In this post we’re going to create a very simple user authentication
system in PHP. It’d be like the one’s you see while logging in to
various sites/services (emails, forums, social networking sites etc)
User authentication is a way for sites to know who you are among the other
registered users and showing you relevant content (may be confidential). For
example it’s only you ho is authorized to see your emails because you
only know your authentication information.
In this post we’re going to create two files, a HTML page which will
collect the username and password in a form. These information will then be
send to a PHP script, which will verify and show the required information.
Below is the PHP code:
<?php
//define some constants
define("USERNAME", "goodjoe");
define("PASSWORD", "123456");
define("REALNAME", "Joe Burns");
//have the data being passed
$user=$_GET['user'];
$pass=$_GET['pass'];
//if username and password match
if($user==USERNAME && $pass==PASSWORD)
{
echo "<h1>Hello ".REALNAME."</h1>";
echo "<p>Nice to see you logging in again...</p>";
echo "<p>USER: <i>".USERNAME."</i></p>";
}
//if not
else
{
echo "<h1>Wrong username or password!</h1>";
}
?>
The code above is pretty straightforward. You may change the constants that
hold the user information.
Now, as you know from Taking
User Inputs to Create Personalized Pages II, we need a HTML page with
a form to send information to this script. Here it is:
<html>
<head>
<title>Simple Uesr Authentication System</title>
</head>
<body>
<form name="form1" method="get" action="verify.php">
<p>Uername
<input name="user" type="text" id="user">
</p>
<p>Password
<input name="pass" type="password" id="pass">
</p>
<p>
<input type="submit" name="Submit" value="Submit">
</p>
</form>
</body>
</html>
Refer to Taking
User Inputs to Create Personalized Pages II to know more about the
form tag. Note that the PHP script must be of the name as in the “action=…”
of the form tag and in the same directory as the HTML page.
Notice this line
<input name="pass" type="password" id="pass">The above code creates an element that shows asterisks (*) on entering anything,
just like on other sites.
Now, we’re ready to put these files on the server and request the HTML
page. Do it and play with the page for a while!
This is how it’d look.
A few points to note:
-
This is a very simple example and holds the user information in the script
itself (hard coded). Real sites store user information in Databases.
-
For real-life applications, we’d also need to use session variables
or cookies.
[Update: Read the next post An
Example of User Authentication System in PHP II]
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