SPUG: HTTP Headers

[Parr, Ryan]

I like this solution very much. It works flawlessly. Thanks!

-- Ryan

-----Original Message-----
From: Trevor Leffler [mailto:tleffler at u.washington.edu]
Sent: Tuesday, December 11, 2001 10:35 AM
To: spug-list at pm.org
Subject: Re: SPUG: HTTP Headers


Ryan,

First off, I'm going to ignore that you're storing entire binary docs in 
your DB, rather than letting your web server serve them up via the 
filesystem.  Anywho...

We came up with one possible solution, which assumes you're using 
Apache.  Create a link URL such as:

	/download/CMS_SOP.doc?docid=334

Since the real filename is in the URL, your browser will use it in the 
"Save" dialog box.

The /download directory has only a .htaccess file with these contents:

ErrorDocument 404 /somepath/nph-download.cgi

Since /download/CMS_SOP.doc doesn't actually exist, the nph-download.cgi 
script gets called instead.  That script then finds the document via 
your DB thanks to the docid you passed it (we just store the private 
path to the doc, rather than the doc itself), prints the appropriate 
HTTP headers and Content-type, and streams the file contents to the browser.

The reason you use an nph- script is to override the server headers, 
which will show a 404 "File not found" status.  You'll want to start by 
printing something like:

print "HTTP/1.1 200 OK\n",
       "Server: $ENV{SERVER_SOFTWARE}\n";

Then print an error page is something fails, or your Content-type and 
contents if everything succeeds.

As an aside, you might think about using adequately random docid's, or 
perhaps encrypting them so that I can't download all your documents via 
iteration.  That is, if doc access is an issue.

Have fun!
-- 
Trevor Leffler, Software Developer
PETTT / Ed-Tech Development Group
University of Washington
(206) 616-3406 / OUGL 230, Box 353080


Parr, Ryan wrote:

> I'm currently moving the intranet site I work on to be completely database
> based. However, I'm running into a snag with delivering documents to the
> user. Rather, delivering documents other than HTML to the user.
> 
> If I have my CGI load a word doc that's stored in the database, and send
it
> to the user with the appropriate mime type, the browser can handle it
> appropriately. Unfortunately though, I have no way to specify a filename
for
> the content. So instead of receiving an Open/Save dialog for CMS_SOP.doc
> they receive an Open/Save dialog for /cgi-bin/loadpage.cgi?id=334, or the
> browser loads the word doc with the filename /cgi-bin/loadpage.cgi?id=334.
> 
> I haven't been able to find any standard HTTP headers that deal with this
> scenario, nor any IE specific extension headers. I'm in a controlled
> environment so everyone has IE 4+. This approach to document delivery
seems
> natural enough to me that I'm sure a thousand developers before me have
> attempted it, certainly some with success. Have any of you?
> 
> -- Ryan Parr
> 
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