Symfony is an object-oriented PHP5 framework based on the MVC model. Symfony allows for the separation of business rules, server logic and presentation views of a web application. It also contains numerous tools and classes aimed at shortening the development time of a complex web application.

A framework adds new mechanisms on top of a programming language, and these mechanisms automate many of the development patterns used for a given purpose. A framework also adds structure to the code, and pushes the developer to write better, more readable and maintainable code. A framework also makes programming easier, since it packages complex operations into simple statements.

A framework is usually developed with the same language that it extends. A PHP5 framework is a set of files written in PHP5.

A framework will add layering to an application. In general, they divide applications in three layers:

Web application frameworks intend to facilitate the development of… web applications (websites, Intranets, etc.). Building a basic dynamic website can be easily achieved with existing programming languages, and PHP is known for its simplicity and broadly adopted for that purpose. With PHP alone, you can already query a database, manage session cookies, access files in the server, etc. But when it comes to building a more complex website, where business logic increases the volume of code to maintain, the need of a web application framework arises.

Symfony is a complete framework designed to help and speedup the development of web applications.

It is based on the following concepts:

The main concept underlying the symfony framework is that the most common tasks are done automatically so that the developer can focus entirely on the specifics of an application. There is no need to reinvent the wheel every time a new web application is built.

To fulfill these requirements, symfony was written entirely in PHP5. It has been thoroughly tested in various real world projects, and is actually in use for high demand e-business websites. It is compatible with most of the available databases, among which:

The symfony object model relies on three distinct layers:

Common features of web projects are made easy since Symfony natively automates them:

In addition, to fulfill the requirements of enterprises having their own coding guidelines and project management rules, symfony can be entirely reconfigured using YAML configuration files. It provides by default, several development environments, and is bundled with tools to easily achieve the following operations:

Symfony uses some code fragments of other open source projects:

Whether you are a PHP5 expert or a beginner in web application programming doesn't matter. The main factor that should direct your decision is the size of your project.

If you want to develop a simple website with five to ten pages, having limited access to a database and no obligation for performance, availability or documentation, then you should stick with PHP alone. You wouldn't take much advantage of the features of a web application framework, and using object orientation or a MVC model would only slow down your development. Symfony is not optimized to run efficiently on a shared server with only CGI support.

On the other hand, if you develop bigger web applications, with a heavy business logic, PHP alone is not enough. If you plan to maintain or extend your application in the future, you will need your code to be lightweight, readable and effective. If you want to use the latest advances in user interaction (like AJAX) in an intuitive way, you can't just write hundreds of lines of JavaScript. If you want to have fun and develop fast, then PHP alone will probably be disappointing. For all these cases, symfony is made for you.

And of course, if you are a professional web developer, you already know all the benefits of web application frameworks, and you need one which is mature, well documented, and with a large community. Search no more, for symfony is your solution.

So far I have cut all PHP frameworks to three possibilities - PRADO, Symphony and Zend Framework. It's funny how all three of them while having the same outcome in mind, bring *totally* different approach to the problem and therefore deliver various products.

It looks like PRADO is strong in event/component approach, Zend in "doing the basics" and the rock-solid background of "The PHP Company", and Symphony? I like the admin-generation part of the software, it's probably the best of what you can find.

documented on: 2006-10-17, Michal Til