php，mySQL和AJAX：无法跨同一域中的脚本使用会话

Question

I have the following pages: page1.php, page2.php and page3.php. Code in each of them is as below

CODE:

page1.php

<script type="text/javascript">

$(function(){
    $('#imgID').upload({
        submit_to_url: "page2.php",
        file_name: 'myfile1',
        description : "Image",
        limit : 1,      
        file_types : "*.jpg",

    })
}); 

</script>

<body>
<form action="page3.php" method="post" enctype="multipart/form-data" name="frm1" id="frm1">
//Some other text fields
  <input type="submit" name="submit" id="submit" value="Submit" />
</form>

</body>

page2.php

<?php session_start();
$a = $_SESSION['a'];
$b = $_SESSION['b'];
$c = $_SESSION['c'];

$res = mysql_query("SELECT col FROM table WHERE col1 = $a AND col2 = $b AND col3 = $c LIMIT 1");
$num_rows = mysql_num_rows($res);
echo $num_rows; //echos 0 when in fact it should have been 1 because the data in the Session exists.

//Ok let's proceed further
//... Do some stuff...
//Store some more values and create new session variables (and assume that page1.php is going to be able to use it)
$_SESSION['d'] = 'd';
$_SESSION['e'] = 'e';
$_SESSION['f'] = 'f';

if (move_uploaded_file($_FILES['file']['tmp_name'], $file)) 
{ 
  echo "success"; 
} 
else 
{
 echo "error ".$_FILES['file']['error'];
}

?>

page3.php

<?php session_start(); 
if( isset($_POST['submit']) )
{
  //These sessions are non-existent although the AJAX request 
  //to page2.php may have created them when called via AJAX from within page1.php 
  echo $_SESSION['d'].$_SESSION['e'].$_SESSION['f']; ?> 
}
?>

1. As the code says it I am posting some info via AJAX call from page1.php to page2.php. page2.php is supposed to be able to use the session values from page1.php ie $_SESSION['a'], $_SESSION['b'] and $_SESSION['c'] but it does not. Why? How can I fix this?

2. page2.php is creating some more sessions after some processing is done and a response is sent back to page1.php. The submit button of the form on page1.php is hit and the page gets POST'ed to page3.php. But when the SESSION info that gets created in page2.php is echoed, it's blank signifying that SESSIONS from page2.php are not used. How can I fix this?

I looked over a lot of information and have spent about 50 hours trying to do different things with my scripts before arriving at the above conclusions. My app. is custom made using function (not OOPS) and does not use any PHP frameworks & I am not even about to use any as my knowledge of OOP concepts is limited any many frameworks are object oriented. I came across race conditions, but the solutions provided don't help too much. One more solution of using DB to hold sessions and seek and retrieve from DB is the last thing on my mind and I really want to avoid creating table, coding and maintaining code for a task as simple as just keeping sessions across pages in the same domain.

So my request is: Is there a way that I can solve the above problem(s) via simple coding in present conditions? Any help is appreciated.

Thank you.

EDIT: Also I have sensitive information contained in the SESSIONS that I cannot pass back and forth via the pages using GET or POST. So using SESSIONS is really helpful for me. So if any coding can help me achieve this, that would be really helpful. Thanks.

Answer 1

From the SWFUpload documentation:

Cookie issue

On Windows the Non-IE Flash Player plugin (FireFox, Opera, Safari, etc) will send the IE cookies regardless of the browser used. This breaks authentication and sessions for many server-side scripting technologies.

Developers should manually pass Session and Authentication cookie information and manually restore Sessions on the Server Side if they wish to use Sessions

The SWFUpload package contains work-around sample code for PHP and ASP.Net

I suspect SWFUpload causes your problem.

Check if your javascript posts the session_id:

new SWFUpload({
   ...
   post_params: {
     "PHPSESSID" : "<?php echo session_id(); ?>"
   }
}

And if your PHP script reacts to the sent session_id.

if (isset($_POST["PHPSESSID"])) {
    session_id($_POST["PHPSESSID"]);
}
session_start();

( session.auto_start should be disabled in your php.ini or .htaccess)

Answer 2

What is .upload()? Does it come from a library/plugin? If so, what one?

Does the move_uploaded_file() call get executed successfully?

From the events you describe it sounds to me like the form is being submitted straight to page3.

The code you've posted seems very incomplete (missing javascript, missing form fields, missing where $_SESSION members ab and c are set). You should create a minimalistic example and post the complete code.