 WebProWorld Dev Forum |
Server woes
Well I’m looking for a new server for my personal business that is about to launch but weighing the pros and cons I will require mass storage down the road but it will cost more to implicate it later so right now I’m looking at the Vision 4U 4TB NAS Enterprise Server Running
Instant Messenger as Communication?
There is an ongoing debate in our office about the use of Instant Messenger as a form of legitimate, useful, appropriate, and professional communication. In the last week, I've been contacted by two potential affiliates who wished to communicate via IM.
Blocking websites without a server
I've been working at a high school and we're dealing with a problem. Our students are spending important time playing online games and using AIM through the web. We'd like to block certain sites, but we do not have a server. Does anyone have any suggestions on blocking certain websites?
|
|
|
|
Time is money. Network Failures can be costly. Use IPCheck Server Monitor & PRTG Traffic Grapher to protect your business before problems get out of hand. Download them both today!
|
Recent Articles |
PHP to HTML – Getting Dynamic Pages Indexed
Most will agree Php has become the common language for creating dynamic Websites. Although the language is simple and efficient, developers are finding trouble getting traffic to their Php site.
Do-It-Yourself Usability Testing: Your Questions Answered
So, if you have followed all of our Usability articles, outlining how to create useful content, layout, and navigation, then you may feel your website is set and ready and usable. WRONG! Well, it may be usable, but how do you know for sure? Many top companies spend thousands of dollars to design their websites and then never even actually look at them themselves to see how usable they are.
Website Content Usability
In recent articles we have discussed the importance of layout and navigation in creating a website with a high usability rating. However, all the best navigation in the world will do you no good if your visitors are navigating around bad content. Beauty may be skin deep, but usability isn't just about looking good.
Developing Your Site for Performance : Compression and Other Server-Side Enhancements
This is the fifth part of a five part article. Read part four here. While our twenty tips for code optimization in Part I began with the developer's source code, our discussion of cache control in Part II led us steadily towards the server-side in our quest for maximum Web site performance.
Developing Your Site for Performance : Optimal Cache Control
Now that our code has been optimized in order to send as little data as possible, in Part II, we will focus primarily on sending that data as infrequently as possible by means of better utilization of caching on the Web.
Developing Your Site For Performance : JavaScript/File-Related Optimization
More and more sites rely on JavaScript to provide navigational menus, form validation, and a variety of other useful things. Not surprisingly, much of this code is quite bulky and begs for optimization.
Developing Your Site For Performance : Markup/CSS Optimization
Typical markup is either very tight, hand-crafted and standards-focused, filled with comments and formatting white space, or it is bulky, editor-generated markup with excessive indenting, editor-specific comments often used as control structures, and even redundant or needless markup or code.
Developing Your Site for Performance : Client-Side Code Optimization
Let's begin by taking a look at client-side code optimization -- the easiest and generally cheapest to implement of the three site acceleration techniques.
Track Your Visitors, Using PHP
There are many different traffic analysis tools, ranging from simple counters to complete traffic analyzers. Although there are some free ones, most of them come with a price tag. Why not do it yourself?
Why Guerrilla Consultants Need Great Web Sites
In a world where anyone can access the archives of the Smithsonian Institute with a click of the mouse, potential clients will not be satisfied if a consultant's Web site turns up nothing but marketing babble. Clients come to your web site for one reason: to solve a problem. They expect your site to look professional, be easy to navigate, and offer content that helps them understand how you can help them.
|
|
 |
| 01.19.05
PHP And Cookies; A Good Mix!
 By Dennis Pallett
Cookies have long been used in PHP scripts, and are a very useful function. But what exactly are cookies? Maybe you have used then, but you still don't know exactly what they are. Or you are completely new to cookies?
It doesn't matter, because in this tutorial I will show you exactly what cookies are, and what they are used for.
Cookies in a nutshell
Cookies are small pieces of information that is stored on the computer of your visitors. Each browser handles it differently, but most simply store the information in a small text file. Internet Explorer has a special folder, which can be found in your C:\Windows or C:\Windows\System32 folder. You can delete all your cookies, by going to the Options and 'Clearing Cookies' or deleting them by hand. I don't recommend this though.
Almost every website uses cookies. If you go to Amazon.com, you will get several cookies. The same goes for CNN.com. Even Google uses cookies! They are extremely useful for (temporarily) storing information. For example, if you have a login system for your visitors, you could save their userid and password (very heavily encrypted!) so they are automatically logged in the next time they visit your website.
Or you could remember their last visit, and highlight everything that is new. And that's just the beginning.
 Using Cookies
Using cookies in PHP is extremely easy. In fact, there is nothing to it, because of PHP's inbuilt setcookie() function (http://php.net/setcookie). Have a look at the documentation, and then try the following example:
<?php
// Set a cookie
// Cookie name: name
// Cookie value: Dennis Pallett
// Cookie expire: in 24 hours
setcookie ('name', 'Dennis Pallett', time() + (60*60*24));
?>
If you run the code above, then a cookie will be set. That's all. The cookie name and value are pretty obvious. The cookie expire is when the cookie expires, or goes away. Simply use the time() function (http://php.net/time) and add the number of seconds you want to have the cookie available to it. In the example I added 60*60*24=86400 seconds, or 24 hours.
If you have looked at the documentation, you probably noticed there are additional arguments. As the documentation says, the path is to limit a cookie to a specific path on your web server. This is often used when you run multiple instances of the same script in separate directories. You can safely omit this argument when it doesn't matter if the cookie is available site-wide.
There is also the domain argument. This can be used to limit the cookie to a specific sub-domain, e.g. test.example.com. You can also safely ignore this argument, or set it to .example.com (note the beginning period, this is essential!).
Finally, there is also the secure argument. This argument is only used for cookies that are sent over a secure HTTPS connection (SSL). Just ignore this argument, unless you're working with a secure connection.
One thing that should be mentioned is that cookies must be set, before you display any HTML/text. It's probably best if you turn on output buffering by putting ob_start() (http://php.net/ob_start) at the top of your page.
Now that you have set a cookie, you probably want to retrieve the value as well. After all, that is the whole point of using cookies. Thankfully, as PHP is ever so easy, you can retrieve the same way as you retrieve a GET value. See the following example to retrieve the value of the previous example:
<?php
echo 'Your name is ' . $_COOKIE['name'];
?>
This should print "Your name is Dennis Pallett". There's nothing more to it. It's just that easy!
Finally, one thing you probably want to do as well is remove cookies. This is as easy as setting them. Simply change the value of the cookie to FALSE, and change the expire date to -3000 seconds. See the following example:
<?php
setcookie ('name', FALSE, time()-1000);
?>
Checking if cookies are enabled
Before you start using cookies, you must make sure your visitor has cookies enabled. This can be done with a simply PHP checking script. Unfortunately, the PHP page needs to reload to check for cookies. But this can be done very transparently, and your visitor should hardly notice anything.
The following example will first set a test cookie, then reload the page, and finally check whether cookies are enabled.
<?php
error_reporting (E_ALL ^ E_WARNING ^ E_NOTICE);
// Check if cookie has been set or not
if ($_GET['set'] != 'yes') {
// Set cookie
setcookie ('test', 'test', time() + 60);
// Reload page
header ("Location: checkcookies.php?set=yes");
} else {
// Check if cookie exists
if (!empty($_COOKIE['test'])) {
echo "Cookies are enabled on your browser";
} else {
echo "Cookies are NOT enabled on your browser";
}
}
?>
Run the code above, and see what the output is. Check if cookies are enabled in your browser. If they're not enabled, then you can enable them by going to your browser's options. Unfortunately, this is different from each browser, so I can't give you exact instructions. But Google can.
Storing Arrays
One feature of cookies that is often missed in articles is the ability to story arrays. Cookies can be used to store multi-dimensional arrays, which can be extremely useful to store data.
Consider the following code;
<?php
setcookie ("name[first]", "Dennis", time() + (60*60*24));
setcookie ("name[last]", "Pallett", time() + (60*60*24));
?>
You can then display these two cookies using the following code:
?php
echo "First Name: " . $_COOKIE['name']['first'];
echo "
Last Name: " . $_COOKIE['name']['last'];
?
The cookie 'name' is an array, and has multiple values. You can even go deeper and have multi-dimensional arrays, e.g. $_COOKIE['name']['test']['something']['value']. You could store whole arrays of data in cookies. But beware that you don't store too much data, there are certain size limits to cookies.
| Time is money. Network Failures can be costly. Use IPCheck Server Monitor & PRTG Traffic Grapher to protect your business before problems get out of hand. Download them both today! |
|
In Conclusion...
Cookies are really versatile, and can be used for a lot of different purposes. Many websites use cookies, and cookies can really make your website more personalized. Using cookies in PHP isn't hard at all, and you should be able to use them without any difficulty.
Before actively using cookies in your website, you must check whether the visitor has enabled them in their browser. If they don't have cookies enabled, you must either redirect to a non-cookies version of your website, or you can make sure your website also works without cookies.
You can download a sample script at http://www.phpit.net/, where cookies are used in a (somewhat) practical way. In this example, there is a logging module, called log.php and a display module, called history.php. Basically, you include the log.php in other PHP pages, and then you can view history.php to lookup all the pages you have viewed and how often. The example uses arrays, and stores them in cookies.
The examples in this article can be downloaded at http://www.phpit.net/.
If you have a really unique practical way of using cookies, please let me know at dennis [AT] nocertainty [DOT] com. I'd really like to hear about interesting ways of using cookies.
*Previously published at ArticleCity.com
About the Author:
Dennis Pallett is a young tech writer, with much experience in ASP, PHP and other web technologies. He enjoys writing, and has written several articles and tutorials. To find more of his work, look at his websites at http://www.phpit.net, http://www.aspit.net and http://www.ezfaqs.com. |
