Php Using Composer For Dependency Management Complete Guide

Prerequisites:

• You should have PHP installed on your computer.
• Basic knowledge of PHP programming.

Step 1: Install Composer

First, you need to download and install Composer.

For Windows:

1. Download the Composer Windows installer from getcomposer.org/Composer-Setup.exe.
2. Run the installer.
3. Follow the prompts to complete the installation.

For macOS and Linux:

1. Open your terminal.
2. Download the installer using curl.

   php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
   

3. Verify the installer.

   php -r "if (hash_file('sha384', 'composer-setup.php') === 'e21205b207c3ff031906575712edab6f13eb0b361f2085f1f1237b7126d785e826a450292b6cfd1d64d92e6563bbde02') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
   

4. Install Composer globally.

   sudo php composer-setup.php --install-dir=/usr/local/bin --filename=composer
   

5. Verify that Composer was installed correctly.

   composer --version
   

Step 2: Create a New PHP Project

Let’s start a new PHP project to demonstrate how Composer works.

1. Navigate to your desired directory where you want to create the new project.

   cd your/desired/path
   

2. Create a new directory for your project.

   mkdir my-php-project
   

3. Move into the newly created directory.

   cd my-php-project
   

4. Initialize a new Composer project.

   composer init
   

   During this process, Composer will ask you a variety of questions about your project. You can just press Enter to accept the default options unless you have specific settings you’d like to define.

Step 3: Add a Dependency

Now let’s add a package to our project. We’ll use Monolog, which is a logging library.

1. Run the following command to require Monolog:

   composer require monolog/monolog
   

   This command tells Composer to fetch the Monolog library and add it to the project under the vendor directory.

2. Composer updates your composer.json file with the new dependency and creates or updates the composer.lock file, which holds details about all installed packages.

Step 4: Autoload Dependencies

Composer can generate an autoloader that lets us include our dependencies without explicitly requiring the files.

1. Composer automatically generates a vendor/autoload.php file. Include this file in your project to enable autoloading of all dependencies.

2. Create a new PHP file called index.php in your project directory.

   touch index.php
   

3. Edit index.php and add some code to use Monolog.

   <?php
   
   // Include Composer's autoloader
   require 'vendor/autoload.php';
   
   // Create a logger channel
   $logger = new Monolog\Logger('my_logger');
   
   // Now add a stream handler pointing to a file
   $logger->pushHandler(new Monolog\Handler\StreamHandler(__DIR__.'/app.log', Monolog\Logger::WARNING));
   
   // Add records to the log
   $logger->warning('Foo');
   $logger->error('Bar');
   ?>
   

Step 5: Test Your Project

To see if everything worked correctly, run the index.php script.

1. Use the following command in your terminal:

   php index.php
   

2. After running this command, check for a file named app.log in your project directory. It should contain entries similar to these:

   [2022-01-01 12:34:56] my_logger.WARNING: Foo [] []
   [2022-01-01 12:34:57] my_logger.ERROR: Bar [] []
   

Step 6: Update Dependencies

Sometimes you may want to update your dependencies to their latest versions. You can do this with Composer:

1. Use the following command in your terminal:

   composer update
   

   This checks the composer.lock file to see if any installed package has a newer version than what is specified in composer.json.

Step 7: Remove a Dependency

If you no longer need a package, you can remove it with Composer.

1. Use the following command:

   composer remove monolog/monolog
   

   This command removes the specified package from your composer.json file and regenerates the composer.lock file as well as the autoloader.

Step 8: Using a Local Package

Sometimes you might want to use a local package that is not available on Packagist. Here’s how you can do that:

1. Create another directory for your local package.

   mkdir ../my-local-package
   

2. Inside ../my-local-package, initialize a new Composer project and create an autoload file.

   cd ../my-local-package
   composer init --name="you/my-local-package" --stability="dev" --no-interaction
   touch src/MyLocalClass.php
   

3. In src/MyLocalClass.php, add a simple class.

   <?php
   
   namespace MyLocalPackage;
   
   class MyLocalClass {
       public function sayHello() {
           return "Hello from MyLocalClass!";
       }
   }
   

4. Go back to the original project and link the local package.

   cd ../my-php-project
   composer config repositories.mylocalpath path ../my-local-package
   composer require you/my-local-package:*
   

5. Edit index.php (or create a new file) to use the MyLocalClass from the local package.

   <?php
   
   // Include Composer's autoloader
   require 'vendor/autoload.php';
   
   // Include the class from the local package
   $class = new \MyLocalPackage\MyLocalClass();
   echo $class->sayHello();
   ?>
   

6. Run your script to test:

   php index.php
   

Conclusion

In this tutorial, we’ve demonstrated how to install Composer, create a PHP project, add, autoload and remove dependencies, and even link in a local dependency package. Composer plays a huge role in modern PHP development, making managing dependencies seamless and efficient.