[rrd-users] RRDs::graph without temporary files?

Todd Caine todd_caine at eli.net
Sat May 27 00:00:39 MEST 2000

Hello All,

I'm trying to create a CGI script which can print a graph to
STDOUT and capture that image in a <IMG SRC> html tag. 
Assume for now that you have a GIF called graph.gif.  You 
could write a program called image.cgi to do the following:


my $image_file = $ARGV[0]

open(IMG, "< $image_file");
print "Content-type: image/gif\n\n";
print <IMG>;

Now from an HTML document you could say:

<IMG SRC="image.cgi?graph.gif">

And the image should be displayed on your web browser.  I
have tested this and it works.

Now if you don't want to create an actual file(image.gif),
read it, and then print it, you can use a '-' as the 
filename argument to RRDs::graph and it will print to 
STDOUT.  I've actually done this and redirected it to a 
file and it does create a real image.  But when trying to 
write a script to do the following:

# image.cgi
print "Content-type: image/gif\n\n";
RRDs::graph('-', '-s -86400', ....);

I can't get it to work through the <IMG
SRC="image.cgi?arguments"> tag.  Any ideas?


	<!--	Todd Caine - tcaine at eli.net
		Software Engineer
		Electric Lightwave, Inc.
		4400 NE 77th Avenue
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