POST/PUT/PATCH

[beno]

What is the best way to handle requests with payloads? I can't figure out how to access the request body and pass it on.

Related question: is it possible to basically clone an incoming request, modify some aspects (like the host and path) of it and then execute that?

[Anton Fagerberg]

Rackla is built using Plug so everything you can do in Plug, you can also do in Rackla. You can either use the Plug.Conn.read_body/2 or you can use Plug.Parsers if you want to do more complex things.

Example:

{:ok, body, conn} = Plug.Conn.read_body(conn)

It is not possible to convert an incoming "Plug request" to a "Rackla request", but that would actually be a really good feature. I will look into that!

[beno]

Great, thanks, I got it working. I knew there was a way, but my Elixir-fu just isn't all that great.

To be honest, I was fully expecting that request-proxy trick to be the core feature of an API-Gateway framework like Rackla. So I am glad you are looking into it! Thanks again.

Edit: FYI, here's how I ended up solving it:

defmodule Router do

  use Plug.Router
  import Rackla

  plug :match
  plug :dispatch

  defp proxy(url, conn) do
    method = conn.method |> String.downcase |> String.to_atom
    {:ok, body, _conn} = Plug.Conn.read_body(conn)
    %Rackla.Request{url: url, method: method, body: body, headers: conn.req_headers}
    |> request
    |> response
  end

  match "/admin/*path" do
    "http://admin.example.com:9292/v1/#{Enum.join(path,"/")}"
    |> proxy(conn)
  end

  match _ do
   send_resp(conn, 404, "Endpoint not found")
  end

end

[Anton Fagerberg]

Nice solution!

You should always reassign conn to the new conn returned by the function and not do _conn. (It will probably work anyway but this is the desired practice.)

As of version 1.1.0, you can now use the built in function incoming_request:

get "/test/a-simple-request-proxy" do
  # You should check for errors
  {:ok, the_request} = incoming_request()

  the_request
  |> Map.put(:url, "http://new-url.com")
  |> request
  |> response
end

Look for the macro incoming_requestin the documentation!

[beno]

O that is sweet. Thanks!

[beno]

Hi, I hadn't had a chance to implement this yet, but I now have and there are two issues I'd like to report:

• When I write the code as above, I run into a compilation error

** (CompileError) lib/deal_manager.ex: invalid quoted expression: %{}
(rackla) expanding macro: Rackla.incoming_request/0

I can get around this by calling incoming_request(%{}).

• The incoming request loses the query_string. Can't have that 😄
  Not a real issue form me since I rewrite the url, but still.

Other than that it all seems to work, but I haven't done all my tests yet.

[Anton Fagerberg]

Thanks for the report! I'll fix these issues as soon as possible :)

[Anton Fagerberg]

Fixed in 1.2.1! (See #25)