KasmVNC/kasmweb/docs/API.md

noVNC API

The interface of the noVNC client consists of a single RFB object that is instantiated once per connection.

RFB

The RFB object represents a single connection to a VNC server. It communicates using a WebSocket that must provide a standard RFB protocol stream.

Constructor

RFB()

• Creates and returns a new RFB object.

Properties

viewOnly

• Is a boolean indicating if any events (e.g. key presses or mouse movement) should be prevented from being sent to the server. Disabled by default.

focusOnClick

• Is a boolean indicating if keyboard focus should automatically be moved to the remote session when a mousedown or touchstart event is received.

touchButton

• Is a long controlling the button mask that should be simulated when a touch event is recieved. Uses the same values as MouseEvent.button. Is set to 1 by default.

clipViewport

• Is a boolean indicating if the remote session should be clipped to its container. When disabled scrollbars will be shown to handle the resulting overflow. Disabled by default.

dragViewport

• Is a boolean indicating if mouse events should control the relative position of a clipped remote session. Only relevant if clipViewport is enabled. Disabled by default.

scaleViewport

• Is a boolean indicating if the remote session should be scaled locally so it fits its container. When disabled it will be centered if the remote session is smaller than its container, or handled according to clipViewport if it is larger. Disabled by default.

resizeSession

• Is a boolean indicating if a request to resize the remote session should be sent whenever the container changes dimensions. Disabled by default.

showDotCursor

• Is a boolean indicating whether a dot cursor should be shown instead of a zero-sized or fully-transparent cursor if the server sets such invisible cursor. Disabled by default.

background

• Is a valid CSS background style value indicating which background style should be applied to the element containing the remote session screen. The default value is rgb(40, 40, 40) (solid gray color).

capabilities Read only

• Is an Object indicating which optional extensions are available on the server. Some methods may only be called if the corresponding capability is set. The following capabilities are defined:

  name	type	description
  power	boolean	Machine power control is available

Events

connect

• The connect event is fired when the RFB object has completed the connection and handshaking with the server.

disconnect

• The disconnect event is fired when the RFB object disconnects.

credentialsrequired

• The credentialsrequired event is fired when more credentials must be given to continue.

securityfailure

• The securityfailure event is fired when the security negotiation with the server fails.

clipboard

• The clipboard event is fired when clipboard data is received from the server.

bell

• The bell event is fired when a audible bell request is received from the server.

desktopname

• The desktopname event is fired when the remote desktop name changes.

capabilities

• The capabilities event is fired when RFB.capabilities is updated.

Methods

RFB.disconnect()

• Disconnect from the server.

RFB.sendCredentials()

• Send credentials to server. Should be called after the credentialsrequired event has fired.

RFB.sendKey()

• Send a key event.

RFB.sendCtrlAltDel()

• Send Ctrl-Alt-Del key sequence.

RFB.focus()

• Move keyboard focus to the remote session.

RFB.blur()

• Remove keyboard focus from the remote session.

RFB.machineShutdown()

• Request a shutdown of the remote machine.

RFB.machineReboot()

• Request a reboot of the remote machine.

RFB.machineReset()

• Request a reset of the remote machine.

RFB.clipboardPasteFrom()

• Send clipboard contents to server.

Details

RFB()

The RFB() constructor returns a new RFB object and initiates a new connection to a specified VNC server.

Syntax

let rfb = new RFB( target, url [, options] );

Parameters

target

• A block HTMLElement that specifies where the RFB object should attach itself. The existing contents of the HTMLElement will be untouched, but new elements will be added during the lifetime of the RFB object.

url

• A DOMString specifying the VNC server to connect to. This must be a valid WebSocket URL.

options Optional

• An Object specifying extra details about how the connection should be made.

  Possible options:

  shared

  • A boolean indicating if the remote server should be shared or if any other connected clients should be disconnected. Enabled by default.

  credentials

  • An Object specifying the credentials to provide to the server when authenticating. The following credentials are possible:

    name	type	description
    "username"	DOMString	The user that authenticates
    "password"	DOMString	Password for the user
    "target"	DOMString	Target machine or session

  repeaterID

  • A DOMString specifying the ID to provide to any VNC repeater encountered.

  wsProtocols

  • Protocols to use in the WebSocket connection, the default is: ['binary']

connect

The connect event is fired after all the handshaking with the server is completed and the connection is fully established. After this event the RFB object is ready to recieve graphics updates and to send input.

disconnect

The disconnect event is fired when the connection has been terminated. The detail property is an Object that contains the property clean. clean is a boolean indicating if the termination was clean or not. In the event of an unexpected termination or an error clean will be set to false.

credentialsrequired

The credentialsrequired event is fired when the server requests more credentials than were specified to RFB(). The detail property is an Object containing the property types which is an Array of DOMString listing the credentials that are required.

securityfailure

The securityfailure event is fired when the handshaking process with the server fails during the security negotiation step. The detail property is an Object containing the following properties:

Property	Type	Description
status	long	The failure status code
reason	DOMString	The optional reason for the failure

The property status corresponds to the SecurityResult status code in cases of failure. A status of zero will not be sent in this event since that indicates a successful security handshaking process. The optional property reason is provided by the server and thus the language of the string is not known. However most servers will probably send English strings. The server can choose to not send a reason and in these cases the reason property will be omitted.

clipboard

The clipboard event is fired when the server has sent clipboard data. The detail property is an Object containing the property text which is a DOMString with the clipboard data.

bell

The bell event is fired when the server has requested an audible bell.

desktopname

The desktopname event is fired when the name of the remote desktop changes. The detail property is an Object with the property name which is a DOMString specifying the new name.

capabilities

The capabilities event is fired whenever an entry is added or removed from RFB.capabilities. The detail property is an Object with the property capabilities containing the new value of RFB.capabilities.

RFB.disconnect()

The RFB.disconnect() method is used to disconnect from the currently connected server.

Syntax

RFB.disconnect( );

RFB.sendCredentials()

The RFB.sendCredentials() method is used to provide the missing credentials after a credentialsrequired event has been fired.

Syntax

RFB.sendCredentials( credentials );

Parameters

credentials

• An Object specifying the credentials to provide to the server when authenticating. See RFB() for details.

RFB.sendKey()

The RFB.sendKey() method is used to send a key event to the server.

Syntax

RFB.sendKey( keysym, code [, down] );

Parameters

keysym

• A long specifying the RFB keysym to send. Can be 0 if a valid code is specified.

code

• A DOMString specifying the physical key to send. Valid values are those that can be specified to KeyboardEvent.code. If the physical key cannot be determined then null shall be specified.

down Optional

• A boolean specifying if a press or a release event should be sent. If omitted then both a press and release event are sent.

RFB.sendCtrlAltDel()

The RFB.sendCtrlAltDel() method is used to send the key sequence left Control, left Alt, Delete. This is a convenience wrapper around RFB.sendKey().

Syntax

RFB.sendCtrlAltDel( );

RFB.focus()

The RFB.focus() method sets the keyboard focus on the remote session. Keyboard events will be sent to the remote server after this point.

Syntax

RFB.focus( );

RFB.blur()

The RFB.blur() method remove keyboard focus on the remote session. Keyboard events will no longer be sent to the remote server after this point.

Syntax

RFB.blur( );

RFB.machineShutdown()

The RFB.machineShutdown() method is used to request to shut down the remote machine. The capability power must be set for this method to have any effect.

Syntax

RFB.machineShutdown( );

RFB.machineReboot()

The RFB.machineReboot() method is used to request a clean reboot of the remote machine. The capability power must be set for this method to have any effect.

Syntax

RFB.machineReboot( );

RFB.machineReset()

The RFB.machineReset() method is used to request a forced reset of the remote machine. The capability power must be set for this method to have any effect.

Syntax

RFB.machineReset( );

RFB.clipboardPasteFrom()

The RFB.clipboardPasteFrom() method is used to send clipboard data to the remote server.

Syntax

RFB.clipboardPasteFrom( text );

Parameters

text

• A DOMString specifying the clipboard data to send. Currently only characters from ISO 8859-1 are supported.