Avoid Multiple Submissions

s_steele

Hi,

I have a fairly large PHP app running and the biggest problem experienced by users is that using the back button and the refresh button has a nasty habit of resulting in double entry (ie. the same item is added to the database every time they press refresh).

Does anybody have any suggestions as to a solution to this problem? Even better, does anyone have a class that fixes it 🙂

thanks in advance,

Simon Steele
http://www.pnotepad.org/

Sj0wKOoMel

Maybe you should use an unique ID with your post.
Keep track of your ID's with a session ( array )
Every time a post is done again by a refresh.
Your code matches the id's in your session variable and insert if it doenst exsist yet

s_steele

Any ideas for a good way to generate a unique ID. When programming C++ I would use a guid or something similar - I'd prefer not to have to use a DB sequence.

cheers,

Simon Steele
http://www.pnotepad.org/

Sj0wKOoMel

This maybe isnt very original( but for your original problem this should be fine ) use the same session and keep track of a counter variable.

🙂

the_Igel

You can go this way.

A submission goes to the script, say, 'post.php'.
This script processes the information, does all you need, and then redirects a user to another page, that shows him the output. Then refreshing this page won't submit anything.
To be more accurate, you may completely remove post.php from history list. The only way i know is to use the javascript redirect
'window.location.replace()', but it isn't much reliable 'cause JS may be off.

s_steele

Thanks, I had considered the last but rejected it because users can still use the back button - and I don't want to rely on Javascript. I've implemented the method suggested further up (thanks!) and it seems to work great.

thanks all,

Simon Steele,
Programmers Notepad - http://www.pnotepad.org/