Elli on Elixir

In addition to the answers above, I would like to write up a complete guide on getting knutin/elli to work with Elixir. The above answers are correct, but I needed some more information to get up and running in my new elixir project.

Implement a handler that has @behaviour :elli_handler

This is your router/controller. A bare minimum example version of this looks like this:

 # lib/elli_handler.ex
 defmodule ElliHandler do
   @behaviour :elli_handler
   alias :elli_request, as: Request
    
   def handle(req, args) do
     handle(Request.method(req), Request.path(req), req, args)
   end
    
   def handle(:GET, _, req, args) do
     # do something with the request.
     # e.g. you can use Request.get_arg/2 to fetch a query param
     say = Request.get_arg("say", req)
     # Return a tuple with 3 elements
     # status code, list of header tuples, response body
     {200, [], "echo, #{say}"}
   end
    
   # Here you can react to all kinds of events of the full connection/request/response cycle
   # You must implement this, otherwise elli wont function properly, as it evaluates
   # the return value of handle_event/3.
   def handle_event(event, args, config) do
     # Here would be a good point to handle logging.
     # IO.inspect([event, args, config])
     :ok
   end
    
 end

Lets use an app that starts an elli supervisor

 # lib/elli_supervisor.ex
 defmodule ElliSupervisor do
   use Supervisor

   def start_link(ref, options) do
     Supervisor.start_link(__MODULE__, options, name: ref)
   end

   def init(options) do
     children = [
       worker(:elli, [options], id: :elli_http_server)
     ]
     supervise(children, strategy: :one_for_one)
   end

   def shutdown(ref) do
     case Supervisor.terminate_child(ref, :elli_http_server) do
       :ok -> Supervisor.delete_child(ref, :elli_http_server)
       err -> err
     end
   end
 end

 # lib/app.ex
 defmodule App do
   use Application

   def start(_type, _args) do
     import Supervisor.Spec, warn: false
     # lets start our elli supervisor, setting its options
     # callback should be set to the elli handler that implements the elli_handler behaviour
     # port will be the port elli is listening on, defaults to 8080
     ElliSupervisor.start_link(__MODULE__, callback: ElliHandler, port: 3000)
   end

 end

 # in mix.exs
 def application do
   [
     mod: {App, []}
   ]
 end

Add elli as a dependency to your mix.exs

Run mix get.deps to install your dependencies. Start your server with mix run --no-halt or in a console using iex -S mix.
```
 # in mix.exs
 defp deps do
   [
     # elli is our web server layer
     {:elli, github: "knutin/elli"}
   ]
 end
```