Merge pull request #84 from haskell-servant/wip-json-decode-eof

fix a bug in our `eitherDecodeLenient` function
This commit is contained in:
Alp Mestanogullari 2015-05-23 12:56:31 +01:00
commit 5c25c56d50
2 changed files with 55 additions and 38 deletions

View file

@ -66,17 +66,19 @@ module Servant.API.ContentTypes
) where
#if !MIN_VERSION_base(4,8,0)
import Control.Applicative ((<*))
import Control.Applicative ((*>), (<*))
#endif
import Control.Arrow (left)
import Control.Monad
import Data.Aeson (FromJSON, ToJSON, Value,
encode, parseJSON)
import Data.Aeson (FromJSON, ToJSON, encode,
parseJSON)
import Data.Aeson.Parser (value)
import Data.Aeson.Types (parseEither)
import Data.Attoparsec.ByteString (endOfInput, parseOnly)
import Data.Attoparsec.ByteString.Char8 (endOfInput, parseOnly,
skipSpace, (<?>))
import qualified Data.ByteString as BS
import Data.ByteString.Lazy (ByteString, fromStrict, toStrict)
import Data.ByteString.Lazy (ByteString, fromStrict,
toStrict)
import qualified Data.ByteString.Lazy as B
import Data.Monoid
import Data.String.Conversions (cs)
@ -87,8 +89,8 @@ import qualified Data.Text.Lazy.Encoding as TextL
import Data.Typeable
import GHC.Exts (Constraint)
import qualified Network.HTTP.Media as M
import Network.URI (escapeURIString, isUnreserved,
unEscapeString)
import Network.URI (escapeURIString,
isUnreserved, unEscapeString)
-- * Provided content types
data JSON deriving Typeable
@ -291,10 +293,22 @@ instance MimeRender OctetStream BS.ByteString where
-- | Like 'Data.Aeson.eitherDecode' but allows all JSON values instead of just
-- objects and arrays.
--
-- Will handle trailing whitespace, but not trailing junk. ie.
--
-- >>> eitherDecodeLenient "1 " :: Either String Int
-- Right 1
--
-- >>> eitherDecodeLenient "1 junk" :: Either String Int
-- Left "trailing junk after valid JSON: endOfInput"
eitherDecodeLenient :: FromJSON a => ByteString -> Either String a
eitherDecodeLenient input = do
v :: Value <- parseOnly (Data.Aeson.Parser.value <* endOfInput) (cs input)
parseEither parseJSON v
eitherDecodeLenient input =
parseOnly parser (cs input) >>= parseEither parseJSON
where
parser = skipSpace
*> Data.Aeson.Parser.value
<* skipSpace
<* (endOfInput <?> "trailing junk after valid JSON")
-- | `eitherDecode`
instance FromJSON a => MimeUnrender JSON a where

View file

@ -8,14 +8,15 @@ module Servant.API.ContentTypesSpec where
#if !MIN_VERSION_base(4,8,0)
import Control.Applicative
import Data.Monoid
#endif
import Control.Arrow
import Data.Aeson
import Data.Aeson.Parser (jstring)
import Data.Attoparsec.ByteString (parseOnly)
import Data.Either
import Data.Function (on)
import Data.Proxy
import Data.ByteString.Char8 (ByteString, append, pack)
import qualified Data.ByteString.Lazy as BSL
import Data.List (maximumBy)
@ -36,54 +37,56 @@ spec :: Spec
spec = describe "Servant.API.ContentTypes" $ do
describe "The JSON Content-Type type" $ do
let p = Proxy :: Proxy JSON
it "handles whitespace at end of input" $ do
mimeUnrender p "[1] " `shouldBe` Right [1 :: Int]
it "handles whitespace at beginning of input" $ do
mimeUnrender p " [1] " `shouldBe` Right [1 :: Int]
it "does not like junk at end of input" $ do
mimeUnrender p "[1] this probably shouldn't work"
`shouldSatisfy` (isLeft :: Either a [Int] -> Bool)
it "has mimeUnrender reverse mimeRender for valid top-level json ([Int]) " $ do
let p = Proxy :: Proxy JSON
property $ \x -> mimeUnrender p (mimeRender p x) == Right (x::[Int])
it "has mimeUnrender reverse mimeRender for valid top-level json " $ do
let p = Proxy :: Proxy JSON
property $ \x -> mimeUnrender p (mimeRender p x) == Right (x::SomeData)
describe "The FormUrlEncoded Content-Type type" $ do
let isNonNull ("", "") = False
isNonNull _ = True
let p = Proxy :: Proxy FormUrlEncoded
it "has mimeUnrender reverse mimeRender" $ do
let p = Proxy :: Proxy FormUrlEncoded
property $ \x -> all isNonNull x
property $ \x -> all (/= mempty) x
==> mimeUnrender p (mimeRender p x) == Right (x::[(TextS.Text,TextS.Text)])
it "has mimeUnrender reverse exportParams (Network.URL)" $ do
let p = Proxy :: Proxy FormUrlEncoded
property $ \x -> all isNonNull x
property $ \x -> all (/= mempty) x
==> (mimeUnrender p . cs . exportParams . map (cs *** cs) $ x) == Right (x::[(TextS.Text,TextS.Text)])
it "has importParams (Network.URL) reverse mimeRender" $ do
let p = Proxy :: Proxy FormUrlEncoded
property $ \x -> all isNonNull x
property $ \x -> all (/= mempty) x
==> (fmap (map (cs *** cs)) . importParams . cs . mimeRender p $ x) == Just (x::[(TextS.Text,TextS.Text)])
describe "The PlainText Content-Type type" $ do
let p = Proxy :: Proxy PlainText
it "has mimeUnrender reverse mimeRender (lazy Text)" $ do
let p = Proxy :: Proxy PlainText
property $ \x -> mimeUnrender p (mimeRender p x) == Right (x::TextL.Text)
it "has mimeUnrender reverse mimeRender (strict Text)" $ do
let p = Proxy :: Proxy PlainText
property $ \x -> mimeUnrender p (mimeRender p x) == Right (x::TextS.Text)
describe "The OctetStream Content-Type type" $ do
let p = Proxy :: Proxy OctetStream
it "is id (Lazy ByteString)" $ do
let p = Proxy :: Proxy OctetStream
property $ \x -> mimeRender p x == (x :: BSL.ByteString)
&& mimeUnrender p x == Right x
it "is fromStrict/toStrict (Strict ByteString)" $ do
let p = Proxy :: Proxy OctetStream
property $ \x -> mimeRender p x == BSL.fromStrict (x :: ByteString)
&& mimeUnrender p (BSL.fromStrict x) == Right x