How does the live, real-time typing work in Google Wave?

Question

I'm sure Wave doesn't poll the server every millisecond to find out if the other user has typed something... so how can I see what the other person is typing as they type? And without hogging the bandwidth.

There is some information in one of the answers here http://stackoverflow.com/questions/928744/what-technologies-is-google-wave-using — Greg Leaver, Jun 17 '09 at 18:07

Yoni Roit · Accepted Answer · 2014-08-27T18:22:45.950

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Persistent HTTP, Comet

Keep your HTTP connection alive and send characters as they are typed

*Edit in 2014: also, take a look at WebSocket and HTTP/1.1 Upgrade header. Browsers started implementing this around 2010, so I'm adding this to original answer.

edited Aug 27 '14 at 18:22

answered May 31 '09 at 16:43

Yoni Roit

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Does it really use Comet bcoz it use GWT? – Rahul Garg Jul 21 '09 at 11:04
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comet is a buzzword, it's not any defined framework or technology. you can implement it with gwt, without gwt, and however you like – Yoni Roit Jul 21 '09 at 16:16

score 6 · Answer 2 · edited Oct 07 '21 at 07:13

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They probably use Web Sockets, aka server-sent events: http://www.w3.org/TR/websockets The underlying protocol can be found (as a draft) at the IETF.

Update: it doesn't seem WebSockets has any implementation yet; and a video from Google I/O (go to 11:00) talks about a long lived HTTP GET request.

edited Oct 07 '21 at 07:13

Community

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answered Jun 03 '09 at 09:06

Thomas Broyer

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Didn't know there was a restriction like that for users! I'll vote you up to give you some more rep. – Rich Bradshaw Jun 03 '09 at 09:10
Thanks for your vote, I've now edited my answer to include "more than one hyperlink", and thus actually link to the IETF draft. – Thomas Broyer Jun 05 '09 at 01:11

score 4 · Answer 3 · answered Aug 17 '09 at 21:29

Server Push in GWT

Server push is the Wait, Respond, Close, Re-Open paradigm:

Wait: When the GWT code makes a call to your server for some data that you don't have yet, freeze (wait)
Respond: Once the requested data is
available, respond with it
Close: Then, close the connection.
Re-Open: Once your GWT code receives the response, immediately open up a new connection to query for the next event.

score 3 · Answer 4 · answered Jun 17 '09 at 17:50

See Video Google Wave: Powered by GWT around at minute 55 (near the end)

Q: How you implement the persistent Connections, the long living http connections

A: Future Plan: HTML5 Web Sockets. Longer term. That's what we use at the moment.

Q: Is there a platform or library for this we can download and play with?

A: Not sure. Don't think so

P.S.: That's what he said. To me it did not make much sense ("future plans" vs "using at the moment"). Any native english speaker might want to verify if I transcribed it correctly?

It's confusing because it's slightly out of context. The answer meant basically: Yes, we're using hanging requests (aka "Comet"). The future plan is to move to WebSockets when implementations are available. — Mark Renouf, Jun 17 '09 at 20:35

score 1 · Answer 5 · answered Nov 23 '09 at 15:11

the entire reason for WebSockets is to have the browser keep a bi-directional socket open to a server so that real time communications can be used. When someone types on the other end, in a wave client, it triggers an event that is sent to the server and the server in turn looks to see who should also receive the event and pass them the event, in this case the typed letter.

WebSocket and Comet are different.

Granville

score 1 · Answer 6 · answered Jun 05 '09 at 08:35

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Pure speculation but could it be using the Server Side DOM events from the HTML 5 spec?

answered Jun 05 '09 at 08:35

Keith Bloom

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score 0 · Answer 7 · answered Aug 14 '09 at 21:30

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Probably comet for now websocket in the future. Because it works in Firefox 3.5 and from what I've read the websocket is only available in the nightly builds of FF... I could be wrong though... as it appears to not work in IE at all.

answered Aug 14 '09 at 21:30

Serhiy

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score 0 · Answer 8 · answered May 24 '10 at 01:08

I spent some time reverse-engineering the Google Wave client code (shameless plug for http://antimatter15.com/misc/read/ which is a read-only public client for google wave for all public waves without need of robots or gadgets which was a lot more useful a month ago when Google didn't launch the upgrades).

Anyway, Google uses the GWT framework with certain aspects of the Google Closure library (which is actually open source and documented) and they use the goog.net.BrowserChannel library, which from the comments is also used for chat functionality within gmail.

http://closure-library.googlecode.com/svn/docs/closure_goog_net_browserchannel.js.html

score -1 · Answer 9 · answered Nov 22 '09 at 19:04

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I would assume that they use ajax requests. Do an XMLHttpRequest, which is asynchronous, and when the server has something to send your browser the javascript callback that was registered gets the data and does whatever with it. So basically the browser requests the next event, handles it, repeats indefinitely.

answered Nov 22 '09 at 19:04

Seth

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XMLHttpRequest is send once, if no answer was received , connection is terminated, that it. nobody will wait anything. that what "comet" technology does, non-endless GET request.. read about this on wiki. – holms Nov 07 '11 at 05:26

How does the live, real-time typing work in Google Wave?

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