BasicAuth should have a tag for config

Stop relying on the realm to be the tag.

servant-examples/basic-auth/basic-auth.hs

@@ -42,7 +42,7 @@ type PrivateAPI = Get '[JSON] PrivateData
 
 -- | our API
 type API = "public"  :> PublicAPI
-      :<|> "private" :> BasicAuth "foo-realm" User :> PrivateAPI
+      :<|> "private" :> BasicAuth "foo-tag" "foo-realm" User :> PrivateAPI
 
 -- | a value holding a proxy of our API type
 api :: Proxy API
@@ -63,10 +63,9 @@ authCheck =
 
 -- | We need to supply our handlers with the right configuration. In this case,
 -- Basic Authentication requires a Config Entry with the 'BasicAuthCheck' value
--- tagged with the realm that BasicAuth protects (in this case "foo-realm").
--- This config is then supplied to 'server' and threaded to the BasicAuth HasServer
--- handlers.
-serverConfig :: Config (ConfigEntry "foo-realm" (BasicAuthCheck User) ': '[])
+-- tagged with "foo-tag" This config is then supplied to 'server' and threaded 
+-- to the BasicAuth HasServer handlers.
+serverConfig :: Config (ConfigEntry "foo-tag" (BasicAuthCheck User) ': '[])
 serverConfig = authCheck .: EmptyConfig
 
 -- | an implementation of our server. Here is where we pass all the handlers to our endpoints.

servant-server/src/Servant/Server/Internal.hs

@@ -484,16 +484,16 @@ instance HasServer api => HasServer (HttpVersion :> api) where
 
 -- | Basic Authentication
 instance (KnownSymbol realm, HasServer api)
-    => HasServer (BasicAuth realm usr :> api) where
-  type ServerT (BasicAuth realm usr :> api) m = usr -> ServerT api m
-  type HasCfg (BasicAuth realm usr :> api) c
-    = (HasConfigEntry c realm (BasicAuthCheck usr), HasCfg api c)
+    => HasServer (BasicAuth tag realm usr :> api) where
+  type ServerT (BasicAuth tag realm usr :> api) m = usr -> ServerT api m
+  type HasCfg (BasicAuth tag realm usr :> api) c
+    = (HasConfigEntry c tag (BasicAuthCheck usr), HasCfg api c)
 
   route Proxy cfg subserver = WithRequest $ \ request ->
     route (Proxy :: Proxy api) cfg (subserver `addAuthCheck` authCheck request)
     where
        realm = BC8.pack $ symbolVal (Proxy :: Proxy realm)
-       baCfg = getConfigEntry (Proxy :: Proxy realm) cfg
+       baCfg = getConfigEntry (Proxy :: Proxy tag) cfg
        authCheck req = runBasicAuth req realm baCfg
 
 -- | General Authentication

servant/src/Servant/API/Auth.hs

@@ -17,7 +17,7 @@ import           GHC.TypeLits  (Symbol)
 -- In Basic Auth, username and password are base64-encoded and transmitted via
 -- the @Authorization@ header. Handshakes are not required, making it
 -- relatively efficient.
-data BasicAuth (realm :: Symbol) (usr :: *)
+data BasicAuth (tag :: k) (realm :: Symbol) (usr :: *)
   deriving (Typeable)
 
 -- | A generalized Authentication combinator.