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Re: Method for server push via Never-ended documents (xhtml, xml, svg)...

From: Rick <graham.rick@gmail.com>
Date: Fri, 8 May 2009 16:49:22 -0400
Message-ID: <18569e000905081349m4467b519ye48bed6ea9f79bb3@mail.gmail.com>
To: Félix Hauri <felix@f-hauri.ch>
Cc: www-html@w3.org, www-svg@w3.org
Hi Félix:

I don't speak for the SVG Working Group, ex-member.  There has been
discussion in the past about streaming SVG and how it should work.  I
don't know what the sate of that is.

You can achieve a similar effect now using XMLHTTPRequest (Ajax) and
multipart/mime by leaving the connection open so you don't have the
overhead of new connection objects.

The industry term for this is Comet.

I pan to implement this but I haven't done so yet.

Here are some links that I have put aside for further study:

http://www.captain.at/ajax-file-upload.php
http://www.megasolutions.net/javascript/ajax-multipart-problem-75580.aspx
http://bytes.com/groups/javascript/648903-ajax-multipart-problem
http://forums.java.net/jive/thread.jspa?messageID=327125
http://prototype.lighthouseapp.com/projects/8886/tickets/498-prototype-messes-up-the-multipart-boundary

On Fri, May 8, 2009 at 6:05 AM, Félix Hauri <felix@f-hauri.ch> wrote:
> Hi,
>
> I would like to present an idea of ``never-ended'' document,
> following the notion of ``Progressive rendering''.
>  http://www.w3.org/TR/2004/WD-SVG12-20041027/progressiverendering.html
> ( and of course, become some observations from your expertise ;)
>
> There is a work about:
>  - Remote monitoring via svg dynamiques files (even mixed in xhtml docs).
>  - Minimise network traffic and server load,
>  - Reducing network connections to maintaining only one.
>
> My first approach was to use NPH-Server-Push in
> response to a regular XMLHttpRequest, in multipart mode.
>  http://perso.f-hauri.ch/~felix/svg/cpu.svg
>
> The ``traditional'' method (using XMLHttpRequest in javascrit loop)
> (You could look the Sun over Bex(VS/Switzerland) at
>  http://www.websolaire.ch/power.svg ;)
> work fine but use more bandwidth because of sending HTTP headers
> at each exchange, and more server load because of cgi fork at each
> exchange.
>
> My proposal is to send the xhtml *and* the pushed values
> in the only one first connexion to server, as one xhtml
> stream with the form:
> <html>
>  <head>
>  <script type="text/javascript">
>   ...
>   function initvars(values) {
>     ...
>     stream_elm.removeChild(stream_elm.lastChild);
>   }
>   function do1job(values) {
>     ...
>     stream_elm.removeChild(stream_elm.lastChild);
>   }
>  </script>
>  </head>
>  <body>
>  ...
>  <div id="stream" style="display:none">
>  <script language="javascript">initvars(1,2,3,4)</script>
> --- cutted end of never-ended-xhtml stream ---
>
> There is a prototype you can look (and download) at
>  http://perso.f-hauri.ch/~felix/marcm/vmstat.cgi
> The perl is not very well writen, and the javascript
> could only be read in dumped stream, you could blame me,
> but I'm alone and don't dispose as many time i need...
> (I wanna clean them, isolate functions, export them as
>  CGI object library, but this could take some time ago)
>
> This demo script could work in standalone mode, on linux system:
>  $ su - nobody
>  $ cd /tmp
>  $ wget http://perso.f-hauri.ch/~felix/marcm/vmstat.cgi/download/vmstat.pl
>  $ chmod +x vmstat.pl
>  $ ./vmstat.pl
>  Server started at port 8881
> You could look a dump with -x parameter:
>  $ ./vmstat.pl -x
>  Set-Cookie: delay=1; path=/; expires=dim, 07 jun 2009 11:17:26 CEST
>  ...
>  Content-Type: text/xml; charset=utf-8
>
>  <!DOCTYPE html
>  ...
>  </p>
>  <div id="stream" style="display:none">
>  <script language="javascript">initvars(1035880,2007920,1)</script>
>
> Firsts remark:
>  - Idealy, the </body> must be present, but if so, the client
>   (tested with mozilla and opera) will close network connexion.
>  - Idealy, further request must be sent in following the first
>   request, in the same network connexion, but there are
>   limitation from clients.
>
> In hope this could inspire your team to improve XHTML (and/or SVG)
> specifications, and awaiting for your observations, please become
> my thanks for your efforts to maintaining and make evoluate publics
> standards.
>
> --
>  Félix Hauri - Informaticien consultant  |\      /|       ___  _
>  --------------------------------------  | \ __ / |      /    -   /   o
>  7, rue Centrale / CH-1450 Sainte-Croix  | .    . |     /_  ___  /
>  Tél: (+41/0) 24 454 54 04  Fax:..54 00  |   /\   |    /   /__/ /   /  \/
>  http://www.f-hauri.ch                   | \ __ / |   /   /__  /_  /_  /\
>  email: felix@f-hauri.ch                  \ ____ /   ---------------------
>
>
>



-- 
Cheers!
Rick
Received on Friday, 8 May 2009 20:50:05 GMT

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