twain-2.1.0.0: Tiny web application framework for WAI.
Safe HaskellNone
LanguageHaskell2010

Web.Twain

Description

Twain is a tiny web application framework for WAI

  • ResponderM for composing responses with do notation.
  • Routing with path captures that decompose ResponderM into middleware.
  • Parameter parsing for cookies, path, query, and body.
  • Helpers for redirects, headers, status codes, and errors.
{--}

import Network.Wai.Handler.Warp (run)
import Web.Twain

main :: IO ()
main = do
  run 8080 $
    foldr ($)
      (notFound missing)
      [ get "/" index
      , post "echo:name" echo
      ]

index :: ResponderM a
index = send $ html "Hello World!"

echo :: ResponderM a
echo = do
  name <- param "name"
  send $ html $ "Hello, " <> name

missing :: ResponderM a
missing = send $ html "Not found..."
Synopsis

Documentation

data ResponderM a Source #

ResponderM is an Either-like monad that can "short-circuit" and return a response, or pass control to the next middleware. This provides convenient branching with do notation for redirects, error responses, etc.

Instances

Instances details
Monad ResponderM Source # 
Instance details

Defined in Web.Twain.Types

Methods

(>>=) :: ResponderM a -> (a -> ResponderM b) -> ResponderM b #

(>>) :: ResponderM a -> ResponderM b -> ResponderM b #

return :: a -> ResponderM a #

Functor ResponderM Source # 
Instance details

Defined in Web.Twain.Types

Methods

fmap :: (a -> b) -> ResponderM a -> ResponderM b #

(<$) :: a -> ResponderM b -> ResponderM a #

Applicative ResponderM Source # 
Instance details

Defined in Web.Twain.Types

Methods

pure :: a -> ResponderM a #

(<*>) :: ResponderM (a -> b) -> ResponderM a -> ResponderM b #

liftA2 :: (a -> b -> c) -> ResponderM a -> ResponderM b -> ResponderM c #

(*>) :: ResponderM a -> ResponderM b -> ResponderM b #

(<*) :: ResponderM a -> ResponderM b -> ResponderM a #

MonadIO ResponderM Source # 
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Defined in Web.Twain.Types

Methods

liftIO :: IO a -> ResponderM a #

MonadThrow ResponderM Source # 
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Defined in Web.Twain.Types

Methods

throwM :: Exception e => e -> ResponderM a #

MonadCatch ResponderM Source # 
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Defined in Web.Twain.Types

Methods

catch :: Exception e => ResponderM a -> (e -> ResponderM a) -> ResponderM a #

Routing

route :: Maybe Method -> PathPattern -> ResponderM a -> Middleware Source #

Route request matching optional Method and PathPattern to ResponderM.

notFound :: ResponderM a -> Application Source #

Respond if no other route responds.

Sets the status to 404.

Requests

param :: ParsableParam a => Text -> ResponderM a Source #

Get a parameter. Looks in query, path, cookie, and body (in that order).

If no parameter is found, or parameter fails to parse, next is called which passes control to subsequent routes and middleware.

paramEither :: ParsableParam a => Text -> ResponderM (Either HttpError a) Source #

Get a parameter or error if missing or parse failure.

paramMaybe :: ParsableParam a => Text -> ResponderM (Maybe a) Source #

Get an optional parameter.

Returns Nothing for missing parameter. Throws HttpError on parse failure.

params :: ResponderM [Param] Source #

Get all parameters from query, path, cookie, and body (in that order).

file :: Text -> ResponderM (FileInfo ByteString) Source #

Get uploaded FileInfo.

If missing parameter or empty file, pass control to subsequent routes and middleware.

fileMaybe :: Text -> ResponderM (Maybe (FileInfo ByteString)) Source #

Get optional uploaded FileInfo.

Nothing is returned for missing parameter or empty file content.

files :: ResponderM [File ByteString] Source #

Get all uploaded files.

fromBody :: FromJSON a => ResponderM a Source #

Get the JSON value from request body.

header :: Text -> ResponderM (Maybe Text) Source #

Get the value of a request Header. Header names are case-insensitive.

headers :: ResponderM [Header] Source #

Get the request headers.

Responses

send :: Response -> ResponderM a Source #

Send a Response.

send $ text "Hello, World!"

Send an html response:

send $ html "<h1>Hello, World!</h1>"

Modify the status:

send $ status status404 $ text "Not Found"

Send a response withHeader:

send $ withHeader (hServer, "Twain + Warp") $ text "Hello"

Send a response withCookie:

send $ withCookie "key" "val" $ text "Hello"

next :: ResponderM a Source #

Pass control to the next route or middleware.

redirect301 :: Text -> Response Source #

Create a redirect response with 301 status (Moved Permanently).

redirect302 :: Text -> Response Source #

Create a redirect response with 302 status (Found).

redirect303 :: Text -> Response Source #

Create a redirect response 303 status (See Other).

text :: Text -> Response Source #

Construct a Text response.

Sets the Content-Type and Content-Length headers.

html :: ByteString -> Response Source #

Construct an HTML response.

Sets the Content-Type and Content-Length headers.

json :: ToJSON a => a -> Response Source #

Construct a JSON response using ToJSON.

Sets the Content-Type and Content-Length headers.

xml :: ByteString -> Response Source #

Construct an XML response.

Sets the Content-Type and Content-Length headers.

css :: ByteString -> Response Source #

Construct a CSS response.

Sets the Content-Type and Content-Length headers.

raw :: Status -> [Header] -> ByteString -> Response Source #

Construct a raw response from a lazy ByteString.

Sets the Content-Length header if missing.

withHeader :: Header -> Response -> Response Source #

Add a Header to response.

withCookie :: Text -> Text -> Response -> Response Source #

Add a cookie to the response with the given key and value.

Note: This uses defaultSetCookie.

withCookie' :: SetCookie -> Response -> Response Source #

Add a SetCookie to the response.

expireCookie :: Text -> Response -> Response Source #

Add a header to expire (unset) a cookie with the given key.

Errors

data HttpError Source #

Constructors

HttpError Status String 

Instances

Instances details
Eq HttpError Source # 
Instance details

Defined in Web.Twain.Types

Show HttpError Source # 
Instance details

Defined in Web.Twain.Types

Exception HttpError Source # 
Instance details

Defined in Web.Twain.Types

Middleware

withMaxBodySize :: Word64 -> Middleware Source #

Specify maximum request body size in bytes.

Defaults to 64KB.

Parameters

class ParsableParam a where Source #

Parse values from request parameters.

Minimal complete definition

parseParam

Methods

parseParam :: Text -> Either HttpError a Source #

parseParamList :: Text -> Either HttpError [a] Source #

Default implementation parses comma-delimited lists.

Instances

Instances details
ParsableParam Bool Source # 
Instance details

Defined in Web.Twain.Types

ParsableParam Char Source # 
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Defined in Web.Twain.Types

ParsableParam Double Source # 
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ParsableParam Float Source # 
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ParsableParam Int Source # 
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ParsableParam Int8 Source # 
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ParsableParam Int16 Source # 
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ParsableParam Int32 Source # 
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ParsableParam Int64 Source # 
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ParsableParam Integer Source # 
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Defined in Web.Twain.Types

ParsableParam Natural Source # 
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Defined in Web.Twain.Types

ParsableParam Word Source # 
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ParsableParam Word8 Source # 
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ParsableParam Word16 Source # 
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ParsableParam Word32 Source # 
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ParsableParam Word64 Source # 
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Defined in Web.Twain.Types

ParsableParam () Source # 
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Defined in Web.Twain.Types

ParsableParam ByteString Source # 
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ParsableParam ByteString Source # 
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Defined in Web.Twain.Types

ParsableParam Text Source # 
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Defined in Web.Twain.Types

ParsableParam Text Source # 
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Defined in Web.Twain.Types

ParsableParam a => ParsableParam [a] Source # 
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Defined in Web.Twain.Types

Re-exports

data FileInfo c #

Information on an uploaded file.

Instances

Instances details
Eq c => Eq (FileInfo c) 
Instance details

Defined in Network.Wai.Parse

Methods

(==) :: FileInfo c -> FileInfo c -> Bool #

(/=) :: FileInfo c -> FileInfo c -> Bool #

Show c => Show (FileInfo c) 
Instance details

Defined in Network.Wai.Parse

Methods

showsPrec :: Int -> FileInfo c -> ShowS #

show :: FileInfo c -> String #

showList :: [FileInfo c] -> ShowS #