Play HATEOAS client

This is a simple playframework module for working with HATEOAS services.

Features

• chain service calls following links
• provide http authentication information
• provide custom http headers
• expand uri templates (using https://github.com/arktekk/uri-template)

Getting the module

The module can be included by adding the resolvers

resolvers += Resolver.url("thovid play modules on github (releases)", url("http://thovid.github.com/releases/"))(Resolver.ivyStylePatterns)

resolvers += Resolver.url("thovid play modules on github (snapshots)", url("http://thovid.github.com/snapshots/"))(Resolver.ivyStylePatterns)

to the build file and using the dependency

"de.thovid" %% "play-hateoas-client" % "1.0.0"

Supported versions

Currently, only playframework 2.2.x and scala 2.10 are supported. The module is in an early stage of development. The current version is 1.0.0.

Using the module

The module expects service calls to return links in the format

{
  "some_content": "xzy",
  "links": [
    {
	  "rel": "self",
	  "path": "http://some.url/stuff/123"
	},
	{
	  "rel": "update",
	  "path": "http://some.url/other-stuff/123"
	
	}
  ]
}

Example usage:

1. Simple get:

val result = HATEOAS.client
  .at("http://localhost/samples/1")
  .get()
  .asJson {
    case (200, json) => name(json)
  }

gets the content of the url as json (of type play.api.libs.json.JsValue). The result is of type Future[Either[String, A]], where A is the type of the partial function provided to the asJson method.

If an error occurred, or if the partial function is not defined for the result (for example, if the status code is not 200 in the example above), e Left[String] containing the error message is returned.

2. Get following a link:

val result = HATEOAS.client  
  .at(s"http://localhost/samples")
  .following("self", selectedBy("samples" -> "id", "2"))
  .get()
  .asJson {
    case (OK, json) => name(json)
  }

The code above makes two calls: First a GET to the provided url. It expects the response to contain a json array named samples containing objects with attribute id. It selects the entry with id = "2" and executes a GET on the link named "self" provided with this entry. The result of the second GET is handed over to the partial function parsing the result.

Licence

APACHE 2 License http://www.apache.org/licenses/LICENSE-2.0.txt