Description

Httprevayler is a groovy implementation of a transparent prevalent rest server.

A Jetty server is embedded to do the Http job. The prevalence is provided by Prevayler. The prevalent transparency is achieved journaling Http requests and snapshoting the domain models tree.

The basics

This is the simplest server (listening at localhost on port 8484) you can create:

class MyServer {
	static void main(String[] args) {
		PrevalentServer server = new PrevalentServer(8484);
		server.startRunning(new Object(), new MyResource())
	}
}

class MyResource extends SimpleResource {
	def doGet() {
		'hello!'
	}
}

Run on a command line to see the result:

curl localhost:8484

Doing something

The startRunning method receives two parameters: the root of domain models tree and a SimpleResource.

class MessagesServer {
	static void main(String[] args) {
		PrevalentServer server = new PrevalentServer(8484);
		server.startRunning(new MessagesApp(), new MessagesResource())
	}
}

class MessagesApp {
	def messages = []
}

class MessagesResource extends SimpleResource {
	def doGet() {
		domain.messages
	}
	
	def doPost() {
		domain.messages << request.parameterMap['text']
	}
}

Try this:

curl -XPOST -H "Content-type:application/json" http://localhost:8484 -d '{"text":"Some message"}'
curl -XPOST -H "Content-type:application/json" http://localhost:8484 -d '{"text":"Another message"}'
curl localhost:8484
-- stop the server and start again --
curl localhost:8484

It just works, like a magic ;-)

Routing

If more than one Resource is needed, it is necessary to use a router. As a SimpleRouter is a SimpleResource, just use the Router on startRunning call.

class MyRouter extends SimpleRouter {
	MyRouter() {
		attach("/messages", MessagesResource.class)
		attach("/messages/:id", MessagesResource.class)
		attach("/tasks/:year/:month", DreSemestralResource.class)
	}
}

...