HTML and CSS Reference
In-Depth Information
Chapter 6
VNC with the Remote
Framebuffer Protocol
In the previous chapters, you learned how to layer two powerful protocols, XMPP and
STOMP, over WebSocket. With these protocols, we were able to examine chat, presence,
and messaging, all of which can be used to create rich applications and implement systems
to power our browser-based world. In Chapter 4, we saw how we could use a widely
used standard chat protocol with WebSocket and enabled a traditional desktop-based
chat application to be used over the Web, as well as witnessed the benefits of layering
WebSocket with a standard chat protocol. Similarly, in Chapter 5, we looked at how
to interact with TCP-based message brokers from web applications. In both cases, we
explored the transition between a traditional, desktop application-based world to a
web-enabled world, and looked at how the full-duplex, low-latency connection over
the Web provided by WebSocket can be beneficial to such applications. In this chapter,
we look at an even more complex (yet standard) protocol and how to transform it using
WebSocket as the communication platform.
With applications distributed among desktops using myriad operating systems,
programs, and browser versions, it has become increasingly important for users to be
system-agnostic, for Information Technology groups to be able to support any system
from anywhere, and for application developers to be able to operate on any system.
There are also times when users need to access a specific operating system. One popular
way to access a specific system is using VNC (Virtual Network Computing).
VNC lets you share desktops over any network. It essentially allows you to view and
control the interface of another computer remotely and can be thought of as the GUI
(graphical user interface) equivalent to Telnet. You can also think of VNC as a long, virtual
cable that enables you to view and control another desktop with its mouse, keyboard, and
video signals.
As its name implies, VNC is used over networks. Due to challenges that we'll
investigate in this chapter, VNC has not been easily used over the Web. With HTML5 and
WebSocket, we can overcome some of these challenges and examine how highly portable
rich Internet applications can leverage HTML5 and WebSocket to use VNC.
In this chapter, we'll explore how you can use WebSocket with the Remote
Framebuffer (RFB) Protocol to expand virtual network computing to the Web. We'll also
look at how, as a binary protocol, RFB uses the WebSocket API in a different way than the
text-oriented protocols we discussed in the previous two chapters. After taking a look
at RFB and VNC, we'll step through how to build a VNC client that connects to an open
