Create an HTTP/WebSocket daemonized server (experimental)

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Description

Creates an HTTP/WebSocket server on the specified host and port. The server is daemonized so R interactive sessions are not blocked to handle requests.

Usage

1
startDaemonizedServer(host, port, app)

Arguments

host

A string that is a valid IPv4 address that is owned by this server, or "0.0.0.0" to listen on all IP addresses.

port

A number or integer that indicates the server port that should be listened on. Note that on most Unix-like systems including Linux and Mac OS X, port numbers smaller than 1025 require root privileges.

app

A collection of functions that define your application. See Details.

Details

In contrast to servers created by startServer, calls to service are not needed to accept and handle connections. If the port cannot be bound (most likely due to permissions or because it is already bound), an error is raised.

The app parameter is where your application logic will be provided to the server. This can be a list, environment, or reference class that contains the following named functions/methods:

call(req)

Process the given HTTP request, and return an HTTP response. This method should be implemented in accordance with the Rook specification.

onHeaders(req)

Optional. Similar to call, but occurs when headers are received. Return NULL to continue normal processing of the request, or a Rook response to send that response, stop processing the request, and ask the client to close the connection. (This can be used to implement upload size limits, for example.)

onWSOpen(ws)

Called back when a WebSocket connection is established. The given object can be used to be notified when a message is received from the client, to send messages to the client, etc. See WebSocket.

The startPipeServer variant is not supported yet.

Value

A handle for this server that can be passed to stopDaemonizedServer to shut the server down.

See Also

startServer