session & back button not working.

flafer

Hi All,
i'm building a website with a login form, it start a session if the username & passsword entered are correct and jump to the next page.
But when i hit the back button won't go back to the initial page, gives an error:
"Data Missing
This document resulted from a POST operation and has expired from the cache. If you wish you can repost the form data to recreate the document by
pressing the reload button."

this is the parts of the code:

page1.php:
<?

....
....
if($id != 0){
session_start();
$verified_user=$id;
session_register("verified_user");
include("http://127.0.0.1/page2.php");
}

...
..
?>

page2.php:
<?
...
..
session_start();
// rest of code
...
..
?>

There is any missing code in the 2 pages? or something else?
Thanx in advance for any help.
Fat

theslinky

When you say "jumps to the next page" do you mean you redirect to another page using Header("Location: xxx")?

if so, then then when you click back, it will of course print a report form message because that page was accessed by POSTing a form.

Instead of redirect, why not print something on that page itself?

perhaps i'm misunderstanding the situation; please do post more details 🙂

-sridhar

jayant

On the page you want that should get reloaded, have the following :

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");    // Date in the past
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
                                                     // always modified
header("Cache-Control: no-store, no-cache, must-revalidate");  // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");                          // HTTP/1.0

These set of headers should be at the page which redirects.

flafer

Hello again,
The idea of headers does not really work , because when i press back button, i get an empty new form.

This is the way i conceived my code "bad or good? just started"

verify2.php
<?
// ...DB code, get $id.
if($id != 0)
{
session_start();
$verified_user=$id;
session_register("verified_user");
header('location:http://127.0.0.1/travel_form.php');
}
else{
echo("<font size=4 color=red>Your logging failed! Try again.</font><BR>");
header('location:http://127.0.0.1/login.php');
}
//...
?>

travel_form.php
<?

<form action="form_actions.php" method="POST">
// ... travel_form code
<input type="submit" name="button" value="Submit">
<input type="submit" name="button" value="Save & Continue">
<input type="reset" name="clear_button" value="Clear">
<input type="submit" name="button" value="Preview">
<input type="submit" name="button" value="Logout">
//....
</form>
?>

form_actions.php
<?
session_start();
switch($HTTP_POST_VARS["button"]) {
case "Submit":
// ...submit code
break;
case "Preview":
// preview code [preview on this page]
// use the back button to return
break;
case "Save & Continue":
// ...save and continue code
// & rightback to the filled "travel_form.php"
break;
case "Logout":
echo("<font size=4 color=red>You logged out! Thank you for using TLF. </font><BR>");
include("http://127.0.0.1/login.php");
session_unset($verified_user);
session_destroy();
break;
default:
// ...
}

My questions are:
1. how can i make the session work with this code[means when i press back button or forward, i will get my old values in the form.]?
2. When i will click on "Save & Continue", how can i get back to 'travel_form.php' with the filled values in it?
3. even session_destroy() in the logout coding won't work, something missing?

Reagrds,
Fat.

mrmufin

travel_form.php
<?

form_actions.php
<?
session_start();

// This looks frighteningly familiar...:

switch($HTTP_POST_VARS["button"]) {
case "Submit":
// ...submit code
break;
case "Preview":
// preview code [preview on this page]
// use the back button to return
break;
case "Save & Continue":
// ...save and continue code
// & rightback to the filled "travel_form.php"
break;
case "Logout":
echo("<font size=4 color=red>You logged out! Thank you for using TLF. </font><BR>");
include("http://127.0.0.1/login.php");
session_unset($verified_user);
session_destroy();
break;
default:
// ...
}

My questions are:
1. how can i make the session work with this code[means when i press back button or forward, i will get my old values in the form.]?

First, you need to make sure that you're NOT sending any expiration date in the header, nor a pragma no-cache directive.

I can't help you with the PHP sessions shtuff, I "rolled my own" session manager before PHP had built-in sessions, and I've used it ever since.

When i will click on "Save & Continue", how can i get back to 'travel_form.php' with the filled values in it?

Whenever you need to do stuff like this, you have to assign those variables when you're generating the form. Typically, when I need to re-populate a form with data from the last post, I build the form dynamically, assigning the values from the last post. For example:

Name: <input type="text" name="name" value="<?php echo $HTTP_POST_VARS["name"]; ?>">

This will populate the form field with whatever values were sent in the POST directive.

While this is pretty simple for text-fields, it gets more complex for things like drop-down menus and radio buttons, for which I've designed a handful of custom functions.

Also, if you're sending your site visitor from one form to the next and then to the next, you might wanna consider either stashing the data from each post in a database somewhere, or carrying all the data from each post in hidden form elements. Hidden form elements should run a little faster, but it also gives us clever folks (who enjoy creating our own forms and submitting them to remote servers!) the opportunity to do bad things to the data.

even session_destroy() in the logout coding won't work, something missing?

Sorry, no PHP sessions experience.

Reagrds,
Fat. [/B][/QUOTE]

flafer

Hi All,
i tried the headers given in the above message of "jayant" , put them in "travel_form.php" & "form_actions" and tried the syntax given by Mr muffin:
Name: <input type="text" name="name" value="<?php echo $HTTP_POST_VARS["name"]; ?>">

but the form "travel_form.php" comeback empty!!!

is it because i'm using an extra form to the action in "form_actions.php"?

Any one can help ?
as well still the session_destroy(); not working.

Any help? Thanx in advance.
fat.

flafer

Hi Guys,
in my previous email, i had a problem that i can not solve it, hope somebody will help me.

i do have the "travel_form.php" where the method used is "post" to "actions_form.php".

in "actions_form.php", the statement :
switch($HTTP_POST_VARS["button"])
is OK means i can access the variable "button" by $HTTP_POST_VARS.
but in the first form "travel_form.php" i have a statement :
<input type="text" name="realname" size="40" value="<? echo $HTTP_POST_VARS["realname"]; ?>" >

where the variable "realname" coming always empty string, Why the old value is not returned?
if it's not possible, is there any other method to do that.

Thanks in advance.

note:refer to the code in the previous email.😕 😕

mikefn

To make it able view your old variables, you need to use session.
First of all, on the first page (travel_form.php), you need to register the session name.
Then, after that, on the second page (form_actions.php), you need to put all the form fields that have been transferred from the previous page into the session.
Here is the example:

<?
// page1.php

// Create session "sess_try"
session_start();
if (!session_is_registered("sess_try"))
session_register("sess_try");

echo "<form action=test2.php method=post>";

... // rest of codes that you want to put, such as forms in html

// to make it able to see old values if you hit "go back" from page2.php

echo <input type=text name=test value='$sess_try[test]'>";

<?
// page2.php

session_start();

// put the form values from the previous into session
foreach($HTTP_POST_VARS as $key=>$value) {
$sess_try[$key] = $value;
}

... // rest of codes
?>

Hope this solve your problem ...

Mike ... 🙂

email

you may want to try the hidden attribute in html.
<input type=hidden name="abc" value="<?= $abc ?>">