Clearing POST DATA for Browser Refresh

[tmax]

PHP Pros:

I have a simple html form that submits data to a php script, which
processes it, and then redisplays the same page, but with a "thank you"
message in place of the html form. This is all working fine. However,
when refresh the browser, I get the following message displayed:

"The page you are trying to view contains POSTDATA. If you resend the
data, any action the form carried out (such as as search or online
purchse) will be repeated. To resend the data, click OK. Otherwise,
click Cancel."

Obviously I don't want my users to resend the data to me.

What do I need to do code-wise so that when the browser is refreshed,
the page is reloaded without this message being displayed.

Thanks in advance.

[David Haynes]

Re: Clearing POST DATA for Browser Refresh

tmax wrote:[color=blue]
> PHP Pros:
>
> I have a simple html form that submits data to a php script, which
> processes it, and then redisplays the same page, but with a "thank you"
> message in place of the html form. This is all working fine. However,
> when refresh the browser, I get the following message displayed:
>
> "The page you are trying to view contains POSTDATA. If you resend the
> data, any action the form carried out (such as as search or online
> purchse) will be repeated. To resend the data, click OK. Otherwise,
> click Cancel."
>
> Obviously I don't want my users to resend the data to me.
>
> What do I need to do code-wise so that when the browser is refreshed,
> the page is reloaded without this message being displayed.
>
> Thanks in advance.[/color]
Don't redirect to the form; redirect to a summary page without the form
or make your form page sensitive to whether the $_POST data is available
and do not have it emit a <form> if the $_POST data is available.

I prefer the first method over the second.

-david-

[d]

Re: Clearing POST DATA for Browser Refresh

"tmax" <tmax@comcast.n et> wrote in message
news:8281b$43f2 1506$481a8e8e$1 8008@PGTV.COM.. .[color=blue]
> PHP Pros:
>
> I have a simple html form that submits data to a php script, which
> processes it, and then redisplays the same page, but with a "thank you"
> message in place of the html form. This is all working fine. However,
> when refresh the browser, I get the following message displayed:
>
> "The page you are trying to view contains POSTDATA. If you resend the
> data, any action the form carried out (such as as search or online
> purchse) will be repeated. To resend the data, click OK. Otherwise, click
> Cancel."
>
> Obviously I don't want my users to resend the data to me.
>
> What do I need to do code-wise so that when the browser is refreshed, the
> page is reloaded without this message being displayed.
>
> Thanks in advance.[/color]

In the script to which the form submits, store the $_POST data somewhere
else, say a session. Then, use this:

header("Locatio n: http://host/path/to/script.php");
exit();

to bounce the user to another page. Most browsers know to not re-submit the
post data to this new page. The new script can even be the originating
one - as long as you use the location: header, you'll be fine. You can then
access the submitted data wherever you stored it.

PS. if you're using a session to store the data, call session_write_c lose()
before the header() call, otherwise nasty things happen on some browsers.

dave

[frizzle]

Re: Clearing POST DATA for Browser Refresh


d wrote:[color=blue]
> "tmax" <tmax@comcast.n et> wrote in message
> news:8281b$43f2 1506$481a8e8e$1 8008@PGTV.COM.. .[color=green]
> > PHP Pros:
> >
> > I have a simple html form that submits data to a php script, which
> > processes it, and then redisplays the same page, but with a "thank you"
> > message in place of the html form. This is all working fine. However,
> > when refresh the browser, I get the following message displayed:
> >
> > "The page you are trying to view contains POSTDATA. If you resend the
> > data, any action the form carried out (such as as search or online
> > purchse) will be repeated. To resend the data, click OK. Otherwise, click
> > Cancel."
> >
> > Obviously I don't want my users to resend the data to me.
> >
> > What do I need to do code-wise so that when the browser is refreshed, the
> > page is reloaded without this message being displayed.
> >
> > Thanks in advance.[/color]
>
> In the script to which the form submits, store the $_POST data somewhere
> else, say a session. Then, use this:
>
> header("Locatio n: http://host/path/to/script.php");
> exit();
>
> to bounce the user to another page. Most browsers know to not re-submit the
> post data to this new page. The new script can even be the originating
> one - as long as you use the location: header, you'll be fine. You can then
> access the submitted data wherever you stored it.
>
> PS. if you're using a session to store the data, call session_write_c lose()
> before the header() call, otherwise nasty things happen on some browsers.
>
> dave[/color]

Just curious, but is there / would you recommend a good alternative for
the Sessions?

Frizzle.

[tmax]

Re: Clearing POST DATA for Browser Refresh

Well, I've tried everything that has been suggested so far - thanks for
everyone's input.

However, let me restate the problems differently as I believe it wasn't
correct to begin with.

I have a file: index.php

index.php contains a form, which when submitted for processing, calls
itself using <form method="POST" action="{$_SERV ER['PHP_SELF']}">

When the form is submitted and index.php is reevaluated, I have the
following IF statement: (FYI: 'submit' is the name of the submit button.)
------------
IF ( !isset($_POST['submit']) ) {
// The form has NOT been SUBMITTED - display the form

echo <<<htmloutput
<form method="POST" action="{$_SERV ER['PHP_SELF']}">
...
</form>
htmloutput;

} ELSE {
// The form was SUBMITTED - process the form

process the form data, etc. and print in PLACE of the form the
following:

echo "Informatio n submitted... Thank you.";
}
-------------

I understand I can redirect to a (different) summary page, but all I
want to do is replace the form with the summary message. The problem
comes into being when, after the summary message is displayed, the user
goes to refresh the browser. The browser is still caching the form data
for resubmission. I've tried things like: unset($_POST) or
unset($_POST['submit']) (and all the other form fields) but that has no
affect.

Any other suggestions?

Thanks in advance.



d wrote:[color=blue]
> "tmax" <tmax@comcast.n et> wrote in message
> news:8281b$43f2 1506$481a8e8e$1 8008@PGTV.COM.. .
>[color=green]
>>PHP Pros:
>>
>>I have a simple html form that submits data to a php script, which
>>processes it, and then redisplays the same page, but with a "thank you"
>>message in place of the html form. This is all working fine. However,
>>when refresh the browser, I get the following message displayed:
>>
>>"The page you are trying to view contains POSTDATA. If you resend the
>>data, any action the form carried out (such as as search or online
>>purchse) will be repeated. To resend the data, click OK. Otherwise, click
>>Cancel."
>>
>>Obviously I don't want my users to resend the data to me.
>>
>>What do I need to do code-wise so that when the browser is refreshed, the
>>page is reloaded without this message being displayed.
>>
>>Thanks in advance.[/color]
>
>
> In the script to which the form submits, store the $_POST data somewhere
> else, say a session. Then, use this:
>
> header("Locatio n: http://host/path/to/script.php");
> exit();
>
> to bounce the user to another page. Most browsers know to not re-submit the
> post data to this new page. The new script can even be the originating
> one - as long as you use the location: header, you'll be fine. You can then
> access the submitted data wherever you stored it.
>
> PS. if you're using a session to store the data, call session_write_c lose()
> before the header() call, otherwise nasty things happen on some browsers.
>
> dave
>
>[/color]

[P-Rage]

Re: Clearing POST DATA for Browser Refresh

I have to ask, why would you assume your users would refresh that page
rather than following a link somewhere else?

[P-Rage]

Re: Clearing POST DATA for Browser Refresh

I have to ask, why would you assume your users would refresh that page
rather than following a link somewhere else?

[Marc van Lieshout]

Re: Clearing POST DATA for Browser Refresh

I don't think there is another solution than storing state information
somehwere.
I would use the following method:

1. Before displaying the form, generate some unique number
2. add this number in a hidden field in the form.
3. When the user submits, mark the number as 'used'
4. When the user submits again, ignore the data, because the number
has already been 'used' up.

The simplest way to do this is to create a counter, either in a file on disk
or in
a database. Before you send the form to the client, increment the counter
and send
the counter value in a hidden field in the form.

If you save the form data in a database table, add a 'counter' field to the
table.
When the form is first submitted, a record with the counter value sent with
the form should not exist. Save data and counter.
If the form is submitted for a second or third time, the counter is already
present in
your table, so you should ignore the data in the post.

Using a session cookie is, I think, less work.


"tmax" <tmax@comcast.n et> wrote in message
news:8281b$43f2 1506$481a8e8e$1 8008@PGTV.COM.. .[color=blue]
> PHP Pros:
>
> I have a simple html form that submits data to a php script, which
> processes it, and then redisplays the same page, but with a "thank you"
> message in place of the html form. This is all working fine. However,
> when refresh the browser, I get the following message displayed:
>
> "The page you are trying to view contains POSTDATA. If you resend the
> data, any action the form carried out (such as as search or online
> purchse) will be repeated. To resend the data, click OK. Otherwise, click
> Cancel."
>
> Obviously I don't want my users to resend the data to me.
>
> What do I need to do code-wise so that when the browser is refreshed, the
> page is reloaded without this message being displayed.
>
> Thanks in advance.[/color]

[tmax]

Re: Clearing POST DATA for Browser Refresh


True, they could instead following some other link and decide not to
refresh the page. However, I would like the page to function such that
refreshing the page simply re-displays a new blank form (after all,
refreshing a page is conceptually akin to resetting.)

I started off on this path thinking that this format should be
relatively easy to code with one if-else statement. So far, it has been
easy to code (the form and summary message work great, with very little
coding). I keep thinking that there is some PHP mechanism that isn't
being used properly here (due to my PHP inexperience.)

Any suggestions?

P-Rage wrote:[color=blue]
> I have to ask, why would you assume your users would refresh that page
> rather than following a link somewhere else?
>[/color]

[d]

Re: Clearing POST DATA for Browser Refresh

"frizzle" <phpfrizzle@gma il.com> wrote in message
news:1139946264 .842789.257780@ o13g2000cwo.goo glegroups.com.. .[color=blue]
>
> d wrote:[color=green]
>> "tmax" <tmax@comcast.n et> wrote in message
>> news:8281b$43f2 1506$481a8e8e$1 8008@PGTV.COM.. .[color=darkred]
>> > PHP Pros:
>> >
>> > I have a simple html form that submits data to a php script, which
>> > processes it, and then redisplays the same page, but with a "thank you"
>> > message in place of the html form. This is all working fine. However,
>> > when refresh the browser, I get the following message displayed:
>> >
>> > "The page you are trying to view contains POSTDATA. If you resend the
>> > data, any action the form carried out (such as as search or online
>> > purchse) will be repeated. To resend the data, click OK. Otherwise,
>> > click
>> > Cancel."
>> >
>> > Obviously I don't want my users to resend the data to me.
>> >
>> > What do I need to do code-wise so that when the browser is refreshed,
>> > the
>> > page is reloaded without this message being displayed.
>> >
>> > Thanks in advance.[/color]
>>
>> In the script to which the form submits, store the $_POST data somewhere
>> else, say a session. Then, use this:
>>
>> header("Locatio n: http://host/path/to/script.php");
>> exit();
>>
>> to bounce the user to another page. Most browsers know to not re-submit
>> the
>> post data to this new page. The new script can even be the originating
>> one - as long as you use the location: header, you'll be fine. You can
>> then
>> access the submitted data wherever you stored it.
>>
>> PS. if you're using a session to store the data, call
>> session_write_c lose()
>> before the header() call, otherwise nasty things happen on some browsers.
>>
>> dave[/color]
>
> Just curious, but is there / would you recommend a good alternative for
> the Sessions?[/color]

Databases or files spring to mind :)
[color=blue]
> Frizzle.
>[/color]

[d]

Re: Clearing POST DATA for Browser Refresh

"tmax" <tmax@comcast.n et> wrote in message
news:1f9bd$43f2 3b15$481a8e8e$2 9885@PGTV.COM.. .[color=blue]
> Well, I've tried everything that has been suggested so far - thanks for
> everyone's input.
>
> However, let me restate the problems differently as I believe it wasn't
> correct to begin with.[/color]

I understand completely what you're asking :)

Try this code:

<?

session_start() ;

if (isset($_POST["data"])) {
$_SESSION["data"]=$_POST["data"];
session_write_c lose();
header("Locatio n: ".$_SERVER["SCRIPT_URI "]);
exit();
}

if (isset($_SESSIO N["data"])) {
?>
<html>
<head><title>Th anks!</title></head>
<body>
Thank you for submitting your data:<br>
<?=$_SESSION["data"];?>
</body>
</html>
<?
} else {
?>
<html>
<head><title>Pl ease Submit</title></head>
<body>
Use the form to submit your data:<br>
<form method="post">
<input type="text" name="data"><br >
<input type="submit" value="Go!">
</form>
</body>
</html>
<?
}
?>

It will show a form, and take that posted data and store it in a session.
Then, the script re-directs you back to itself, and that redirection stops
your browser wanting to resubmit the data when refreshed. The session is
then checked, and if the data is present, a thank-you note is displayed. If
not, it then shows the initial form.

dave

[d]

Re: Clearing POST DATA for Browser Refresh

"tmax" <tmax@comcast.n et> wrote in message
news:a3153$43f2 5750$481a8e8e$2 9897@PGTV.COM.. .[color=blue]
>
> True, they could instead following some other link and decide not to
> refresh the page. However, I would like the page to function such that
> refreshing the page simply re-displays a new blank form (after all,
> refreshing a page is conceptually akin to resetting.)
>
> I started off on this path thinking that this format should be relatively
> easy to code with one if-else statement. So far, it has been easy to code
> (the form and summary message work great, with very little coding). I
> keep thinking that there is some PHP mechanism that isn't being used
> properly here (due to my PHP inexperience.)
>
> Any suggestions?[/color]

The header("Locatio n: ") command :) See my other post... ;)
[color=blue]
> P-Rage wrote:[color=green]
>> I have to ask, why would you assume your users would refresh that page
>> rather than following a link somewhere else?
>>[/color][/color]

[tmax]

Re: Clearing POST DATA for Browser Refresh

Thank You Dave!!!

This code works - I used ob_start() to get around some header() errors,
but after implementing that, my form and page works exactly as I
intended it to. Learned quite a bit from all of this too. Thanks again!

Travis


d wrote:[color=blue]
> "tmax" <tmax@comcast.n et> wrote in message
> news:1f9bd$43f2 3b15$481a8e8e$2 9885@PGTV.COM.. .
>[color=green]
>>Well, I've tried everything that has been suggested so far - thanks for
>>everyone's input.
>>
>>However, let me restate the problems differently as I believe it wasn't
>>correct to begin with.[/color]
>
>
> I understand completely what you're asking :)
>
> Try this code:
>
> <?
>
> session_start() ;
>
> if (isset($_POST["data"])) {
> $_SESSION["data"]=$_POST["data"];
> session_write_c lose();
> header("Locatio n: ".$_SERVER["SCRIPT_URI "]);
> exit();
> }
>
> if (isset($_SESSIO N["data"])) {
> ?>
> <html>
> <head><title>Th anks!</title></head>
> <body>
> Thank you for submitting your data:<br>
> <?=$_SESSION["data"];?>
> </body>
> </html>
> <?
> } else {
> ?>
> <html>
> <head><title>Pl ease Submit</title></head>
> <body>
> Use the form to submit your data:<br>
> <form method="post">
> <input type="text" name="data"><br >
> <input type="submit" value="Go!">
> </form>
> </body>
> </html>
> <?
> }
> ?>
>
> It will show a form, and take that posted data and store it in a session.
> Then, the script re-directs you back to itself, and that redirection stops
> your browser wanting to resubmit the data when refreshed. The session is
> then checked, and if the data is present, a thank-you note is displayed. If
> not, it then shows the initial form.
>
> dave
>
>[/color]

[Jerry Stuckle]

Re: Clearing POST DATA for Browser Refresh

tmax wrote:[color=blue]
> Thank You Dave!!!
>
> This code works - I used ob_start() to get around some header() errors,
> but after implementing that, my form and page works exactly as I
> intended it to. Learned quite a bit from all of this too. Thanks again!
>
> Travis
>
>
> d wrote:
>[color=green]
>> "tmax" <tmax@comcast.n et> wrote in message
>> news:1f9bd$43f2 3b15$481a8e8e$2 9885@PGTV.COM.. .
>>[color=darkred]
>>> Well, I've tried everything that has been suggested so far - thanks
>>> for everyone's input.
>>>
>>> However, let me restate the problems differently as I believe it
>>> wasn't correct to begin with.[/color]
>>
>>
>>
>> I understand completely what you're asking :)
>>
>> Try this code:
>>
>> <?
>>
>> session_start() ;
>>
>> if (isset($_POST["data"])) {
>> $_SESSION["data"]=$_POST["data"];
>> session_write_c lose();
>> header("Locatio n: ".$_SERVER["SCRIPT_URI "]);
>> exit();
>> }
>>
>> if (isset($_SESSIO N["data"])) {
>> ?>
>> <html>
>> <head><title>Th anks!</title></head>
>> <body>
>> Thank you for submitting your data:<br>
>> <?=$_SESSION["data"];?>
>> </body>
>> </html>
>> <?
>> } else {
>> ?>
>> <html>
>> <head><title>Pl ease Submit</title></head>
>> <body>
>> Use the form to submit your data:<br>
>> <form method="post">
>> <input type="text" name="data"><br >
>> <input type="submit" value="Go!">
>> </form>
>> </body>
>> </html>
>> <?
>> }
>> ?>
>>
>> It will show a form, and take that posted data and store it in a
>> session. Then, the script re-directs you back to itself, and that
>> redirection stops your browser wanting to resubmit the data when
>> refreshed. The session is then checked, and if the data is present, a
>> thank-you note is displayed. If not, it then shows the initial form.
>>
>> dave
>>[/color][/color]

His code should work fine as long as you don't have *anything* before
the first line - including blank lines, spaces and DOCTYPE statements.

You should not need ob_start().

--
=============== ===
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attgl obal.net
=============== ===

[Jasen Betts]

Re: Clearing POST DATA for Browser Refresh

On 2006-02-14, tmax <tmax@comcast.n et> wrote:[color=blue]
> PHP Pros:
>
> I have a simple html form that submits data to a php script, which
> processes it, and then redisplays the same page, but with a "thank you"
> message in place of the html form. This is all working fine. However,
> when refresh the browser, I get the following message displayed:
>
> "The page you are trying to view contains POSTDATA. If you resend the
> data, any action the form carried out (such as as search or online
> purchse) will be repeated. To resend the data, click OK. Otherwise,
> click Cancel."
>
> Obviously I don't want my users to resend the data to me.
>
> What do I need to do code-wise so that when the browser is refreshed,
> the page is reloaded without this message being displayed.
>
> Thanks in advance.[/color]

I think this will work.


when they post the form issue a redirect


(use a fixed pitch font or the following won't make much sense)

user posts automatic user navigates
form -----> redirect ------> thankyou --------> further
page page

when the user goes back from the "further" page they'll hit the
thankyou page (which was got by the redirect so no data to post)
(back again gets them to the form.)


Bye.
Jasen