Abhi’s Weblog

Getting started with Symfony - A PHP Framework - Part 1

Written on October 15, 2008 – 6:03 pm | by admin

Hello Friends,

Since past few weeks I have been pushed into something which I have never favored i.e. using a framework for my development. Using a framework can become even more harder if you know all the actual HTML, CSS, JS, PHP coding. Then you just wonder WHY? WHY? WHY?

Anyways I had to do it using Symfony PHP framework and there was no way out. As I couldn’t find much help outside http://symfony-project.com , it made even more difficult for me to implement and understand symfony.  So I thought of writing a tutorial, which can help many others like me out there and also act as a reference for me in future. Here instead of giving a theory lecture straight up, we will learn along with little hands-on developments.

Installation:
Before installing Symfony I assume we already have Apache, PHP 5 and MySQL installed on your system. If you don’t have them already installed, read this post of mine on how to configure WAMP on your windows. How to Install Apache, PHP 5 and MySQL on Windows?

This method works equally on Windows and Unix systems. On windows open your command line and on Unix open a terminal window.

1. Go to My Computer -> Right Click -> Click on Properties -> Advanced Tab -> Environment Variables -> Create a PATH variable if it doesn’t already exists -> Add C:\PHP\ as the PATH variable value.
2. Go to Start -> Run -> Type cmd -> Type C:\> pear channel-discover pear.symfony-project.com
3. Type C:\> pear install symfony/symfony-1.0.18 , it will install symfony latest stable version for you. (1.0 at the time of writing this tutorial)
4. If you are having trouble installing, post a message here or refer http://www.symfony-project.org/installation/1_0 for more details.

So now you have symfony framework installed and we will learn how to build our first project in symfony.

My first Project:
Before we go ahead in making our first php project using symfony, just a little theory without which its impossible to understand the flow. Symfony projects are designed as follows:

       My First Project –> Application 1 —-> Module 1
                                  |                              |
                                  |                              –> Module 2
                                  |
                                  -> Application 2 —-> Module 1
                                  |                              |
                                  |                              –> Module 2
                                  |                              |

                                  |                              –> Module 3
                                  |
                                  -> Application 3 —-> Module 1

So in your Project your can have multiple Applications and inside every application you can have multiple Modules.

1. Go to your Apache Web Folder (Document Root) which in my case is C:\Workspace.
2. Create a folder called Symfony. We will keep all our symfony related development work in this folder.
3. Go inside the folder C:\Workspace\Symfony and create another folder for our 1st project. Lets name it HelloWorld
4. Open your command line and go to the above folder path i.e. type ‘cd C:\Workspace\Symfony\HelloWorld’ on your command line.
5. Type ’symfony init-project HelloWorld’ and press enter. This will automatically create the project directory structure for you. Don’t be afraid if you see some 10 folders being create by the last command.

Don’t close the command line window, we will need that throughout.

So by now we have our first symfony project folder ready (structurally). But to view this on your browser we need atleast 1 application and atleast 1 module in that application. Lets create them quickly.

1. Type ’symfony init-app HelloWorld’ and press enter. This will create an application folder C:\Workspace\Symfony\HelloWorld\apps\HelloWorld. Now lets create a module inside this application
2. Type ’symfony init-module HelloWorld HelloWorld’ and press enter. This command means, create a module named HelloWorld inside application HelloWorld. Generic level syntax is ’symfony init-module [application] [module]’

So we have our first symfony project ready. Type http://localhost/Symfony/HelloWorld/web in your browser window and press enter. You will see a page like this:

Figure 1

But this is not what it should be. If you read the page, it says “If you see no image in this page, you may need to configure your web server so that it gains access to the symfony_data/web/sf directory”.

So all you need is to copy folder C:\php5\pear\data\symfony\web\sf (in my case) to C:\Workspace\Symfony\HelloWorld\web\sf. If you don’t find sf folder at the specified place, kindly search for it on your system. It was created when we were installing symfony.

After copying the folder refresh your web page again and see if you see any difference. For me it looks like:

Figure 2

Well Congratulations ! You just made your first symfony project. But unfortunately you know 0% of what did. Right? Lets understand what exactly is going in the background.

A bit about MVC Architecture:
Symfony follows MVC (Model-Viewer-Controller) Architecture to the core. If you haven’t worked with MVC architectural frameworks before, it can really take sometime to get a feel of it. I took about a week to actually understand what goes in the background.

MVC Architecture is nothing but breaking your whole page code into three parts namely Model (Database) , Viewer (Frontend HTML Pages) and Controller (Which fetches data from Model i.e. database and provide it in required format to Viewer i.e. what we finally see on our browsers). This is a very layman definition which I have given. We will slowly and gradually see each aspect of MVC in Symfony.

A bit about ORM (Object Relational Mapping):
This is yet another programming technique which you will find in each and every framework. In layman language, ORM provides you an object to handle your database. You need not write a SQL Query in actual at any point in your project. You will access all your database rows using this ORM Object.

Strange it may seem at first, but consider a big project running on MySQL with a lot of INSERT queries. Now at some point in time when database size reaches > 50 Gb or so and you are finding MySQL not efficient enough to handle such a large database, you would want to change to a database like Oracle. In such a scenario, ORM takes all the headache off from you, as you need not care about the actual SQL queries that goes in the background. ORM automatically takes care of this stuff.

Understanding Symfony Directory Structure:
The Symfony directory structure of our first project will look like this:

Figure 3

Remember we still don’t have anything dealing with the databases, hence I can say that Model layer is still missing from the directory structure. But let us first complete our targeted “Hello World” application.

1. Go to HelloWorld/apps/HelloWorld/config folder and open the file rounting.yml
2. Change the 4th line in that file from - param: { module: default, action: index } to param: { module: HelloWorld, action: index }
3. We will learn about all .yml files which you see, but as of now lets focus on what we just did. By default our Symfony project points to a default module created by Symfony. Thats why we see Figure 2 above. By changing the above piece of code, we are telling our HelloWorld application inside HelloWorld project that, by default point to my HelloWorld Module. Confusing! Read the last line again and continue reading
4. Go to HelloWorld/apps/HelloWorld/modules/HelloWorld/actions and open the file actions.class.php
5. Comment the following php code $this->forward(’default’, ‘module’); inside executeIndex() method.
6. Go back to your command line and type: ’symfony clear-cache’
7. Type http://localhost/Symfony/HelloWorld/web in your browser window and press enter.

Bingo! You see a blank white page. Lets understand what we actually did. But before that just a few points on how a page is actually displayed in Symfony.

1. When we type http://localhost/Symfony/HelloWorld/web in our browser, index.php in the web folder goes to routing.yml file
2. Routing file then tells which module to follow by default. By following Step 2 above, we directed the flow to our HelloWorld module.
3. Then flow goes to the actions.class.php file of the module provided by Routing file. Hence in our case it must have gone to actions.class.php file of HelloWorld module.
4. It looks for executeIndex() method in the class file, executes it and
5. Finally goes to indexSuccess.php file placed under the template folder of our HelloWorld Module.

But since our actions class method was already diverting the flow to the default module, flow won’t have come to step 5 above and would have gone to default symfony module. By commenting out the line in step 5 above, we actually skip this forwarding and the flow comes to indexSuccess.php file under templates module. And finally since indexSuccess.php file is a blank file, we see a blank page.

Read the above 2 point charts carefully. If you can understand this flow, you already conquered half the symfony.

Note: All this will go waste if you forget ’symfony clear-cache’ in step 6 above. As a rule of thumb, always run this command when ever you make any changes to any of the .yml files.

My First Project “HelloWorld”
Open indexSuccess.php and type <h1>Hello World</h1> into it. Run http://localhost/Symfony/HelloWorld/web in our browser, and thats it You will see a page like below.

And with that we completed our Part 1 of this Symfony tutorial series. In upcoming parts of the series we will learn how to manage databases and build a bit more complex application and modules. Post your doubts and comments if any.

Note: I am myself learning many parts in Symfony and I myself gather knowledge by experimentation and through various web sources. Hence if a Symfony expert is reading this and find anything wrong, kindly correct me.

Tags: Symfony, PHP, Framework, MVC, ORM, Hello World

--------------------------------------

Related Posts

--------------------------------------

Symfony model layer tips and tricks - A PHP Framework - Part 3

How to build a login-registration system using Symfony - A PHP Framework - Part 2

Essential frameworks for web development

How to get started with web development?

Music and My Guitar : How it all started (Part 1)

Tags: Framework, MVC, ORM, PHP, Symfony