Fixing /ip to use client's ip when available

lib/httparrot/ip_handler.ex

@@ -10,8 +10,21 @@ defmodule HTTParrot.IPHandler do
 
   def get_json(req, state) do
     {{ip, _port}, req} = :cowboy_req.peer(req)
+    {:ok, forwarded_for, _} = :cowboy_req.parse_header(<<"x-forwarded-for">>, req)
+    case forwarded_for do
+      :undefined ->
+        {response(ip), req, state}
+      _ ->
+        {response(to_tuple(forwarded_for)), req, state}
+    end
+  end
 
-    {response(ip), req, state}
+  defp to_tuple(client_ip) do
+    client_ip
+    |> hd
+    |> String.split(".")
+    |> Enum.map(fn(x) -> String.to_integer(x) end)
+    |> List.to_tuple
   end
 
   defp response(:local) do

test/ip_handler_test.exs

@@ -13,6 +13,7 @@ defmodule HTTParrot.IPHandlerTest do
   test "returns prettified json with origin" do
     ip = {127, 1, 2, 3}
     expect(:cowboy_req, :peer, 1, {{ip, :host}, :req2})
+    expect(:cowboy_req, :parse_header, 2, {:ok, :undefined, :req2})
     expect(JSX, :encode!, [{[[origin: "127.1.2.3"]], :json}])
 
     assert get_json(:req1, :state) == {:json, :req2, :state}
@@ -21,8 +22,21 @@ defmodule HTTParrot.IPHandlerTest do
     assert validate JSX
   end
 
+  test "returns prettified json with client ip when available" do
+    ip = {127, 1, 2, 3}
+    expect(:cowboy_req, :peer, 1, {{ip, :host}, :req2})
+    expect(:cowboy_req, :parse_header, 2, {:ok, ["190.1.2.3"], :req2})
+    expect(JSX, :encode!, [{[[origin: "190.1.2.3"]], :json}])
+
+    assert get_json(:req1, :state) == {:json, :req2, :state}
+
+    assert validate :cowboy_req
+    assert validate JSX
+  end
+
   test "returns empty when running over unix sockets" do
     expect(:cowboy_req, :peer, 1, {{:local, ""}, :req2})
+    expect(:cowboy_req, :parse_header, 2, {:ok, :undefined, :req2})
     expect(JSX, :encode!, [{[[origin: ""]], :json}])
 
     assert get_json(:req1, :state) == {:json, :req2, :state}