PHP Session webpage after authentication

Posted on 2014-03-23
Medium Priority
Last Modified: 2014-04-06
Hello All,

I have accomplished my first login web page using php and mysql, but in order to start a "session" or to redirect the user that has logged in to their home page wher their data is, how can I do this?

Here's my php code for my login page:


      $uname = $_POST['uname'];
      $password = $_POST['password'];
      $sql = mysql_query("SELECT * FROM users WHERE uname = '$uname' AND password= '$password'");
      if(mysql_num_rows($sql) > 0){
            echo "You are now Logged in";
      else {
            echo "Wrong Username and Password";      
$form = <<<EOT
<form action="Login.php" method="POST">
Username: <input type="text" name="uname"/><br/>
Password: <input type="password" name="password"/><br/>
<input type="submit" value="Login" name="submit"/>

echo $form;


Question by:LuiLui77
  • 3
LVL 35

Expert Comment

by:Terry Woods
ID: 39949463
A little knowledge can be a dangerous thing. In case you weren't aware, if a user enters the following value to your login form, the consequences are not good (no username or password would be required):
' or 1=1 or '

Open in new window

Or, potentially worse (this might drop your users table from the database; don't do it!):
'; drop table users; --'

Open in new window

More info here on sanitising user input: http://www.experts-exchange.com/Web_Development/Web_Languages-Standards/PHP/Q_27699398.html

Looks like some good details on using sessions here: http://www.experts-exchange.com/Web_Development/Web_Languages-Standards/PHP/Q_23573048.html
LVL 35

Expert Comment

by:Terry Woods
ID: 39949473
There also some information here on how to redirect after form submission: http://www.experts-exchange.com/Web_Development/Web_Languages-Standards/PHP/Q_24926053.html

These days I'm using the CodeIgniter framework, which does redirects automatically, but my understanding is that you should be redirecting after every successful POST form submission (ie those that change information), otherwise you get unwanted browser behaviour (such as the wrong page loading when a user opens a bookmark, or a resubmit information question when refreshing the page).
LVL 111

Accepted Solution

Ray Paseur earned 1500 total points
ID: 39949956
This article explains the essential design patterns for PHP client authentication (all web sites do the basics the same way).  It shows how the PHP session is used.

This article explains PHP sessions.

This article explains why you want to put aside MySQL and instead choose one of the supported database extensions like MySQLi or PDO.

And in case you're new to PHP and want to get some good learning resources (instead of copying code you found on the internet) try the resources called out in this article.
LVL 35

Expert Comment

by:Terry Woods
ID: 39951435
Good one Ray. Odd that my search didn't find any of those!

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