stephen at melbpc.org.au
stephen at melbpc.org.au
Tue Mar 29 01:12:09 AEDT 2011
Perhaps of interest .. HTML5 'WebSockets'
To see how these new websockets work, have a look here:
If your browser supports WebSockets, the world market information
at the bottom of the page will refresh every couple of seconds. For
example, as i write this, the Aussie dollar is worth 2.75 cents more
than the US dollar. Oops, now it's 2.81 .. and, now it's 2.83 cents :)
The new Mozilla browser supports HTML5 WebSockets, whereas IEv8 does not.
Here's a news article regarding WebSockets ..
New Protocol Turbocharges the Web: WebSockets lets the Web handle complex
communications in real time.
Monday, March 28, 2011 By Paul Boutin
Over the past 15 years, Web-based applications have gradually replaced
those based on other networking protocols for everything from personal
communications to home electricity meters.
But there's a major shortcoming in the hypertext transfer protocolHTTP
the system used to communicate over the Web. HTTP was originally designed
for serving up simple documents and files to Web browsers, not for
complex, real-time interaction.
Under the original HTTP protocol, a client, such as a Web browser, must
open a connection to a server, make a request, wait for a response, and
then close the connection.
If the client needs more data, it must open a new connection. It's like
hanging up the phone and redialing after every sentence of conversations.
And if the server has new info for the client, it must wait until the
client requests it rather than sending it over instantly.
This redundancy chews up bandwidth. Worse, it makes it nearly impossible
to keep a Web client stuffed with up-to-the-second information. In some
situations, such as financial trading, those lost milliseconds can mean
Web developers have been hacking around HTTP's limitations for years with
programming techniques such as Comet, which delays closing an HTTP
connection in order to transmit more data. But what they really want is a
connection between client and server that stays open indefinitely and
allows both parties to send data back and forth as needed.
The nearly-complete HTML5 standard for current and future Web software
includes just such a solution, a new protocol called WebSockets.
This protocol allows a Web client to create a connection, keep it open as
long as it wants, and both send and receive data continuously.
Kaazing, a startup based in Mountain View, California, was a leading
developer of the WebSockets standard.
The company now sells a product that serves as a software gateway,
allowing WebSocket connections between existing Web clientsbrowsers,
phones, and desktop softwareand the back-end systems to which they
connect. CEO Jonas Jacobi, who spent eight years working on Java-based
corporate software for Oracle, says WebSocket technology is promising not
just because it's faster, but because it's cheaper. "It removes the need
for a lot of middleware," he says. "That's not where companies want to be
putting their engineering resources; they want to focus on improving the
product they deliver."
So far, Kaazing's early customers tend to be in the financial sector,
where milliseconds count in transactions at banks, hedge funds,
exchanges, and private trading firms.
The company has partnered with Informatica, a maker of messaging
software, to develop a WebSocket-based internal communications system for
Mike Pickett, a vice president at Informatica, says the appeal of
WebSocket tech is that "it is agnostic to the specific type of [Web]
browserIE, Firefox, Chrome. Developers don't have to write a specific
extension for each browser," which they often do for workaround
solutions. (Currently, Internet Explorer requires an add-on to handle
WebSockets.) Chrome, Firefox, Opera, and some other browsers have support
built-in. If your browser supports WebSockets, you can watch a demo of
financial markets updating several times a second at the bottom of this
Kaazing's other early customers tend to be online gambling companies like
Unibet. That's because betting requires up-to-the-second odds, which are
hard to provide without a persistent connection.
Importantly, WebSockets aren't exclusive to Kaazing. Google has been an
early champion. Besides building the technology into its Chrome browser,
the company supports a site that shows developers how to implement it.
Ian Hickson, who leads HTML5 specifications for Google, wrote, "Reducing
kilobytes of data to 2 bytes [...] and reducing latency from 150
milliseconds to 50 milliseconds is far more than marginal. In fact, these
two factors alone are enough to make WebSockets seriously interesting to
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