WebSocket {httpuv}

WebSocket class

Description

A WebSocket object represents a single WebSocket connection. The object can be used to send messages and close the connection, and to receive notifications when messages are received or the connection is closed.

Details

Note that this WebSocket class is different from the one provided by the package named websocket. This class is meant to be used on the server side, whereas the one in the websocket package is to be used as a client. The WebSocket class in httpuv has an older API than the one in the websocket package.

WebSocket objects should never be created directly. They are obtained by passing an onWSOpen function to startServer.

Fields

request

The Rook request environment that opened the connection. This can be used to inspect HTTP headers, for example.

Methods

onMessage(func)

Registers a callback function that will be invoked whenever a message is received on this connection. The callback function will be invoked with two arguments. The first argument is TRUE if the message is binary and FALSE if it is text. The second argument is either a raw vector (if the message is binary) or a character vector.

onClose(func)

Registers a callback function that will be invoked when the connection is closed.

send(message)

Begins sending the given message over the websocket. The message must be either a raw vector, or a single-element character vector that is encoded in UTF-8.

close()

Closes the websocket connection.

Methods

Public methods

• WebSocket$new()

• WebSocket$onMessage()

• WebSocket$onClose()

• WebSocket$send()

• WebSocket$close()

• WebSocket$clone()

Method new()

Usage

WebSocket$new(handle, req)

Method onMessage()

Usage

WebSocket$onMessage(func)

Method onClose()

Usage

WebSocket$onClose(func)

Method send()

Usage

WebSocket$send(message)

Method close()

Usage

WebSocket$close(code = 1000L, reason = "")

Method clone()

The objects of this class are cloneable with this method.

Usage

WebSocket$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

## Not run: 
# A WebSocket echo server that listens on port 8080
startServer("0.0.0.0", 8080,
  list(
    onHeaders = function(req) {
      # Print connection headers
      cat(capture.output(str(as.list(req))), sep = "\n")
    },
    onWSOpen = function(ws) {
      cat("Connection opened.\n")

      ws$onMessage(function(binary, message) {
        cat("Server received message:", message, "\n")
        ws$send(message)
      })
      ws$onClose(function() {
        cat("Connection closed.\n")
      })

    }
  )
)

## End(Not run)