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Helium is a DSL for REST API specifications and also a Java API for processing descriptions written in this language.

How to write a spec

Our main purpose is to describe some REST service API. We start with naming, small description, and base service URI.

service {
  name 'Twitter API'
  description 'Piece of Twitter API'
  version 1.1

  location "https://api.twitter.com/${version}"
}

Now we describe the first method which returns user profile:

// This is a description of user profile response structure
type "UserProfile" message {
  id long required
  screen_name 'string' required
  profile_image_url_https 'string' optional
}

service {
  // ...

  // Here's our method description
  get "/users/show.json" spec {
    name 'Get user profile'
    description '''
      Returns a variety of information about the user specified by the required user_id
      or screen_name parameter. The author's most recent Tweet will be returned inline when possible.
    '''
    parameters {
      user_id long optional
      screen_name 'string' optional
      include_entities boolean optional
    }
    response "UserProfile"
  }
}

Project Handlers

Currently Java API contains handlers for:

• API tests generation
• Java source code generation