March 11, 2015

JAX-RS Client API Groovy DSL, prototype

Groovy language is DSL friendly language.  See http://groovy-lang.org/dsls.html or http://groovy.codehaus.org/Writing+Domain-Specific+Languages.

Let me share with you my JAX-RS Client API Groovy DSL prototype, code is available in GitHub https://github.com/shamoh/jersey-groovy repo. It just supports GET and POST methods. This is really just concept prototype. But it shows power of Groovy and way how simplified JAX-RS Client API could look like.

The GitHub repository contains couple of unit tests to show the DSL. And also uses Spock Framework what is another Groovy DSL example, in this case as testing framework/API.

Examples

GET plain text, no parameters

JAX-RS Client API:
WebTarget target = ClientBuilder.newClient().target(RESOURCE_URL)
def response = target.request(TEXT_PLAIN_TYPE).get(String)
response == "Hello World!"
Jersey Groovy DSL:
def response = GET[RESOURCE_URL].text
response == "Hello World!"


GET plain text, path parameter

JAX-RS Client API:
WebTarget target = ClientBuilder.newClient().target(RESOURCE_URL)
def response = target.path("Jersey").request(TEXT_PLAIN_TYPE).get(String)
response == "Hello Jersey!"
Jersey Groovy DSL:
def response = GET[RESOURCE_URL/"Jersey"].text
response == "Hello Jersey!"


GET XML, path parameter

JAX-RS Client API:
WebTarget target = ClientBuilder.newClient().target(RESOURCE_URL)
def response = target.path("Jersey").request(APPLICATION_XML_TYPE).get(Message)
response instanceof Message
response.greeting == "Hello Jersey!"
Jersey Groovy DSL:
def response = (GET[RESOURCE_URL/"Jersey"] & APPLICATION_XML_TYPE) as Message
response instanceof Message
response.greeting == "Hello Jersey!"


POST plain text, response text

JAX-RS Client API:
WebTarget target = ClientBuilder.newClient().target(RESOURCE_URL)
def Entity entity = Entity.entity("Jersey", TEXT_PLAIN_TYPE);
def response = target.request().post(entity, String)
response == "Hello Jersey!"
Jersey Groovy DSL:
def response = POST[RESOURCE_URL] << "Jersey" as String
response == "Hello Jersey!"

POST object as JSON, response text

JAX-RS Client API:
WebTarget target = ClientBuilder.newClient().target(RESOURCE_URL)
def Entity entity = Entity.entity(new Message("Jersey", new Date()), APPLICATION_JSON_TYPE)
def response = target.request().post(entity, String)
response == "Hello Jersey!"
Jersey Groovy DSL:
def response = (POST[RESOURCE_URL] | APPLICATION_JSON_TYPE) \
                   << new Message("Jersey", new Date()) as String
response == "Hello Jersey!"

(And finally there is simple slide deck to introduce the DSL API, same examples.)

Enjoy.