream(), not piping
feedparser.parseStream(fs.createReadStream('./feed'), callback);

What is the parsed output produced by feedparser?

Feedparser parses each feed into a meta portion and one or more articles.

Regardless of the format of the feed, the meta and each article contain a uniform set of generic properties patterned after (although not identical to) the RSS 2.0 format, as well as all of the properties originally contained in the feed. So, for example, an Atom feed may have a meta.description property, but it will also have a meta['atom:subtitle'] property.

The purpose of the generic properties is to provide the user a uniform interface for accessing a feed's information without needing to know the feed's format (i.e., RSS versus Atom) or having to worry about handling the differences between the formats. However, the original information is also there, in case you need it. In addition, Feedparser supports some popular namespace extensions (or portions of them), such as portions of the itunes, media, feedburner and pheedo extensions. So, for example, if a feed article contains either an itunes:image or media:thumbnail, the url for that image will be contained in the article's image.url property.

All generic properties are "pre-initialized" to null (or empty arrays or objects for certain properties). This should save you from having to do a lot of checking for undefined, such as, for example, when you are using jade templates.

In addition, all properties (and namespace prefixes) use only lowercase letters, regardless of how they were capitalized in the original feed. ("xmlUrl" and "pubDate" also are still used to provide backwards compatibility.) This decision places ease-of-use over purity -- hopefully, you will never need to think about whether you should camelCase "pubDate" ever again.

List of meta propreties

• title
• description
• link (website link)
• xmlurl (the canonical link to the feed, as specified by the feed)
• date (most recent update)
• pubdate (original published date)
• author
• language
• image (an Object containing url and title properties)
• favicon (a link to the favicon -- only provided by Atom feeds)
• copyright
• generator
• categories (an Array of Strings)

List of article propreties

• title
• description (frequently, the full article content)
• summary (frequently, an excerpt of the article content)
• link
• origlink (when FeedBurner or Pheedo puts a special tracking url in the link property, origlink contains the original link)
• date (most recent update)
• pubdate (original published date)
• author
• guid (a unique identifier for the article)
• comments (a link to the article's comments section)
• image (an Object containing url and title properties)
• categories (an Array of Strings)
• source (an Object containing url and title properties pointing to the original source for an article; see the RSS Spec for an explanation of this element)
• enclosures (an Array of Objects, each representing a podcast or other enclosure and having a url property and possibly type and length properties)
• meta (an Object containing all the feed meta properties; especially handy when using the EventEmitter interface to listen to article emissions)

Contributors

The following are the major contributors of node-feedparser (in no specific order).

• Dan MacTough (danmactough)

Although node-feedparser no longer shares any code with node-easyrss, it was the original inspiration and a starting point.

License

(The MIT License)

Copyright (c) 2011-2012 Dan MacTough <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.