Merge provider redirect handlers into one module

Author: jrchatruc

src/handlers/github_redirect_handler.erl

@@ -0,0 +1,37 @@
+-module(provider_redirect_handler).
+
+%%% HTTP handler that redirects the user to the OAuth endpoint of the corresponding
+%%% provider with the client_id that identifies this application
+
+-export([init/3,
+         handle/2,
+         terminate/3]).
+
+init(_Type, Req, []) ->
+  {ok, Req, no_state}.
+
+handle(Req, State) ->
+  {Provider, _} = cowboy_req:binding(provider, Req),
+  {EnvVar, ProviderUrl} = provider_vars(binary_to_list(Provider)),
+
+  case os:getenv(EnvVar, false) of
+    false ->
+      lager:error([Provider, <<" credentials not found in environment">>]);
+    ClientId ->
+      Url = [ProviderUrl | ClientId],
+      {ok, Req2} = cowboy_req:reply(303, [{<<"location">>, Url}], Req),
+      {ok, Req2, State}
+  end.
+
+terminate(_Reason, _Req, _State) ->
+  ok.
+
+provider_vars("google") ->
+    {"GOOGLE_CLIENTID",
+    [<<"https://accounts.google.com/o/oauth2/auth">>,
+    <<"?response_type=code&redirect_uri=https://holidaypinger.com/oauth/google/callback&scope=email profile&client_id=">>]};
+
+provider_vars("github") ->
+    {"GITHUB_CLIENTID",
+    [<<"http://github.com/login/oauth/authorize">>,
+    <<"?scope=user:email&client_id=">>]}.

src/handlers/google_redirect_handler.erl

@@ -13,9 +13,8 @@ start(_StartType, _StartArgs) ->
                                            {"/js/[...]", cowboy_static, {priv_dir, holiday_ping, "/ui/resources/public/js"}},
                                            {"/css/[...]", cowboy_static, {priv_dir, holiday_ping, "/ui/resources/public/css"}},
                                            {"/img/[...]", cowboy_static, {priv_dir, holiday_ping, "/ui/resources/public/img"}},
-                                           {"/oauth/google", google_redirect_handler, []},
+                                           {"/oauth/:provider", provider_redirect_handler, []},
                                            {"/api/auth/google/code", google_callback_handler, []},
-                                           {"/oauth/github", github_redirect_handler, []},
                                            {"/api/auth/github/code", github_callback_handler, []},
                                            {"/api/users", user_handler, []},
                                            {"/api/users/confirmation", confirmation_handler, []},

src/handlers/provider_redirect_handler.erl

@@ -64,5 +64,5 @@ build_holiday_access_token(Email, Name, AvatarUrl) ->
     name => Name,
     avatar => AvatarUrl
    },
-  {ok, Token} = hp_auth:token_encode(Data),
+  {ok, Token} = token_encode(Data),
   Token.