Your client application can use the Blogger Data API to create new blog posts, edit or delete existing blog posts, and query for blog posts that match particular criteria.

In addition to providing some background on the capabilities of the Blogger Data API, this document provides examples of basic Data API interactions using raw XML and HTTP. After reading this document, you may want to learn more about interacting with the API using our client libraries by reading the programming-language-specific sections of this developer’s guide.

#!/usr/bin/env ruby

require 'rubygems'
require 'feed_tools'

FeedTools.configurations[:feed_cache] = "DatabaseFeedCache"

puts "Getting feed 1st time..."
f = FeedTools::Feed.open('http://www.slashdot.org/index.rss')
puts "1. live? #{f.live?}"
puts "Getting feed 2nd time..."
f = FeedTools::Feed.open('http://www.slashdot.org/index.rss')
puts "2. live? #{f.live?}"

Assuming FeedTools can find a database.yml file and the database has thecached_feeds table described in the FeedTools documentation, the above script will cache the feed after the first time and f.live? will return false the second time you run it.

I also added an index on the href column in cached_feeds. All the lookups are done on that column and the migration that comes with FeedTools doesn’t have any indices. 

Since both blog engines were on different servers and used different database schema’s, rather than delving into the depths of SQL magic to bring all of the content across (mapping tables, foreign keys and data, etc), I took an approach of using XML-RPC to migrate the content instead.

XML-RPC is a style of web services supported by both MovableType and Typo to provide access to blogs over the web programatically. There’s various different API’savailable for MovableType and Typo including metaWeblog, Blogger, and MT, all supporting various methods of accessing and posting articles. Clients and servers of these API’s have been implemented in many varied languages as well.

feed = FeedTools::Feed.open('http://dekstop.de/weblog/index.xml')
puts feed.title
feed.items.each { |item|
  puts item.title
  puts item.link
}

Requesting a feed every time you run your script is fine as long as you only parse your own feeds, but you should be a bit more polite as soon as you start requesting someone else’s feed. Over time feeds can cost site owners a lot of bandwidth, so keep that in mind when you start developing your own feed reader. A proper aggregator keeps a local cache of all feeds and only downloads feeds when they have actually changed, not every time the application is run.

FeedTools has excellent support for keeping and managing such a local cache, it’s just not documented very well. So in order to address that I’ll show you how I’ve been caching feed requests with FeedTools 0.2.17, and as you’ll see it’s quite simple as long as you are aware of some caveats.