Http Values

Http without mutable state

Rationale

Java's servlet api is designed around side effects on the response. It has a signature like this:

javax.servlet.Servlet
public void service(ServletRequest req,
                    ServletResponse res)
             throws ServletException,
                    java.io.IOException

I wanted to treat the http request/response process as a function, like so

// Client
trait Sender {
  def send(request: RequestValue): ResponseValue
}

// Server
trait Receiver {
  def receive(request: RequestValue): ResponseValue
}

This allows implementors to test pure functions rather than dealing with streams.

There is also a good bit of support for handling dispatch in a testable way. A server can compose a bunch of named receivers together, an be confident that any path collisions will fail immediately with a sensible error message, rather than having an arbitrary receiver pick up the request.

Limitations

• The request and response values are reified immediately. This is usually not a problem unless your application typically ignores large portions of the request or response and thus could be optimized by waiting until they needed to be reified.
• By design, this library does not handle streaming. If you need streaming this is the wrong tool for the job.