Network.Wai.Handler.Warp

A fast, light-weight HTTP server handler for WAI.

Run a Warp server

run :: Port -> Application -> IO ()

Run an Application on the given port. This calls runSettings with defaultSettings.

runSettings :: Settings -> Application -> IO ()

Run an Application with the given Settings.

runSettingsSocket :: Settings -> Socket -> Application -> IO ()

Same as runSettings, but uses a user-supplied socket instead of opening one. This allows the user to provide, for example, Unix named socket, which can be used when reverse HTTP proxying into your application.

Note that the settingsPort will still be passed to Applications via the serverPort record.

runSettingsConnection :: Settings -> IO (Connection, SockAddr) -> Application -> IO ()

Allows you to provide a function which will return a Connection. In cases where creating the Connection can be expensive, this allows the expensive computations to be performed in a separate thread instead of the main server loop.

Since 1.3.5

runSettingsConnectionMaker :: Settings -> IO (IO Connection, SockAddr) -> Application -> IO ()

Allows you to provide a function which will return a function which will return Connection.

Settings

data Settings

Various Warp server settings. This is purposely kept as an abstract data type so that new settings can be added without breaking backwards compatibility. In order to create a Settings value, use defaultSettings and record syntax to modify individual records. For example:

 defaultSettings { settingsTimeout = 20 }

defaultSettings :: Settings

The default settings for the Warp server. See the individual settings for the default value.

Setters

setPort :: Int -> Settings -> Settings

Port to listen on. Default value: 3000

Since 2.1.0

setHost :: HostPreference -> Settings -> Settings

Interface to bind to. Default value: HostIPv4

Since 2.1.0

setOnException :: (Maybe Request -> SomeException -> IO ()) -> Settings -> Settings

What to do with exceptions thrown by either the application or server. Default: ignore server-generated exceptions (see InvalidRequest) and print application-generated applications to stderr.

Since 2.1.0

setOnExceptionResponse :: (SomeException -> Response) -> Settings -> Settings

A function to create Response when an exception occurs.

Default: 500, text/plain, "Something went wrong"

Since 2.1.0

setOnOpen :: (SockAddr -> IO Bool) -> Settings -> Settings

What to do when a connection is open. When False is returned, the connection is closed immediately. Otherwise, the connection is going on. Default: always returns True.

Since 2.1.0

setOnClose :: (SockAddr -> IO ()) -> Settings -> Settings

What to do when a connection is close. Default: do nothing.

Since 2.1.0

setTimeout :: Int -> Settings -> Settings

Timeout value in seconds. Default value: 30

Since 2.1.0

setIntercept :: (Request -> IO (Maybe (Source IO ByteString -> Connection -> IO ()))) -> Settings -> Settings

Register some intercept handler to deal with specific requests. Prime use case: websockets.

Default: always return Nothing.

Since 2.1.0

setManager :: Manager -> Settings -> Settings

Use an existing timeout manager instead of spawning a new one. If used, settingsTimeout is ignored.

Since 2.1.0

setFdCacheDuration :: Int -> Settings -> Settings

Cache duratoin time of file descriptors in seconds. 0 means that the cache mechanism is not used. Default value: 10

setBeforeMainLoop :: IO () -> Settings -> Settings

Code to run after the listening socket is ready but before entering the main event loop. Useful for signaling to tests that they can start running, or to drop permissions after binding to a restricted port.

Default: do nothing.

Since 2.1.0

setNoParsePath :: Bool -> Settings -> Settings

Perform no parsing on the rawPathInfo.

This is useful for writing HTTP proxies.

Default: False

Since 2.1.0

Getters

getPort :: Settings -> Int

Get the listening port.

Since 2.1.1

getHost :: Settings -> HostPreference

Get the interface to bind to.

Since 2.1.1

Accessors

Note: these accessors are deprecated, please use the set versions instead.

settingsPort :: Settings -> Int

Deprecated: Use setPort instead

Port to listen on. Default value: 3000

settingsHost :: Settings -> HostPreference

Deprecated: Use setHost instead

Default value: HostIPv4

settingsOnException :: Settings -> Maybe Request -> SomeException -> IO ()

Deprecated: Use setOnException instead

What to do with exceptions thrown by either the application or server. Default: ignore server-generated exceptions (see InvalidRequest) and print application-generated applications to stderr.

settingsOnExceptionResponse :: Settings -> SomeException -> Response

Deprecated: Use setOnExceptionResponse instead

A function to create Response when an exception occurs.

Default: 500, text/plain, "Something went wrong"

Since 2.0.3

settingsOnOpen :: Settings -> SockAddr -> IO Bool

Deprecated: Use setOnOpen instead

What to do when a connection is open. When False is returned, the connection is closed immediately. Otherwise, the connection is going on. Default: always returns True.

settingsOnClose :: Settings -> SockAddr -> IO ()

Deprecated: Use setOnClose instead

What to do when a connection is close. Default: do nothing.

settingsTimeout :: Settings -> Int

Deprecated: Use setTimeout instead

Timeout value in seconds. Default value: 30

settingsIntercept :: Settings -> Request -> IO (Maybe (Source IO ByteString -> Connection -> IO ()))

Deprecated: Use setIntercept instead

settingsManager :: Settings -> Maybe Manager

Deprecated: Use setManager instead

Use an existing timeout manager instead of spawning a new one. If used, settingsTimeout is ignored. Default is Nothing

settingsFdCacheDuration :: Settings -> Int

Deprecated: Use setFdCacheDuration instead

Cache duratoin time of file descriptors in seconds. 0 means that the cache mechanism is not used. Default value: 10

settingsBeforeMainLoop :: Settings -> IO ()

Deprecated: Use setBeforeMainLoop instead

Code to run after the listening socket is ready but before entering the main event loop. Useful for signaling to tests that they can start running, or to drop permissions after binding to a restricted port.

Default: do nothing.

Since 1.3.6

settingsNoParsePath :: Settings -> Bool

Deprecated: Use setNoParsePath instead

Perform no parsing on the rawPathInfo.

This is useful for writing HTTP proxies.

Default: False

Since 2.0.3

Debugging

exceptionResponseForDebug :: SomeException -> Response

Default implementation of settingsOnExceptionResponse for the debugging purpose. 500, text/plain, a showed exception.

defaultShouldDisplayException :: SomeException -> Bool

Apply the logic provided by defaultExceptionHandler to determine if an exception should be shown or not. The goal is to hide exceptions which occur under the normal course of the web server running.

Since 2.1.3

Data types

data HostPreference

Which host to bind.

Note: The IsString instance recognizes the following special values:

• * means HostAny
• *4 means HostIPv4
• !4 means HostIPv4Only
• *6 means HostIPv6
• !6 means HostIPv6Only

Constructors

HostAny

HostIPv4

HostIPv4Only

HostIPv6

HostIPv6Only

Host String

Instances

Eq HostPreference

Ord HostPreference

Read HostPreference

Show HostPreference

IsString HostPreference

type Port = Int

TCP port number.

data InvalidRequest

Error types for bad Request.

Constructors

NotEnoughLines [String]

BadFirstLine String

NonHttp

IncompleteHeaders

ConnectionClosedByPeer

OverLargeHeader

Instances

Eq InvalidRequest

Show InvalidRequest

Typeable InvalidRequest

Exception InvalidRequest

data ConnSendFileOverride

Whether or not ConnSendFileOverride in Connection can be overridden. This is a kind of hack to keep the signature of Connection clean.

Constructors

NotOverride

Don't override

Override Socket

Override with this Socket

Connection

data Connection

Data type to manipulate IO actions for connections.

Constructors

Connection

Fields

connSendMany :: [ByteString] -> IO ()

connSendAll :: ByteString -> IO ()

connSendFile :: FilePath -> Integer -> Integer -> IO () -> [ByteString] -> IO ()

filepath, offset, length, hook action, HTTP headers

connClose :: IO ()

connRecv :: IO ByteString

connBuffer :: Buffer

connBufferSize :: BufSize

connSendFileOverride :: ConnSendFileOverride

socketConnection :: Socket -> IO Connection

Default action value for Connection.

Internal

Version

warpVersion :: String

The version of Warp.

Data types

data InternalInfo

Internal information.

Constructors

InternalInfo

Fields

threadHandle :: Handle

fdCacher :: Maybe MutableFdCache

dateCacher :: DateCache

type HeaderValue = ByteString

The type for header value used with HeaderName.

type IndexedHeader = Array Int (Maybe HeaderValue)

Array for a set of HTTP headers.

requestMaxIndex :: Int

The size for IndexedHeader for HTTP Request. From 0 to this corresponds to "Content-Length", "Transfer-Encoding", "Expect", "Connection", "Range", and "Host".

Time out manager

module Network.Wai.Handler.Warp.Timeout

File descriptor cache

withFdCache :: Int -> (Maybe MutableFdCache -> IO a) -> IO a

Creating MutableFdCache and executing the action in the second argument. The first argument is a cache duration in second.

getFd :: MutableFdCache -> FilePath -> IO (Fd, Refresh)

Getting Fd and Refresh from the mutable Fd cacher.

data MutableFdCache

Mutable Fd cacher.

type Refresh = IO ()

An action to activate a Fd cache entry.

Date

withDateCache :: (DateCache -> IO a) -> IO a

Creating DateCache and executing the action.

getDate :: DateCache -> IO GMTDate

Getting GMTDate based on DateCache.

data DateCache

The type of the cache of the Date header value.

type GMTDate = ByteString

The type of the Date header value.

Request and response

recvRequest

Arguments

:: Settings

-> Connection

-> InternalInfo

-> SockAddr

Peer's address.

-> Source IO ByteString

Where HTTP request comes from.

-> IO (Request, IndexedHeader, IO (ResumableSource IO ByteString), Maybe ByteString)

Request passed to Application, IndexedHeader of HTTP request for internal use, leftover source (i.e. body and other HTTP reqeusts in HTTP pipelining), leftovers from request header parsing (used for raw responses)

Receiving a HTTP request from Connection and parsing its header to create Request.

sendResponse

Arguments

:: Connection

-> InternalInfo

-> (forall a. IO a -> IO a)

Restore masking state.

-> Request

HTTP request.

-> IndexedHeader

Indexed header of HTTP request.

-> Maybe ByteString

leftovers from header parsing

-> Response

HTTP response including status code and response header.

-> IO Bool

Returing True if the connection is persistent.

Sending a HTTP response to Connection according to Response.

Applications/middlewares MUST specify a proper ResponseHeaders. so that inconsistency does not happen. No header is deleted by this function.

Especially, Applications/middlewares MUST take care of Content-Length, Content-Range, and Transfer-Encoding because they are inserted, when necessary, regardless they already exist. This function does not insert Content-Encoding. It's middleware's responsibility.

The Date and Server header is added if not exist in HTTP response header.

There are three basic APIs to create Response:

responseFile :: Status -> ResponseHeaders -> FilePath -> Maybe FilePart -> Response

HTTP response body is sent by sendfile(). Applications are categorized into simple and sophisticated. Simple applications should specify Nothing to Maybe FilePart. The size of the specified file is obtained by disk access. Then Range is handled. Sophisticated applications should specify Just to Maybe FilePart. They should treat Range (and If-Range) by thierselves. In both cases, Content-Length and Content-Range (if necessary) are automatically added into the HTTP response header. If Content-Length and Content-Range exist in the HTTP response header, they would cause inconsistency. Status is also changed to 206 if necessary.

responseBuilder :: Status -> ResponseHeaders -> Builder -> Response

HTTP response body is created from Source. Typically, Transfer-Encoding: chunked is used. If Content-Length is specified, Transfer-Encoding: chunked is not used.

responseSource :: Status -> ResponseHeaders -> Source IO (Flush Builder) -> Response

HTTP response body is created from Builder. Typically, Transfer-Encoding: chunked is used. If Content-Length is specified, Transfer-Encoding: chunked is not used.