Adds "new" query parameter to subscription endpoint.

Since Slack webhooks will always hit the API via POST HTTP requests, a
REST API approach is more complicated. To achieve good seggregation the
API will use query parameters, in this case, to add subscriptions "new"
will be used.

Furthermore, a bug has been fixed where the Plug.Conn wasn't being added
the json headers appropiately.

lib/web/router.ex

@@ -13,12 +13,12 @@ defmodule Londibot.Router do
   post("/disruptions", do: send_resp(conn, 200, Londibot.Controller.report_all(:disruptions)))
 
   post "/subscription" do
-    message =
+    conn =
       conn
+      |> Plug.Conn.fetch_query_params()
       |> Util.with_json_headers()
-      |> SubscriptionHandler.handle()
 
-    send_resp(conn, 200, message)
+    send_resp(conn, 200, SubscriptionHandler.handle(conn))
   end
 
   match(_, do: send_resp(conn, 404, "Nothing found here!"))

lib/web/subscription_handler.ex

@@ -4,8 +4,11 @@ defmodule Londibot.Web.SubscriptionHandler do
 
   @subscription_store Application.get_env(:londibot, :subscription_store)
 
-  def handle(conn = %Plug.Conn{body_params: bp}), do: handle(bp)
-  def handle(body_params) do
+  def handle(conn = %Plug.Conn{body_params: bp, query_params: qp}), do: handle(bp, qp)
+  def handle(bp = %{"channel_id" => c, "text" => t}, %{"q" => "new"}), do: process_subscription(bp)
+  def handle(%{}, %{}), do: reprompt_message()
+
+  def process_subscription(body_params) do
     body_params
     |> to_subscription()
     |> @subscription_store.save()
@@ -20,8 +23,12 @@ defmodule Londibot.Web.SubscriptionHandler do
     %Subscription{channel_id: c, tfl_lines: lines}
   end
 
-  def subscription_saved_message do
-    %{text: "Subscription saved!", response_type: "in_channel"}
+  def subscription_saved_message, do: to_payload("Subscription saved!")
+
+  def reprompt_message, do: to_payload("error: empty request")
+
+  defp to_payload(message) do
+    %{text: message, response_type: "in_channel"}
     |> Poison.encode!()
   end
 end

test/web/router_test.exs

@@ -30,15 +30,15 @@ defmodule Londibot.RouterTest do
       |> World.create()
 
       conn =
-        conn(:post, "/subscription", %{channel_id: "123", text: "aaa"})
+        conn(:post, "/subscription?q=new", %{channel_id: "123", text: "aaa"})
         |> Router.call(@opts)
 
       assert conn.state == :sent
       assert conn.status == 200
 
       expected = {
         200,
-        [{"cache-control", "max-age=0, private, must-revalidate"}],
+        [{"cache-control", "max-age=0, private, must-revalidate"}, {"content-type", "application/json; charset=utf-8"}],
         "{\"text\":\"Subscription saved!\",\"response_type\":\"in_channel\"}"}
       assert expected == Plug.Test.sent_resp(conn)
     end

test/web/subscription_handler_test.exs

@@ -22,7 +22,8 @@ defmodule Londibot.Web.SubscriptionHandlerTest do
     |> World.create()
 
     message =
-      conn(:post, "/", %{"channel_id" => "123", "text" => "victoria"})
+      conn(:post, "/subscription?q=new", %{"channel_id" => "123", "text" => "victoria"})
+      |> Plug.Conn.fetch_query_params()
       |> SubscriptionHandler.handle()
 
     assert message == SubscriptionHandler.subscription_saved_message()