PHP forum page refresh

pld

Hi all!

First post here, so I hope someone may be able to answer my silly question...

I have a page that is basically a simple forum. This is my first time coding with php and mysql, but not my first with html and javascript.

My problem is that I have a form for adding a post to the forum. it calls back the same page with some variables POSTed that I catch to see if someone has triggered. Then if they have I enter the new post to the forum.

Everything works fine, except in the case of refreshing the page after I have posted something already. When I refresh, the page still has the variables, and i end up with double posts. is there a way to stop this easily? perhaps by clearing the variables after I have used them?

thebiglife

Ah, a problem I had myself, therefore I'll try and help you along the way.

I use cookie or session variable holding a random value (in my case, the date and time)

There are several ways around this and here is my effort

Set a random number on the post page in a hidden field,
when submitted, import this post/get variable, where you make your database call, surround it with an if condition. On initial viewing:

if session's random number does not equal posted random number , make the database call then set the session variable to equal posted random number.

next time page is refreshed, the database call will not happen, because session random number is equal to posted random number.

Thats the theory. You do the coding.

Other ways i have heard would be to make an extra expensive database call, and double check if this new message id has already been stored.

Or, when people no longer scorn on iframes, have an iframe offscreen which the form targets, and use that to make the database calls, that offscreen iframe could never be refreshed.

hope that is some help.

pld

Thanks for the advice! I'll give it a shot and see if I can possibly get it working...

pld

Thanks for the advice! I'll give it a shot and see if I can possibly get it working...

pld

LOL, looks like this site has the same problem i do (accidentally refreshed, and look at what happened!)
funny stuff!

thebiglife

if your're right, i suppose that shows that not a lot of people do a refresh or force refresh. I am quite surprised that happened though on here. I might have to try it myself.

thebiglife

didn't get it for me, but the way this site has sorted out the refresh problem is that it has an intermediate page that handles database query.

Well that is the theory, you seem to have proved thats wrong, but it shouldn't be.

This forum sends info to a page which then adds the message then redirects, so the final page shouldn't have the header information of post etc...

pld

I had hit the back button on the browser, and got a page expired page, but IE6 offers you the ability to try to resend the data (browser caching the info?). I click on resend, and voila! double post...

thebiglife

didn't get it for me, but the way this site has sorted out the refresh problem is that it has an intermediate page that handles database query.

Well that is the theory, you seem to have proved thats wrong, but it shouldn't be.

This forum sends info to a page which then adds the message then redirects, so the final page shouldn't have the header information of post etc...

thebiglife

Basically this is one downfall of an intermediate page, especially when it is abused by me and you. However this way doesn't have to rely on cookies being enabled,

the way i use and described does. Therefore any poor sod who doesn't accept the cookie cannot add a message.

As you can see, each way has a flaw.

i reckon this forum chain is damn fine lesson on the whole refresh question.

pld

indeed.

very true, and i appreciate your help with this. i'll get to coding and see what i can come up with.

thanks again.

Dark_Storm

On my homemade forum, when a user clicks the Submit button to submit his post, there is a hidden input tag named Submitted with value Yes. When the user clicks on the Submit button, the page reloads, but since the Submitted variable now exists, it catches my if ($Submitted) conditional. Inside it, i do

if (mysql_query($yourquery))
{
     print ("Your post has been submitted Redirecting you to <ahref=wahtever>Here</a>.!<meta refresh=to forum>");
     die;
}

YOu can rig a up a custon thing inside your meta refresh so that it passes variables to catch a Display conditional to display your post.
I think that this is the intermediate page that you used but whatever. Mine is better 😃

pld

thebiglife,

just so you know, your solution worked pretty well. Thanks again for the help, i really appreciate it.