My last post dealt with calling Google Apps API methods from a Ruby script.  I had hoped that I’d be able to do everything I needed with RESTful methods, but after a short while it became increasingly difficult, and I had to resign to using the Google API client GEM.  Initially I was resistant to using the pre-packaged solution as I like to know what’s going on under-the-hood when I’m interfacing with something, but it became apparent that the advantages to using the GEM far outweighed the simplicity of RESTful calls, especially with some of the APIs that I was going to be interfacing with.

As it turns out there are some very good reasons to use the google-api-client gem.  Since you can easily inspect the object’s methods and properties you can determine all the methods associated with an API.  For instance, to get the methods available for the version 3 Calendar api, once you’ve created a client object do the following:

api = client.discovered_api('calendar', 'v3')
puts api.methods

Nice right?

Even more useful is the ability to determine the APIs available, and their version numbers:

puts "Title \t ID \t Preferred"
client.discovered_apis.each do |gapi|
  puts "#{gapi.title} \t #{gapi.id} \t #{gapi.preferred}"
end

And that gives you a great start for attacking the Google API documentation.

There are some additional differences for creating a client connection.  You’ll need to have a private key file accessible to your script, on top of the usual server-side configurations.  You’ll also need to check out the advantages of using a “service account client”, which allow you to run API calls as a specific user, which is extremely useful when dealing with the somewhat flawed Google Apps access security model.