Optimization when auth role coincides with anon role

No need to set/reset role because it is already correct

README.md

@@ -1,4 +1,4 @@
-## Serve a RESTful API from any Postgres database
+![Logo](static/logo.png "Logo")
 
 [![Build Status](https://circleci.com/gh/begriffs/postgrest.png?circle-token=f723c01686abf0364de1e2eaae5aff1f68bd3ff2)](https://circleci.com/gh/begriffs/postgrest/tree/master)
 
@@ -50,7 +50,7 @@ guide](https://github.com/begriffs/postgrest/wiki/Security-and-Permissions).
 
 If you're used to servers written in interpreted languages (or named
 after precious gems), prepare to be pleasantly surprised by PostgREST
-performance.
+performance. ([see the load test](https://github.com/begriffs/postgrest/wiki/Performance-and-Scaling))
 
 Three factors contribute to the speed. First the server is written
 in [Haskell](https://new-www.haskell.org/) using the
@@ -125,12 +125,12 @@ and the [guide to routing](https://github.com/begriffs/postgrest/wiki/Routing).
 
 * Watching endpoint changes with sockets and Postgres pubsub
 * Specifying per-view HTTP caching
-* Inferring good default caching policies from the Postgres stats
-* Generating mock data to test clients
+* Inferring good default caching policies from the Postgres stats collector
+* Generating mock data for test clients
 * Maintaining separate connection pools per role to avoid "set/reset
   role" performance penalty
 * Describe more relationships with Link headers
-* Depending on accept headers, render OPTIONS as [RAML] or a
+* Depending on accept headers, render OPTIONS as [RAML](http://raml.org/) or a
   relational diagram
 * Add two-legged auth with OAuth 1.0a(?)
 * ... the other [issues](https://github.com/begriffs/postgrest/issues)

postgrest.cabal

@@ -1,5 +1,5 @@
 name:                  postgrest
-version:               0.2.4.8
+version:               0.2.4.9
 synopsis:              The database is your api
 license:               MIT
 license-file:          LICENSE

src/Main.hs

@@ -49,13 +49,14 @@ main = do
         . gzip def . cors corsPolicy
         . staticPolicy (only [("favicon.ico", "static/favicon.ico")])
       anonRole = cs $ configAnonRole conf
+      currRole = cs $ configDbUser conf
 
   H.session pgSettings sessSettings $ H.sessionUnlifter >>= \unlift ->
     liftIO $ runSettings appSettings $ middle $ \req respond -> do
       body <- strictRequestBody req
       respond =<< catchJust isSqlError
         (unlift $ H.tx Nothing
-                $ authenticated anonRole (app body) req)
+                $ authenticated currRole anonRole (app body) req)
         (return . sqlError)
 
   where

src/Middleware.hs

@@ -22,30 +22,18 @@ import Network.URI (URI(..), parseURI)
 import Auth (LoginAttempt(..), signInRole, setRole, resetRole)
 import Codec.Binary.Base64.String (decode)
 
--- data Environment = Test | Production deriving (Eq)
-
--- safeAction :: Request -> Bool
--- safeAction = (`notElem` ["PATCH", "PUT"]) . requestMethod
-
--- withSavepoint :: Environment -> (Connection -> Application) ->
---                  Connection -> Application
--- withSavepoint env app conn req respond =
---   if env == Production && safeAction req
---     then go
---     else Database.PostgreSQL.Simple.withSavepoint conn go
---   where go = app conn req respond
-
-authenticated :: forall s. Text -> (Request -> H.Tx H.Postgres s Response) ->
-       Request -> H.Tx H.Postgres s Response
-authenticated anon app req = do
+authenticated :: forall s. Text -> Text ->
+                 (Request -> H.Tx H.Postgres s Response) ->
+                 Request -> H.Tx H.Postgres s Response
+authenticated currentRole anon app req = do
   attempt <- httpRequesterRole (requestHeaders req)
   case attempt of
     MalformedAuth ->
       return $ responseLBS status400 [] "Malformed basic auth header"
     LoginFailed ->
       return $ responseLBS status401 [] "Invalid username or password"
-    LoginSuccess role -> runInRole role
-    NoCredentials -> runInRole anon
+    LoginSuccess role -> if role /= currentRole then runInRole role else app req
+    NoCredentials ->     if anon /= currentRole then runInRole anon else app req
 
  where
    httpRequesterRole :: RequestHeaders -> H.Tx H.Postgres s LoginAttempt

test/SpecHelper.hs

@@ -44,14 +44,15 @@ pgSettings = H.ParamSettings "localhost" 5432 "postgrest_test" "" "postgrest_tes
 
 withApp :: ActionWith Application -> IO ()
 withApp perform =
-  let anonRole = cs $ configAnonRole cfg in
+  let anonRole = cs $ configAnonRole cfg
+      currRole = cs $ configDbUser cfg in
   perform $ middle $ \req resp ->
     H.session pgSettings testSettings $ H.sessionUnlifter >>= \unlift ->
       liftIO $ do
         body <- strictRequestBody req
         resp =<< catchJust isSqlError
           (unlift $ H.tx Nothing
-                  $ authenticated anonRole (app body) req)
+                  $ authenticated currRole anonRole (app body) req)
           (return . sqlError)
 
   where middle = cors corsPolicy