servant-client

automatical derivation of querying functions for servant webservices

http://haskell-servant.readthedocs.org/

Version on this page:0.13.0.1@rev:2
LTS Haskell 24.0:0.20.3.0@rev:1
Stackage Nightly 2025-07-14:0.20.3.0@rev:1
Latest on Hackage:0.20.3.0@rev:1

See all snapshots servant-client appears in

BSD-3-Clause licensed by Servant Contributors
Maintained by [email protected]
This version can be pinned in stack with:servant-client-0.13.0.1@sha256:a55598131c6a19c3a97187a929d58309c82fb2a73a0cc6f5df9874eadfb627de,4112

Module documentation for 0.13.0.1

servant-client

servant

This library lets you automatically derive Haskell functions that let you query each endpoint of a servant webservice.

Example

type MyApi = "books" :> Get '[JSON] [Book] -- GET /books
        :<|> "books" :> ReqBody Book :> Post '[JSON] Book -- POST /books

myApi :: Proxy MyApi
myApi = Proxy

getAllBooks :: Manager -> BaseUrl -> ExceptT String IO [Book]
postNewBook :: Book -> Manager -> BaseUrl -> ExceptT String IO Book
-- 'client' allows you to produce operations to query an API from a client.
(getAllBooks :<|> postNewBook) = client myApi

Changes

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

0.13.0.1

  • Support base-compat-0.10

0.13

  • Streaming endpoint support. (#836)
  • servant Add Servant.API.Modifiers (#873)
  • servant-client Support http-client’s CookieJar (#897 #883)

0.12.0.1

  • Send Accept header. (#858)

0.12

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

0.11

Other changes

  • Path components are escaped (#696)
  • Req reqPath field changed from String to BS.Builder (#696)
  • Include Req in failure errors (#740)

0.10

Breaking changes

There shouldn’t be breaking changes. Released as a part of servant suite.

Other changes

  • Add MonadBase and MonadBaseControl instances for ClientM (#663)

  • client asks for any content-type in Accept contentTypes non-empty list (#615)

  • Add ClientLike class that matches client functions generated using client with client data structure. (#640)

  • Allow direct use of ‘RequestBody’ (#661)

0.9.1.1

  • Add MonadThrow and MonadCatch instances for ClientM

0.9

  • BACKWARDS INCOMPATIBLE: client now returns a ClientM which is a Reader for BasicEnv. BasicEnv comprises the HttpManager and BaseUrl that have had to be passed to each method returned by client.

0.7.1

  • Support GHC 8.0
  • ServantError has an Eq instance now.

0.6

  • client no longer takes BaseUrl and Manager arguments. Instead, each function returned by client requires these two arguments.

0.5

  • Use the text package instead of String.
  • Support for the HttpVersion, IsSecure, RemoteHost and Vault combinators
  • Added support for path on BaseUrl.
  • client now takes an explicit Manager argument.
  • Use http-api-data instead of Servant.Common.Text
  • Client functions now consider any 2xx successful.
  • Remove matrix params.
  • Added support for Basic authentication
  • Add generalized authentication support via the AuthClientData type family and AuthenticateReq data type

0.4.1

  • The HasClient instance for Delete cts () now does not care at all about content types provided.

0.4

  • Delete now is like Get, Post, Put, and Patch and returns a response body
  • Support content-type aware combinators and Accept/Content-type headers
  • Added a lot of tests
  • Support multiple concurrent threads
  • Use ServantError to report Errors instead of String
  • Make the clients for Raw endpoints return the whole Response value (to be able to access response headers for example)
  • Support for PATCH
  • Make () instances expect No Content status code, and not try to decode body.
  • Add support for response headers

0.2.2

  • Add TLS support
  • Add matrix parameter support