## File: README.md
## noVNC: HTML VNC client library and application
[](https://github.com/novnc/noVNC/actions?query=workflow%3ATest)
[](https://github.com/novnc/noVNC/actions?query=workflow%3ALint)
### Description
noVNC is both a HTML VNC client JavaScript library and an application built on
top of that library. noVNC runs well in any modern browser including mobile
browsers (iOS and Android).
Many companies, projects and products have integrated noVNC including
[OpenStack](http://www.openstack.org),
[OpenNebula](http://opennebula.org/),
[LibVNCServer](http://libvncserver.sourceforge.net), and
[ThinLinc](https://cendio.com/thinlinc). See
[the Projects and companies wiki page](https://github.com/novnc/noVNC/wiki/Projects-and-companies-using-noVNC)
for a more complete list with additional info and links.
### Table of contents
- [News/help/contact](#newshelpcontact)
- [Features](#features)
- [Screenshots](#screenshots)
- [Browser requirements](#browser-requirements)
- [Server requirements](#server-requirements)
- [Quick start](#quick-start)
- [Installation from snap package](#installation-from-snap-package)
- [Integration and deployment](#integration-and-deployment)
- [Authors/Contributors](#authorscontributors)
### News/help/contact
The project website is found at [novnc.com](http://novnc.com).
If you are a noVNC developer/integrator/user (or want to be) please join the
[noVNC discussion group](https://groups.google.com/forum/?fromgroups#!forum/novnc).
Bugs and feature requests can be submitted via
[github issues](https://github.com/novnc/noVNC/issues). If you have questions
about using noVNC then please first use the
[discussion group](https://groups.google.com/forum/?fromgroups#!forum/novnc).
We also have a [wiki](https://github.com/novnc/noVNC/wiki/) with lots of
helpful information.
If you are looking for a place to start contributing to noVNC, a good place to
start would be the issues that are marked as
["patchwelcome"](https://github.com/novnc/noVNC/issues?labels=patchwelcome).
Please check our
[contribution guide](https://github.com/novnc/noVNC/wiki/Contributing) though.
If you want to show appreciation for noVNC you could donate to a great non-
profits such as:
[Compassion International](http://www.compassion.com/),
[SIL](http://www.sil.org),
[Habitat for Humanity](http://www.habitat.org),
[Electronic Frontier Foundation](https://www.eff.org/),
[Against Malaria Foundation](http://www.againstmalaria.com/),
[Nothing But Nets](http://www.nothingbutnets.net/), etc.
### Features
* Supports all modern browsers including mobile (iOS, Android)
* Supported authentication methods: none, classical VNC, RealVNC's
RSA-AES, Tight, VeNCrypt Plain, XVP, Apple's Diffie-Hellman,
UltraVNC's MSLogonII
* Supported VNC encodings: raw, copyrect, rre, hextile, tight, tightPNG,
ZRLE, JPEG, Zlib, H.264
* Supports scaling, clipping and resizing the desktop
* Supports back & forward mouse buttons
* Local cursor rendering
* Clipboard copy/paste with full Unicode support
* Translations
* Touch gestures for emulating common mouse actions
* Licensed mainly under the [MPL 2.0](http://www.mozilla.org/MPL/2.0/), see
[the license document](LICENSE.txt) for details
### Screenshots
Running in Firefox before and after connecting:
See more screenshots
[here](http://novnc.com/screenshots.html).
### Browser requirements
noVNC uses many modern web technologies so a formal requirement list is
not available. However these are the minimum versions we are currently
aware of:
* Chrome 89, Firefox 89, Safari 15, Opera 75, Edge 89
### Server requirements
noVNC follows the standard VNC protocol, but unlike other VNC clients it does
require WebSockets support. Many servers include support (e.g.
[x11vnc/libvncserver](http://libvncserver.sourceforge.net/),
[QEMU](http://www.qemu.org/), and
[MobileVNC](http://www.smartlab.at/mobilevnc/)), but for the others you need to
use a WebSockets to TCP socket proxy. noVNC has a sister project
[websockify](https://github.com/novnc/websockify) that provides a simple such
proxy.
### Quick start
* Use the `novnc_proxy` script to automatically download and start websockify, which
includes a mini-webserver and the WebSockets proxy. The `--vnc` option is
used to specify the location of a running VNC server:
`./utils/novnc_proxy --vnc localhost:5901`
* If you don't need to expose the web server to public internet, you can
bind to localhost:
`./utils/novnc_proxy --vnc localhost:5901 --listen localhost:6081`
* Point your browser to the cut-and-paste URL that is output by the `novnc_proxy`
script. Hit the Connect button, enter a password if the VNC server has one
configured, and enjoy!
### Installation from snap package
Running the command below will install the latest release of noVNC from snap:
`sudo snap install novnc`
#### Running noVNC from snap directly
You can run the snap package installed novnc directly with, for example:
`novnc --listen 6081 --vnc localhost:5901 # /snap/bin/novnc if /snap/bin is not in your PATH`
If you want to use certificate files, due to standard snap confinement restrictions you need to have them in the /home/\/snap/novnc/current/ directory. If your username is jsmith an example command would be:
`novnc --listen 8443 --cert ~jsmith/snap/novnc/current/self.crt --key ~jsmith/snap/novnc/current/self.key --vnc ubuntu.example.com:5901`
#### Running noVNC from snap as a service (daemon)
The snap package also has the capability to run a 'novnc' service which can be
configured to listen on multiple ports connecting to multiple VNC servers
(effectively a service running multiple instances of novnc).
Instructions (with example values):
List current services (out-of-box this will be blank):
```
sudo snap get novnc services
Key Value
services.n6080 {...}
services.n6081 {...}
```
Create a new service that listens on port 6082 and connects to the VNC server
running on port 5902 on localhost:
`sudo snap set novnc services.n6082.listen=6082 services.n6082.vnc=localhost:5902`
(Any services you define with 'snap set' will be automatically started)
Note that the name of the service, 'n6082' in this example, can be anything
as long as it doesn't start with a number or contain spaces/special characters.
View the configuration of the service just created:
```
sudo snap get novnc services.n6082
Key Value
services.n6082.listen 6082
services.n6082.vnc localhost:5902
```
Disable a service (note that because of a limitation in snap it's currently not
possible to unset config variables, setting them to blank values is the way
to disable a service):
`sudo snap set novnc services.n6082.listen='' services.n6082.vnc=''`
(Any services you set to blank with 'snap set' like this will be automatically stopped)
Verify that the service is disabled (blank values):
```
sudo snap get novnc services.n6082
Key Value
services.n6082.listen
services.n6082.vnc
```
### Integration and deployment
Please see our other documents for how to integrate noVNC in your own software,
or deploying the noVNC application in production environments:
* [Embedding](docs/EMBEDDING.md) - For the noVNC application
* [Library](docs/LIBRARY.md) - For the noVNC JavaScript library
### Authors/Contributors
See [AUTHORS](AUTHORS) for a (full-ish) list of authors. If you're not on
that list and you think you should be, feel free to send a PR to fix that.
* Core team:
* [Samuel Mannehed](https://github.com/samhed) (Cendio)
* [Pierre Ossman](https://github.com/CendioOssman) (Cendio)
* Previous core contributors:
* [Joel Martin](https://github.com/kanaka) (Project founder)
* [Solly Ross](https://github.com/DirectXMan12) (Red Hat / OpenStack)
* Notable contributions:
* UI and icons : Pierre Ossman, Chris Gordon
* Original logo : Michael Sersen
* tight encoding : Michael Tinglof (Mercuri.ca)
* RealVNC RSA AES authentication : USTC Vlab Team
* Included libraries:
* base64 : Martijn Pieters (Digital Creations 2), Samuel Sieb (sieb.net)
* DES : Dave Zimmerman (Widget Workshop), Jef Poskanzer (ACME Labs)
* Pako : Vitaly Puzrin (https://github.com/nodeca/pako)
Do you want to be on this list? Check out our
[contribution guide](https://github.com/novnc/noVNC/wiki/Contributing) and
start hacking!
---
## File: 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()`](#rfb-1)
- Creates and returns a new `RFB` object.
### Properties
`background`
- Is a valid CSS [background][mdn-bg] 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).
[mdn-bg]: https://developer.mozilla.org/en-US/docs/Web/CSS/background
`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
`clippingViewport` *Read only*
- Is a `boolean` indicating if the remote session is currently being
clipped to its container. Only relevant if `clipViewport` is
enabled.
`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.
`compressionLevel`
- Is an `int` in range `[0-9]` controlling the desired compression
level. Value `0` means no compression. Level 1 uses a minimum of CPU
resources and achieves weak compression ratios, while level 9 offers
best compression but is slow in terms of CPU consumption on the server
side. Use high levels with very slow network connections.
Default value is `2`.
`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.
`focusOnClick`
- Is a `boolean` indicating if keyboard focus should automatically be
moved to the remote session when a `mousedown` or `touchstart`
event is received. Enabled by default.
`qualityLevel`
- Is an `int` in range `[0-9]` controlling the desired JPEG quality.
Value `0` implies low quality and `9` implies high quality.
Default value is `6`.
`resizeSession`
- Is a `boolean` indicating if a request to resize the remote session
should be sent whenever the container changes dimensions. 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.
`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.
### Events
[`bell`](#bell)
- The `bell` event is fired when a audible bell request is received
from the server.
[`capabilities`](#capabilities)
- The `capabilities` event is fired when `RFB.capabilities` is
updated.
[`clipboard`](#clipboard)
- The `clipboard` event is fired when clipboard data is received from
the server.
[`clippingviewport`](#clippingviewport)
- The `clippingviewport` event is fired when `RFB.clippingViewport` is
updated.
[`connect`](#connect)
- The `connect` event is fired when the `RFB` object has completed
the connection and handshaking with the server.
[`credentialsrequired`](#credentialsrequired)
- The `credentialsrequired` event is fired when more credentials must
be given to continue.
[`desktopname`](#desktopname)
- The `desktopname` event is fired when the remote desktop name
changes.
[`disconnect`](#disconnect)
- The `disconnect` event is fired when the `RFB` object disconnects.
[`securityfailure`](#securityfailure)
- The `securityfailure` event is fired when the security negotiation
with the server fails.
[`serververification`](#serververification)
- The `serververification` event is fired when the server identity
must be confirmed by the user.
### Methods
[`RFB.approveServer()`](#rfbapproveserver)
- Proceed connecting to the server. Should be called after the
[`serververification`](#serververification) event has fired and the
user has verified the identity of the server.
[`RFB.blur()`](#rfbblur)
- Remove keyboard focus from the remote session.
[`RFB.clipboardPasteFrom()`](#rfbclipboardpastefrom)
- Send clipboard contents to server.
[`RFB.disconnect()`](#rfbdisconnect)
- Disconnect from the server.
[`RFB.focus()`](#rfbfocus)
- Move keyboard focus to the remote session.
[`RFB.getImageData()`](#rfbgetimagedata)
- Return the current content of the screen as an ImageData array.
[`RFB.machineReboot()`](#rfbmachinereboot)
- Request a reboot of the remote machine.
[`RFB.machineReset()`](#rfbmachinereset)
- Request a reset of the remote machine.
[`RFB.machineShutdown()`](#rfbmachineshutdown)
- Request a shutdown of the remote machine.
[`RFB.sendCredentials()`](#rfbsendcredentials)
- Send credentials to server. Should be called after the
[`credentialsrequired`](#credentialsrequired) event has fired.
[`RFB.sendCtrlAltDel()`](#rfbsendctrlaltdel)
- Send Ctrl-Alt-Del key sequence.
[`RFB.sendKey()`](#rfbsendkey)
- Send a key event.
[`RFB.toBlob()`](#rfbtoblob)
- Return the current content of the screen as Blob encoded image file.
[`RFB.toDataURL()`](#rfbtodataurl)
- Return the current content of the screen as data-url encoded image file.
### Details
#### RFB()
The `RFB()` constructor returns a new `RFB` object and initiates a new
connection to a specified VNC server.
##### Syntax
```js
new RFB(target, urlOrChannel);
new RFB(target, urlOrChannel, options);
```
###### Parameters
**`target`**
- A block [`HTMLElement`][mdn-elem] 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.
[mdn-elem]: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement
**`urlOrChannel`**
- A `DOMString` specifying the VNC server to connect to. This must be
a valid WebSocket URL. This can also be a `WebSocket` or `RTCDataChannel`.
**`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`
- An `Array` of `DOMString`s specifying the sub-protocols to use
in the WebSocket connection. Empty by default.
#### bell
The `bell` event is fired when the server has requested an audible
bell.
#### 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`.
#### clippingviewport
The `clippingviewport` event is fired whenever `RFB.clippingViewport`
changes between `true` and `false`. The `detail` property is a `boolean`
with the new value of `RFB.clippingViewport`.
#### 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.
#### credentialsrequired
The `credentialsrequired` event is fired when the server requests more
credentials than were specified to [`RFB()`](#rfb-1). The `detail`
property is an `Object` containing the property `types` which is an
`Array` of `DOMString` listing the credentials that are required.
#### 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.
#### 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.
#### 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.
#### 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][rfb-secresult]
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.
[rfb-secresult]: https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst#securityresult
#### serververification
The `serververification` event is fired when the server provides
information that allows the user to verify that it is the correct server
and protect against a man-in-the-middle attack. The `detail` property is
an `Object` containing the property `type` which is a `DOMString`
specifying which type of information the server has provided. Other
properties are also available, depending on the value of `type`:
`"RSA"`
- The server identity is verified using just a RSA key. The property
`publickey` is a `Uint8Array` containing the public key in a unsigned
big endian representation.
#### RFB.approveServer()
The `RFB.approveServer()` method is used to signal that the user has
verified the server identity provided in a `serververification` event
and that the connection can continue.
##### Syntax
```js
RFB.approveServer();
```
#### 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
```js
RFB.blur();
```
#### RFB.clipboardPasteFrom()
The `RFB.clipboardPasteFrom()` method is used to send clipboard data
to the remote server.
##### Syntax
```js
RFB.clipboardPasteFrom(text);
```
###### Parameters
**`text`**
- A `DOMString` specifying the clipboard data to send.
#### RFB.disconnect()
The `RFB.disconnect()` method is used to disconnect from the currently
connected server.
##### Syntax
```js
RFB.disconnect();
```
#### 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
```js
RFB.focus();
RFB.focus(options);
```
###### Parameters
**`options`** *Optional*
- A `object` providing options to control how the focus will be
performed. Please see [`HTMLElement.focus()`][mdn-focus] for
available options.
[mdn-focus]: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus
#### RFB.getImageData()
The `RFB.getImageData()` method is used to return the current content of
the screen encoded as [`ImageData`][mdn-imagedata].
[mdn-imagedata]: https://developer.mozilla.org/en-US/docs/Web/API/ImageData
##### Syntax
```js
RFB.getImageData();
```
#### 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
```js
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
```js
RFB.machineReset();
```
#### 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
```js
RFB.machineShutdown();
```
#### RFB.sendCredentials()
The `RFB.sendCredentials()` method is used to provide the missing
credentials after a `credentialsrequired` event has been fired.
##### Syntax
```js
RFB.sendCredentials(credentials);
```
###### Parameters
**`credentials`**
- An `Object` specifying the credentials to provide to the server
when authenticating. See [`RFB()`](#rfb-1) for details.
#### 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
```js
RFB.sendCtrlAltDel();
```
#### RFB.sendKey()
The `RFB.sendKey()` method is used to send a key event to the server.
##### Syntax
```js
RFB.sendKey(keysym, code);
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`][mdn-keycode].
If the physical key cannot be determined then `null` shall be
specified.
[mdn-keycode]: https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/code
**`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.toBlob()
The `RFB.toBlob()` method is used to return the current content of the
screen encoded as [`Blob`][mdn-blob].
[mdn-blob]: https://developer.mozilla.org/en-US/docs/Web/API/Blob
##### Syntax
```js
RFB.toBlob(callback);
RFB.toBlob(callback, type);
RFB.toBlob(callback, type, quality);
```
###### Parameters
**`callback`**
- A callback function which will receive the resulting
[`Blob`][mdn-blob] as the single argument
**`type`** *Optional*
- A string indicating the requested MIME type of the image
**`quality`** *Optional*
- A number between 0 and 1 indicating the image quality.
#### RFB.toDataURL()
The `RFB.toDataURL()` method is used to return the current content of the
screen encoded as a data URL that could for example be put in the `src` attribute
of an `img` tag.
##### Syntax
```js
RFB.toDataURL();
RFB.toDataURL(type);
RFB.toDataURL(type, encoderOptions);
```
###### Parameters
**`type`** *Optional*
- A string indicating the requested MIME type of the image
**`encoderOptions`** *Optional*
- A number between 0 and 1 indicating the image quality.
---
## File: docs/API-internal.md
# 1. Internal modules
The noVNC client is composed of several internal modules that handle
rendering, input, networking, etc. Each of the modules is designed to
be cross-browser and independent from each other.
Note however that the API of these modules is not guaranteed to be
stable, and this documentation is not maintained as well as the
official external API.
## 1.1 Module list
* __Keyboard__ (core/input/keyboard.js): Keyboard input event handler with
non-US keyboard support. Translates keyDown and keyUp events to X11
keysym values.
* __Display__ (core/display.js): Efficient 2D rendering abstraction
layered on the HTML5 canvas element.
* __Clipboard__ (core/clipboard.js): Clipboard event handler.
* __Websock__ (core/websock.js): Websock client from websockify
with transparent binary data support.
[Websock API](https://github.com/novnc/websockify-js/wiki/websock.js) wiki page.
## 1.2 Callbacks
For the Mouse, Keyboard, Display, and Clipboard objects, the callback
functions are assigned to configuration attributes, just as for the RFB
object. The WebSock module has a method named 'on' that takes two
parameters: the callback event name, and the callback function.
## 2. Modules
## 2.1 Keyboard module
### 2.1.1 Configuration attributes
None
### 2.1.2 Methods
| name | parameters | description
| ------ | ---------- | ------------
| grab | () | Begin capturing keyboard events
| ungrab | () | Stop capturing keyboard events
### 2.1.3 Callbacks
| name | parameters | description
| ---------- | -------------------- | ------------
| onkeypress | (keysym, code, down) | Handler for key press/release
## 2.2 Display module
### 2.2.1 Configuration attributes
| name | type | mode | default | description
| ------------ | ----- | ---- | ------- | ------------
| scale | float | RW | 1.0 | Display area scale factor 0.0 - 1.0
| clipViewport | bool | RW | false | Use viewport clipping
| width | int | RO | | Display area width
| height | int | RO | | Display area height
### 2.2.2 Methods
| name | parameters | description
| ------------------ | ------------------------------------------------------- | ------------
| viewportChangePos | (deltaX, deltaY) | Move the viewport relative to the current location
| viewportChangeSize | (width, height) | Change size of the viewport
| absX | (x) | Return X relative to the remote display
| absY | (y) | Return Y relative to the remote display
| resize | (width, height) | Set width and height
| flip | (from_queue) | Update the visible canvas with the contents of the rendering canvas
| pending | () | Check if there are waiting items in the render queue
| flush | () | Resume processing the render queue unless it's empty
| fillRect | (x, y, width, height, color, from_queue) | Draw a filled in rectangle
| copyImage | (old_x, old_y, new_x, new_y, width, height, from_queue) | Copy a rectangular area
| imageRect | (x, y, width, height, mime, arr) | Draw a rectangle with an image
| blitImage | (x, y, width, height, arr, offset, from_queue) | Blit pixels (of R,G,B,A) to the display
| drawImage | (img, x, y) | Draw image and track damage
| autoscale | (containerWidth, containerHeight) | Scale the display
## 2.3 Clipboard module
### 2.3.1 Configuration attributes
None
### 2.3.2 Methods
| name | parameters | description
| ------------------ | ----------------- | ------------
| writeClipboard | (text) | An async write text to clipboard
| grab | () | Begin capturing clipboard events
| ungrab | () | Stop capturing clipboard events
### 2.3.3 Callbacks
| name | parameters | description
| ------- | ---------- | ------------
| onpaste | (text) | Called following a target focus event and an async clipboard read
---
## File: docs/EMBEDDING.md
# Embedding and deploying noVNC application
This document describes how to embed and deploy the noVNC application, which
includes settings and a full user interface. If you are looking for
documentation on how to use the core noVNC library in your own application,
then please see our [library documentation](LIBRARY.md).
## Files
The noVNC application consists of the following files and directories:
* `vnc.html` - The main page for the application and where users should go. It
is possible to rename this file.
* `app/` - Support files for the application. Contains code, images, styles and
translations.
* `core/` - The core noVNC library.
* `vendor/` - Third party support libraries used by the application and the
core library.
The most basic deployment consists of simply serving these files from a web
server and setting up a WebSocket proxy to the VNC server.
## Parameters
The noVNC application can be controlled via a number of settings. All of
them are available in the UI for the user to change, but they can also
be set via other means:
* Via the URL, either as a query parameter:
```
https://www.example.com/vnc.html?reconnect=0&shared=1
```
or as a fragment:
```
https://www.example.com/vnc.html#reconnect=0&shared=1
```
The latter might be preferred as it is not sent to the server.
* Via the files `defaults.json` and `mandatory.json`
Currently, the following options are available:
* `autoconnect` - Automatically connect as soon as the page has finished
loading.
* `reconnect` - If noVNC should automatically reconnect if the connection is
dropped.
* `reconnect_delay` - How long to wait in milliseconds before attempting to
reconnect.
* `host` - The WebSocket host to connect to. This setting is deprecated
in favor of specifying a URL in `path`.
* `port` - The WebSocket port to connect to. This setting is deprecated
in favor of specifying a URL in `path`.
* `encrypt` - If TLS should be used for the WebSocket connection. This
setting is deprecated in favor of specifying a URL in `path`.
* `path` - The WebSocket URL to use. It can be either an absolute URL,
or a URL relative vnc.html. If `host` is specified, then `path` will
be interpreted as the path component in the URL instead.
* `password` - The password sent to the server, if required.
* `repeaterID` - The repeater ID to use if a VNC repeater is detected.
* `shared` - If other VNC clients should be disconnected when noVNC connects.
* `bell` - If the keyboard bell should be enabled or not.
* `view_only` - If the remote session should be in non-interactive mode.
* `view_clip` - If the remote session should be clipped or use scrollbars if
it cannot fit in the browser.
* `resize` - How to resize the remote session if it is not the same size as
the browser window. Can be one of `off`, `scale` and `remote`.
* `quality` - The session JPEG quality level. Can be `0` to `9`.
* `compression` - The session compression level. Can be `0` to `9`.
* `logging` - The console log level. Can be one of `error`, `warn`, `info` or
`debug`.
* `keep_device_awake` - Should we prevent the (local) display from going into
sleep mode while a connection is active? Useful for view-only sessions where
there unlikely to be any keyboard/mouse activity to keep the device active.
## HTTP serving considerations
### Browser cache issue
If you serve noVNC files using a web server that provides an ETag header, and
include any options in the query string, a nasty browser cache issue can bite
you on upgrade, resulting in a red error box. The issue is caused by a mismatch
between the new vnc.html (which is reloaded because the user has used it with
new query string after the upgrade) and the old javascript files (that the
browser reuses from its cache). To avoid this issue, the browser must be told
to always revalidate cached files using conditional requests. The correct
semantics are achieved via the (confusingly named) `Cache-Control: no-cache`
header that needs to be provided in the web server responses.
### Example server configurations
Apache:
```
# In the main configuration file
# (Debian/Ubuntu users: use "a2enmod headers" instead)
LoadModule headers_module modules/mod_headers.so
# In the or block related to noVNC
Header set Cache-Control "no-cache"
```
Nginx:
```
# In the location block related to noVNC
add_header Cache-Control no-cache;
```
---
## File: docs/LIBRARY.md
# Using the noVNC JavaScript library
This document describes how to make use of the noVNC JavaScript library for
integration in your own VNC client application. If you wish to embed the more
complete noVNC application with its included user interface then please see
our [embedding documentation](EMBEDDING.md).
## API
The API of noVNC consists of a single object called `RFB`. The formal
documentation for that object can be found in our [API documentation](API.md).
## Example
noVNC includes a small example application called `vnc_lite.html`. This does
not make use of all the features of noVNC, but is a good start to see how to
do things.
## Conversion of modules
noVNC is written using ECMAScript 6 modules. This is not supported by older
versions of Node.js. To use noVNC with those older versions of Node.js the
library must first be converted.
Fortunately noVNC includes a script to handle this conversion. Please follow
the following steps:
1. Install Node.js
2. Run `npm install` in the noVNC directory
The result of the conversion is available in the `lib/` directory.
---
## File: utils/README.md
## WebSockets Proxy/Bridge
Websockify has been forked out into its own project. `novnc_proxy` will
automatically download it here if it is not already present and not
installed as system-wide.
For more detailed description and usage information please refer to
the [websockify README](https://github.com/novnc/websockify/blob/master/README.md).
The other versions of websockify (C, Node.js) and the associated test
programs have been moved to
[websockify](https://github.com/novnc/websockify). Websockify was
formerly named wsproxy.