Sinatra-inspired web routing DSL, includes streaming. Interested in feedback

I subscribe to the Python credo of “Explicit is better than Implicit”. ^.^

It’s a simple guide however certainly gives an answer I wouldn’t argue with.

Here is what an example chat server currently looks like, with this DSL

defmodule Example do
  use Tokumei

  config :port, 8080
  config :static, "./public"
  config :templates, "./templates"

  route "/" do
    get() ->
      ok(home_page())
    post(%{body: body}) ->
      {:ok, %{message: message}} = PublishForm.parse(body)
      {:ok, _} = ChatRoom.publish(message)
      redirect("/")
  end

  route "/updates" do
    get() ->
      {:ok, _} = ChatRoom.join()
      SSE.stream(:updates)
  end

  SSE.streaming :updates do
    {:message, message} ->
      {:send, %{event: "chat", data: "message"}
    _ ->
      {:nosend}
  end
end

Hopefully it the majority of the example is self explanatory.I hope to push the first version to hex soon

There is now a first release of this router. The Tokumei framework has a super alpha first release and a generator to get you started

mix archive.install https://github.com/crowdhailer/tokumei/raw/master/tokumei_new.ez
mix tokumei.new my_app
cd my_app
iex -S mix

A more thorough example, which includes streaming server sent event, is included in the source repo. It’s a chatroom naturally.

Working on an update that will route to specific modules, rather than writing actions inline. This will be helpful in writing larger applications. I am looking for opinions on possibilities for the routing sytanx.

required features are

• fixed matching
• variable matching
• wildcard matching
• subpath mounting
• named routes for helpers

Option 1
as above, i.e. path first.
advantages are not having to repeat path declaration and being able to automatically return 405 response

@name :posts
route "/posts",
  GET: ShowPostsPage,
  POST: CreatePost

@name :post
route "/posts/:id",
  GET: ShowPostPage,
  PUT: UpdatePost

@name :search
route "/search/*blob",
  GET: SearchPage

mount "/api", APIController

Option 2
method first
advantages are similar to plug/sinatra/rails

@name :posts
get "/posts", ShowPostsPage,
post "/posts", CreatePost

@name :post
get "/posts/:id", ShowPostPage
put "/posts/:id", UpdatePost

@name :search
get "/search/*blob", SearchPage

mount "/api", APIControlle

I’d think Option 2 would be best so you could potentially match to out of order get/post’s like is common in Plug/Phoenix.

Sorry, I don’t know what you mean by this:

The streaming solution above was unsatisfactory. keeping track of streaming state from several possible endpoints in a single module was challenging.

A better idea is to use a module for each endpoint each of those having several callbacks for the state of the stream. This PR expands on the idea. Unified streaming solution. by CrowdHailer · Pull Request #47 · CrowdHailer/raxx · GitHub

I can report that experiments on a streaming interface have now finished.
The most flexible approach was to use multiple callbacks for various stages in the streaming process.

Here is an example of a client streaming data to a server.

defmodule StreamingRequest do
  use Raxx.Server

  def handle_headers(%Raxx.Request{method: :PUT, body: true}, _config) do
    {:ok, io_device} = File.open("my/path")
    {[], {:file, device}}
  end

  def handle_fragment(fragment, state = {:file, device}) do
    IO.write(device, fragment)
    {[], state}
  end

  def handle_trailers(_trailers, state) do
    Raxx.response(:see_other)
    |> Raxx.set_header("location", "/")
  end
end

Here is an example of a server streaming data to the client.

defmodule SubscribeToMessages do
  use Raxx.Server

  def handle_headers(_request, _config) do
    {:ok, _} = ChatRoom.join()
    Raxx.response(:ok)
    |> Raxx.set_header("content-type", "text/plain")
    |> Raxx.set_body(true)
  end

  def handle_info({ChatRoom, data}, config) do
    {[Raxx.fragment(data)], config}
  end
end

For full details see the Raxx.Server documentation
I hope to share a few example usecases in the next few weeks.

ace_http 0.5.0 released with HTTP/1.1 support for streaming.

This release of :ace_http implements the Raxx Streaming interface described above (latest interface docs