src/Servant-API-Alternative.html · typeable/servant

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typeable/servant/src/Servant-API-Alternative.html

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1<?xml version="1.0" encoding="UTF-8"?>

2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

3<html>

4<head>

5

6<title>src/Servant/API/Alternative.hs</title>

7<link type='text/css' rel='stylesheet' href='hscolour.css' />

8</head>

9<body>

10<pre><a name="line-1"></a>{-# LANGUAGE TypeFamilies #-}

11<a name="line-2"></a>{-# LANGUAGE TypeOperators #-}

12<a name="line-3"></a>{-# LANGUAGE ScopedTypeVariables #-}

13<a name="line-4"></a>module Servant.API.Alternative where

14<a name="line-5"></a>

15<a name="line-6"></a>import Data.Monoid

16<a name="line-7"></a>import Data.Proxy

17<a name="line-8"></a>import Servant.Server

18<a name="line-9"></a>

19<a name="line-10"></a>-- | Union of two APIs, first takes precedence in case of overlap.

20<a name="line-11"></a>--

21<a name="line-12"></a>-- Example:

22<a name="line-13"></a>--

23<a name="line-14"></a>-- > type MyApi = "books" :> Get [Book] -- GET /books

24<a name="line-15"></a>-- > :<|> "books" :> ReqBody Book :> Post Book -- POST /books

25<a name="line-16"></a>data a :<|> b = a :<|> b

26<a name="line-17"></a>infixr 8 :<|>

27<a name="line-18"></a>

28<a name="line-19"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- | A server for @a ':<|>' b@ first tries to match the request again the route

29<a name="line-20"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- represented by @a@ and if it fails tries @b@. You must provide a request

30<a name="line-21"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- handler for each route.

31<a name="line-22"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>--

32<a name="line-23"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > type MyApi = "books" :> Get [Book] -- GET /books

33<a name="line-24"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > :<|> "books" :> ReqBody Book :> Post Book -- POST /books

34<a name="line-25"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- >

35<a name="line-26"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > server :: Server MyApi

36<a name="line-27"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > server = listAllBooks :<|> postBook

37<a name="line-28"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > where listAllBooks = ...

38<a name="line-29"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>-- > postBook book = ...

39<a name="line-30"></a><a name="instance%20HasServer%20(a%20:%3c%7c%3e%20b)"></a>instance (HasServer a, HasServer b) => HasServer (a :<|> b) where

40<a name="line-31"></a> type Server (a :<|> b) = Server a :<|> Server b

41<a name="line-32"></a> route Proxy (a :<|> b) request respond =

42<a name="line-33"></a> route pa a request $ \ mResponse ->

43<a name="line-34"></a> if isMismatch mResponse

44<a name="line-35"></a> then route pb b request $ \mResponse' -> respond (mResponse <> mResponse')

45<a name="line-36"></a> else respond mResponse

46<a name="line-37"></a>

47<a name="line-38"></a> where pa = Proxy :: Proxy a

48<a name="line-39"></a> pb = Proxy :: Proxy b

49</pre></body>

50</html>