On SitePoint.com today there's a new tutorial showing how to create a random number generator in PHP (with the help of methods like mt_rand and mt_srand).

Computers cannot generate random numbers. A machine which works in ones and zeros is unable to magically invent its own stream of random data. However, computers can implement mathematical algorithms which produce pseudo-random numbers. They look like random numbers. They feel like random distributions. But they're fake; the same sequence of digits is generated if you run the algorithm twice.

Included in the post is code showing how to use the random functions and how to create a class (Random) that provides a few methods to help make generation easier - "seed" and "num". It first calls "seed" with a number to start the random generator off with and then "num" in a loop to pull out random values based on that.

On PHPMaster.com today there's a new tutorial about using a feature in the upcoming PHP release (5.4) to make it easier to work with more modular code - using traits.

In this article I will discuss traits, a new feature introduced in PHP 5.4 to overcome [issues where multiple inheritance is needed]. The concept of traits itself is nothing new to programming and is used in other languages like Scala and Perl. They allows us to horizontally reuse code across independent classes in different class hierarchies.

Included in the post is example code showing what the use of a trait looks like and a method for creating a Singleton that can spawn instances of two classes. Also included are examples of:

• using multiple traits at once,
• traits made up of traits,
• the importance of order,
• aliasing to avoid conflicts,
• reflection
• and a few other features that come along with their use.

Continuing on from the first part of their tutorial series about creating a simple ad tracker for your web application, Developer Drive is back with part two, a more in-depth look at the actual object design and code.

In our last PHP Ad Tracker lesson, we constructed the database tables for our ad banner application. Now we are ready to construct the data object that will hold the variables and functions that will display, add, edit and delete the data in those tables.

They cover each of the variables they'll be using with a summary of what they're used for as well as the various functions to be defined and what they'll return. Following this, they get into the actual development - creating an "ads" class and defining the methods to get the current ad count, get the number of clients and pull the actual client/ad data.

In a recent post to his blog, Gonzalo Ayuso shares a few tips on preventing SQL injection attacks on your applications.

Security is a part of our work as developers. We need to ensure our applications against malicious attacks. SQL Injection is one of the most common possible attacks. Basically SQL Injection is one kind of attack that happens when someone injects SQL statements in our application. You can find a lot of info about SQL Injection attack. Basically you need to follow the security golden rule: "Filter input, Escape output".

He advocates the use of the PDO abstraction layer to filter out a lot of the issues. Using its prepared statements, you can easily strip out things that just adding slashes to user input wouldn't prevent. He also includes a reminder about database permissions - allowing only certain users the ability to, for example, delete can help provide one more level of security (in other words, don't use a "super user" in production).

Following up on their previous look at the component architecture of the Yii framework, PHPMaster has posted this new tutorial showing how the framework allows you to do some event-based programming.

An application event is something that occurs which might be of interest to other bits of code. A standard event in most GUI applications would be a "click" event, but the sky's the limit and what events you define is really up to you. [...] The details can be provided by application-specific modules allowing you to keep individual requirements separate from your reusable code. Events allow you to attach a potentially unlimited amount of functionality without changing your core modules and components.

In his example, he shows how to create an event handler that is triggered when the user registers on the site. This event (CEvent) is then registered with the system and is attached via a call in the controller's "init" method.

On the NetTuts.com site there's a new tutorial showing you how to introduce the Memcached tool to your application - a quick and easy way to cache data and optimize performance.

Your latest PHP/MySQL website is finally online. And it's awesome. But it's not as fast as you want it to be, because of the many SQL queries running every time a page is generated. And above that, you have the feeling it will not scale well under heavy loads. And you are most likely right. In this tutorial, we will see how you can greatly improve your website's responsiveness [...] by implementing a cache layer between your code and your database. The good news is it is fairly easy, and can be done in a few minutes!

They help you get the memcached server installed (a one-liner in most linux distributions) and how to install the memcached extension using PECL. Code is included showing you how to connect to the server, store data into the cache based on a generated key and how to pull the same data back out.

In a new tutorial today from PHPMaster.com, they show you how to combine Javascript and a PHP feature to track the progress of an upload to your web application.

A problem that has plagued web developers for years is how to add real-time information to their applications, such as a progress bar for file uploads. [...] JavaScript can access a file's name, type, and even the width and height of a local image, but it wasn't until HTML5 that it could access a file's size. [...] In this article I'll show you how [the session.upload_progress] feature can be used to create a simple upload progress bar without any external libraries or browser dependencies.

The tutorial provides all the steps you'll need to get it working - defining the form with the extra required field, styling it and plugging the Javascript in to call a small script to get the progress of the upload. It returns the difference between the content-length of the file and the current size (as a percentage of 100).

Artur Ejsmont has a recent post to his blog showing how to get a MongoDB PECL extension to compile in a 32bit OSX environment (Snow Leopard).

Here is a quick step by step guide on how to get mongodb and PHP5.2 mongo pecl extension going on your MacOSX in 32bit mode! NOTE: 32 bit mongodb binaries have 2GB address space limit so you wont be able to process too much on your laptop. You will still be able to code and connect to remote instances just fine.

His process includes five steps - well, eight if you count the optional "install MongoDB" ones too - complete with the commands you'll need to get things compiled, ready for copy and paste. You can find the MongoDB PECL package here.

Jeremy Cook is back with the next part of his series looking at the handy features PHP's SPL provides. In this new post he looks at the ArrayAccess interface and how it can make your data more accessible to PHP's own array handing functions.

ArrayAccess allows you to treat an object that implements it as if it is an array for the purposes of setting, unsetting and retrieving data from it. Please note the emphasis in the last sentence! ArrayAccess does not make an object behave like an array in any other way. If you pass an object that implements ArrayAccess to a PHP array function such as in_array() you'll still get an error. This will become a little clearer with some of the examples below.

He shows what you'll need to use this interface in your class - implementing the interface and defining a set of four methods to get/set and check for the value in your array. He includes a practical example of pulling data back from an API and wrapping it in a class to make accessing it simpler (also implementing the Countable interface as well, see the previous post for more on that). Code is include to illustrate how it can be used.

On the Script-Tutorials.com site today there's a new tutorial about form validation using a combination of jQuery on the frontend and PHP on the backend.

In this tutorial, I will show you how to create an attractive, pleasant to look form for your website and then I will explain you how to dynamically validate them using Javascript. We'll also cover server-side validation with PHP to make everything 100% safe. This tutorial will help you to add more functionality to your forms which leads to better user experience and better quality of your website.

His sample form (name, password, email and gender) is made from some pretty simple HTML markup. The real trick comes with the jQuery validation on each field handled in an onKeyUp. Included are both a "password strength" method and an email validation method to check the format of the address. Errored fields have their background color changed to indicate that they've failed and some basic validation (length, password match, etc.) are also included. The PHP does much of the same validation once the form is posted and returns any error messages that might have come up.

You can download the code or try out a live demo to see the scripts together in action.