This demo service is a vanilla implementation of a Rails application using Crichton. It exposes several resources representing Diagnostic Repair Drones (DRDs).
The demo service uses a sample API Descriptor Document in Crichton, which describes a simple state machine with conditions on the various transitions. These conditions would typically be determined in the context of a request and passed in as options in the response. It further describes the semantics of the resources and the protocol-specific implementations used to generate the responses.
In order to explore Crichton's runtime generation of available transitions based on both the state of resources and the
satisfied conditions, a condition query parameter can be added in the browser to mimic this on the fly, as discussed
in the examples below.
$ bundle install
$ rake setup
$ bundle exec rails s -p 3000
Note: In some instances, it may be necessary to run bundle update to update the crichton gem with the latest
version since it currently points to a Github branch.
Take a look at the controllers and models to see the basic implementation for both single entities and resources that embed other resources with meta-data.
Crichton supports the media type text/html which allows interacting with an API directly in a browser. Enter the API
by opening http://localhost:3000 in a browser and and follow your nose. You will find a list of available resource
entry points.
Click a URL link to navigate to the associated entry point. You can add the following conditions, either as a single value or comma-separated list at any time, to see what changes when interacting with a resource:
- can_do_anything
- can_create
- can_update
- can_delete
- can_activate
- can_deactivate
- airlock_open
E.g. http://localhost:3000/drds?conditions=can_delete,can_activate
Crichton also supports a number of media-types out of the box. You can explore these supported media types using curl:
$ curl --header "Accept: application/vnd.hale+json" GET http://localhost:3000/drds
You can add the conditions query parameter here as well.
$ curl --header "Accept: application/vnd.hale+json" GET http://localhost:3000/drds?conditions=airlock_open
Don't miss the ALPS profile link when you view source in the head tag for responses and as a "Rel" link at the
localhost:3000 root. This profile (http://localhost:3000/alps/DRDs) is generated from the associated resource
descriptor in the API Descriptor Document and represents all the semantics and affordances that you will find in a
response.
You will notice there are no view templates defined to support the HTML and XHTML media-types. If you are wondering
what happens if I include an HTML view, change the name of the index.html.orb file to
index.html.erb and then reload the URL http://localhost:3000/drds.
Hint: It works like it should.