Rafael Dohms has an interesting new post to his site today looking at a library he's developed (inspired by the Symfony Validation library) to help filtering values with rules defined in annotations.

PHP does not have native Annotations support, however many projects have been using doc blocks to add value and semantics to code, like PHPUnit, Doctrine and Symfony. The Doctrine did a really good job in making available a Annotation parser kit, which allows you to bring the power of annotations into you own project. This opens up a few possibilities.

He shows the current use of the Validation library with a sample check of a $name variable for "not blank". His tool, DMS, extends this functionality and gives you access to both custom filtering methods and standard PHP functions to filter the resulting variable value. He includes an example showing two variables with filters StripTags, StripNewlines and Trim as well as the code to execute the filtering. You can get the library either ready to integrate with Symfony/Doctrine or as a standalone tool.

In this post to his blog Trevor Morris talks about his own introduction to the Fuel framework and some of his investigation into working with its forms support and validating the user input that comes from them.

I have been working on developing a website with the newest PHP framework on the block - Fuel, which describes itself as "a simple, flexible, community driven PHP 5.3 web framework based on the best ideas of other frameworks with a fresh start". [...] Although Fuel is a new framework, it borrows a lot of ideas from two very popular PHP frameworks, CodeIgniter and Kohana.

He starts off with one concern, a lack of documentation around some things that made it difficult for him to work with the HTML form helpers. He includes an example code snippet to show a basic email form field generation. Behind the scenes, he shows how to use the Validation library to add rules on the fields and check for a pass/fail status on the fields.

Shameer Chamal has a quick tutorial posted to his blog today showing how you can create a basic ajax validation feature for your Kohana-based web application.

If you are new to Kohana framework, implementing validation will be an adventure, especially if you are looking for ajax validation. In this article I will present a simple way to implement some necessary validations using ajax in a sign up form.

He starts with a simple view containing the login form and including a few extra files (like the Javascript helper for the validation). Next he creates the user model that will do the backend check to see if the user already exists. Finally the controller and Javascript are created to bring all the pieces together. The Javascript uses the jQuery framework to make things a bit more convenient and runs a check against the backend for the given username with the response returned as a JSON message.

On PHPBuilder.com there's a new article showing you how to create a dynamic username validator with the combination of PHP, MySQL and jQuery to do some of the front end work.

One of the easiest ways to streamline the registration process is by providing the user with real-time feedback regarding username availability. This is accomplished by monitoring the registration form's username field and immediately following the user's completion of this field, rather than waiting for the user to complete all fields and submit the form. Although a seemingly complex feature, it's actually easily accomplished thanks to the powerful jQuery library.

His scripts bases its checking on an "accounts" table that holds the username and password. The javascript (jQuery) handles the "blur" event on the username text field in the form and runs a check against a backend script to see if that username exists in the database (bound parameters used for helping to prevent SQL injections).

In a new post to his blog Chris Roane looks at a method for some advanced form validation using both server-side and client-side validation (with the help of jQuery).

Last year I wrote an article in how to implement basic validation for a form with PHP. I decided to re-look at this and improve what I did in that article. This time we are going to make a more advanced PHP form that is more responsive and effective. This PHP sample code has many advantages over the previous article. Not only that, but for the most part it is easier to implement with more complexed forms where you need more than basic validation.

He uses PHP5, jQuery and a helpful validation plugin than handles a lot of the heavy lifting for you in defining a validate() method with the field names and checks to perform on them. You just apply this to the form and it works like magic. Don't forget the backend though - he includes code to check for things like values being set and specific checks on a few fields.

In a new post to his blog Brandon Savage talks about how some of your current validation rules (and restrictions on input values) could be causing blind spots in your application that you don't even know are an issue.

Our blind spots about validation can and do harm real users if they're poorly or incompletely thought out. What might seem like a completely rational limit to us might hurt a real user who needs to exceed that limit, through no fault of their own. How many women are "BETTYJEAN" because their first name "can't" have a space in it?

He makes a few suggestions developers can do to help the situation and get their current project's validation back out into 20-20 vision:

• Accept valid data in any form provided by the user.
• Where possible, use well-developed validation libraries.
• Do not place artificial limits on valid data.
• Do place valid limits on specific data.