The Symfony Framework – Installation and Configuration

Wojciech Bancer

September 2015

 In this article by Wojciech Bancer, author of the book, Symfony2 Essentials, we will learn the basics of Symfony, its installation, configuration, and use. The Symfony framework is currently one of the most popular PHP frameworks existing within the PHP developer's environment. Version 2, which was released a few years ago, has been a great improvement, and in my opinion was one of the key elements for making the PHP ecosystem suitable for larger enterprise projects. The framework version 2.0 not only required the modern PHP version (minimal version required for Symfony is PHP 5.3.8), but also uses state-of-the-art technology — namespaces and anonymous functions. Authors also put a lot of efforts to provide long term support and to minimize changes, which break the compatibility between versions. Also, Symfony forced developers to use a few useful design concepts. The key one, introduced in Symfony, was DependencyInjection.

(For more resources related to this topic, see here.)

In most cases, the article will refer to the framework as Symfony2. If you want to look over the Internet or Google about this framework, apart from using Symfony keyword you may also try to use the Symfony2 keyword. This was the way recommended some time ago by one of the creators to make searching or referencing to the specific framework version easier in future.

Key reasons to choose Symfony2

Symfony2 is recognized in the PHP ecosystem as a very well-written and well-maintained framework. Design patterns that are recommended and forced within the framework allow work to be more efficient in the group, this allows better tests and the creation of reusable code.

Symfony's knowledge can also be verified through a certificate system, and this allows its developers to be easily found and be more recognized on the market. Last but not least, the Symfony2 components are used as parts of other projects, for example, look at the following:

  • Drupal
  • phpBB
  • Laravel
  • eZ Publish and more

Over time, there is a good chance that you will find the parts of the Symfony2 components within other open source solutions.

Bundles and extendable architecture are also some of the key Symfony2 features.

They not only allow you to make your work easier through the easy development of reusable code, but also allows you to find smaller or larger pieces of code that you can embed and use within your project to speed up and make your work faster.

The standards of Symfony2 also make it easier to catch errors and to write high-quality code; its community is growing every year.

The history of Symfony

There are many Symfony versions around, and it's good to know the differences between them to learn how the framework was evolving during these years. The first stable Symfony version — 1.0 — was released in the beginning of 2007 and was supported for three years. In mid-2008, version 1.1 was presented, which wasn't compatible with the previous release, and it was difficult to upgrade any old project to this.

Symfony 1.2 version was released shortly after this, at the end of 2008. Migrating between these versions was much easier, and there were no dramatic changes in the structure. The final versions of Symfony 1's legacy family was released nearly one year later. Simultaneously, there were two version releases, 1.3 and 1.4. Both were identical, but Symfony 1.4 did not have deprecated features, and it was recommended to start new projects with it. Version 1.4 had 3 years of support.

If you look into the code, version 1.x was very different from version 2. The company that was behind Symfony (the French company, SensioLabs) made a bold move and decided to rewrite the whole framework from scratch.

The first release of Symfony2 wasn't perfect, but it was very promising. It relied on Git submodules (the composer did not exist back then). The 2.1 and 2.2 versions were closer to the one we use now, although it required a lot of effort to migrate to the upper level. Finally, the Symfony 2.3 was released — the first long-term support version within the 2.x branch. After this version, the changes provided within the next major versions (2.4, 2.5, and 2.6) are not so drastic and usually they do not break compatibility.

This article was written based on the latest stable Symfony 2.7.4 version and was tested with PHP 5.5). This Symfony version is marked as the so called long-term support version, and updates for it will be released for 3 years since the first 2.7 version release.

Installation

Prior to installing Symfony2, you don't need to have a configured web server. If you have at least PHP version 5.4, you can use the standalone server provided by Symfony2. This server is suitable for development purposes and should not be used for production. It is strongly recommend to work with a Linux/UNIX system for both development and production deployment of Symfony2 framework applications. While it is possible to install and operate on a Windows box, due to its different nature, working with Windows can sometimes force you to maintain a separate fragment of code for this system.

Even if your primary OS is Windows, it is strongly recommended to configure Linux system in a virtual environment. Also, there are solutions that will help you in automating the whole process. As an example, see more on https://www.vagrantup.com/ website.

To install Symfony2, you can use a few methods as follows:

  • Use a new Symfony2 installer script (currently, the only officially recommended). Please note that installer requires at least PHP 5.4.
  • Use a composer dependency manager to install a Symfony project.
  • Download a zip or tgz package and unpack it.
  • It does not really matter which method you choose, as they all give you similar results.

Installing Symfony2 by using an installer

To install Symfony2 through an installer, go to the Symfony website at http://symfony.com/download, and install the Symfony2 installer by issuing the following commands:

$ sudo curl -LsS http://symfony.com/installer -o /usr/local/bin/symfony
$ sudo chmod +x /usr/local/bin/symfony

After this, you can install Symfony by just typing the following command:

$ symfony new <new_project_folder>

To install the Symfony2 framework for a to-do application, execute the following command:

$ symfony new <new_project_folder>

This command installs the latest Symfony2 stable version on the newly created todoapp folder, creates the Symfony2 application, and prepares some basic structure for you to work with.

After the app creation, you can verify that your local PHP is properly configured for Symfony2 by typing the following command:

$ php app/check.php

If everything goes fine, the script should complete with the following message:

[OK]
Your system is ready to run Symfony projects

Symfony2 is equipped with a standalone server. It makes development easier. If you want to run this, type the following command:

$ php app/console server:run

If everything went alright, you will see a message that your server is working on the IP 127.0.0.1 and port 8000. If there is an error, make sure you are not running anything else that is listening on port 8000. It is also possible to run the server on a different port or IP, if you have such a requirement, by adding the address and port as a parameter, that is:

$ php app/console server:run 127.0.0.1:8080

If everything works, you can now type the following:

http://127.0.0.1:8000/

Now, you will visit Symfony's welcome page.

This page presents you with a nice welcome information and useful documentation link.

The Symfony2 directory structure

Let's dive in to the initial directory structure within the typical Symfony application. Here it is:

  • app
  • bin
  • src
  • vendor
  • web

While Symfony2 is very flexible in terms of directory structure, it is recommended to keep the basic structure mentioned earlier.

The following table describes their purpose:

Directory

Used for

app

This holds information about general configuration, routing, security configuration, database parameters, and many others. It is also the recommended place for putting new view files. This directory is a starting point.

bin

It holds some helper executables. It is not really important during the development process, and rarely modified.

src

This directory holds the project PHP code (usually your bundles).

vendor

These are third-party libraries used within the project. Usually, this directory contains all the open source third-party bundles, libraries, and other resources. It's worth to mention that it's recommended to keep the files within this directory outside the versioning system. It means that you should not modify them under any circumstances. Fortunately, there are ways to modify the code, if it suits your needs more. This will be demonstrated when we implement user management within our to-do application.

web

This is the directory that is accessible through the web server. It holds the main entry point to the application (usually the app.php and app_dev.php files), CSS files, JavaScript files, and all the files that need to be available through the web server (user uploadable files).

So, in most cases, you will be usually modifying and creating the PHP files within the src/ directory, the view and configuration files within the app/ directory, and the JS/CSS files within the web/ directory.

The main directory also holds a few files as follows:

  • .gitignore
  • README.md
  • composer.json
  • composer.lock

The .gitignore file's purpose is to provide some preconfigured settings for the Git repository, while the composer.json and composer.lock files are the files used by the composer dependency manager.

What is a bundle?

Within the Symfony2 application, you will be using the "bundle" term quite often. Bundle is something similar to plugins. So it can literally hold any code controllers, views, models, and services. A bundle can integrate other non-Symfony2 libraries and hold some JavaScript/CSS code as well. We can say that almost everything is a bundle in Symfony2; even some of the core framework features together form a bundle. A bundle usually implements a single feature or functionality. The code you are writing when you write a Symfony2 application is also a bundle.

There are two types of bundles. The first kind of bundle is the one you write within the application, which is project-specific and not reusable. For this purpose, there is a special bundle called AppBundle created for you when you install the Symfony2 project.

Also, there are reusable bundles that are shared across the various projects either written by you, your team, or provided by a third-party vendors. Your own bundles are usually stored within the src/ directory, while the third-party bundles sit within the vendor/ directory.

The vendor directory is used to store third-party libraries and is managed by the composer. As such, it should never be modified by you.

There are many reusable open source bundles, which help you to implement various features within the application. You can find many of them to help you with User Management, writing RESTful APIs, making better documentation, connecting to Facebook and AWS, and even generating a whole admin panel. There are tons of bundles, and everyday brings new ones.

If you want to explore open source bundles, and want to look around what's available, I recommend you to start with the http://knpbundles.com/ website.

The bundle name is correlated with the PHP namespace. As such, it needs to follow some technical rules, and it needs to end with the Bundle suffix. A few examples of correct names are AppBundle and AcmeDemoBundle, CompanyBlogBundle or CompanySocialForumBundle, and so on.

Composer

Symfony2 is built based on components, and it would be very difficult to manage the dependencies between them and the framework without a dependency manager. To make installing and managing these components easier, Symfony2 uses a manager called composer.

You can get it from the https://getcomposer.org/ website. The composer makes it easy to install and check all dependencies, download them, and integrate them to your work. If you want to find additional packages that can be installed with the composer, you should visit https://packagist.org/. This site is the main composer repository, and contains information about most of the packages that are installable with the composer.

To install the composer, go to https://getcomposer.org/download/ and see the download instruction. The download instruction should be similar to the following:

$ curl -sS https://getcomposer.org/installer | php

If the download was successful, you should see the composer.phar file in your directory. Move this to the project location in the same place where you have the composer.json and composer.lock files. You can also install it globally, if you prefer to, with these two commands:

$ curl -sS https://getcomposer.org/installer | php
$ sudo mv composer.phar /usr/local/bin/composer

You will usually need to use only three composer commands: require, install, and update.

The require command is executed when you need to add a new dependency. The install command is used to install the package. The update command is used when you need to fetch the latest version of your dependencies as specified within the JSON file.

The difference between install and update is subtle, but very important. If you are executing the update command, your composer.lock file gets updated with the version of the code you just fetched and downloaded. The install command uses the information stored in the composer.lock file and the fetch version stored in this file.

When to use install? For example, if you deploy the code to the server, you should use install rather than update, as it will deploy the version of the code stored in composer.lock, rather than download the latest version (which may be untested by you). Also, if you work in a team and you just got an update through Git, you should use install to fetch the vendor code updated by other developers.

You should use the update command if you want to check whether there is an updated version of the package you have installed, that is, whether a new minor version of Symfony2 will be released, then the update command will fetch everything.

As an example, let's install one extra package for user management called FOSUserBundle (FOS is a shortcut of Friends of Symfony). We will only install it here; we will not configure it.

To install FOSUserBundle, we need to know the correct package name and version. The easiest way is to look in the packagist site at https://packagist.org/ and search for the package there. If you type fosuserbundle, the search should return a package called friendsofsymfony/user-bundle as one of the top results. The download counts visible on the right-hand side might be also helpful in determining how popular the bundle is.

If you click on this, you will end up on the page with the detailed information about that bundle, such as homepage, versions, and requirements of the package.

Type the following command:

$ php composer.phar require friendsofsymfony/user-bundle ^1.3
Using version ^1.3 for friendsofsymfony/user-bundle
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
- Installing friendsofsymfony/user-bundle (v1.3.6)
   Loading from cache

friendsofsymfony/user-bundle suggests installing willdurand/propel-typehintable-behavior (Needed when using the propel implementation)
Writing lock file
Generating autoload files
...

Which version of the package you choose is up to you. If you are interested in package versioning standards, see the composer website at https://getcomposer.org/doc/01-basic-usage.md#package-versions to get more information on it.

The composer holds all the configurable information about dependencies and where to install them in a special JSON file called composer.json. Let's take a look at this:

{
"name": "wbancer/todoapp",
"license": "proprietary",
"type": "project",
"autoload": {
"psr-0": {
   "": "src/",
   "SymfonyStandard": "app/SymfonyStandard/"
}
},
"require": {
"php": ">=5.3.9",
"symfony/symfony": "2.7.*",
"doctrine/orm": "~2.2,>=2.2.3,<2.5",
// [...]
"incenteev/composer-parameter-handler": "~2.0",
"friendsofsymfony/user-bundle": "^1.3"
},
"require-dev": {
"sensio/generator-bundle": "~2.3"
},
"scripts": {
"post-root-package-install": [
"SymfonyStandard\\Composer::hookRootPackageInstall"
],
"post-install-cmd": [
// post installation steps
],
"post-update-cmd": [
// post update steps
]
},
"config": {
"bin-dir": "bin"
},
"extra": {
// [...]
}
}

The most important section is the one with the require key. It holds all the information about the packages we want to use within the project. The key scripts contain a set of instructions to run post-install and post-update. The extra key in this case contains some settings specific to the Symfony2 framework. Note that one of the values in here points out to the parameter.yml file. This file is the main file holding the custom machine-specific parameters. The meaning of the other keys is rather obvious.

If you look into the vendor/ directory, you will notice that our package has been installed in the vendor/friendsofsymfony/user-bundle directory.

The configuration files

Each application has a need to hold some global and machine-specific parameters and configurations. Symfony2 holds configuration within the app/config directory and it is split into a few files as follows:

  • config.yml
  • config_dev.yml
  • config_prod.yml
  • config_test.yml
  • parameters.yml
  • parameters.yml.dist
  • routing.yml
  • routing_dev.yml
  • security.yml
  • services.yml

All the files except the parameters.yml* files contain global configuration, while the parameters.yml file holds machine-specific information such as database host, database name, user, password, and SMTP configuration.

The default configuration file generated by the new Symfony command will be similar to the following one.

This file is auto-generated during the composer install:

parameters:
   database_driver: pdo_mysql
   database_host: 127.0.0.1
   database_port: null
   database_name: symfony
   database_user: root
   database_password: null
   mailer_transport: smtp
   mailer_host: 127.0.0.1
   mailer_user: null
   mailer_password: null
   secret: 93b0eebeffd9e229701f74597e10f8ecf4d94d7f

As you can see, it mostly holds the parameters related to database, SMTP, locale settings, and secret key that are used internally by Symfony2. Here, you can add your custom parameters using the same syntax. It is a good practice to keep machine-specific data such as passwords, tokens, api-keys, and access keys within this file only. Putting passwords in the general config.yml file is considered as a security risk bug.

The global configuration file (config.yml) is split into a few other files called routing*.yml that contain information about routing on the development and production configuration. The file called as security.yml holds information related to authentication and securing the application access. Note that some files contains information for development, production, or test mode. You can define your mode when you run Symfony through the command-line console and when you run it through the web server. In most cases, while developing you will be using the dev mode.

The Symfony2 console

To finish, let's take a look at the Symfony console script. We used it before to fire up the development server, but it offers more. Execute the following:

$ php app/console

You will see a list of supported commands. Each command has a short description. Each of the standard commands come with help, so I will not be describing each of them here, but it is worth to mention a few commonly used ones:

Command

Description

app/console: cache:clear

Symfony in production uses a lot of caching. Therefore, if you need to change values within a template (twig) or within configuration files while in production mode, you will need to clear the cache. Cache is also one of the reasons why it's worth to work in the development mode.

app/console container:debug

Displays all configured public services

app/console router:debug

Displays all routing configuration along with method, scheme, host, and path.

app/console security:check

Checks your composer and packages version against known security vulnerabilities. You should run this command regularly.

Summary

In this article, we have demonstrated how to use the Symfony2 installer, test the configuration, run the deployment server, and play around with the Symfony2 command line. We have also installed the composer and learned how to install a package using it.

To demonstrate how Symfony2 enables you to make web applications faster, we will try to learn through examples that can be found in real life. To make this task easier, we will try to produce a real to-do web application with modern look and a few working features.

In case you are interested in knowing other Symfony books that Packt has in store for you, here is the link:

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