Refreshing in forms using post

Suppose I have a form. Upon submission, the metadata is posted to a
processing script (a separate PHP file), which parses it and then sends the
user back to a particular page using the header function. If said user
clicks their browser's back button, the aforementioned processing script
will re-parse that post data and create a duplicate record. How can I
prevent this? Cache control?

Thanks,
--
Matt Grimm
Web Developer
The Health TV Channel, Inc.
(a non - profit organization)
3820 Lake Otis Parkway
Anchorage, AK 99508
907.770.6200 ext. 686
907.336.6205 (fax)
E-mail: mgrimm@healthtvchannel.org
Web: www.healthtvchannel.org

What header are you using? If you use Location header, this should not
happen.

Matt Grimm wrote:
> Suppose I have a form. Upon submission, the metadata is posted to a
> processing script (a separate PHP file), which parses it and then sends the
> user back to a particular page using the header function. If said user
> clicks their browser's back button, the aforementioned processing script
> will re-parse that post data and create a duplicate record. How can I
> prevent this? Cache control?
>
> Thanks,
> --
> Matt Grimm
> Web Developer
> The Health TV Channel, Inc.
> (a non - profit organization)
> 3820 Lake Otis Parkway
> Anchorage, AK 99508
> 907.770.6200 ext. 686
> 907.336.6205 (fax)
> E-mail: mgrimm@healthtvchannel.org
> Web: www.healthtvchannel.org
>

Hello Matt,

Monday, December 1, 2003, 10:31:23 PM, you wrote:

MG> Suppose I have a form. Upon submission, the metadata is posted to a
MG> processing script (a separate PHP file), which parses it and then sends the
MG> user back to a particular page using the header function. If said user
MG> clicks their browser's back button, the aforementioned processing script
MG> will re-parse that post data and create a duplicate record. How can I
MG> prevent this? Cache control?

There is no 100% reliable method of controlling the cache of any
browser. Why not, in your processing script, set a flag or issue
something to the users session to the effect of "already submitted
this form". Then if they do click back and submit it all again you can
check for the existence of this value and give them a nice friendly
error message ("Thanks for your enthusiasm, but you've already done
this!") :)

--
Best regards,
Richard mailto:rich@launchcode.co.uk