Sessions and cookies are very widely used around the internet. A session can be something as simple as displaying the user's name on the page, and it can do as much as keeping a user logged into a forum (or entire user site). Cookies can keep a user's information stored on their computer, even after the session is stopped. Using them together can be very easy and pretty powerful.
PART 1: Learning Sessions
Sessions are very easy to use. All a session does is store a variable with the server while the session is running. The session is closed when the browser is closed. You start a session using the session_start() function.
<?php
session_start();
?>
Now, of course, that's not all, but that is the most important part of using sessions. You must ALWAYS start the session before you can get any variables from the session. Now, let's put a variable into the session...let's use a username that has been posted from a form on the previous page.
<?php
$username = $_POST['username'];
session_start();
$_SESSION['username'] = $username;
?>
And there you go! Now you can call on the username variable like so...
<?php
session_start();
$username = $_SESSION['username'];
?>
Also, you may have heard of the session_register() function. I don't like to use this one, visit the link to see why, but basically, using my method is more widely accepted.
PART 2: Learning Cookies
Yes, yes, I know there are a few other cookie tutorials. Yes, I know cookies aren't always that great. But this is MY TUTORIAL, so I'll teach what I want >:)
Setting a cookie is pretty easy too...almost as easy as setting up a session. We use set_cookie() to set cookies.
There are 6 parts to set in a cookie...but you only need three to get the cookie to work properly, as the others will fill in default.
Let's set two cookies...one from a username field on a form on the previous page, and one from a password field.
<?php
$username = $_POST['username'];
$password = $_POST['password'];
set_cookie("username", $username, time()+3600);
set_cookie("password", $password, time()+3600);
?>
Now, the cookies' names are username and password, and they both store the correct variables. You can md5 the password if you want...but this is just a quick overview.
Lastly, the time part tells how long until the cookie expires. Here's what you add to the time() for however long you want until the cookie expires.
31536000 - 1 Year
604800 - 1 Week
86400 - 1 day
3600 - 1 hour
60 - 30 minutes
20 - 10 minutes
The other fields are...
- The path the cookie is able to be accessed from, default is the directory (and all under) that the cookie was placed by
- The domain the cookie can be used by (including subdomain)
- Wether or not the cookie is secure
Here's a cookie with all the fields in place...just to show what it looks like. If you want to study up on it, check out the PHP tutorial for it, which is the last link I gave you.
set_cookie("username", $username, time()+3600, "/", ".site.com", 1);
PART 3: Having Cookies and Sessions Talk To Each Other
This is even as simple as the last two steps. Check to see if there are cookies...and if there are, set the session. If not, do the default action to get the information from the user to set the session. We will be using the very amazing isset() function.
<?php
if (isset($_COOKIE['username']) && isset($_COOKIE['password'])) {
$username = $_COOKIE['username'];
$password = $_COOKIE['password'];
session_start();
$_SESSION['username'] = $username;
$_SESSION['password'] = $password;
header("Location: http://www.site.com/admin/");
die();
} else {
echo "<form method=POST>
<input type='text' size='30' name='username' />
<input type='password' size='30' name='password' />
<input type='submit' value='Submit!' />
</form>";
// Now just follow steps one and two.
}
?>
PART 4: The Conclusion
This was a simple, bare-bones, easily customizable tutorial. It is meant to be changed and modified to fit your specific project, and to brush over the topics of sessions and cookies.
Please, give any feedback and modifications you can to this tutorial, as that's what's best about PHP: Main!
