Re: [Gnuplot-info] Using GNUplot, plot data and show that graph into web browser.

[Micha W. <mw...@gm...>]

Mostafijur Rahman wrote:
> I want to plot data using GNUplot and want to show the graph file in the web browser using PHP.
I try to do the same with perl. BTW I think its gnuplot and has nothing
to do with GNU (see "Does gnuplot have anything to do with the FSF and
the GNU project?"
<http://www.gnuplot.info/faq/faq.html#SECTION00037000000000000000> 1.7)

> Is it possible to plot data in GNUplot from PHP code and show into web browser?

You could add "<img src="/cgi-bin/plot.php?sin(x)"/> to your website and
  create a plot.php that calls gnuplot and make gnuplot output to
standard out. Something like:

print "Content-Type: image/png\n\n";

print `echo 'set term png; set output; plot sin(x)'|gnuplot`;

But there is a HUGE PROBLEM, assume someone enters something like "< rm
-rf" (with the  quotes) (or ;`rm -rf` or something evil you did not
think of yet). Assume futhermore you replace sin(x) with the input of
the user (in our case "< rm -rf"), your plot command (which looks like
plot "< rm -rf") would then delete files, so there is a HUGE SECURITY ISSUE.

The only way of which I know to avoid this is by letting the user select
between different functions to plot and have somthing like

if input==A then plot sin(x)
if input==B then plot cos(x)

which is useless since you could create the plots in advance.

> If possible please can you tell me how.

Please be responsible and do not use the BROKEN CODE above!

Micha