1.1. Symfony in Brief

A framework streamlines application development by automating many of the patterns employed for a given purpose. A framework also adds structure to the code, prompting the developer to write better, more readable, and more maintainable code. Ultimately, a framework makes programming easier, since it packages complex operations into simple statements.

Symfony is a complete framework designed to optimize the development of web applications by way of several key features. For starters, it separates a web application's business rules, server logic, and presentation views. It contains numerous tools and classes aimed at shortening the development time of a complex web application. Additionally, it automates common tasks so that the developer can focus entirely on the specifics of an application. The end result of these advantages means there is no need to reinvent the wheel every time a new web application is built!

Symfony was written entirely in PHP 5. 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 engines, including MySQL, PostgreSQL, Oracle, and Microsoft SQL Server. It runs on *nix and Windows platforms. Let's begin with a closer look at its features.

1.1.1. Symfony Features

Symfony was built in order to fulfill the following requirements:

• Easy to install and configure on most platforms (and guaranteed to work on standard *nix and Windows platforms)
• Database engine-independent
• Simple to use, in most cases, but still flexible enough to adapt to complex cases
• Based on the premise of convention over configuration — the developer needs to configure only the unconventional
• Compliant with most web best practices and design patterns
• Enterprise-ready — adaptable to existing information technology (IT) policies and architectures, and stable enough for long-term projects
• Very readable code, with phpDocumentor comments, for easy maintenance
• Easy to extend, allowing for integration with other vendor libraries

1.1.1.1. Automated Web Project Features

Most of the common features of web projects are automated within symfony, as follows:

• The built-in internationalization layer allows for both data and interface translation, as well as content localization.
• The presentation uses templates and layouts that can be built by HTML designers without any knowledge of the framework. Helpers reduce the amount of presentation code to write by encapsulating large portions of code in simple function calls.
• Forms support automated validation and repopulation, and this ensures a good quality of data in the database and a better user experience.
• Output escaping protects applications from attacks via corrupted data.
• The cache management features reduce bandwidth usage and server load.
• Authentication and credential features facilitate the creation of restricted sections and user security management.
• Routing and smart URLs make the page address part of the interface and search-engine friendly.
• Built-in e-mail and API management features allow web applications to go beyond the classic browser interactions.
• Lists are more user-friendly thanks to automated pagination, sorting, and filtering.
• Factories, plug-ins, and mixins provide a high level of extensibility.
• Ajax interactions are easy to implement thanks to one-line helpers that encapsulate cross-browser-compatible JavaScript effects.

1.1.1.2. Development Environment and Tools

To fulfill the requirements of enterprises having their own coding guidelines and project management rules, symfony can be entirely customized. It provides, by default, several development environments and is bundled with multiple tools that automate common software-engineering tasks:

• The code-generation tools are great for prototyping and one-click back-end administration.
• The built-in unit and functional testing framework provides the perfect tools to allow test-driven development.
• The debug panel accelerates debugging by displaying all the information the developer needs on the page he's working on.
• The command-line interface automates application deployment between two servers.
• Live configuration changes are possible and effective.
• The logging features give administrators full details about an application's activities.

1.1.2. Who Made Symfony and Why?

The first version of symfony was released in October 2005 by project founder Fabien Potencier, coauthor of this book. Fabien is the CEO of Sensio (sensio.com), a French web agency well known for its innovative views on web development.

Back in 2003, Fabien spent some time inquiring about the existing open source development tools for web applications in PHP. He found that none fulfilled the previously described requirements. When PHP 5 was released, he decided that the available tools had reached a mature enough stage to be integrated into a full-featured framework. He subsequently spent a year developing the symfony core, basing his work on the Mojavi Model-View-Controller (MVC) framework, the Propel object-relational mapping (ORM), and the Ruby on Rails templating helpers.

Fabien originally built symfony for Sensio's projects, because having an effective framework at your disposal presents an ideal way to develop applications faster and more efficiently. It also makes web development more intuitive, and the resulting applications are more robust and easier to maintain. The framework entered the proving grounds when it was employed to build an e-commerce website for a lingerie retailer, and subsequently was applied to other projects.

After successfully using symfony for a few projects, Fabien decided to release it under an open source license. He did so to donate this work to the community, to benefit from user feedback, to showcase Sensio's experience, and because it's fun.

For symfony to be a successful open source project, it needed to have extensive documentation, in English, to increase the adoption rate. Fabien asked fellow Sensio employee François Zaninotto, the other author of this book, to dig into the code and write an online book about it. It took quite a while, but when the project was made public, it was documented well enough to appeal to numerous developers. The rest is history.

1.1.3. The Symfony Community

As soon as the symfony website (symfony-project.org) was launched, numerous developers from around the world downloaded and installed the framework, read the online documentation, and built their first application with symfony, and the buzz began to mount.

Web application frameworks were getting popular at that time, and the need for a full-featured framework in PHP was high. Symfony offered a compelling solution due to its impressive code quality and significant amount of documentation--two major advantages over the other players in the framework category. Contributors soon began to surface, proposing patches and enhancements, proofreading the documentation, and performing other much-needed roles.

The public source repository and ticketing system offer a variety of ways to contribute, and all volunteers are welcome. Fabien is still the main committer in the trunk of the source code repository, and guarantees the quality of the code.

Today, the symfony forum, mailing lists, and Internet Relay Chat (IRC) channel offer ideal support outlets, with seemingly each question getting an average of four answers. Newcomers install symfony every day, and the wiki and code snippets sections host a lot of user-contributed documentation. The number of known symfony applications increases by an average of five per week, and counting.

The symfony community is the third strength of the framework, and we hope that you will join it after reading this book.

1.1.4. Is Symfony for Me?

Whether you are a PHP 5 expert or a newcomer to web application programming, you will be able to use symfony. The main factor in deciding whether or not to do so is the size of your project.

If you want to develop a simple website with five to ten pages, limited access to a database, and no obligations to ensuring its performance or providing documentation, then you should stick with PHP alone. You wouldn't gain much from a web application framework, and using object orientation or an MVC model would likely only slow down your development process. As a side note, symfony is not optimized to run efficiently on a shared server where PHP scripts can run only in Common Gateway Interface (CGI) mode.

On the other hand, if you develop more complex web applications, with heavy business logic, PHP alone is not enough. If you plan on maintaining or extending 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. In all these cases, symfony is 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 that is mature, well documented, and has a large community. Search no more, for symfony is your solution.