Add twitch.tv plugin

.env.example

@@ -41,6 +41,9 @@ SLACK_CLIENT_SECRET=x
 SPOTIFY_CLIENT_ID=x
 SPOTIFY_CLIENT_SECRET=x
 
+TWITCH_CLIENT_ID=x
+TWITCH_CLIENT_SECRET=x
+
 UPCASE_CLIENT_ID=x
 UPCASE_CLIENT_SECRET=x
 

example/Main.hs

@@ -47,6 +47,7 @@ import Yesod.Auth.OAuth2.Nylas
 import Yesod.Auth.OAuth2.Salesforce
 import Yesod.Auth.OAuth2.Slack
 import Yesod.Auth.OAuth2.Spotify
+import Yesod.Auth.OAuth2.Twitch
 import Yesod.Auth.OAuth2.Upcase
 import Yesod.Auth.OAuth2.WordPressDotCom
 
@@ -147,6 +148,7 @@ mkFoundation = do
         , loadPlugin oauth2Salesforce "SALES_FORCE"
         , loadPlugin oauth2Slack "SLACK"
         , loadPlugin (oauth2Spotify []) "SPOTIFY"
+        , loadPlugin oauth2Twitch "TWITCH"
         , loadPlugin oauth2WordPressDotCom "WORDPRESS_DOT_COM"
         , loadPlugin oauth2Upcase "UPCASE"
         ]

src/Yesod/Auth/OAuth2/Twitch.hs

@@ -0,0 +1,56 @@
+{-# LANGUAGE OverloadedStrings #-}
+-- |
+--
+-- OAuth2 plugin for http://twitch.tv
+--
+-- * Authenticates against twitch
+-- * Uses twitch user id as credentials identifier
+--
+module Yesod.Auth.OAuth2.Twitch
+  ( oauth2Twitch
+  , oauth2TwitchScoped
+  ) where
+
+import Yesod.Auth.OAuth2.Prelude
+
+import qualified Data.Text.Encoding as T
+
+newtype User = User Text
+
+instance FromJSON User where
+  parseJSON = withObject "User" $ \o -> User <$> o .: "user_id"
+
+pluginName :: Text
+pluginName = "twitch"
+
+defaultScopes :: [Text]
+defaultScopes = ["user:read:email"]
+
+oauth2Twitch :: YesodAuth m => Text -> Text -> AuthPlugin m
+oauth2Twitch = oauth2TwitchScoped defaultScopes
+
+oauth2TwitchScoped :: YesodAuth m => [Text] -> Text -> Text -> AuthPlugin m
+oauth2TwitchScoped scopes clientId clientSecret =
+  authOAuth2 pluginName oauth2 $ \manager token -> do
+    (User userId, userResponse) <- authGetProfile
+      pluginName
+      manager
+      token
+      "https://id.twitch.tv/oauth2/validate"
+
+    pure Creds { credsPlugin = pluginName
+               , credsIdent  = userId
+               , credsExtra  = setExtra token userResponse
+               }
+ where
+  oauth2 = OAuth2
+    { oauth2ClientId          = clientId
+    , oauth2ClientSecret      = Just clientSecret
+    , oauth2AuthorizeEndpoint = "https://id.twitch.tv/oauth2/authorize"
+                                  `withQuery` [scopeParam " " scopes]
+    , oauth2TokenEndpoint     = "https://id.twitch.tv/oauth2/token"
+                                  `withQuery` [ ("client_id", T.encodeUtf8 clientId)
+                                              , ("client_secret", T.encodeUtf8 clientSecret)
+                                              ]
+    , oauth2RedirectUri       = Nothing
+    }

yesod-auth-oauth2.cabal

@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: d3ba666a53fb63a2f059501ac04eca709a905d0dd1f806ea5a7cd64e06ef890d
+-- hash: 233909874fdbdbd71fa70c49f5a4223b4150b85d9415dbbed7fde2fff9e5ebcf
 
 name:           yesod-auth-oauth2
 version:        0.7.0.1
@@ -57,6 +57,7 @@ library
       Yesod.Auth.OAuth2.Salesforce
       Yesod.Auth.OAuth2.Slack
       Yesod.Auth.OAuth2.Spotify
+      Yesod.Auth.OAuth2.Twitch
       Yesod.Auth.OAuth2.Upcase
       Yesod.Auth.OAuth2.WordPressDotCom
   other-modules: