by enygma
There are many ways to go about authenticating a user for your site, some are more secure than others. The one that will be discussed here is doing the authentication from a MySQL database.

To begin with, we will help you create the database that we will use to authenticate off of. Keep in mind, this is a very simple tutorial and there are many other ways for you to do this. Obviously, you'll need MySQL up and running on your machine and know a bit about how to use it. If you don't know how to use MySQL yet, poke around on the net and look for an introduction. I'm sure there is one somewhere.

On numerous occassions I have been asked how to serve images from a non-web accessible directory. A lot of sites now a days sell content and with the latest in php technologies like sessions and such, people like to use session management and authentication on their websites, without using .htaccess files in their directory. The easiest solution to protecting images is by reading them from a directory outside the document root on the webserver and serving it to another php script. This helps in two ways.
1. People cannot link directly to your images via a URL.
2. You can use another script to serve the image and make people login to view the image as well you could use your own html design dynamically around the image.

The goal of this tutorial, as you probably guessed by the title, is to help you (yes you) create your very own news-driven web site. Now, this doesn't have to be a system as glorified as something like Slashdot or some of the other big news sites. All you may need is a simple system for displaying news and for editing/adding news to the front page. Well, look no further - I will show you how to create a nice simple news-driven site using nothing but some pretty simple PHP and a MySQL database. Now, this can be done without a database by using a text file or something, but that's a bit more difficult. You'd have to write something to parse out the info you needed and something to put it in the right place when you were adding to it. For the sake of ease, we're going to use a simple MySQL database.

In the following tutorial I'll show you a peek at the power of coupling GD with PHP to create a basic button. The GD extension is more or less an addon for PHP to allow for image manipulation and creation and has to be compiled in when you compile PHP and the rest of the software. The GD extensions currently support PNG and JPEG image formats, as GIF support was removed in version 1.6 because of legalities dealing with the GIF format. (A patch is available to restore this functionality.) The following tutorial will be using PNG format images (the images on this tutorial are saved in the GIF format, and are not dynamically created. Just for compatibility's sake). In using the GD extensions, they must be compiled with PHP if using on a unix platform, or the extension php*_gd.dll must be loaded on win32 platforms. The code can get a bit complicated and I'll assume you know some basics of PHP.

What is a cookie?

Sometimes it becomes necessary to track certain user details like (No. Of Visits, names, last visit, etc). The client machine stores such information and sends it to the web server whenever there is a request. Cookies data are sent along with the HTTP headers. You can look at this URL to know more about how they work. http:www.cookiecentral.comfaq

Difference between session and cookie?

The key difference would be cookies are stored in your hard disk whereas a session aren't stored in your hard disk. Sessions are basically like tokens, which are generated at authentication. A session is available as long as the browser is opened.

Sessions are popularly used, as the there is a chance of your cookies getting blocked if the user browser security setting is set high.

Note: When you issue a session_start() it generates a session ID and places that on the client side in a cookie. There are also some ways to avoid this using the tag rewrite.