Comments on: IFrame + Script Tags = Portable Comet

By: Michael Carter

Michael Carter — Wed, 08 Aug 2007 16:42:33 +0000

Orbited is a comet daemon that works on many platforms for many languages. It supports comet style long-polling as well as Iframe streaming. It also has a clear scaling path.

By: David law

David law — Mon, 09 Jul 2007 05:02:56 +0000

Itâ€™s a fair pointâ€¦Alexâ€™s original Comet article doesnâ€™t only talk about streaming, but also about a distributed event model (as in Twisted). I guess the JSON-P method is a kind of Comet-lite.

By: Office » Ajaxian Office

Office » Ajaxian Office — Mon, 31 Jul 2006 13:52:08 +0000

[...] Ajaxian OfficeTuesday, June 6th, 2006. IFrame + Script Tags = Portable Comet. Category: XmlHttpRequest , Examples , IE , Office , Comet. In a recent post , I explain the difficulties of Comet (Streaming/Push) in IE [...]

By: Kvark

Kvark — Tue, 27 Jun 2006 11:45:50 +0000

I purly love this aproach, but im looking for a demo that uses same connection to send and revice data, is this possible? Anyone seen a example of this?

Im looking for an example:

Explenation:
1.Create a long lived http connection, attach a listener on server side for incoming msg (preferable java or php).

2.Click on a button on the page, that uses the already establish connection and send “hi” to the server, the server responed on the same connection channel with “hello there”.

By: Gregory

Gregory — Tue, 20 Jun 2006 01:19:30 +0000

Nutz – I don’t remember if I tried it back when I played with this idea, so I tried it again, and alas, it makes no difference in the memory usage. Whether you remove every script tag as soon as it’s processed or not, the memory keeps growing.

By: Nutz

Nutz — Sat, 17 Jun 2006 06:50:44 +0000

Gregory – true, however a call to a Javascript function to loop through the DOM to remove those script tags that have arrived from the server should sort that.

By: Gregory

Gregory — Thu, 15 Jun 2006 03:38:40 +0000

One big problem with pushlets (or IFrame and scripts tags) is that the browser (at least IE) reads everything into memory, never releases it and eventually slows down PC to a halt. After all its just one huge page for all it knows.
It may work well for low traffic and/or short-lived sessions, but leave it for a few days or try it on a high volume data stream and you’ll see what I mean.

By: Tal Broda

Tal Broda — Sat, 10 Jun 2006 19:04:06 +0000

David,

If CGI:IRC is using push, how come i don’t see the loading indication for the lifetime of the page? How did you get around that?

Thanks,
Tal.

By: David Leadbeater

David Leadbeater — Wed, 07 Jun 2006 22:15:40 +0000

This is the exact technique that CGI:IRC uses. It has worked pretty well in most browsers (and it has hardly needed changing since I wrote in late 2002!).

By: Ryan Gahl

Ryan Gahl — Wed, 07 Jun 2006 22:09:31 +0000

…and you’re all just fine with Ajaxian’s commenting system?

At the very least you could all do your normal post, and then make another post pointing out that the commenting system sucks. I think then they might get it. Maybe. Probably not, it’s been broken forever so why would they fix it now?

Oh well, at any rate I can take comfort in knowing where I can find a completely blank page on the internet. Just gotta make a post on Ajaxian.

By: Steven Roussey

Steven Roussey — Wed, 07 Jun 2006 21:49:10 +0000

Keeping sockets open in Java is much easier to do than, say, PHP, where you are totally out of luck (well, you could use both, I suppose). I’m not sure what Ruby and others provide.

By: Ben Joldersma

Ben Joldersma — Wed, 07 Jun 2006 21:02:42 +0000

Jeremy,

It depends how the connections are managed. If you are allocating a spare thread for them, then polling will perform better. But if you implement it correctly, with minimal resources allocated, you should be able to keep several thousand sockets open without too much problem.

I haven’t actually done it mind you — but in theory that’s how it should work ;)

By: Jeremy

Jeremy — Wed, 07 Jun 2006 19:37:33 +0000

Does anyone have any data on server performance with polling vs. comet to push data from a server? On a production system with 100′s of users ould it be better to do an AJAX request every 5 seconds to look for an update from the server or do the iframe hack to keep a connection open? The Comet/iframe method worries me if there are 100′s of open connections to the server that aren’t closing. But at the same time, pounding the server by 100′s of users every 5 seconds doesn’t seem happy either. What are your thoughts on performance between these two methods?

By: Office » Office Furniture | Office Chairs | Home Office Furniture

Office » Office Furniture | Office Chairs | Home Office Furniture — Wed, 07 Jun 2006 17:47:55 +0000

[...] Ajaxian OfficeTheir vision is to be a complete, fully functional MS Office clone on-line. They let you import Excel and Word and other formats into their products. Michael Arrington: You guys have a reputation of [...]

By: Ryan Gahl

Ryan Gahl — Wed, 07 Jun 2006 17:39:19 +0000

@Tom and @Ajaxian: Yep, they NEED to fix the commenting system… I can’t believe this is still not working properly. That, and the shear volume of worthless posts is getting me pretty close to deleting this feed.

By: » Internet Explorer (IE) Gets Hit by a Comet :: Nate Ritter ::

» Internet Explorer (IE) Gets Hit by a Comet :: Nate Ritter :: — Wed, 07 Jun 2006 15:04:14 +0000

[...] Ajaxian has a great little post (”IFrame + Script Tags = Portable Comet“) about IE and Comet and how they don’t play nice together yet. But, they also mention that there is a (hack hack) workaround. It uses IFrame and script tags. [...]

By: Ruben

Ruben — Wed, 07 Jun 2006 14:22:10 +0000

It’s funny how the popularity of the web browsers as an application development environment brings back old problems as new. I think i solved this in 2000. In any case, if you’re using Javeline TelePort or Javeline FrameWork this solution is in there.

By: Andy

Andy — Wed, 07 Jun 2006 02:33:07 +0000

I did something similar, Scott, using a hand-rolled web server that multiplexed connections to avoid running a huge number of CGI processes just to send data out. There was a “control socket” that other local processes could connect to “dispatch” additional data to any one (or all) of the listening clients.

Not everything needs to be done using CGI and stateless HTTP — use HTTP to initiate the connection, (since that’s what the browser talks), but then hand the whole thing off to custom code.

By: Scott Schiller

Scott Schiller — Wed, 07 Jun 2006 01:39:52 +0000

Pardon the double-comment. Here’s a link directly to the code involved, with some technical explanation.

http://www.schillmania.com/projects/rpc-js/rpc-js.js

I think Google is using a somewhat similar approach with Gmail (as Alex Russell covered several months ago,) and while it works, I think it’s a crazy hack. A technical feat mind you, but still – actually being used in a large-production site? – woah! :)

(Then again, we used to say that about Javascript animation.)

By: Scott Schiller

Scott Schiller — Wed, 07 Jun 2006 01:35:38 +0000

I did some fiddling around with this a while back, trying to do a multi-client chat thing with a broadcast socks server. It worked, but the whole thing is pretty experimental. I tried to explain the technique as well. Enter some junk name and then up your font size. ;)

http://www.schillmania.com/projects/rpc-js/