# 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()`](#rfb-1)
  - Creates and returns a new `RFB` object.

### Properties

`localCursor`
  - Is a `boolean` indicating if a client side cursor should be
    requested. Disabled by default.

`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.

`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`](https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button).
    Is set to `1` by default.

`scale`
  - Is a `double` indicating how the framebuffer contents should be
    scaled before being rendered on to the canvas. See also
    [`RFB.autoscale()`](#rfbautoscale). Is set to `1.0` by default.

`viewport`
  - Is a `boolean` indicating if the canvas should be clipped to its
    container. When disabled the container must be able to handle the
    resulting overflow. Disabled by default.

`viewportDrag`
  - Is a `boolean` indicating if mouse events should control the
    relative position of a clipped canvas. Only relevant if `viewport`
    is enabled. Disabled by default.

`disconnectTimeout`
  - Is a `long` indicating how many seconds to wait for a disconnect
    request to complete. Is set to `3` by default.

`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
    | `resize` | `boolean` | The framebuffer can be resized

### Event handlers

[`RFB.onupdatestate()`](#rfbonupdatestate)
  - An event handler called when the connection state of the `RFB`
    object changes.

[`RFB.onnotification()`](#rfbonnotification)
  - An event handler called when the `RFB` usage has a message to
    display to the user.

[`RFB.ondisconnected()`](#rfbondisconnected)
  - An event handler called when the `RFB` object disconnects.

[`RFB.oncredentialsrequired()`](#rfboncredentialsrequired)
  - An event hander called when more credentials must be given to
    continue.

[`RFB.onclipboard()`](#rfbonclipboard)
  - An event handler called when clipboard data is received from the
    server.

[`RFB.onbell()`](#rfbonbell)
  - An event handler called when a audible bell request is received
    from the server.

[`RFB.onfbresize()`](#rfbonfbresize)
  - An event handler called when the framebuffer size is changed.

[`RFB.ondesktopname()`](#rfbondesktopname)
  - An event handler called when the remote desktop name changes.

[`RFB.oncapabilities()`](#rfboncapabilities)
  - An event handler called when `RFB.capabilities` is updated.

### Methods

[`RFB.connect()`](#rfbconnect)
  - Connect to a server.

[`RFB.disconnect()`](#rfbdisconnect)
  - Disconnect from the server.

[`RFB.sendCredentials()`](#rfbsendcredentials)
  - Send credentials to server. Should be called after
    [`oncredentialsrequired`](#rfboncredentialsrequired) has been
    called.

[`RFB.sendKey()`](#rfbsendKey)
  - Send a key event.

[`RFB.sendCtrlAltDel()`](#rfbsendctrlaltdel)
  - Send Ctrl-Alt-Del key sequence.

[`RFB.machineShutdown()`](#rfbmachineshutdown)
  - Request a shutdown of the remote machine.

[`RFB.machineReboot()`](#rfbmachinereboot)
  - Request a reboot of the remote machine.

[`RFB.machineReset()`](#rfbmachinereset)
  - Request a reset of the remote machine.

[`RFB.clipboardPasteFrom()`](#rfbclipboardPasteFrom)
  - Send clipboard contents to server.

[`RFB.autoscale()`](#rfbautoscale)
  - Set `RFB.scale` so that the framebuffer fits a specified container.

[`RFB.clippingDisplay()`](#rfbclippingDisplay)
  - Returns `true` if the framebuffer is larger than what is currently
    displayed on the canvas.

[`RFB.requestDesktopSize()`](#rfbrequestDesktopSize)
  - Send a request to change the remote desktop size.

[`RFB.viewportChangeSize()`](#rfbviewportChangeSize)
  - Change size of the viewport.

### Details

#### RFB()

The `RFB()` constructor returns a new `RFB` object. The object will
initially be disconnected and [`RFB.connect()`](#rfbconnect) must be
called before the object will be useful.

##### Syntax

    var rfb = new RFB( target );

###### Parameters

**`target`**
  - A [`HTMLCanvasElement`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement)
    that specifies where graphics should be rendered and input events
    should be monitored.

#### RFB.onupdatestate

The `onupdatestate` event handler is fired after the noVNC connection
state changes. Here is a list of the states that are reported:

| connection state  | description
| ----------------- | ------------
| `"connecting"`    | starting to connect
| `"connected"`     | connected normally
| `"disconnecting"` | starting to disconnect
| `"disconnected"`  | disconnected

Note that a `RFB` objects can not transition from the disconnected
state in any way, a new instance of the object has to be created for
new connections.

##### Syntax

    RFB.onupdatestate = function(rfb, state) { ... }

#### RFB.onnotification

The `onnotification` event handler is fired when the `RFB` object wants
a message displayed to the user. **`msg`** is a `DOMString` specifying
the actual message, and **`level`** is a `DOMString` indicating the
severity of the message. The following levels are currently defined:

  - `"normal"`
  - `"warn"`
  - `"error"`

**`options`** is currently unused.

##### Syntax

    RFB.onnotification = function(rfb, msg, level, options) { ... }

#### RFB.ondisconnected

The `ondisconnected` event handler is fired when the connection has
been terminated. **`reason`** is `undefined` for a clean termination
and a `DOMString` specifying the reason in the event of an unexpected
termination.

##### Syntax

    RFB.ondisconnected = function(rfb, reason) { ... }

#### RFB.oncredentialsrequired

The `oncredentialsrequired` event handler is fired when the server
requests more credentials than were specified to
[`RFB.connect()`](#rfbconnect). The **`types`** argument is a list of
all the credentials that are required.

##### Syntax

    RFB.oncredentialsrequired = function(rfb, types) { ... }

#### RFB.onclipboard

The `onclipboard` event handler is fired when the server has sent
clipboard data.

##### Syntax

    RFB.onclipboard = function(rfb, text) { ... }

#### RFB.onbell

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

##### Syntax

    RFB.onbell = function(rfb) { ... }

#### RFB.onfbresize

The `onfbresize` event handler is fired when the framebuffer has
changed dimensions.

##### Syntax

    RFB.onfbresize = function(rfb, width, height) { ... }

#### RFB.ondesktopname

The `ondesktopname` event handler is fired when the name of the remote
desktop changes.

##### Syntax

    RFB.ondesktopname = function(rfb, name) { ... }

#### RFB.oncapabilities

The `oncapabilities` event handler is fired whenever an entry is added
or removed from `RFB.capabilities`.

##### Syntax

    RFB.oncapabilities = function(rfb, capabilites) { ... }

#### RFB.connect()

The `RFB.connect()` method is used to initiate a new connection to a
specified VNC server.

##### Syntax

    RFB.connect( url [, options] );

###### Parameters

**`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.

#### 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 `RFB.oncredentialsrequired` has been fired.

##### Syntax

    RFB.sendCredentials( credentials );

###### Parameters

**`credentials`**
  - An `Object` specifying the credentials to provide to the server
    when authenticating. See [`RFB.connect()`](#rfbconnect) 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`](https://developer.mozilla.org/en-US/docs/Web/API/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()`](#rfbsendkey).

##### Syntax

    RFB.sendCtrlAltDel( );

#### 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.

#### RFB.autoscale()

The `RFB.autoscale()` method is used to automatically adjust
`RFB.scale` to fit given dimensions.

##### Syntax

    RFB.autoscale( width, height, downscaleOnly );

###### Parameters

**`width`**
  - A `long` specifying the maximum width of the canvas in CSS pixels.

**`height`**
  - A `long` specifying the maximum height of the canvas in CSS pixels.

**`downscaleOnly`**
  - A `boolean` specifying if the scale must be kept below `1.0`.

#### RFB.clippingDisplay()

The `RFB.clippingDisplay()` method is used to determine if the
framebuffer is larger than the current canvas, i.e. it is being
clipped.

##### Syntax

    RFB.clippingDisplay( );

###### Return value

Returns a `boolean` indicating if the framebuffer is currently being
clipped.

#### RFB.requestDesktopSize()

The `RFB.requestDesktopSize()` method is used to request a change of
the framebuffer. The capability `resize` must be set for this method to
have any effect.

Note that this is merely a request and the server may deny it.
[`RFB.onfbresize`](#rfbonfbresize) will be called when the framebuffer
actually changes dimensions.

##### Syntax

    RFB.requestDesktopSize( width, height );

###### Parameters

**`width`**
  - A `long` specifying the new requested width in CSS pixels.

**`height`**
  - A `long` specifying the new requested height in CSS pixels.

#### RFB.viewportChangeSize()

The `RFB.viewportChangeSize()` method is used to change the size of the
canvas rather than the underlying framebuffer.

This method has no effect if `RFB.viewport` is set to `false`.

##### Syntax

    RFB.viewportChangeSize( width, height );

###### Parameters

**`width`**
  - A `long` specifying the new width in CSS pixels.

**`height`**
  - A `long` specifying the new height in CSS pixels.