Network.Wai.Handler.Warp

Port to listen on. Default value: 3000

Since 2.1.0

Interface to bind to. Default value: HostIPv4

Since 2.1.0

What to do with exceptions thrown by either the application or server. Default: defaultOnException

Since 2.1.0

A function to create a Response when an exception occurs. Default: defaultOnExceptionResponse

Note that an application can handle its own exceptions without interfering with Warp:

myApp :: Application
myApp request respond = innerApp `catch` onError
  where
    onError = respond . response500 request

response500 :: Request -> SomeException -> Response
response500 req someEx = responseLBS status500 -- ...

Since 2.1.0

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

Since 2.1.0

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

Since 2.1.0

"Slow-loris" timeout lower-bound value in seconds. Connections where network progress is made less frequently than this may be closed. In practice many connections may be allowed to go without progress for up to twice this amount of time. Note that this timeout is not applied to application code, only network progress.

Default value: 30

Since 2.1.0

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

Since 2.1.0

Cache duration time of file descriptors in seconds. 0 means that the cache mechanism is not used.

The FD cache is an optimization that is useful for servers dealing with static files. However, if files are being modified, it can cause incorrect results in some cases. Therefore, we disable it by default. If you know that your files will be static or you prefer performance to file consistency, it's recommended to turn this on; a reasonable value for those cases is 10. Enabling this cache results in drastic performance improvement for file transfers.

Default value: 0, was previously 10

Since 3.0.13

Cache duration time of file information in seconds. 0 means that the cache mechanism is not used.

The file information cache is an optimization that is useful for servers dealing with static files. However, if files are being modified, it can cause incorrect results in some cases. Therefore, we disable it by default. If you know that your files will be static or you prefer performance to file consistency, it's recommended to turn this on; a reasonable value for those cases is 10. Enabling this cache results in drastic performance improvement for file transfers.

Default value: 0

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

Perform no parsing on the rawPathInfo.

This is useful for writing HTTP proxies.

Default: False

Since 2.1.0

A code to install shutdown handler.

For instance, this code should set up a UNIX signal handler. The handler should call the first argument, which closes the listen socket, at shutdown.

Example usage:

settings :: IO () -> Settings
settings shutdownAction = setInstallShutdownHandler shutdownHandler defaultSettings
  where
    shutdownHandler closeSocket =
      void $ installHandler sigTERM (Catch $ shutdownAction >> closeSocket) Nothing

Note that by default, the graceful shutdown mode lasts indefinitely (see setGracefulShutdownTimeout). If you install a signal handler as above, upon receiving that signal, the custom shutdown action will run and all outstanding requests will be handled.

You may instead prefer to do one or both of the following:

• Only wait a finite amount of time for outstanding requests to complete, using setGracefulShutdownTimeout.

• Only catch one signal, so the second hard-kills the Warp server, using CatchOnce.

Default: does not install any code.

Since 3.0.1

Default server name to be sent as the "Server:" header if an application does not set one. If an empty string is set, the "Server:" header is not sent. This is true even if an application set one.

Since 3.0.2

The maximum number of bytes to flush from an unconsumed request body.

By default, Warp does not flush the request body so that, if a large body is present, the connection is simply terminated instead of wasting time and bandwidth on transmitting it. However, some clients do not deal with that situation well. You can either change this setting to Nothing to flush the entire body in all cases, or in your application ensure that you always consume the entire request body.

Default: 8192 bytes.

Since 3.0.3

Code to fork a new thread to accept a connection.

This may be useful if you need OS bound threads, or if you wish to develop an alternative threading model.

Default: void . forkIOWithUnmask

Since 3.0.4

Code to accept a new connection.

Useful if you need to provide connected sockets from something other than a standard accept call.

Default: defaultAccept

Since 3.3.24

Do not use the PROXY protocol.

Since 3.0.5

Require PROXY header.

This is for cases where a "dumb" TCP/SSL proxy is being used, which cannot add an X-Forwarded-For HTTP header field but has enabled support for the PROXY protocol.

See http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt and http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/TerminologyandKeyConcepts.html#proxy-protocol.

Only the human-readable header format (version 1) is supported. The binary header format (version 2) is not supported.

Since 3.0.5

Use the PROXY header if it exists, but also accept connections without the header. See setProxyProtocolRequired.

WARNING: This is contrary to the PROXY protocol specification and using it can indicate a security problem with your architecture if the web server is directly accessible to the public, since it would allow easy IP address spoofing. However, it can be useful in some cases, such as if a load balancer health check uses regular HTTP without the PROXY header, but proxied connections do include the PROXY header.

Since 3.0.5

Size in bytes read to prevent Slowloris attacks. Default value: 2048

Since 3.1.2

Disable HTTP2.

Since 3.1.7

Setting a log function.

Since 3.X.X

Setting a log function for HTTP/2 server push.

Since: 3.2.7

Set the graceful shutdown timeout. A timeout of Nothing will wait indefinitely, and a number, if provided, will be treated as seconds to wait for requests to finish, before shutting down the server entirely.

Graceful shutdown mode is entered when the server socket is closed; see setInstallShutdownHandler for an example of how this could be done in response to a UNIX signal.

Since 3.2.8

A timeout to limit the time (in milliseconds) waiting for FIN for HTTP/1.x. 0 means uses immediate close. Default: 0.

Since 3.3.5

A timeout to limit the time (in milliseconds) waiting for FIN for HTTP/2. 0 means uses immediate close. Default: 2000.

Since 3.3.5

Set the maximum header size that Warp will tolerate when using HTTP/1.x.

Since 3.3.8

Setting the header value of Alternative Services (AltSvc:).

Since 3.3.11

Set the maximum buffer size for sending Builder responses.

Since 3.3.22

Get the listening port.

Since 2.1.1

Get the interface to bind to.

Since 2.1.1

Get the action on opening connection.

Get the action on closeing connection.

Get the exception handler.

Get the graceful shutdown timeout

Since 3.2.8

A timeout to limit the time (in milliseconds) waiting for FIN for HTTP/1.x. 0 means uses immediate close.

Since 3.3.5

A timeout to limit the time (in milliseconds) waiting for FIN for HTTP/2. 0 means uses immediate close.

Since 3.3.5

Printing an exception to standard error if defaultShouldDisplayException returns True.

Since: 3.1.0

Apply the logic provided by defaultOnException 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

Sending 400 for bad requests. Sending 500 for internal server errors. Since: 3.1.0 Sending 413 for too large payload. Sending 431 for too large headers. Since 3.2.27

Exception handler for the debugging purpose. 500, text/plain, a showed exception.

Since: 2.0.3.2

HTTP/2 specific data.

Since: 3.2.7

Accessor for PushPromise in HTTP2Data.

Since: 3.2.7

Accessor for TrailersMaker in HTTP2Data.

Since: 3.2.8 but the type changed in 3.3.0

Default HTTP/2 specific data.

Since: 3.2.7

Getting HTTP2Data through vault of the request. Warp uses this to receive HTTP2Data from Middleware.

Since: 3.2.7

Setting HTTP2Data through vault of the request. Application or Middleware should use this.

Since: 3.2.7

Modifying HTTP2Data through vault of the request. Application or Middleware should use this.

Since: 3.2.8

HTTP/2 push promise or sever push. This allows files only for backward-compatibility while the HTTP/2 library supports other types.

Since: 3.2.7

Accessor for a URL path in PushPromise. E.g. "/style/default.css".

Since: 3.2.7

Accessor for FilePath in PushPromise. E.g. "FILE_PATH/default.css".

Since: 3.2.7

Accessor for ResponseHeaders in PushPromise "content-type" must be specified. Default value: [].

Since: 3.2.7

Accessor for Weight in PushPromise. Default value: 16.

Since: 3.2.7

Default push promise.

Since: 3.2.7