How does redirect after post works? [duplicate]
Possible Duplicate:
Back button re-submit form data ($_POST)
some guys suggest me rather then editing the question put it as new question that's why i am doing so...
<?php
session_start();
if(isset($_POST['username']) && ($_POST['password']))
{
$con=mysql_connect("localhost","root","");
if(!$con)
{
die('Could Not Connect:'.mysql_error());
}
mysql_select_db("tcs",$con);
$usr=$_POST["username"]; //pick username from login page
$pwd=hash('sha1',$_POST['password']); //pick password from login page and use hash algorithm to encrypt it
$query="select * from employee where Username='$usr' and Password='$pwd'"; //serch that single row in which both r found
$result=mysql_query($query,$con);
if ($result)
{
$row=mysql_fetch_array($result);
if (($row["Username"]==$usr) && ($row["Password"]==$pwd))
{
$_SESSION['employee']['id']=$row['User Id'];
$_SESSION['employee']['username']=$row['Username'];
}
else
{
echo "Login Not Successfull";
}
开发者_如何学Python }
}
else
{
echo 'Error! Username & Password were not sent!';
}
$_SESSION['user_authenticated'] = true;
?>
<html>
<body bgcolor="black">
<?php
if($_SESSION['user_authenticated'])
{
echo "<font color=red>"."<h3 align=center>"."Welcome ".$_SESSION['employee']['username']."</h3>"."</font>";
echo "<br />"."<a href='upload_file.php'>"."<font color='white'>"."<h4>"."Up-Load Files"."</h4>"."<font>"."</a>";
echo "<br />"."<br />"."<a href='list_files.php'>"."<font color='white'>"."<h4>"."List All Up-Loaded Files"."</h4>"."<font>"."</a>";
}
?>
</font>
<a href="logout_file.php"><font color="white"><h3 align="right">Sign Out</h3></font></a>
<font color="white">
</body>
</html>
Ok fine now i am getting the point.But there is one more problem.Suppose i am on signin-action page which have a link of sign out.When i click on sign out button i am re-directed to sign in page.ok no problem but again if i press back button again i am asked to resend the data(even after sign out) and again i am on sign-in-action page why so. It is wrong yar..What to do this.For all other pages like if i click on sign out button from upload button->redirected to sign-in and if i press back button it shows u are signed out. I don't know how to check session variable exit for signinaction
as felix sir told me to check this http://www.thefutureoftheweb.com/blog/get-redirect-after-post
but really i am not getting what this guy is saying.I am sorry i am not so techanical becuase i am a begineer I know what problem i am facing...
as far as i know
if (count($_POST)) { //checking how many time data is being resend.
// process the POST data
add_comment($_POST); //what this function do i dont know
// redirect to the same page without the POST data
header("Location: ".$_SERVER['PHP_SELF']); //i think it is like
//refreshing without get input again from allpication form
die;
}
Please, explain it, especially what is this $_server(;PHP_SELF)
About $_SERVER - see this.
加载中,请稍侯......
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