eeva/servant
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Modified the tutorial to reflect the changes to servant-client (explicit parameters)

Browse Source
This commit is contained in:
mbg 2016-03-30 22:50:29 +01:00
parent 9e1ba9221d
commit a9200cd050
1 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
doc/tutorial/Client.lhs
View File

@ -15,13 +15,13 @@ need to have some language extensions and imports:
module Client where module Client where
import Control.Monad.Trans.Except (ExceptT, runExceptT)
import Data.Aeson import Data.Aeson
import Data.Proxy import Data.Proxy
import GHC.Generics import GHC.Generics
import Network.HTTP.Client (newManager, defaultManagerSettings) import Network.HTTP.Client (Manager, newManager, defaultManagerSettings)
import Servant.API import Servant.API
import Servant.Client import Servant.Client
import Servant.Common.Req (ClientM, runClientM)
``` ```
Also, we need examples for some domain specific data types: Also, we need examples for some domain specific data types:
@ -71,13 +71,19 @@ What we are going to get with **servant-client** here is 3 functions, one to que
``` haskell ``` haskell
position :: Int -- ^ value for "x" position :: Int -- ^ value for "x"
-> Int -- ^ value for "y" -> Int -- ^ value for "y"
-> ClientM Position -> Manager -- ^ the HTTP client to use
-> BaseUrl -- ^ the URL at which the API can be found
-> ExceptT ServantError IO Position
hello :: Maybe String -- ^ an optional value for "name" hello :: Maybe String -- ^ an optional value for "name"
-> ClientM HelloMessage -> Manager -- ^ the HTTP client to use
-> BaseUrl -- ^ the URL at which the API can be found
-> ExceptT ServantError IO HelloMessage
marketing :: ClientInfo -- ^ value for the request body marketing :: ClientInfo -- ^ value for the request body
-> ClientM Email -> Manager -- ^ the HTTP client to use
-> BaseUrl -- ^ the URL at which the API can be found
-> ExceptT ServantError IO Email
``` ```
Each function makes available as an argument any value that the response may Each function makes available as an argument any value that the response may
@ -114,17 +120,17 @@ data BaseUrl = BaseUrl
That's it. Let's now write some code that uses our client functions. That's it. Let's now write some code that uses our client functions.
``` haskell ``` haskell
queries :: ClientM (Position, HelloMessage, Email) queries :: Manager -> BaseUrl -> ExceptT ServantError IO (Position, HelloMessage, Email)
queries = do queries manager baseurl = do
pos <- position 10 10 pos <- position 10 10 manager baseurl
message <- hello (Just "servant") message <- hello (Just "servant") manager baseurl
em <- marketing (ClientInfo "Alp" "alp@foo.com" 26 ["haskell", "mathematics"]) em <- marketing (ClientInfo "Alp" "alp@foo.com" 26 ["haskell", "mathematics"]) manager baseurl
return (pos, message, em) return (pos, message, em)
run :: IO () run :: IO ()
run = do run = do
manager <- newManager defaultManagerSettings manager <- newManager defaultManagerSettings
res <- runClientM queries (BaseUrl Http "localhost" 8081 "") manager res <- runExceptT (queries manager (BaseUrl Http "localhost" 8081 ""))
case res of case res of
Left err -> putStrLn $ "Error: " ++ show err Left err -> putStrLn $ "Error: " ++ show err
Right (pos, message, em) -> do Right (pos, message, em) -> do