The latest version of this document is on GitHub. Changelog for servant package contains significant entries for all core packages.

0.18.3

Significant changes

• Add response header support to UVerb (#1420)

Other changes

• Support GHC-9.0.1.
• Bump bytestring, hspec, base64-bytestring and QuickCheck dependencies.

0.18.2

Significant changes

• Support Fragment combinator.

0.18.1

Significant changes

• Union verbs

Other changes

• Bump “tested-with” ghc versions
• Loosen bound on base16-bytestring

0.18

Significant changes

• Support for ghc8.8 (#1318, #1326, #1327)

0.17

Significant changes

• Add NoContentVerb #1028 #1219 #1228

  The NoContent API endpoints should now use NoContentVerb combinator. The API type changes are usually of the kind

  - :<|> PostNoContent '[JSON] NoContent
  + :<|> PostNoContent
  

  i.e. one doesn’t need to specify the content-type anymore. There is no content.

• Capture can be Lenient #1155 #1156

  You can specify a lenient capture as

  :<|> "capture-lenient"  :> Capture' '[Lenient] "foo" Int :> GET
  

  which will make the capture always succeed. Handlers will be of the type Either String CapturedType, where Left err represents the possible parse failure.

Other changes

• servant-client servant-client-core servant-http-streams Fix Verb with headers checking content type differently #1200 #1204

  For Verbs with response Headers, the implementation didn’t check for the content-type of the response. Now it does.

• servant-client servant-http-streams HasClient instance for Stream with Headers #1170 #1197

• servant-client Redact the authorization header in Show and exceptions #1238

0.16

• Rename ServantError to ClientError, ServantErr to ServerError #1131

• servant-client-core Rearrange modules. No more Internal modules, whole API is versioned. #1130

• servant-client-core RequestBody is now

  = RequestBodyLBS LBS.ByteString
  | RequestBodyBS BS.ByteString
  | RequestBodySource (SourceIO LBS.ByteString)
  

  i.e. no more replicates http-clients API. #1117

• servant-client-core Keep structured exceptions in ConnectionError constructor of ClientError #1115

  -| ConnectionError Text
  +| ConnectionError SomeException
  

• servant-client-core Preserve failing request in FailureResponse constructor of ClientError #1114

  -FailureResponse Response
  +-- | The server returned an error response including the
  +-- failing request. 'requestPath' includes the 'BaseUrl' and the
  +-- path of the request.
  +FailureResponse (RequestF () (BaseUrl, BS.ByteString)) Response
  

• servant-client Fix (implement) StreamBody instance #1110

• servant-client Update CookieJar with intermediate request/responses (redirects) #1104

0.15

• Streaming refactoring. #991 #1076 #1077

  The streaming functionality (Servant.API.Stream) is refactored to use servant’s own SourceIO type (see Servant.Types.SourceT documentation), which replaces both StreamGenerator and ResultStream types.

  New conversion type-classes are ToSourceIO and FromSourceIO (replacing ToStreamGenerator and BuildFromStream). There are instances for conduit, pipes and machines in new packages: servant-conduit servant-pipes and servant-machines respectively.

  Writing new framing strategies is simpler. Check existing strategies for examples.

  This change shouldn’t affect you, if you don’t use streaming endpoints.

• servant-client Separate streaming client. #1066

  We now have two http-client based clients, in Servant.Client and Servant.Client.Streaming.

  Their API is the same, except for

  • Servant.Client cannot request Stream endpoints.
  • Servant.Client is run by direct runClientM :: ClientM a -> ClientEnv -> IO (Either ServantError a)
  • Servant.Client.Streaming can request Stream endpoints.
  • Servant.Client.Streaming is used by CPSised withClientM :: ClientM a -> ClientEnv -> (Either ServantError a -> IO b) -> IO b

  To access Stream endpoints use Servant.Client.Streaming with withClientM; otherwise you can continue using Servant.Client with runClientM. You can use both too, ClientEnv and BaseUrl types are same for both.

  Note: Servant.Client.Streaming doesn’t stream non-Stream endpoints. Requesting ordinary Verb endpoints (e.g. Get) will block until the whole response is received.

  There is Servant.Client.Streaming.runClientM function, but it has restricted type. NFData a constraint prevents using it with SourceT, Conduit etc. response types.

  runClientM :: NFData a => ClientM a -> ClientEnv -> IO (Either ServantError a)
  

  This change shouldn’t affect you, if you don’t use streaming endpoints.

• servant-client-core Related to the previous: streamingResponse is removed from RunClient. We have a new type-class:

  class RunClient m =>  RunStreamingClient m where
      withStreamingRequest :: Request -> (StreamingResponse -> IO a) ->  m a
  

• Drop support for GHC older than 8.0 #1008 #1009

• servant-client-core Add NFData (GenResponse a) and NFData ServantError instances. #1076

• servant-client-core Add aeson and Lift BaseUrl instances #1037

0.14.1

• Merge in servant-generic (by Patrick Chilton) into servant (Servant.API.Generic), servant-client-code (Servant.Client.Generic) and servant-server (Servant.Server.Generic).

0.14

• Stream takes a status code argument

  -Stream method        framing ctype a
  +Stream method status framing ctype a
  

  (#966 #972)

• ToStreamGenerator definition changed, so it’s possible to write an instance for conduits.

  -class ToStreamGenerator f a where
  -   toStreamGenerator :: f a -> StreamGenerator a
  +class ToStreamGenerator a b | a -> b where
  +   toStreamGenerator :: a -> StreamGenerator b
  

  (#959)

• Added NoFraming streaming strategy (#959)

• servant-client-core Free Client implementation. Useful for testing HasClient instances. (#920)

• servant-client-core Add hoistClient to HasClient. Just like hoistServer allows us to change the monad in which request handlers of a web application live, we also have hoistClient for changing the monad in which client functions live. Read tutorial section for more information. (#936)

  iF you have own combinators, you’ll need to define a new method of HasClient class, for example:

  type Client m (MyCombinator :> api) = MyValue :> Client m api
  hoistClientMonad pm _ nt cl = hoistClientMonad pm (Proxy :: Proxy api) nt . cl
  

0.13.0.1

• Support base-compat-0.10

0.13

• Streaming endpoint support. (#836)
• servant Add Servant.API.Modifiers (#873)

0.12

• First version. Factored out of servant-client all the functionality that was independent of the http-client backend.