servant/servant-server/test/Servant/Server/ErrorSpec.hs

{-# LANGUAGE DataKinds             #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings     #-}
{-# LANGUAGE TypeFamilies          #-}
{-# LANGUAGE TypeOperators         #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Servant.Server.ErrorSpec (spec) where

import           Control.Monad.Trans.Except (throwE)
import           Data.Aeson                 (encode)
import qualified Data.ByteString.Char8      as BC
import qualified Data.ByteString.Lazy.Char8 as BCL
import           Data.Proxy
import           Network.HTTP.Types         (hAccept, hAuthorization,
                                             hContentType, methodGet,
                                             methodPost, methodPut)
import           Safe                       (readMay)
import           Test.Hspec
import           Test.Hspec.Wai

import           Servant

spec :: Spec
spec = describe "HTTP Errors" $ do
    errorOrderSpec
    prioErrorsSpec
    errorRetrySpec
    errorChoiceSpec

-- * Auth machinery (reused throughout)

-- | 'BasicAuthCheck' holds the handler we'll use to verify a username and password.
errorOrderAuthCheck :: BasicAuthCheck ()
errorOrderAuthCheck =
  let check (BasicAuthData username password) =
        if username == "servant" && password == "server"
        then return (Authorized ())
        else return Unauthorized
  in BasicAuthCheck check

------------------------------------------------------------------------------
-- * Error Order {{{

type ErrorOrderApi = "home"
                  :> BasicAuth "error-realm" ()
                  :> ReqBody '[JSON] Int
                  :> Capture "t" Int
                  :> Post '[JSON] Int

errorOrderApi :: Proxy ErrorOrderApi
errorOrderApi = Proxy

errorOrderServer :: Server ErrorOrderApi
errorOrderServer = \_ _ _ -> throwE err402

-- On error priorities:
--
-- We originally had
--
-- 404, 405, 401, 415, 400, 406, 402
--
-- but we changed this to
--
-- 404, 405, 401, 406, 415, 400, 402
--
-- for servant-0.7.
--
-- This change is due to the body check being irreversible (to support
-- streaming). Any check done after the body check has to be made fatal,
-- breaking modularity. We've therefore moved the accept check before
-- the body check, to allow it being recoverable and modular, and this
-- goes along with promoting the error priority of 406.
errorOrderSpec :: Spec
errorOrderSpec =
  describe "HTTP error order" $
    with (return $ serveWithContext errorOrderApi
                   (errorOrderAuthCheck :. EmptyContext)
                   errorOrderServer
         ) $ do
  let badContentType  = (hContentType, "text/plain")
      badAccept       = (hAccept, "text/plain")
      badMethod       = methodGet
      badUrl          = "nonexistent"
      badBody         = "nonsense"
      badAuth         = (hAuthorization, "Basic foofoofoo")
      goodContentType = (hContentType, "application/json")
      goodAccept      = (hAccept, "application/json")
      goodMethod      = methodPost
      goodUrl         = "home/2"
      goodBody        = encode (5 :: Int)
      -- username:password = servant:server
      goodAuth        = (hAuthorization, "Basic c2VydmFudDpzZXJ2ZXI=")

  it "has 404 as its highest priority error" $ do
    request badMethod badUrl [badAuth, badContentType, badAccept] badBody
      `shouldRespondWith` 404

  it "has 405 as its second highest priority error" $ do
    request badMethod goodUrl [badAuth, badContentType, badAccept] badBody
      `shouldRespondWith` 405

  it "has 401 as its third highest priority error (auth)" $ do
    request goodMethod goodUrl [badAuth, badContentType, badAccept] badBody
      `shouldRespondWith` 401

  it "has 406 as its fourth highest priority error" $ do
    request goodMethod goodUrl [goodAuth, badContentType, badAccept] badBody
      `shouldRespondWith` 406

  it "has 415 as its fifth highest priority error" $ do
    request goodMethod goodUrl [goodAuth, badContentType, goodAccept] badBody
      `shouldRespondWith` 415

  it "has 400 as its sixth highest priority error" $ do
    request goodMethod goodUrl [goodAuth, goodContentType, goodAccept] badBody
      `shouldRespondWith` 400

  it "has handler-level errors as last priority" $ do
    request goodMethod goodUrl [goodAuth, goodContentType, goodAccept] goodBody
      `shouldRespondWith` 402

type PrioErrorsApi = ReqBody '[JSON] Integer :> "foo" :> Get '[JSON] Integer

prioErrorsApi :: Proxy PrioErrorsApi
prioErrorsApi = Proxy

-- Check whether matching continues even if a 'ReqBody' or similar construct
-- is encountered early in a path. We don't want to see a complaint about the
-- request body unless the path actually matches.
prioErrorsSpec :: Spec
prioErrorsSpec = describe "PrioErrors" $ do
  let server = return
  with (return $ serve prioErrorsApi server) $ do
    let check (mdescr, method) path (cdescr, ctype, body) resp =
          it fulldescr $
            Test.Hspec.Wai.request method path [(hContentType, ctype)] body
              `shouldRespondWith` resp
          where
            fulldescr = "returns " ++ show (matchStatus resp) ++ " on " ++ mdescr
                     ++ " " ++ BC.unpack path ++ " (" ++ cdescr ++ ")"

        get' = ("GET", methodGet)
        put' = ("PUT", methodPut)

        txt   = ("text"        , "text/plain;charset=utf8"      , "42"        )
        ijson = ("invalid json", "application/json;charset=utf8", "invalid"   )
        vjson = ("valid json"  , "application/json;charset=utf8", encode (5 :: Int))

    check get' "/"    txt   404
    check get' "/bar" txt   404
    check get' "/foo" txt   415
    check put' "/"    txt   404
    check put' "/bar" txt   404
    check put' "/foo" txt   405
    check get' "/"    ijson 404
    check get' "/bar" ijson 404
    check get' "/foo" ijson 400
    check put' "/"    ijson 404
    check put' "/bar" ijson 404
    check put' "/foo" ijson 405
    check get' "/"    vjson 404
    check get' "/bar" vjson 404
    check get' "/foo" vjson 200
    check put' "/"    vjson 404
    check put' "/bar" vjson 404
    check put' "/foo" vjson 405

-- }}}
------------------------------------------------------------------------------
-- * Error Retry {{{

type ErrorRetryApi
     = "a" :> ReqBody '[JSON] Int      :> Post '[JSON] Int                -- err402
  :<|> "a" :> ReqBody '[PlainText] Int :> Post '[JSON] Int                -- 1
  :<|> "a" :> ReqBody '[JSON] Int      :> Post '[PlainText] Int           -- 2
  :<|> "a" :> ReqBody '[JSON] String   :> Post '[JSON] Int                -- 3
  :<|> "a" :> ReqBody '[JSON] Int      :> Get  '[JSON] Int                -- 4
  :<|> "a" :> BasicAuth "bar-realm" ()
           :> ReqBody '[JSON] Int      :> Get  '[PlainText] Int           -- 5
  :<|> "a" :> ReqBody '[JSON] Int      :> Get  '[PlainText] Int           -- 6

  :<|>        ReqBody '[JSON] Int      :> Get  '[JSON] Int                -- 7
  :<|>        ReqBody '[JSON] Int      :> Post '[JSON] Int                -- 8

errorRetryApi :: Proxy ErrorRetryApi
errorRetryApi = Proxy

errorRetryServer :: Server ErrorRetryApi
errorRetryServer
     = (\_ -> throwE err402)
  :<|> (\_ -> return 1)
  :<|> (\_ -> return 2)
  :<|> (\_ -> return 3)
  :<|> (\_ -> return 4)
  :<|> (\_ _ -> return 5)
  :<|> (\_ -> return 6)
  :<|> (\_ -> return 7)
  :<|> (\_ -> return 8)

errorRetrySpec :: Spec
errorRetrySpec =
  describe "Handler search" $
    with (return $ serveWithContext errorRetryApi
                         (errorOrderAuthCheck :. EmptyContext)
                         errorRetryServer
         ) $ do

  let jsonCT      = (hContentType, "application/json")
      jsonAccept  = (hAccept, "application/json")
      jsonBody    = encode (1797 :: Int)

  it "should continue when URLs don't match" $ do
    request methodPost "" [jsonCT, jsonAccept] jsonBody
     `shouldRespondWith` 200 { matchBody = Just $ encode (8 :: Int) }

  it "should continue when methods don't match" $ do
    request methodGet "a" [jsonCT, jsonAccept] jsonBody
     `shouldRespondWith` 200 { matchBody = Just $ encode (4 :: Int) }

-- }}}
------------------------------------------------------------------------------
-- * Error Choice {{{

type ErrorChoiceApi
     = "path0" :> Get '[JSON] Int                                     -- 0
  :<|> "path1" :> Post '[JSON] Int                                    -- 1
  :<|> "path2" :> Post '[PlainText] Int                               -- 2
  :<|> "path3" :> ReqBody '[JSON] Int :> Post '[PlainText] Int        -- 3
  :<|> "path4" :> (ReqBody '[PlainText] Int :> Post '[PlainText] Int  -- 4
             :<|>  ReqBody '[PlainText] Int :> Post '[JSON] Int)      -- 5

errorChoiceApi :: Proxy ErrorChoiceApi
errorChoiceApi = Proxy

errorChoiceServer :: Server ErrorChoiceApi
errorChoiceServer = return 0
               :<|> return 1
               :<|> return 2
               :<|> (\_ -> return 3)
               :<|> (\_ -> return 4)
               :<|> (\_ -> return 5)


errorChoiceSpec :: Spec
errorChoiceSpec = describe "Multiple handlers return errors"
                $ with (return $ serve errorChoiceApi errorChoiceServer) $ do

  it "should respond with 404 if no path matches" $ do
    request methodGet "" [] "" `shouldRespondWith` 404

  it "should respond with 405 if a path but not method matches" $ do
    request methodGet "path2" [] "" `shouldRespondWith` 405

  it "should respond with the corresponding error if path and method match" $ do
    request methodPost "path3" [(hContentType, "text/plain;charset=utf-8")] ""
      `shouldRespondWith` 415
    request methodPost "path3" [(hContentType, "application/json")] ""
      `shouldRespondWith` 400
    request methodPost "path4" [(hContentType, "text/plain;charset=utf-8"),
                                (hAccept, "blah")] "5"
      `shouldRespondWith` 406


-- }}}
------------------------------------------------------------------------------
-- * Instances {{{

instance MimeUnrender PlainText Int where
    mimeUnrender _ x = maybe (Left "no parse") Right (readMay $ BCL.unpack x)

instance MimeRender PlainText Int where
    mimeRender _ = BCL.pack . show
-- }}}