Refactor common code

README.md

@@ -18,46 +18,28 @@ Router configuration
 --------------
 
 ```erlang
-{"/auth/google/:action", cowboy_social_google, [
+{"/auth/google/:action", cowboy_social, [
+  {provider, cowboy_social_google},
   % At the end of the flow this handler will be called as
   % Mod:Fun({ok, Auth, Profile}, Req) or Mod:Fun({error, Reason}, Req)
   {handler, {Mod, Fun}},
-  {client_id, <<"440647648374.apps.googleusercontent.com">>},
+  {client_id, <<"...">>},
   {client_secret, <<"...">>},
   {scope, <<"https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile">>},
   {callback_uri, <<"/auth/google/callback">>}
 ]}.
-{"/auth/github/:action", cowboy_social_github, [
-  {handler, {Mod, Fun}},
-  {client_id, <<"883b68d607abddc24f77">>},
-  {client_secret, <<"...">>},
-  {scope, <<>>},
-  {callback_uri, <<"/auth/github/callback">>}
-]}.
-{"/auth/yandex/:action", cowboy_social_yandex, [
-  {handler, {Mod, Fun}},
-  {client_id, <<"f44bd59ddfbe408ab1d29151126385a6">>},
-  {client_secret, <<"...">>},
-  {scope, <<>>},
-  {callback_uri, <<"/auth/yandex/callback">>}
-]}.
-{"/auth/vkontakte/:action", cowboy_social_vkontakte, [
-  {handler, {Mod, Fun}},
-  {client_id, <<"3473116">>},
-  {client_secret, <<"...">>},
-  {scope, <<"uid,first_name,last_name,sex,photo">>},
-  {callback_uri, <<"/auth/vkontakte/callback">>}
-]}.
-{"/auth/mailru/:action", cowboy_social_mailru, [
-  {handler, {Mod, Fun}},
-  {client_id, <<"701614">>},
-  {client_secret, <<"...">>},
-  {secret_key, <<"...">>},
-  {scope, <<>>},
-  {callback_uri, <<"/auth/mailru/callback">>}
-]}.
 ```
 
+Supported providers
+--------------
+- Github
+- Google
+- Mail.ru
+- PayPal
+- Vkontakte
+- Yandex
+- add more, this very simple
+
 License (MIT)
 -------
 

src/cowboy_request.erl

@@ -56,7 +56,7 @@ request(Method, URL, Headers, Body) ->
 % pecypc_log:info({reqerr, _Else}),
       {error, failed}
   end,
-% pecypc_log:info({res, _ResHeaders, Result}),
+% pecypc_log:info({res, Result}),
   Result.
 
 urlencode(Bin) when is_binary(Bin) ->

src/cowboy_social.erl

@@ -15,99 +15,73 @@
 %%
 
 init(_Transport, Req, Opts) ->
-  {ok, Req, Opts}.
+  % compose full redirect URI
+  case key(callback_uri, Opts) of
+    << "http://", _/binary >> -> {ok, Req, Opts};
+    << "https://", _/binary >> -> {ok, Req, Opts};
+    Relative ->
+      {SelfUri, Req2} = cowboy_req:host_url(Req),
+      {ok, Req2, lists:keyreplace(callback_uri, 1, Opts,
+        {callback_uri, << SelfUri/binary, Relative/binary >>})}
+  end.
 
 terminate(_Reason, _Req, _State) ->
   ok.
 
-%%
-%% {"/auth/:provider/:action", cowboy_social, [...]}.
-%%
 handle(Req, Opts) ->
-  Provider = key(provider, Opts),
   % extract flow action name
   {Action, Req2} = cowboy_req:binding(action, Req),
-  % construct callback URI
-  {SelfUri, Req3} = cowboy_req:host_url(Req2),
-  [FullPath] = cowboy_req:get([path], Req3),
-  CallbackUrl = << SelfUri/binary, FullPath/binary >>,
   % perform flow action
-  {ok, Req4} = handle_request(Action, Provider, Opts, CallbackUrl, Req3),
-  {ok, Req4, undefined}.
+  {ok, Req3} = handle_request(Action, Req2, Opts),
+  {ok, Req3, undefined}.
 
 %%
 %% redirect to provider authorization page, expect it to redirect
 %% to our next handler
 %%
-handle_request(<<"login">>, P, O, U, Req)  ->
-  AuthUrl = << (cowboy_social_providers:authorize_url(P))/binary, $?,
-      (cowboy_request:urlencode([
-        {<<"client_id">>, key(client_id, O)},
-        {<<"redirect_uri">>, binary:replace(U, <<"/login">>, <<"/callback">>)},
-        {<<"response_type">>, <<"code">>},
-        {<<"scope">>, key(scope, O)}
-      ]))/binary >>,
-  cowboy_req:reply(303, [{<<"location">>, AuthUrl}], <<>>, Req);
+handle_request(<<"login">>, Req, Opts)  ->
+  cowboy_req:reply(302, [
+      {<<"location">>, (key(provider, Opts)):get_authorize_url(Opts)}
+    ], <<>>, Req);
 
 %%
 %% provider redirected back to us with authorization code
 %%
-handle_request(<<"callback">>, P, O, U, Req) ->
+handle_request(<<"callback">>, Req, Opts) ->
   case cowboy_req:qs_val(<<"code">>, Req) of
     {undefined, Req2} ->
-      finish({error, nocode}, Req2);
+      finish({error, nocode}, Req2, Opts);
     {Code, Req2} ->
-      get_access_token(P, O, U, Code, Req2)
+      get_access_token(Code, Req2, Opts)
   end;
 
 %%
 %% catchall
 %%
-handle_request(_, _, _, _, Req) ->
+handle_request(_, Req, _) ->
   {ok, Req2} = cowboy_req:reply(404, [], <<>>, Req),
   {ok, Req2, undefined}.
 
 %%
 %% exchange authorization code for auth token
 %%
-get_access_token(P, O, U, Code, Req) ->
-  case cowboy_request:post_for_json(cowboy_social_providers:token_url(P), [
-      {<<"code">>, Code},
-      {<<"client_id">>, key(client_id, O)},
-      {<<"client_secret">>, key(client_secret, O)},
-      {<<"redirect_uri">>, U},
-      {<<"grant_type">>, <<"authorization_code">>}
-    ])
-  of
-    {ok, Auth} ->
-      get_user_profile(P, O, Auth, Req);
-    _ ->
-      finish({error, notoken}, Req)
-  end.
+get_access_token(Code, Req, Opts) ->
+  {ok, Auth} = (key(provider, Opts)):get_access_token(Code, Opts),
+  get_user_profile(Auth, Req, Opts).
 
 %%
-%% use auth tocken to extract info from user profile
-%%
-get_user_profile(P, O, Auth, Req) ->
-  AccessToken = key(<<"access_token">>, Auth),
-  case cowboy_request:get_json(cowboy_social_providers:profile_url(P), [
-      {<<"access_token">>, AccessToken}
-        | cowboy_social_providers:custom_data(P, AccessToken, O)
-    ])
-  of
-    {ok, Profile} ->
-      finish({ok, cowboy_social_providers:normalize_profile(P, Auth, Profile)},
-          Req);
-    _ ->
-      finish({error, noprofile}, Req)
-  end.
+%% use auth token to extract info from user profile
+%%
+get_user_profile(Auth, Req, Opts) ->
+  {ok, Profile} = (key(provider, Opts)):get_user_profile(Auth, Opts),
+  finish({ok, Auth, Profile}, Req, Opts).
 
 %%
 %% finalize application flow by calling callback handler
 %%
-finish(Status, Req) ->
-  {{M, F}, Req2} = cowboy_req:meta(callback, Req),
-  M:F(Status, Req2).
+finish(Status, Req, Opts) ->
+  {M, F} = key(handler, Opts),
+  M:F(Status, Req).
 
 %%
 %%------------------------------------------------------------------------------

src/cowboy_social_github.erl

@@ -5,104 +5,62 @@
 -module(cowboy_social_github).
 -author('Vladimir Dronnikov <dronnikov@gmail.com>').
 
--behaviour(cowboy_http_handler).
--export([init/3, terminate/3, handle/2]).
+-export([
+    get_authorize_url/1,
+    get_access_token/2,
+    get_user_profile/2
+  ]).
 
 %%
 %%------------------------------------------------------------------------------
 %% OAUTH2 Application flow
 %%------------------------------------------------------------------------------
 %%
 
-init(_Transport, Req, Opts) ->
-  % compose full redirect URI
-  {SelfUri, Req2} = cowboy_req:host_url(Req),
-  {ok, Req2, lists:keyreplace(callback_uri, 1, Opts,
-      {callback_uri, << SelfUri/binary, (key(callback_uri, Opts))/binary >>})}.
-
-terminate(_Reason, _Req, _State) ->
-  ok.
-
-handle(Req, Opts) ->
-  % extract flow action name
-  {Action, Req2} = cowboy_req:binding(action, Req),
-  % perform flow action
-  {ok, Req3} = handle_request(Action, Req2, Opts),
-  {ok, Req3, undefined}.
-
-%%
-%% redirect to provider authorization page, expect it to redirect
-%% to our next handler
-%%
-handle_request(<<"login">>, Req, Opts)  ->
-  AuthUrl = << (authorize_url())/binary, $?,
-      (cowboy_request:urlencode([
-        {<<"client_id">>, key(client_id, Opts)},
-        {<<"redirect_uri">>, key(callback_uri, Opts)},
-        {<<"scope">>, key(scope, Opts)}
-      ]))/binary >>,
-  cowboy_req:reply(303, [{<<"location">>, AuthUrl}], <<>>, Req);
-
-%%
-%% provider redirected back to us with authorization code
-%%
-handle_request(<<"callback">>, Req, Opts) ->
-  case cowboy_req:qs_val(<<"code">>, Req) of
-    {undefined, Req2} ->
-      finish({error, nocode}, Req2, Opts);
-    {Code, Req2} ->
-      get_access_token(Code, Req2, Opts)
-  end;
-
 %%
-%% catchall
+%% get URL of provider authorization page
 %%
-handle_request(_, Req, _) ->
-  {ok, Req2} = cowboy_req:reply(404, [], <<>>, Req),
-  {ok, Req2, undefined}.
+get_authorize_url(Opts)  ->
+  << "https://github.com/login/oauth/authorize", $?,
+    (cowboy_request:urlencode([
+      {client_id, key(client_id, Opts)},
+      {redirect_uri, key(callback_uri, Opts)},
+      {scope, key(scope, Opts)}
+    ]))/binary >>.
 
 %%
 %% exchange authorization code for auth token
 %%
-get_access_token(Code, Req, Opts) ->
-  try cowboy_request:post_for_json(token_url(), [
-      {<<"code">>, Code},
-      {<<"client_id">>, key(client_id, Opts)},
-      {<<"client_secret">>, key(client_secret, Opts)},
-      {<<"redirect_uri">>, key(callback_uri, Opts)}
-    ])
-  of
-    {ok, Auth} ->
-      get_user_profile(Auth, Req, Opts);
-    _ ->
-      finish({error, notoken}, Req, Opts)
-  catch _:_ ->
-    finish({error, notoken}, Req, Opts)
-  end.
-
-%%
-%% use auth token to extract info from user profile
-%%
-get_user_profile(Auth, Req, Opts) ->
-  AccessToken = key(<<"access_token">>, Auth),
-  try cowboy_request:get_json(profile_url(), [
-      {<<"access_token">>, AccessToken}
-    ])
-  of
-    {ok, Profile} ->
-      finish({ok, normalize_auth(Auth), normalize_profile(Profile)}, Req, Opts);
-    _ ->
-      finish({error, noprofile}, Req, Opts)
-  catch _:_ ->
-    finish({error, noprofile}, Req, Opts)
-  end.
+get_access_token(Code, Opts) ->
+  {ok, Auth} = cowboy_request:post_for_json(
+    <<"https://github.com/login/oauth/access_token">>, [
+      {code, Code},
+      {client_id, key(client_id, Opts)},
+      {client_secret, key(client_secret, Opts)},
+      {redirect_uri, key(callback_uri, Opts)}
+    ]),
+  {ok, [
+    {access_token, key(<<"access_token">>, Auth)},
+    {token_type, key(<<"token_type">>, Auth)},
+    {expires_in, 0}
+  ]}.
 
 %%
-%% finalize application flow by calling callback handler
+%% extract info from user profile
 %%
-finish(Status, Req, Opts) ->
-  {M, F} = key(handler, Opts),
-  M:F(Status, Req).
+get_user_profile(Auth, _Opts) ->
+  {ok, Profile} = cowboy_request:get_json(
+    <<"https://api.github.com/user">>, [
+      {access_token, key(access_token, Auth)}
+    ]),
+  {ok, [
+    {id, << "github:",
+      (list_to_binary(integer_to_list(key(<<"id">>, Profile))))/binary >>},
+    {provider, <<"github">>},
+    {email, key(<<"email">>, Profile)},
+    {name, key(<<"name">>, Profile)},
+    {avatar, key(<<"avatar_url">>, Profile)}
+  ]}.
 
 %%
 %%------------------------------------------------------------------------------
@@ -113,35 +71,3 @@ finish(Status, Req, Opts) ->
 key(Key, List) ->
   {_, Value} = lists:keyfind(Key, 1, List),
   Value.
-
-%%
-%%------------------------------------------------------------------------------
-%% Provider details
-%%------------------------------------------------------------------------------
-%%
-
-authorize_url() ->
-  <<"https://github.com/login/oauth/authorize">>.
-
-token_url() ->
-  <<"https://github.com/login/oauth/access_token">>.
-
-profile_url() ->
-  <<"https://api.github.com/user">>.
-
-normalize_auth(Auth) ->
-  [
-    {access_token, key(<<"access_token">>, Auth)},
-    {token_type, key(<<"token_type">>, Auth)},
-    {expires_in, 0}
-  ].
-
-normalize_profile(Raw) ->
-  [
-    {id, << "github:",
-      (list_to_binary(integer_to_list(key(<<"id">>, Raw))))/binary >>},
-    {provider, <<"github">>},
-    {email, key(<<"email">>, Raw)},
-    {name, key(<<"name">>, Raw)},
-    {avatar, key(<<"avatar_url">>, Raw)}
-  ].