= Rave: A Google Wave robot client framework for Ruby Rave is a framework for building robot applications to participate in Google Wave conversations. See http://wave.google.com/ for Google Wave details. Or if you are interested in the ins-and-outs of the Google Wave protocol, check out http://www.waveprotocol.org/ == Warning! Both Rave and Google Wave are super-alpha. There are a lot of things in the protocol that aren't implemented in Rave yet. And the protocol is changing, so the things that are implemented are likely to break at some point. I will try to keep up, but if you notice anything broken, or if you have a need for something that isn't implemented yet, shoot me an email: diminish7 at gmail dot com. Okay. You've been warned. == The Basics Since Google currently requires that all robots run on App Engine, this tutorial assumes you are using JRuby. You should have JRuby already installed, and you should have the App Engine SDK installed. You can find more information on JRuby at http://jruby.org/, and you can find more information about the App Engine SDK at http://code.google.com/appengine/downloads.html === Install Rave sudo jruby -S gem install rave === Start a new Rave Project Rave comes with a "rave" executable that, among other things, sets up the project structure for you. Setting up a new project looks like this: jruby -S rave create [robot_name] [options] The options include profile_url and image_url, which will set the URL for the robot's profile and avatar, respectively. Here's how the example project "appropriate casey" was set up: jruby -S rave create appropriate-casey profile_url=http://appropriate-casey.appspot.com/_wave/robot/profile image_url=http://appropriate-casey.appspot.com/image.png This will stub out a project called "appropriate-casey". It automatically creates a robot class AppropriateCasey, creates the config files for both Rack and Warbler, and creates the appengine-web.xml file that App Engine will need. For the App Engine file, it assumes that the App Engine project name is the same as the robot's name. So in this case, the application name is appropriate-casey, which means I have to have the URL http://appropriate-casey.appspot.com. If you name your robot something different than the App Engine application ID, just change the <application> line in appengine-web.xml. === Build your robot! The robot.rb file that Rave created contains a class that extends Rave::Models::Robot. All of the logic needed for your robot to talk to App Engine is included in Rave::Models::Robot, so all you really need to do now is define your robot's event listeners. Here is a list of the events that Google Wave can send your robot: * WAVELET_BLIP_CREATED * WAVELET_BLIP_REMOVED * WAVELET_PARTICIPANTS_CHANGED * WAVELET_TIMESTAMP_CHANGED * WAVELET_TITLE_CHANGED * WAVELET_VERSION_CHANGED * BLIP_CONTRIBUTORS_CHANGED * BLIP_DELETED * BLIP_SUBMITTED * BLIP_TIMESTAMP_CHANGED * BLIP_VERSION_CHANGED * DOCUMENT_CHANGED * FORM_BUTTON_CLICKED To add a listener to your robot that will respond to a given event, just define a method with the lower-case version of the event name, that accepts an event and a context. So, I want appropriate-casey to do something whenever a document is changed (the DOCUMENT_CHANGED event), so I add the following method to my robot: def document_changed(event, context) # Do some stuff end The Event object contains the following properties: * type (The type of event, "DOCUMENT_CHANGED" in this case) * timestamp (the timestamp that the event occurred) * modified_by (the user ID of the user who modified the document) * properties (Varies by event type, but this will be a hash with blipID in this case) The Context object contains the following properties: * waves (A hash - the keys are the wave IDs, and the values are the waves) * wavelets (A hash - the keys are the wavelet IDs, and the values are the wavelets) * blips (A hash - the keys are the blip IDs, and the values are the blips) * operations (An array of operations) See the Google Wave documentation for definitions of each of these things... So, with Appropriate Casey, I want to create a robot that looks for people "shouting" in Waves (i.e. writing in all caps with a lot of exclamation points) and convert the text into a more appropriate case. So "I'M NOT YELLING!!!!" would get converted to "I'm not yelling." To do this, I just create a document_changed method in my robot that looks something like this: def document_changed(event, context) unless event.modified_by == "appropriate-casey@appspot.com" || event.modified_by == "spelly@gwave.com" context.blips.values.each do |blip| if blip.content new_sentence = true blip.content.length.times do |index| range = index..index+1 char = blip.content[index, 1] if char =~ /[A-Z]/ && !new_sentence blip.set_text_in_range(range, char.downcase) elsif char =~ /[a-z]/ && new_sentence blip.set_text_in_range(range, char.upcase) elsif char == "!" if new_sentence blip.delete_range(range) else blip.set_text_in_range(range, ".") end end new_sentence = (char =~ /\.!?/ || (char =~ /\s/ && new_sentence)) end end end end end Here's what's going on: first, I'm bailing if the blip was modified by either Appropriate Casey, or the spellchecker. This is just to prevent us from having to do any logic when we know we aren't going to change anything. Then, I iterate through the blips and check their content. Any character that is capital that isn't the start of a sentence gets downcased, any character that is lower case and DOES start a sentence gets upper cased. Exclamations get turned into a period (and additional exclamation points get dropped). There are two API methods being called: blip#set_text_in_range and blip#delete_range. Both of these methods update the content of the blip locally (so the changes happen optimistically) and then send operation requests back to the server so that all users can see the changes. So that's it, my robot is now ready to go: just 17 lines of code. === Packaging for deploy I'm assuming that you have an application set up on App Engine already. Again, for the time being, all robots have to be on App Engine to work with Google Wave. First of all, we need to turn our project into the correct format for App Engine. There is a utility in the "rave" executable for this, so from your robot's top-level folder, run: jruby -S rave war This is basically just a wrapper around the warbler gem, but with some additional cleanup to get things in the right format for App Engine. For example, the complete JRuby jar is too large for App Engine, so Rave replaces it with two jars. Once you've run "rave war", you'll see a tmp/ folder, and a .war file. You can ignore the .war file, as App Engine needs the unpacked version. The tmp/war folder is what will get deployed. === Testing The worst part about App Engine is testing... Rave includes a "server" command that starts up Rack for your application, but that is of limited use, since App Engine has many App Engine-specific issues. Better to use the App Engine SDK (which is still not a perfect match to the deployed environment, but it's better). The App Engine SDK comes with a dev_server command. From your project directory run: path/to/appengine_sdk/bin/dev_server tmp/war This will start the development server on port 8080. You can now hit the following three URLs: * http://localhost:8080/_wave/capabilities.xml * http://localhost:8080/_wave/robot/profile * http://localhost:8080/_wave/robot/jsonrpc The first two are GETs, but the last one requires a POST. See the Google Wave protocol for the expected body of the POST if you want to test locally. === Deploying Use the App Engine SDK to deploy. From your project directory run: path/to/appengine_sdk/bin/appcfg update tmp/war === Using the robot From a Google Wave client, start a new wave, and invite your robot as a participant. Your robot's user name will be [robot_name]@appspot.com. So Casey is at appropriate-casey@appspot.com. === The End That's it. Enjoy! = TODO * Allow other URLs to be set up * Finish porting the existing Python API functionality