From: Rasputin <rasputin@...>
Date: 2003-07-18T19:28:42+09:00
Subject: Re: Question re: graphics output of CGIs (mime-type issue?)

* Hal E. Fulton <hal9000@hypermetrics.com> [0728 01:28]:
> What's the proper way to deliver a grpahical
> file via HTTP?
> 
> For example, supposing a web page has a bit of
> HTML like:
>   
>    <img src="http://foo.com/cgi-bin/myprog.cgi">
> 
> Then how should myprog.cgi deliver its output?
> Is there direct support for this in one of the
> libraries, or do you just have to know how to 
> do it?
> 
> I tried just using a Content-type of image/jpeg,
> but I got garbage in the browser. 

Don't some browsers insist on looking at filetype
rather than mime-type?

Two workarounds spring to mind (I've installed Ruby-GD for this
very reason, but haven't tried yet):

Would this work?
#(Apache,mod_ruby)

<Directory /docroot/genimg/ >
	<FilesMatch ".jpg">
		Options +ExecCGI
		SetHandler ruby-object
		RubyHandler Apache::RubyRun.instance
	</FilesMatch>
</Directory>

Or alternatively (and haven't figured out how to do this yet)

map all requests to a particular location to your cgi
(i.e. requests to http://yourserver.com/edit-img/
	are mapped to http://yourserver.com/cgi-bin/image.cgi
)
then use the trailing path_info to identify what kind of inmage to create:

so 

http://yourserver.com/edit-img/greyscale/images/foo.gif

will return a greyscale version of http://yourserver.com/images/foo.gif,

http://yourserver.com/edit-img/resize/80-200/images/foo.gif 

does the obvious,etc.

This is handy for existing images you need to manipulate, obviously.


-- 
As the trials of life continue to take their toll, remember that there
is always a future in Computer Maintenance.
		-- National Lampoon, "Deteriorata"
Rasputin :: Jack of All Trades - Master of Nuns