[thelist] deleting php vars

[jan guichelaar [artmiks]]

thanx simon
You hit the problem right on the head
and its dead now, so thanx



jan at artmiks.nl

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----- Original Message -----
From: "Simon Perry" <simon.perry at si-designs.co.uk>
To: <thelist at lists.evolt.org>
Sent: Monday, November 03, 2003 12:04 PM
Subject: Re: [thelist] deleting php vars


> ----- Original Message -----
> From: "jan guichelaar [artmiks]"
> > unset ( $HTTP_POST_VARS['var_name']);
> >
> > looks promising, but when i refresh the page, the vars are still there,
> > Still dont know how to prevent people to refresh the page and thus
> > executing the same php-code with the same vars twice.
> > :-(
> Jan,
>
> The problem you are facing is client side not server, the clients browsers
> are the ones who are remembering the post or get data. When you hit
refresh
> in your browser it sends the last request it did again. So if your request
> was post: http://your.sever/page.php?user=fred and you add fred to your
user
> list then unset ( $HTTP_POST_VARS['user']); the server has deleted the
user
> value but not the client, if you refresh the client it will send post:
> http://your.sever/page.php?user=fred again.
>
> You have two choices:
>
> 1. Validate the data before it is entered into the data source to check
for
> duplicates, not bad practice anyway!
>
> 2. Force the browsers behaviour (this is the solution I sent to you
before)
> by sending headers back to the browser that the page content has changed
and
> that it should load a "new" location. This approach is limited by your
page
> flow, to explain further if you are doing something like this:
>
> form-page.php > form-process.php
>
> then you will not be able to control the clients retaining the post data.
To
> be successful you need to write one page that handles the form and data,
see
> the sudo code below.
>
> one-page.php
> if(no post data exists){show form}
> if(post data exists){
> add to data source
> unset ( $HTTP_POST_VARS['user']);
> header("Status:  205 Reset Content");
> //reload the page without the form data
> header("Location: one-page.php");
> }
>
> Now if the client hits refresh the browser will send the last request it
> had, the one we told it to request by using header("Location:
> one-page.php"); that would be get: http://your.sever/one-page.php .
>
> Well, I hope that is clearer than mud for you...
>
> Simon
>
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