couple questions on were some CGI scripts go

[wrigh113]

Hi Folks,

I'm putting this here since you will be dealing with a newbie although I'm sure this could go into another forum.

I'm attempting to get a script to create a png image of some temperature data that I'm collecting in a RRDT database. As far as I can tell the database is being updated via a cron job.

Now the author of the software does give a script that can be used to produce the graphs for display.

Does this file go into the www/cgi-bin folder on my linux box?

How is it run? How do I know what the file name of the png image is?

My thinking and of course lack of programming skills would say this script would run, create a file called XYZ.png, put it in folder ABC and from there I could have a web page pull the file from that folder and display it on the web.

Paths listed for the perl and rrdt are correctly listed for my system btw in this example

 #!/usr/bin/perl -w
#
# DigiTemp v2.1 RRDB Temperature Graph
#
# Copyright 1997-2001 by Brian C. Lane <bcl@brianlane.com> www.brianlane.com
# All Rights Reserved
#
 
# REQUIRES:
#  RRD tool binary
#  CGI (comes with perl5)
 
use RRDp;
use CGI;
 
$cgi = new CGI;                   # Load the CGI routines
 
# Find the RRD executable, look in the standard locations
# If your rrdtool is installed someplace else, fill in the proper location
# below:
if ( -x "/usr/bin/rrdtool") 
{
  RRDp::start "/usr/bin/rrdtool";
} elsif ( -x "/usr/local/bin/rrdtool") {
   RRDp::start "/usr/local/bin/rrdtool";
} elsif ( -x "/usr/local/rrdtool/bin/rrdtool" ) {
   RRDp::start "/usr/local/rrdtool/bin/rrdtool";
} else {
   die "Could not find rrdtool binary\n";
}
 
# The RRD database to get the data from
$rrd = "/tmp/digitemp.rrd";
 
 
# Make the variables easier to use and assign defaults if not set
if( !$cgi->param('starttime') )
{
    $starttime = "-1day";
} else {
    $starttime = $cgi->param('starttime');
}
if( !$cgi->param('endtime') )
{
    $endtime = time;
} else {
    $endtime = $cgi->param('endtime');
}
if( !$cgi->param('width') )
{
    $width = "400";
} else {
    $width = $cgi->param('width');
}
if( !$cgi->param('height') )
{
    $height = "100";
} else {
    $height = $cgi->param('height');
}
if( !$cgi->param('label') )
{
    $label="";
} else {
    $label = $cgi->param('label');
}
$var = $cgi->param('var');
 
# Diagnostic output
#print STDERR "start  = $starttime\n";
#print STDERR "end    = $endtime\n";
#print STDERR "width  = $width\n";
#print STDERR "height = $height\n";
#print STDERR "var    = $var\n";
#print STDERR "label  = $label\n";
 
 
# Output a HTML header for the PNG image to follow
print $cgi->header('image/png');
 
# Generate the graph
RRDp::cmd "graph - --imgformat PNG",
    "--start '$starttime' --end '$endtime'",
    "--width $width --height $height",
    "DEF:room_c=$rrd:room:AVERAGE",
    "DEF:attic_c=$rrd:attic:AVERAGE",
    "DEF:desk_c=$rrd:desk:AVERAGE",
    "CDEF:room_f=room_c,9,*,5,/,32,+",
    "CDEF:attic_f=attic_c,9,*,5,/,32,+",
    "CDEF:desk_f=drink_c,9,*,5,/,32,+",
    "LINE1:room_f#00FF00:'Computer Room'",
    "LINE1:attic_f#FF0000:'Attic'",
    "LINE1:desk_f#0000FF:'Desk'";
 
$answer=RRDp::read;
 
print $$answer;
 
RRDp::end; 
  

[ianj001]

The image will show up in the web page. You can save it from there. You need to put this script in 'webroot' cgi-bin directory. That may be www/cgi-bin in your case. Then call the script from a web browser using http://yourserver/cgi-bin/scriptname where yourserver is your website and scriptname is the name of the script you listed here.