[rrd-users] embedding multiple rrdtool SVG into web page on the fly

Reinhard Scheck Reinhard.Scheck at team-scheck.de
Sat Oct 3 00:03:08 CEST 2009

Hi all,
when using rrdtool graph --imgformat=SVG, the resulting file looks fine and can 
be displayed in my browser using rrdtool 1.3.8 (F11, 64 bit, distro package).

Now, when creating a web page in cacti, graph generation is done in parallel by 
<img ... src='php file to generate rrdtool commands'>
multiple time.

This was changed to
<object ... data='php file to generate rrdtool commands'>
for SVG, but that breaks. Wireshark trace shows, that the plain file is 
preceeded and prepended by a number. Here's part of the TCP stream returned by 
the server for the output of that php (see the numbers 2000 and 106581?):

> HTTP/1.1 200 OK
> Date: Fri, 02 Oct 2009 21:01:38 GMT
> Server: Apache/2.2.13 (Fedora)
> X-Powered-By: PHP/5.2.9
> Expires: Mon, 26 Jul 1997 05:00:00 GMT
> Cache-Control: no-store, no-cache, must-revalidate
> Pragma: no-cache
> Last-Modified: Fri, 02 Oct 2009 21:01:38 GMT
> Cache-Control: post-check=0, pre-check=0
> Keep-Alive: timeout=15, max=88
> Connection: Keep-Alive
> Transfer-Encoding: chunked
> Content-Type: image/svg+xml; charset=utf-8
> 2000
> <?xml version="1.0" encoding="UTF-8"?>
> ....
> </svg>
> 106581
> 0

The same numbers appear when using PNG imgformat, but they don't seem to break 
displaying the image. When using
<object class=... data='SVG file generated by manually running rrdtool'>
everything looks fine.
Does that ring a bell?


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