@@ -1,69 +1,21 @@
11module Servant.QuickCheck.Internal.Predicates where
22
3−import Control.Exception (catch, throw)
4−import Control.Monad (liftM2, unless, when)
5−import Data.Aeson (Object, decode)
6−import Data.Bifunctor (first)
7−import qualified Data.ByteString as SBS
8−import qualified Data.ByteString.Char8 as SBSC
9−import qualified Data.ByteString.Lazy as LBS
10−import Data.CaseInsensitive (foldCase, foldedCase, mk)
11−import Data.Either (isRight)
12−import Data.List.Split (wordsBy)
13−import Data.Maybe (fromMaybe, isJust)
14−import Data.Semigroup (Semigroup (..))
15−import qualified Data.Text as T
16−import Data.Time (UTCTime, defaultTimeLocale, parseTimeM,
17− rfc822DateFormat)
18−import GHC.Generics (Generic)
19−import Network.HTTP.Client (Manager, Request, Response, httpLbs,
20− method, parseRequest, requestHeaders,
21− responseBody, responseHeaders,
22− responseStatus)
23−import Network.HTTP.Media (matchAccept)
24−import Network.HTTP.Types (methodGet, methodHead, parseMethod,
25− renderStdMethod, status100, status200,
26− status201, status300, status401,
27− status405, status500)
28−import Prelude.Compat
29−import System.Clock (Clock (Monotonic), diffTimeSpec,
30− getTime, toNanoSecs)
3+import Data.Monoid ((<>))
4+import GHC.Generics (Generic)
5+import Control.Monad
6+import Network.HTTP.Client (Request, Response)
317
32−import Servant.QuickCheck.Internal.ErrorTypes
33−
34−
35−-- | [__Best Practice__]
36−--
37−-- @500 Internal Server Error@ should be avoided - it may represent some
8+{-
9+-- | @500 Internal Server Error@ should be avoided - it may represent some
3810-- issue with the application code, and it moreover gives the client little
3911-- indication of how to proceed or what went wrong.
4012--
4113-- This function checks that the response code is not 500.
42−--
43−-- /Since 0.0.0.0/
44−not500 :: ResponsePredicate
45−not500 = ResponsePredicate $ \resp ->
46− when (responseStatus resp == status500) $ throw $ PredicateFailure "not500" Nothing resp
14+not500 :: Response b -> IO Bool
15+not500
16+ = ResponsePredicate "not500" _
4717
48−-- | [__Optional__]
49−--
50−-- This function checks that the response from the server does not take longer
51−-- than the specified number of nanoseconds.
52−--
53−-- /Since 0.0.2.1/
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
62− return []
63−
64−-- | [__Best Practice__]
65−--
66−-- Returning anything other than an object when returning JSON is considered
18+-- | Returning anything other than an object when returning JSON is considered
6719-- bad practice, as:
6820--
6921-- (1) it is hard to modify the returned value while maintaining backwards
@@ -75,202 +27,64 @@ notLongerThan maxAllowed
7527--
7628-- This function checks that any @application/json@ responses only return JSON
7729-- objects (and not arrays, strings, numbers, or booleans) at the top level.
78−--
79−-- __References__:
80−--
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>
83−--
84−-- /Since 0.0.0.0/
85−onlyJsonObjects :: ResponsePredicate
30+onlyJsonObjects :: Response b -> IO Bool
8631onlyJsonObjects
87− = ResponsePredicate (\resp -> do
88− case lookup "content-type" (first foldedCase <$> responseHeaders resp) of
89− Nothing -> return ()
90− Just ctype -> when ("application/json" `SBS.isPrefixOf` ctype) $ do
91− case (decode (responseBody resp) :: Maybe Object) of
92− Nothing -> throw $ PredicateFailure "onlyJsonObjects" Nothing resp
93− Just _ -> return ())
32+ = ResponsePredicate "onlyJsonObjects" _
9433
95−-- | __Optional__
96−--
97−-- When creating a new resource, it is good practice to provide a @Location@
34+-- | When creating a new resource, it is good practice to provide a @Location@
9835-- header with a link to the created resource.
9936--
10037-- This function checks that every @201 Created@ response contains a @Location@
10138-- header, and that the link in it responds with a 2XX response code to @GET@
10239-- requests.
10340--
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.
107−--
108−-- __References__:
109−--
110−-- * 201 Created: <https://tools.ietf.org/html/rfc7231#section-6.3.2 RFC 7231 Section 6.3.2>
111−-- * Location header: <https://tools.ietf.org/html/rfc7231#section-7.1.2 RFC 7231 Section 7.1.2>
112−--
113−-- /Since 0.0.0.0/
114−createContainsValidLocation :: RequestPredicate
41+-- References: <RFC 7231, Section 6.3.2 https://tools.ietf.org/html/rfc7231#section-6.3.2>
42+createContainsValidLocation :: Response b -> IO Bool
11543createContainsValidLocation
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
124− Just x -> do
125− resp2 <- httpLbs x mgr
126− status2XX (Just req) resp2 n
127− return [resp, resp2]
128− else return [resp]
44+ = ResponsePredicate "createContainsValidLocation" _
12945
130−-- | [__Optional__]
131−--
132−-- The @Last-Modified@ header represents the time a resource was last
133−-- modified. It is used to drive caching and conditional requests.
134−--
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.
140−--
141−-- The @Last-Modified@ header can also be used in conjunction with the
142−-- @If-Unmodified-Since@ header to drive optimistic concurrency.
143−--
144−-- The @Last-Modified@ date must be in RFC 822 format.
145−--
146−-- __References__:
147−--
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>
153−--
154−-- /Since 0.0.2.1/
155−getsHaveLastModifiedHeader :: RequestPredicate
46+getsHaveLastModifiedHeader :: Response b -> IO Bool
15647getsHaveLastModifiedHeader
157− = RequestPredicate $ \req mgr ->
158− if (method req == methodGet)
159− then do
160− resp <- httpLbs req mgr
161− unless (hasValidHeader "Last-Modified" isRFC822Date resp) $ do
162− throw $ PredicateFailure "getsHaveLastModifiedHeader" (Just req) resp
163− return [resp]
164− else return []
165−
166−
48+ = ResponsePredicate "getsHaveLastModifiedHeader" _
16749
168−-- | [__RFC Compliance__]
169−--
170−-- When an HTTP request has a method that is not allowed,
171−-- a 405 response should be returned. Additionally, it is good practice to
172−-- return an @Allow@
50+-- | When an HTTP request has a method that is not allowed, a 405 response
51+-- should be returned. Additionally, it is good practice to return an @Allow@
17352-- header with the list of allowed methods.
17453--
17554-- This function checks that every @405 Method Not Allowed@ response contains
17655-- an @Allow@ header with a list of standard HTTP methods.
177−--
178−-- Note that 'servant' itself does not currently set the @Allow@ headers.
179−--
180−-- __References__:
181−--
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>
185−--
186−-- /Since 0.0.0.0/
187−notAllowedContainsAllowHeader :: RequestPredicate
56+notAllowedContainsAllowHeader :: Response b -> IO Bool
18857notAllowedContainsAllowHeader
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
58+ = ResponsePredicate "notAllowedContainsAllowHeader" _
19359
194− case filter pred' (zip reqs resp) of
195− (x:_) -> throw $ PredicateFailure "notAllowedContainsAllowHeader" (Just $ fst x) (snd x)
196− [] -> return resp
197− where
198− pred' (_, resp) = responseStatus resp == status405 && not (hasValidHeader "Allow" go resp)
199− where
200− go x = all (\y -> isRight $ parseMethod $ SBSC.pack y)
201− $ wordsBy (`elem` (", " :: [Char])) (SBSC.unpack x)
202−
203−
204−-- | [__RFC Compliance__]
205−--
206−-- When a request contains an @Accept@ header, the server must either return
60+-- | When a request contains an @Accept@ header, the server must either return
20761-- content in one of the requested representations, or respond with @406 Not
20862-- Acceptable@.
20963--
21064-- This function checks that every *successful* response has a @Content-Type@
211−-- header that matches the @Accept@ header. It does *not* check that the server
212−-- matches the quality descriptions of the @Accept@ header correctly.
213−--
214−-- __References__:
215−--
216−-- * @Accept@ header: <https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html RFC 2616 Section 14.1>
217−--
218−-- /Since 0.0.0.0/
219−honoursAcceptHeader :: RequestPredicate
65+-- header that matches the @Accept@ header.
66+honoursAcceptHeader :: Predicate b Bool
22067honoursAcceptHeader
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
229− else return [resp]
230− else return [resp]
231−
68+ = RequestPredicate "honoursAcceptHeader" _
23269
233−-- | [__Best Practice__]
234−--
235−-- Whether or not a representation should be cached, it is good practice to
70+-- | Whether or not a representation should be cached, it is good practice to
23671-- have a @Cache-Control@ header for @GET@ requests. If the representation
23772-- should not be cached, used @Cache-Control: no-cache@.
23873--
239−-- This function checks that @GET@ responses have @Cache-Control@ header.
240−-- It does NOT currently check that the header is valid.
241−--
242−-- __References__:
243−--
244−-- * @Cache-Control@ header: <https://tools.ietf.org/html/rfc7234#section-5.2 RFC 7234 Section 5.2>
74+-- This function checks that @GET@ responses have a valid @Cache-Control@
75+-- header.
24576--
246−-- /Since 0.0.0.0/
247−getsHaveCacheControlHeader :: RequestPredicate
77+-- References: RFC 7234 Section 5.2
78+-- https://tools.ietf.org/html/rfc7234#section-5.2
79+getsHaveCacheControlHeader :: Predicate b Bool
24880getsHaveCacheControlHeader
249− = RequestPredicate $ \req mgr ->
250− if (method req == methodGet)
251− then do
252− resp <- httpLbs req mgr
253− unless (hasValidHeader "Cache-Control" (const True) resp) $ do
254− throw $ PredicateFailure "getsHaveCacheControlHeader" (Just req) resp
255− return [resp]
256− else return []
81+ = ResponsePredicate "getsHaveCacheControlHeader" _
25782
258−-- | [__Best Practice__]
259−--
260−-- Like 'getsHaveCacheControlHeader', but for @HEAD@ requests.
261−--
262−-- /Since 0.0.0.0/
263−headsHaveCacheControlHeader :: RequestPredicate
83+-- | Like 'getsHaveCacheControlHeader', but for @HEAD@ requests.
84+headsHaveCacheControlHeader :: Predicate b Bool
26485headsHaveCacheControlHeader
265− = RequestPredicate $ \req mgr ->
266− if (method req == methodHead)
267− then do
268− resp <- httpLbs req mgr
269− unless (hasValidHeader "Cache-Control" (const True) resp) $
270− throw $ PredicateFailure "headsHaveCacheControlHeader" (Just req) resp
271− return [resp]
272− else return []
273−{-
86+ = ResponsePredicate "headsHaveCacheControlHeader" _
87+
27488-- |
27589--
27690-- If the original request modifies the resource, this function makes two
@@ -311,151 +125,25 @@ optionsContainsValidAllow
311125-- This function checks that any @Link@ headers have values in the correct
312126-- format.
313127--
314−-- __References__:
315−--
316−-- * <https://tools.ietf.org/html/rfc5988 RFC 5988 Section 5>
128+-- References: RFC 5988 Section 5
129+-- https://tools.ietf.org/html/rfc5988
317130linkHeadersAreValid :: Predicate b Bool
318131linkHeadersAreValid
319132 = ResponsePredicate "linkHeadersAreValid" _
320133
321−-}
322−-- | [__RFC Compliance__]
323−--
324−-- Any @401 Unauthorized@ response must include a @WWW-Authenticate@ header.
134+-- | Any @401 Unauthorized@ response must include a @WWW-Authenticate@ header.
325135--
326136-- This function checks that, if a response has status code 401, it contains a
327137-- @WWW-Authenticate@ header.
328138--
329−-- __References__:
330−--
331−-- * @WWW-Authenticate@ header: <https://tools.ietf.org/html/rfc7235#section-4.1 RFC 7235 Section 4.1>
332−--
333−-- /Since 0.0.0.0/
334−unauthorizedContainsWWWAuthenticate :: ResponsePredicate
139+-- References: RFC 7235 Section 4.1
140+-- https://tools.ietf.org/html/rfc7235#section-4.1
141+unauthorizedContainsWWWAuthenticate :: Predicate b Bool
335142unauthorizedContainsWWWAuthenticate
336− = ResponsePredicate $ \resp ->
337− if responseStatus resp == status401
338− then unless (hasValidHeader "WWW-Authenticate" (const True) resp) $
339− throw $ PredicateFailure "unauthorizedContainsWWWAuthenticate" Nothing resp
340− else return ()
341−
342−
343−-- | [__RFC Compliance__]
344−--
345−-- [An HTML] document will start with exactly this string: <!DOCTYPE html>
346−--
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`.
349−--
350−-- __References__:
351−--
352−-- * HTML5 Doctype: <https://tools.ietf.org/html/rfc7992#section-6.1 RFC 7992 Section 6.1>
353−-- /Since 0.3.0.0/
354−htmlIncludesDoctype :: ResponsePredicate
355−htmlIncludesDoctype
356− = ResponsePredicate $ \resp ->
357− if hasValidHeader "Content-Type" (SBS.isPrefixOf . foldCase $ "text/html") resp
358− then do
359− let htmlContent = foldCase . LBS.take 20 $ responseBody resp
360− unless (LBS.isPrefixOf (foldCase "<!doctype html>") htmlContent) $
361− throw $ PredicateFailure "htmlIncludesDoctype" Nothing resp
362− else return ()
363−
364−-- * Predicate logic
365−
366−-- The idea with all this footwork is to not waste any requests. Rather than
367−-- generating new requests and only applying one predicate to the response, we
368−-- apply as many predicates as possible.
369−--
370−-- Still, this is all kind of ugly.
371−
372−-- | A predicate that depends only on the response.
373−--
374−-- /Since 0.0.0.0/
375−newtype ResponsePredicate = ResponsePredicate
376− { getResponsePredicate :: Response LBS.ByteString -> IO ()
377− } deriving (Generic)
378−
379−instance Semigroup ResponsePredicate where
380− ResponsePredicate a <> ResponsePredicate b = ResponsePredicate $ \x -> a x >> b x
381−
382−instance Monoid ResponsePredicate where
383− mempty = ResponsePredicate $ const $ return ()
384− mappend = (<>)
385−
386−-- | A predicate that depends on both the request and the response.
387−--
388−-- /Since 0.0.0.0/
389−newtype RequestPredicate = RequestPredicate
390− { getRequestPredicate :: Request -> Manager -> IO [Response LBS.ByteString]
391− } deriving (Generic)
392−
393−-- TODO: This isn't actually a monoid
394−instance Monoid RequestPredicate where
395− mempty = RequestPredicate (\r m -> httpLbs r m >>= \x -> return ([x]))
396− mappend = (<>)
397−
398−-- TODO: This isn't actually a monoid
399−instance Semigroup RequestPredicate where
400− RequestPredicate a <> RequestPredicate b = RequestPredicate $ \r mgr ->
401− liftM2 (<>) (a r mgr) (b r mgr)
402−
403−-- | A set of predicates. Construct one with 'mempty' and '<%>'.
404−data Predicates = Predicates
405− { requestPredicates :: RequestPredicate
406− , responsePredicates :: ResponsePredicate
407− } deriving (Generic)
408−
409−instance Semigroup Predicates where
410− a <> b = Predicates (requestPredicates a <> requestPredicates b)
411− (responsePredicates a <> responsePredicates b)
412−
413−instance Monoid Predicates where
414− mempty = Predicates mempty mempty
415− mappend = (<>)
416−
417−class JoinPreds a where
418− joinPreds :: a -> Predicates -> Predicates
419−
420−instance JoinPreds (RequestPredicate ) where
421− joinPreds p (Predicates x y) = Predicates (p <> x) y
422−
423−instance JoinPreds (ResponsePredicate ) where
424− joinPreds p (Predicates x y) = Predicates x (p <> y)
425−
426−-- | Adds a new predicate (either `ResponsePredicate` or `RequestPredicate`) to
427−-- the existing predicates.
428−--
429−-- > not500 <%> onlyJsonObjects <%> empty
430−--
431−-- /Since 0.0.0.0/
432−(<%>) :: JoinPreds a => a -> Predicates -> Predicates
433−(<%>) = joinPreds
434−infixr 6 <%>
435−
436−finishPredicates :: Predicates -> Request -> Manager -> IO (Maybe PredicateFailure)
437−finishPredicates p req mgr = go `catch` \(e :: PredicateFailure) -> return $ Just e
438− where
439− go = do
440− resps <- getRequestPredicate (requestPredicates p) req mgr
441− mapM_ (getResponsePredicate $ responsePredicates p) resps
442− return Nothing
443−
444−-- * helpers
445−
446−hasValidHeader :: SBS.ByteString -> (SBS.ByteString -> Bool) -> Response b -> Bool
447−hasValidHeader hdr p r = case lookup (mk hdr) (responseHeaders r) of
448− Nothing -> False
449− Just v -> p v
450−
451−isRFC822Date :: SBS.ByteString -> Bool
452−isRFC822Date s
453− = case parseTimeM True defaultTimeLocale rfc822DateFormat (SBSC.unpack s) of
454− Nothing -> False
455− Just (_ :: UTCTime) -> True
143+ = ResponsePredicate "unauthorizedContainsWWWAuthenticate" _
144+-}
456145
457−status2XX :: Monad m => Maybe Request -> Response LBS.ByteString -> T.Text -> m ()
458−status2XX mreq resp t
459− | status200 <= responseStatus resp && responseStatus resp < status300
460− = return ()
461− | otherwise = throw $ PredicateFailure t mreq resp
146+data Predicate b r
147+ = ResponsePredicate String (Response b -> IO r)
148+ | RequestPredicate String (Request -> [Response b -> IO r] -> IO r)
149+ deriving (Generic)