From 5bf6df34e46881ea003008bbfa6896598cfb7590 Mon Sep 17 00:00:00 2001
From: Luper Rouch <luper.rouch@gmail.com>
Date: Mon, 27 Apr 2015 20:08:39 +0200
Subject: [PATCH] Add /response-headers endpoint

---
 README.md                                 |  1 -
 lib/httparrot.ex                          |  3 +-
 lib/httparrot/response_headers_handler.ex | 26 ++++++++++++++++
 priv/index.html                           |  1 +
 test/response_headers_handler_test.exs    | 36 +++++++++++++++++++++++
 5 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 lib/httparrot/response_headers_handler.ex
 create mode 100644 test/response_headers_handler_test.exs

diff --git a/README.md b/README.md
index 6320766..4ba0bc0 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,6 @@ HTTP server built on top of Cowboy using (mostly) `cowboy_rest` handlers to serv
 ## TODO
 
 * [ ] /deflate Returns deflate-encoded data.
-* [ ] /response-headers?key=val Returns given response headers.
 * [ ] /digest-auth/:qop/:user/:passwd Challenges HTTP Digest Auth.
 
 ## License
diff --git a/lib/httparrot.ex b/lib/httparrot.ex
index 9db1ace..0921f41 100644
--- a/lib/httparrot.ex
+++ b/lib/httparrot.ex
@@ -31,7 +31,8 @@ defmodule HTTParrot do
              {'/robots.txt', HTTParrot.RobotsHandler, []},
              {'/base64/:value', HTTParrot.Base64Handler, []},
              {'/image', HTTParrot.ImageHandler, []},
-             {'/websocket', HTTParrot.WebsocketHandler, []} ] }
+             {'/websocket', HTTParrot.WebsocketHandler, []},
+             {'/response-headers', HTTParrot.ResponseHeadersHandler, []} ] }
     ])
 
     {:ok, http_port} = Application.fetch_env(:httparrot, :http_port)
diff --git a/lib/httparrot/response_headers_handler.ex b/lib/httparrot/response_headers_handler.ex
new file mode 100644
index 0000000..2752ae8
--- /dev/null
+++ b/lib/httparrot/response_headers_handler.ex
@@ -0,0 +1,26 @@
+defmodule HTTParrot.ResponseHeadersHandler do
+  @moduledoc """
+  Returns given response headers.
+  """
+  use HTTParrot.Cowboy, methods: ~w(GET HEAD OPTIONS)
+
+  def malformed_request(req, state) do
+    {qs_vals, req} = :cowboy_req.qs_vals(req)
+    if not Enum.empty?(qs_vals) do
+      {false, req, qs_vals}
+    else
+      {true, req, state}
+    end
+  end
+
+  def content_types_provided(req, state) do
+    {[{{"application", "json", []}, :get_json}], req, state}
+  end
+
+  def get_json(req, qs_vals) do
+    req = Enum.reduce qs_vals, req, fn({key, value}, req) ->
+      :cowboy_req.set_resp_header(key, value, req)
+    end
+    {"", req, qs_vals}
+  end
+end
diff --git a/priv/index.html b/priv/index.html
index 42f9218..a67d007 100644
--- a/priv/index.html
+++ b/priv/index.html
@@ -65,6 +65,7 @@
 <li><a href="/ip" data-bare-link="true"><code>/ip</code></a> Returns Origin IP.</li>
 <li><a href="/user-agent" data-bare-link="true"><code>/user-agent</code></a> Returns user-agent.</li>
 <li><a href="/headers" data-bare-link="true"><code>/headers</code></a> Returns header dict.</li>
+<li><a href="/response-headers?k1=v1&amp;k2=v2" data-bare-link="true"><code>/response-headers</code></a> Returns given response headers.</li>
 <li><a href="/get" data-bare-link="true"><code>/get</code></a> Returns GET data.</li>
 <li><code>/post</code> Returns POST data.</li>
 <li><code>/put</code> Returns PUT data.</li>
diff --git a/test/response_headers_handler_test.exs b/test/response_headers_handler_test.exs
new file mode 100644
index 0000000..14c8a96
--- /dev/null
+++ b/test/response_headers_handler_test.exs
@@ -0,0 +1,36 @@
+defmodule HTTParrot.ResponseHeadersHandlerTest do
+  use ExUnit.Case
+  import :meck
+  import HTTParrot.ResponseHeadersHandler
+
+  setup do
+    new :cowboy_req
+    on_exit fn -> unload end
+    :ok
+  end
+
+  test "malformed_request returns true if query string is empty" do
+    expect(:cowboy_req, :qs_vals, 1, {[], :req2})
+
+    assert malformed_request(:req1, :state) == {true, :req2, :state}
+
+    assert validate :cowboy_req
+  end
+
+  test "malformed_request returns false if query string is not empty" do
+    expect(:cowboy_req, :qs_vals, 1, {[{"foo", "bar"}], :req2})
+
+    assert malformed_request(:req1, :state) == {false, :req2, [{"foo", "bar"}]}
+
+    assert validate :cowboy_req
+  end
+
+  test "query string parameters are sent as headers" do
+    expect(:cowboy_req, :set_resp_header, [{[:k1, :v1, :req1], :req2},
+                                           {[:k2, :v2, :req2], :req3}])
+
+    assert get_json(:req1, [k1: :v1, k2: :v2]) == {"", :req3, [k1: :v1, k2: :v2]}
+
+    assert validate :cowboy_req
+  end
+end