@@ -1,27 +1,69 @@
1module Servant.QuickCheck.Internal.Predicates where
1module Servant.QuickCheck.Internal.Predicates where
3−import Control.Monad
3+import Control.Exception (catch, throw)
4+import Control.Monad (liftM2, unless, when)
4−import Data.Aeson (Object, decode)
5+import Data.Aeson (Object, decode)
5−import Data.Bifunctor (Bifunctor (..))
6+import Data.Bifunctor (first)
7+import qualified Data.ByteString as SBS
8+import qualified Data.ByteString.Char8 as SBSC
6−import qualified Data.ByteString.Lazy as LBS
9+import qualified Data.ByteString.Lazy as LBS
7−import qualified Data.ByteString as SBS
8−import Data.CaseInsensitive (mk)
10+import Data.CaseInsensitive (foldCase, foldedCase, mk)
9−import Data.Monoid ((<>))
11+import Data.Either (isRight)
12+import Data.List.Split (wordsBy)
13+import Data.Maybe (fromMaybe, isJust)
10−import Data.Text (Text)
14+import Data.Semigroup (Semigroup (..))
15+import qualified Data.Text as T
16+import Data.Time (UTCTime, defaultTimeLocale, parseTimeM,
11−import GHC.Generics (Generic)
18+import GHC.Generics (Generic)
12−import Network.HTTP.Client (Manager, Request, Response, httpLbs,
19+import Network.HTTP.Client (Manager, Request, Response, httpLbs,
20+ method, parseRequest, requestHeaders,
13− responseBody, responseStatus, responseHeaders)
21+ responseBody, responseHeaders,
23+import Network.HTTP.Media (matchAccept)
14−import Network.HTTP.Types (status500)
24+import Network.HTTP.Types (methodGet, methodHead, parseMethod,
15−
25+ renderStdMethod, status100, status200,
26+ status201, status300, status401,
27+ status405, status500)
29+import System.Clock (Clock (Monotonic), diffTimeSpec,
32+import Servant.QuickCheck.Internal.ErrorTypes
35+-- | [__Best Practice__]
16−-- | @500 Internal Server Error@ should be avoided - it may represent some
37+-- @500 Internal Server Error@ should be avoided - it may represent some
17-- issue with the application code, and it moreover gives the client little
38-- issue with the application code, and it moreover gives the client little
18-- indication of how to proceed or what went wrong.
39-- indication of how to proceed or what went wrong.
20-- This function checks that the response code is not 500.
41-- This function checks that the response code is not 500.
21−not500 :: ResponsePredicate Text Bool
44+not500 :: ResponsePredicate
22−not500 = ResponsePredicate "not500" (\resp -> not $ responseStatus resp == status500)
45+not500 = ResponsePredicate $ \resp ->
46+ when (responseStatus resp == status500) $ throw $ PredicateFailure "not500" Nothing resp
50+-- This function checks that the response from the server does not take longer
51+-- than the specified number of nanoseconds.
54+notLongerThan :: Integer -> RequestPredicate
55+notLongerThan maxAllowed
56+ = RequestPredicate $ \req mgr -> do
57+ start <- getTime Monotonic
58+ resp <- httpLbs req mgr
59+ end <- getTime Monotonic
60+ when (toNanoSecs (end `diffTimeSpec` start) > maxAllowed) $
61+ throw $ PredicateFailure "notLongerThan" (Just req) resp
64+-- | [__Best Practice__]
24−-- | Returning anything other than an object when returning JSON is considered
66+-- Returning anything other than an object when returning JSON is considered
25-- bad practice, as:
67-- bad practice, as:
27-- (1) it is hard to modify the returned value while maintaining backwards
69-- (1) it is hard to modify the returned value while maintaining backwards
@@ -33,67 +75,202 @@ not500 = ResponsePredicate "not500" (\resp -> not $ responseStatus resp == statu
34-- This function checks that any @application/json@ responses only return JSON
76-- This function checks that any @application/json@ responses only return JSON
35-- objects (and not arrays, strings, numbers, or booleans) at the top level.
77-- objects (and not arrays, strings, numbers, or booleans) at the top level.
81+-- * JSON Grammar: <https://tools.ietf.org/html/rfc7159#section-2 RFC 7159 Section 2>
82+-- * JSON Grammar: <https://tools.ietf.org/html/rfc4627#section-2 RFC 4627 Section 2>
36−onlyJsonObjects :: ResponsePredicate Text Bool
85+onlyJsonObjects :: ResponsePredicate
37onlyJsonObjects
86onlyJsonObjects
87+ = ResponsePredicate (\resp -> do
88+ case lookup "content-type" (first foldedCase <$> responseHeaders resp) of
90+ Just ctype -> when ("application/json" `SBS.isPrefixOf` ctype) $ do
38− = ResponsePredicate "onlyJsonObjects" (\resp -> case decode (responseBody resp) of
91+ case (decode (responseBody resp) :: Maybe Object) of
39− Nothing -> False
92+ Nothing -> throw $ PredicateFailure "onlyJsonObjects" Nothing resp
40− Just (_ :: Object) -> True)
93+ Just _ -> return ())
42−{-
95+-- | __Optional__
43−-- | When creating a new resource, it is good practice to provide a @Location@
97+-- When creating a new resource, it is good practice to provide a @Location@
44-- header with a link to the created resource.
98-- header with a link to the created resource.
46-- This function checks that every @201 Created@ response contains a @Location@
100-- This function checks that every @201 Created@ response contains a @Location@
47-- header, and that the link in it responds with a 2XX response code to @GET@
101-- header, and that the link in it responds with a 2XX response code to @GET@
48-- requests.
102-- requests.
104+-- This is considered optional because other means of linking to the resource
105+-- (e.g. via the response body) are also acceptable; linking to the resource in
106+-- some way is considered best practice.
110+-- * 201 Created: <https://tools.ietf.org/html/rfc7231#section-6.3.2 RFC 7231 Section 6.3.2>
50−-- References: <RFC 7231, Section 6.3.2 https://tools.ietf.org/html/rfc7231#section-6.3.2>
111+-- * Location header: <https://tools.ietf.org/html/rfc7231#section-7.1.2 RFC 7231 Section 7.1.2>
51−createContainsValidLocation :: ResponsePredicate Text Bool
114+createContainsValidLocation :: RequestPredicate
52createContainsValidLocation
115createContainsValidLocation
53− = ResponsePredicate "createContainsValidLocation" (\resp ->
116+ = RequestPredicate $ \req mgr -> do
117+ let n = "createContainsValidLocation"
118+ resp <- httpLbs req mgr
119+ if responseStatus resp == status201
120+ then case lookup "Location" $ responseHeaders resp of
121+ Nothing -> throw $ PredicateFailure n (Just req) resp
122+ Just l -> case parseRequest $ SBSC.unpack l of
123+ Nothing -> throw $ PredicateFailure n (Just req) resp
125+ resp2 <- httpLbs x mgr
126+ status2XX (Just req) resp2 n
127+ return [resp, resp2]
132+-- The @Last-Modified@ header represents the time a resource was last
133+-- modified. It is used to drive caching and conditional requests.
135+-- When using this mechanism, the server adds the @Last-Modified@ header to
136+-- responses. Clients may then make requests with the @If-Modified-Since@
137+-- header to conditionally request resources. If the resource has not
138+-- changed since that date, the server responds with a status code of 304
139+-- (@Not Modified@) without a response body.
141+-- The @Last-Modified@ header can also be used in conjunction with the
142+-- @If-Unmodified-Since@ header to drive optimistic concurrency.
144+-- The @Last-Modified@ date must be in RFC 822 format.
148+-- * 304 Not Modified: <https://tools.ietf.org/html/rfc7232#section-4.1 RFC 7232 Section 4.1>
149+-- * Last-Modified header: <https://tools.ietf.org/html/rfc7232#section-2.2 RFC 7232 Section 2.2>
150+-- * If-Modified-Since header: <https://tools.ietf.org/html/rfc7232#section-3.3 RFC 7232 Section 3.3>
151+-- * If-Unmodified-Since header: <https://tools.ietf.org/html/rfc7232#section-3.4 RFC 7232 Section 3.4>
152+-- * Date format: <https://tools.ietf.org/html/rfc2616#section-3.3 RFC 2616 Section 3.3>
55−getsHaveLastModifiedHeader :: Response b -> IO Bool
155+getsHaveLastModifiedHeader :: RequestPredicate
56getsHaveLastModifiedHeader
156getsHaveLastModifiedHeader
157+ = RequestPredicate $ \req mgr ->
158+ if (method req == methodGet)
160+ resp <- httpLbs req mgr
161+ unless (hasValidHeader "Last-Modified" isRFC822Date resp) $ do
57− = ResponsePredicate "getsHaveLastModifiedHeader" _
162+ throw $ PredicateFailure "getsHaveLastModifiedHeader" (Just req) resp
168+-- | [__RFC Compliance__]
59−-- | When an HTTP request has a method that is not allowed, a 405 response
170+-- When an HTTP request has a method that is not allowed,
60−-- should be returned. Additionally, it is good practice to return an @Allow@
171+-- a 405 response should be returned. Additionally, it is good practice to
61-- header with the list of allowed methods.
173-- header with the list of allowed methods.
63-- This function checks that every @405 Method Not Allowed@ response contains
175-- This function checks that every @405 Method Not Allowed@ response contains
64-- an @Allow@ header with a list of standard HTTP methods.
176-- an @Allow@ header with a list of standard HTTP methods.
178+-- Note that 'servant' itself does not currently set the @Allow@ headers.
182+-- * @Allow@ header: <https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 Section 14.7>
183+-- * Status 405: <https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html RFC 2616 Section 10.4.6>
184+-- * Servant Allow header issue: <https://github.com/haskell-servant/servant/issues/489 Issue #489>
65−notAllowedContainsAllowHeader :: Response b -> IO Bool
187+notAllowedContainsAllowHeader :: RequestPredicate
66notAllowedContainsAllowHeader
188notAllowedContainsAllowHeader
67− = ResponsePredicate "notAllowedContainsAllowHeader" _
189+ = RequestPredicate $ \req mgr -> do
190+ let reqs = [ req { method = renderStdMethod m } | m <- [minBound .. maxBound]
191+ , renderStdMethod m /= method req ]
192+ resp <- mapM (flip httpLbs mgr) reqs
194+ case filter pred' (zip reqs resp) of
195+ (x:_) -> throw $ PredicateFailure "notAllowedContainsAllowHeader" (Just $ fst x) (snd x)
198+ pred' (_, resp) = responseStatus resp == status405 && not (hasValidHeader "Allow" go resp)
200+ go x = all (\y -> isRight $ parseMethod $ SBSC.pack y)
201+ $ wordsBy (`elem` (", " :: [Char])) (SBSC.unpack x)
204+-- | [__RFC Compliance__]
69−-- | When a request contains an @Accept@ header, the server must either return
206+-- When a request contains an @Accept@ header, the server must either return
70-- content in one of the requested representations, or respond with @406 Not
207-- content in one of the requested representations, or respond with @406 Not
71-- Acceptable@.
208-- Acceptable@.
73-- This function checks that every *successful* response has a @Content-Type@
210-- This function checks that every *successful* response has a @Content-Type@
74−-- header that matches the @Accept@ header.
211+-- header that matches the @Accept@ header. It does *not* check that the server
212+-- matches the quality descriptions of the @Accept@ header correctly.
216+-- * @Accept@ header: <https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 Section 14.1>
75−honoursAcceptHeader :: Predicate b Bool
219+honoursAcceptHeader :: RequestPredicate
76honoursAcceptHeader
220honoursAcceptHeader
77− = RequestPredicate "honoursAcceptHeader" _
221+ = RequestPredicate $ \req mgr -> do
222+ resp <- httpLbs req mgr
223+ let scode = responseStatus resp
224+ sctype = lookup "Content-Type" $ responseHeaders resp
225+ sacc = fromMaybe "*/*" $ lookup "Accept" (requestHeaders req)
226+ if status100 < scode && scode < status300
227+ then if isJust $ sctype >>= \x -> matchAccept [x] sacc
228+ then throw $ PredicateFailure "honoursAcceptHeader" (Just req) resp
233+-- | [__Best Practice__]
79−-- | Whether or not a representation should be cached, it is good practice to
235+-- Whether or not a representation should be cached, it is good practice to
80-- have a @Cache-Control@ header for @GET@ requests. If the representation
236-- have a @Cache-Control@ header for @GET@ requests. If the representation
81-- should not be cached, used @Cache-Control: no-cache@.
237-- should not be cached, used @Cache-Control: no-cache@.
83−-- This function checks that @GET@ responses have a valid @Cache-Control@
239+-- This function checks that @GET@ responses have @Cache-Control@ header.
84−-- header.
240+-- It does NOT currently check that the header is valid.
86−-- References: RFC 7234 Section 5.2
87−-- https://tools.ietf.org/html/rfc7234#section-5.2
244+-- * @Cache-Control@ header: <https://tools.ietf.org/html/rfc7234#section-5.2 RFC 7234 Section 5.2>
88−getsHaveCacheControlHeader :: Predicate b Bool
247+getsHaveCacheControlHeader :: RequestPredicate
89getsHaveCacheControlHeader
248getsHaveCacheControlHeader
249+ = RequestPredicate $ \req mgr ->
250+ if (method req == methodGet)
252+ resp <- httpLbs req mgr
253+ unless (hasValidHeader "Cache-Control" (const True) resp) $ do
90− = ResponsePredicate "getsHaveCacheControlHeader" _
254+ throw $ PredicateFailure "getsHaveCacheControlHeader" (Just req) resp
258+-- | [__Best Practice__]
92−-- | Like 'getsHaveCacheControlHeader', but for @HEAD@ requests.
260+-- Like 'getsHaveCacheControlHeader', but for @HEAD@ requests.
93−headsHaveCacheControlHeader :: Predicate b Bool
263+headsHaveCacheControlHeader :: RequestPredicate
94headsHaveCacheControlHeader
264headsHaveCacheControlHeader
265+ = RequestPredicate $ \req mgr ->
266+ if (method req == methodHead)
268+ resp <- httpLbs req mgr
269+ unless (hasValidHeader "Cache-Control" (const True) resp) $
95− = ResponsePredicate "headsHaveCacheControlHeader" _
270+ throw $ PredicateFailure "headsHaveCacheControlHeader" (Just req) resp
99-- If the original request modifies the resource, this function makes two
276-- If the original request modifies the resource, this function makes two
@@ -134,23 +311,56 @@ optionsContainsValidAllow
134-- This function checks that any @Link@ headers have values in the correct
311-- This function checks that any @Link@ headers have values in the correct
135-- format.
312-- format.
137−-- References: RFC 5988 Section 5
314+-- __References__:
138−-- https://tools.ietf.org/html/rfc5988
316+-- * <https://tools.ietf.org/html/rfc5988 RFC 5988 Section 5>
139linkHeadersAreValid :: Predicate b Bool
317linkHeadersAreValid :: Predicate b Bool
140linkHeadersAreValid
318linkHeadersAreValid
141 = ResponsePredicate "linkHeadersAreValid" _
319 = ResponsePredicate "linkHeadersAreValid" _
322+-- | [__RFC Compliance__]
143−-- | Any @401 Unauthorized@ response must include a @WWW-Authenticate@ header.
324+-- Any @401 Unauthorized@ response must include a @WWW-Authenticate@ header.
145-- This function checks that, if a response has status code 401, it contains a
326-- This function checks that, if a response has status code 401, it contains a
146-- @WWW-Authenticate@ header.
327-- @WWW-Authenticate@ header.
148−-- References: RFC 7235 Section 4.1
329+-- __References__:
149−-- https://tools.ietf.org/html/rfc7235#section-4.1
331+-- * @WWW-Authenticate@ header: <https://tools.ietf.org/html/rfc7235#section-4.1 RFC 7235 Section 4.1>
150−unauthorizedContainsWWWAuthenticate :: Predicate b Bool
334+unauthorizedContainsWWWAuthenticate :: ResponsePredicate
151unauthorizedContainsWWWAuthenticate
335unauthorizedContainsWWWAuthenticate
336+ = ResponsePredicate $ \resp ->
337+ if responseStatus resp == status401
338+ then unless (hasValidHeader "WWW-Authenticate" (const True) resp) $
152− = ResponsePredicate "unauthorizedContainsWWWAuthenticate" _
339+ throw $ PredicateFailure "unauthorizedContainsWWWAuthenticate" Nothing resp
153−-}
340+ else return ()
343+-- | [__RFC Compliance__]
345+-- [An HTML] document will start with exactly this string: <!DOCTYPE html>
347+-- This function checks that HTML documents (those with `Content-Type: text/html...`)
348+-- include a DOCTYPE declaration at the top. We do not enforce capital case for the string `DOCTYPE`.
352+-- * HTML5 Doctype: <https://tools.ietf.org/html/rfc7992#section-6.1 RFC 7992 Section 6.1>
354+htmlIncludesDoctype :: ResponsePredicate
356+ = ResponsePredicate $ \resp ->
357+ if hasValidHeader "Content-Type" (SBS.isPrefixOf . foldCase $ "text/html") resp
359+ let htmlContent = foldCase . LBS.take 20 $ responseBody resp
360+ unless (LBS.isPrefixOf (foldCase "<!doctype html>") htmlContent) $
361+ throw $ PredicateFailure "htmlIncludesDoctype" Nothing resp
154-- * Predicate logic
364-- * Predicate logic
156-- The idea with all this footwork is to not waste any requests. Rather than
366-- The idea with all this footwork is to not waste any requests. Rather than
@@ -159,76 +369,93 @@ unauthorizedContainsWWWAuthenticate
160-- Still, this is all kind of ugly.
370-- Still, this is all kind of ugly.
372+-- | A predicate that depends only on the response.
162−data ResponsePredicate n r = ResponsePredicate
375+newtype ResponsePredicate = ResponsePredicate
164− , respPred :: Response LBS.ByteString -> r
376+ { getResponsePredicate :: Response LBS.ByteString -> IO ()
165− } deriving (Functor, Generic)
377+ } deriving (Generic)
167−instance Bifunctor ResponsePredicate where
379+instance Semigroup ResponsePredicate where
168− first f (ResponsePredicate a b) = ResponsePredicate (f a) b
380+ ResponsePredicate a <> ResponsePredicate b = ResponsePredicate $ \x -> a x >> b x
171−instance (Monoid n, Monoid r) => Monoid (ResponsePredicate n r) where
382+instance Monoid ResponsePredicate where
172− mempty = ResponsePredicate mempty mempty
383+ mempty = ResponsePredicate $ const $ return ()
173− a `mappend` b = ResponsePredicate
384+ mappend = (<>)
174− { respPredName = respPredName a <> respPredName b
175− , respPred = respPred a <> respPred b
386+-- | A predicate that depends on both the request and the response.
178−data RequestPredicate n r = RequestPredicate
389+newtype RequestPredicate = RequestPredicate
180− , reqResps :: Request -> Manager -> IO [Response LBS.ByteString]
390+ { getRequestPredicate :: Request -> Manager -> IO [Response LBS.ByteString]
181− , reqPred :: ResponsePredicate n r
182− } deriving (Generic, Functor)
391+ } deriving (Generic)
393+-- TODO: This isn't actually a monoid
184−instance Bifunctor RequestPredicate where
394+instance Monoid RequestPredicate where
185− first f (RequestPredicate a b c) = RequestPredicate (f a) b (first f c)
395+ mempty = RequestPredicate (\r m -> httpLbs r m >>= \x -> return ([x]))
186− second = fmap
396+ mappend = (<>)
188-- TODO: This isn't actually a monoid
398-- TODO: This isn't actually a monoid
189−instance (Monoid n, Monoid r) => Monoid (RequestPredicate n r) where
399+instance Semigroup RequestPredicate where
190− mempty = RequestPredicate mempty (\r m -> return <$> httpLbs r m) mempty
400+ RequestPredicate a <> RequestPredicate b = RequestPredicate $ \r mgr ->
191− a `mappend` b = RequestPredicate
401+ liftM2 (<>) (a r mgr) (b r mgr)
192− { reqPredName = reqPredName a <> reqPredName b
193− , reqResps = \x m -> liftM2 (<>) (reqResps a x m) (reqResps b x m)
194− , reqPred = reqPred a <> reqPred b
197−data Predicates n r = Predicates
198− { reqPreds :: RequestPredicate n r
199− , respPreds :: ResponsePredicate n r
200− } deriving (Generic, Functor)
202−instance (Monoid n, Monoid r) => Monoid (Predicates n r) where
203− mempty = Predicates mempty mempty
204− a `mappend` b = Predicates (reqPreds a <> reqPreds b) (respPreds a <> respPreds b)
403+-- | A set of predicates. Construct one with 'mempty' and '<%>'.
404+data Predicates = Predicates
405+ { requestPredicates :: RequestPredicate
406+ , responsePredicates :: ResponsePredicate
407+ } deriving (Generic)
409+instance Semigroup Predicates where
410+ a <> b = Predicates (requestPredicates a <> requestPredicates b)
411+ (responsePredicates a <> responsePredicates b)
413+instance Monoid Predicates where
414+ mempty = Predicates mempty mempty
208class JoinPreds a where
417class JoinPreds a where
209− joinPreds :: a -> Predicates [Text] [Text] -> Predicates [Text] [Text]
418+ joinPreds :: a -> Predicates -> Predicates
211−instance JoinPreds (RequestPredicate Text Bool) where
420+instance JoinPreds (RequestPredicate ) where
212− joinPreds p (Predicates x y) = Predicates (go <> x) y
421+ joinPreds p (Predicates x y) = Predicates (p <> x) y
213− where go = let p' = first return p
214− in fmap (\z -> if z then [] else reqPredName p') p'
216−instance JoinPreds (ResponsePredicate Text Bool) where
423+instance JoinPreds (ResponsePredicate ) where
217− joinPreds p (Predicates x y) = Predicates x (go <> y)
424+ joinPreds p (Predicates x y) = Predicates x (p <> y)
218− where go = let p' = first return p
219− in fmap (\z -> if z then [] else respPredName p') p'
221−infixr 6 <%>
426+-- | Adds a new predicate (either `ResponsePredicate` or `RequestPredicate`) to
427+-- the existing predicates.
429+-- > not500 <%> onlyJsonObjects <%> empty
222−(<%>) :: JoinPreds a => a -> Predicates [Text] [Text] -> Predicates [Text] [Text]
432+(<%>) :: JoinPreds a => a -> Predicates -> Predicates
223(<%>) = joinPreds
433(<%>) = joinPreds
225−finishPredicates :: Predicates [Text] [Text] -> Request -> Manager -> IO [Text]
436+finishPredicates :: Predicates -> Request -> Manager -> IO (Maybe PredicateFailure)
226−finishPredicates p req mgr = do
437+finishPredicates p req mgr = go `catch` \(e :: PredicateFailure) -> return $ Just e
227− resps <- reqResps (reqPreds p) req mgr
438+ where
228− let preds = reqPred (reqPreds p) <> respPreds p
439+ go = do
229− return $ mconcat [respPred preds r | r <- resps ]
440+ resps <- getRequestPredicate (requestPredicates p) req mgr
441+ mapM_ (getResponsePredicate $ responsePredicates p) resps
231-- * helpers
444-- * helpers
233−hasHeader :: SBS.ByteString -> Response b -> Bool
446+hasValidHeader :: SBS.ByteString -> (SBS.ByteString -> Bool) -> Response b -> Bool
234−hasHeader hdr r = mk hdr `elem` (fst <$> responseHeaders r)
447+hasValidHeader hdr p r = case lookup (mk hdr) (responseHeaders r) of
451+isRFC822Date :: SBS.ByteString -> Bool
453+ = case parseTimeM True defaultTimeLocale rfc822DateFormat (SBSC.unpack s) of
455+ Just (_ :: UTCTime) -> True
457+status2XX :: Monad m => Maybe Request -> Response LBS.ByteString -> T.Text -> m ()
458+status2XX mreq resp t
459+ | status200 <= responseStatus resp && responseStatus resp < status300
461+ | otherwise = throw $ PredicateFailure t mreq resp