feedparser

feedparser

feedparser gem - web feed parser and normalizer (Atom, RSS, JSON Feed, HTML h-entry, etc.)

• home :: github.com/feedparser/feedparser
• bugs :: github.com/feedparser/feedparser/issues
• gem :: rubygems.org/gems/feedparser
• rdoc :: rubydoc.info/gems/feedparser
• forum :: groups.google.com/group/wwwmake

What's News?

October/2017: Added support for attachments / media enclosures in RSS and Atom.

June/2017: Added support for reading feeds in HTML with Microformats incl. h-entry, h-feed and others.

All feed with test assertions for easy (re)use and browsing moved to its own repo, that is, /feeds.

May/2017: Added support for reading feeds in the new JSON Feed format in - surprise, surprise - JSON.

What's a Web Feed?

See the Awesome Feeds page ».

Usage

Structs

Feed • Item • Author • Tag • Attachment • Generator

Feed Struct

Mappings

Note: uses question mark (?) for optional elements (otherwise assume required elements)

Title 'n' Summary

Note: The Feed parser will remove all html tags and attributes from the title (RSS 2.0+Atom), description (RSS 2.0) and subtitle (Atom) content and will unescape HTML entities e.g. & becomes & and so on - always resulting in plain vanilla text.

Feed Struct	RSS 2.0	Notes	Atom	Notes	JSON	Notes
feed.title	title	plain text	title	plain text	title	plain text
feed.summary	description	plain text	subtitle?	plain text	description?	plain text

Dates

Feed Struct	RSS 2.0	Notes	Atom	Notes
feed.updated	lastBuildDate?	RFC-822 format	updated	ISO 801 format
feed.published	pubDate?	RFC-822 format	-

Note: Check - for RSS 2.0 set feed.updated to pubDate or lastBuildDate if only one present? if both present - map as above.

RFC-822 date format e.g. Wed, 14 Jan 2015 19:48:57 +0100

ISO-801 date format e.g. 2015-01-11T09:30:16Z

class Feed
  attr_accessor :format   # e.g. atom|rss 2.0|etc.
  attr_accessor :title    # note: always plain vanilla text - if present html tags will get stripped and html entities unescaped
  attr_accessor :url

  attr_accessor :items

  attr_accessor :summary   # note: is description in RSS 2.0 and subtitle in Atom; always plain vanilla text

  attr_accessor :updated     # note: is lastBuildDate in RSS 2.0
  attr_accessor :published   # note: is pubDate in RSS 2.0; not available in Atom

  attr_accessor :authors
  attr_accessor :tags
  attr_accessor :generator
end

(Source: lib/feedparser/feed.rb)

Item Struct

Title 'n' Summary

Note: The Feed parser will remove all html tags and attributes from the title (RSS 2.0+Atom), description (RSS 2.0) and summary (Atom) content and will unescape HTML entities e.g. & becomes & and so on - always resulting in plain vanilla text.

Note: In plain vanilla RSS 2.0 there's no difference between (full) content and summary - everything is wrapped in a description element; however, best practice is using the content "module" from RSS 1.0 inside RSS 2.0. If there's no content module present the feed parser will "clone" the description and use one version for item.summary and the clone for item.content.

Note: In JSON Feed the title is not required (that is, is optional). The idea is to support "modern" micro blog postings (tweets, toots, etc.) that have no titles. The JSON Feed supports content_html and/or content_text. At least one version must be present.

Note: The content element will assume html content.

Feed Struct	RSS 2.0	Notes	Atom	Notes	JSON	Notes
item.title	title	plain text	title	plain text	title?	plain text
item.summary	description	plain text	summary?	plain text	-tbd-
item.content	content?	html	content?	html	content_html (*)	html

Dates

Item Struct	RSS 2.0	Notes	Atom	Notes
item.updated	pubDate?	RFC-822 format	updated	ISO 801 format
item.published	-	RFC-822 format	published?	ISO 801 format

Note: In plain vanilla RSS 2.0 there's only one pubDate for items, thus, it's not possible to differeniate between published and updated dates for items; note - the item.pubDate will get mapped to item.updated. To set the published date in RSS 2.0 use the dublin core module e.g dc:created, for example.

class Item
  attr_accessor :title   # note: always plain vanilla text - if present html tags will get stripped and html entities
  attr_accessor :url

  attr_accessor :content
  attr_accessor :content_type  # optional for now (text|html|html-escaped|binary-base64) - not yet set

  attr_accessor :summary

  attr_accessor :updated    # note: is pubDate in RSS 2.0 and updated in Atom
  attr_accessor :published  # note: is published in Atom; not available in RSS 2.0 (use dc:created ??)

  attr_accessor :guid     # todo: rename to id (use alias) ??
end

(Source: lib/feedparser/item.rb)

Author Struct

(Source: lib/feedparser/author.rb)

Tag Struct

(Source: lib/feedparser/tag.rb)

Attachment Struct

Also known as Media Enclosure

(Source: lib/feedparser/attachment.rb)

Generator Struct

(Source: lib/feedparser/generator.rb)

Read Feed Example

require 'open-uri'
require 'feedparser'

txt = open( 'http://openfootball.github.io/feed.xml' ).read

feed = FeedParser::Parser.parse( txt )

puts feed.title
# => "football.db - Open Football Data"

puts feed.url
# => "http://openfootball.github.io/"

puts feed.items[0].title
# => "football.db - League Quick Starter Sample - Mauritius Premier League - Create Your Own Repo/League(s) from Scratch"

puts feed.items[0].url
# => "http://openfootball.github.io/2015/08/30/league-quick-starter.html"

puts feed.items[0].updated
# => Sun, 30 Aug 2015 00:00:00 +0000

puts feed.items[0].content
# => "Added a new quick starter sample using the Mauritius Premier League to get you started..."

...

or reading a feed in the new JSON Feed format in - surprise, surprise - JSON; note: nothing changes :-)

txt = open( 'http://openfootball.github.io/feed.json' ).read

feed = FeedParser::Parser.parse( txt )

puts feed.title
# => "football.db - Open Football Data"

puts feed.url
# => "http://openfootball.github.io/"

puts feed.items[0].title
# => "football.db - League Quick Starter Sample - Mauritius Premier League - Create Your Own Repo/League(s) from Scratch"

puts feed.items[0].url
# => "http://openfootball.github.io/2015/08/30/league-quick-starter.html"

puts feed.items[0].updated
# => Sun, 30 Aug 2015 00:00:00 +0000

puts feed.items[0].content_text
# => "Added a new quick starter sample using the Mauritius Premier League to get you started..."

...

Microformats

Microformats let you mark up feeds and posts in HTML with h-entry, h-feed, and friends.

Note: Microformats support in feedparser is optional. Install and require the the microformats gem to read feeds in HTML with Microformats.

require 'microformats'

text =<<HTML
<article class="h-entry">
  <h1 class="p-name">Microformats are amazing</h1>
  <p>Published by
    <a class="p-author h-card" href="http://example.com">W. Developer</a>
     on <time class="dt-published" datetime="2013-06-13 12:00:00">13<sup>th</sup> June 2013</time>

  <p class="p-summary">In which I extoll the virtues of using microformats.</p>

  <div class="e-content">
    <p>Blah blah blah</p>
  </div>
</article>
HTML

feed = FeedParser::Parser.parse( text )

puts feed.format
# => "html"
puts feed.items.size
# =>  1
puts feed.items[0].authors.size
# => 1
puts feed.items[0].content_html  
# => "<p>Blah blah blah</p>"
puts feed.items[0].content_text  
# => "Blah blah blah"
puts feed.items[0].title
# => "Microformats are amazing"
puts feed.items[0].summary
# => "In which I extoll the virtues of using microformats."
puts feed.items[0].published
# => 2013-06-13 12:00:00
puts feed.items[0].authors[0].name
# => "W. Developer"
...

Samples

Feed Reader

Planet Feed Reader in 20 Lines of Ruby

planet.rb:

require 'open-uri'
require 'feedparser'
require 'erb'

# step 1) read a list of web feeds

FEED_URLS = [
  'http://vienna-rb.at/atom.xml',
  'http://weblog.rubyonrails.org/feed/atom.xml',
  'http://www.ruby-lang.org/en/feeds/news.rss',
  'http://openfootball.github.io/feed.json',
]

items = []

FEED_URLS.each do |url|
  feed = FeedParser::Parser.parse( open( url ).read )
  items += feed.items
end

# step 2) mix up all postings in a new page

FEED_ITEM_TEMPLATE = <<EOS
<% items.each do |item| %>
  <div class="item">
    <h2><a href="<%= item.url %>"><%= item.title %></a></h2>
    <div><%= item.content %></div>
  </div>
<% end %>
EOS

puts ERB.new( FEED_ITEM_TEMPLATE ).result

Run the script:

$ ruby ./planet.rb      

Prints:

<div class="item">
  <h2><a href="http://vienna-rb.at/blog/2017/11/06/picks/">Picks / what the vienna.rb team thinks is worth sharing this week</a></h2>
  <div>
   <h3>6/11 Picks!!</h3>
   <p>In a series on this website we'll entertain YOU with our picks...
 ...

Real World Usage

See the Planet Pluto feed reader family:

• Planet Pluto - static planet website generator
• Planet Pluto Live - dynamic (live) planet web apps (using Sinatra, Rails, etc.)

Add your tools, scripts, apps here! Let us know.

Install

Just install the gem:

$ gem install feedparser

License

The feedparser scripts are dedicated to the public domain. Use it as you please with no restrictions whatsoever.

Questions? Comments?

Send them along to the wwwmake Forum/Mailing List. Thanks!