What is Composer?

If you’ve been working with PHP, you might have heard of Composer, but what exactly is it, and why do PHP developers use it? In this post, we’ll explain Composer in simple terms, talk about why it’s useful, and show you how to install it on both Linux and Windows. We’ll also cover some of the important Composer commands you should know.

Dependency Manager for PHP

Composer is a dependency manager for PHP. But what does that mean? In simple terms, it helps you manage the external libraries (or packages) that your project depends on. Instead of manually downloading and including libraries in your project, Composer automates this process for you.

Why Use Composer?

If you’re managing a PHP system, like Smart Report Maker, Composer is an essential tool that simplifies your job. Here’s why you should use Composer from the perspective of someone responsible for installing and maintaining the system:

1. Easy Installation of Required Libraries: Composer automates the process of downloading and installing all the PHP libraries needed for your system. Instead of manually finding, downloading, and setting up each library, you can simply run a command, and Composer will handle it for you.
2. Consistency Across Environments: With Composer, you can ensure that the exact same versions of packages are installed across different environments. This means that whether you’re setting up the system on a development server or a production server, the system will run consistently without unexpected issues caused by different package versions.
3. Simplified Updates: Composer allows you to easily update the system’s dependencies. Instead of manually checking each library for updates and compatibility, Composer can update all packages with a single command. This ensures that your system is always up to date with the latest security patches and features.
4. Automatically Handle Dependencies: Some PHP systems require additional libraries that have their own dependencies. Composer takes care of this by automatically downloading and installing any dependencies needed by the system, saving your time and preventing errors from missing files or libraries.
5. Reduced Human Error: By automating package management, Composer minimizes the risk of missing files, incompatible versions, or outdated libraries, helping you avoid errors that could cause the system to malfunction.
6. Quick Setup for New Servers: When you’re setting up the system on a new server, Composer makes the process fast and easy. You just run composer install, and all necessary packages are downloaded and configured, making the system ready to use with minimal effort.

How composer works?

For example, if your project needs a specific library to send emails, Composer can download it for you and keep it updated. It keeps track of all the packages your project needs in a file called composer.json, which is the heart of your Composer setup. It’s a file that contains all the important information about the packages your project needs, and it allows Composer to know which libraries to download for your project.

Think of it as a shopping list for your project. When you add a package using Composer, the package name and version are added to this file. Here’s what a basic composer.json file looks like:

{
    "require": {
        "phpmailer/phpmailer": "^6.5"
    }
}

In this example:

• The version of PHPMailer needs to be 6.5 or higher.
• The project requires the PHPMailer package.
  

Besides composer.json, two other key components of Composer are the composer.lock file and the vendor directory. These three elements form the core of how Composer operates. While composer.json defines the version ranges of the libraries your project requires, composer.lock acts as a log of the exact versions Composer has installed, especially when dependencies have their own dependencies. All packages installed by Composer are stored in the vendor directory, which includes all third-party libraries needed by the project.

For any project using Composer, like Smart Report Maker, there will be a composer.json file in the root directory with the initial requirements. When you run Composer, it creates the composer.lock file and the vendor directory based on the actual installations.

How to Install Composer

Kindly note that you don’t need to manually install Composer for Smart Report Maker, as the installer script will automatically install it if it’s not already present on your system. However, if the script fails to install Composer due to permission issues or any other reason, you can easily install Composer yourself and then rerun the Smart Report Maker installer script to continue the installation process.

Installing Composer on Linux

It’s recommended to begin with point no 4 to verify whether Composer is already installed on your server.
1- Open your terminal.
2- Download Composer using the following commands:

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

3- Move Composer to a global directory so you can use it from anywhere:

sudo mv composer.phar /usr/local/bin/composer

4- Verify the installation:

composer --version

You should see the Composer version number, which means the installation was successful.

Common Issues When Installing Composer on Linux

When installing Composer on Linux, users may encounter the following issues:

1- Missing PHP extensions: Composer might fail if required PHP extensions like curl, json, or mbstring are missing. Make sure to install them using:

sudo apt-get install php-cli php-mbstring unzip 

2- Insufficient Permissions: Composer may not install globally without sudo permissions. Run the installation command with sudo if required.

3- Network Issues: If you’re behind a proxy or have restricted internet access, Composer may fail to download dependencies. Ensure that your system has proper internet access or configure Composer to work behind a proxy:

composer config -g -- http.proxy http://proxy.example.com:port

Installing Composer on Windows

It’s recommended to begin with point no 3 to verify whether Composer is already installed on your server.

1- Download Composer Setup from the official website
2- Run the installer. The setup wizard will guide you through the installation. It will automatically detect your PHP installation.
3- Verify the installation: Open Command Prompt and type:

composer --version

Key commands for using Composer efficiently

composer install

After you’ve added dependencies to composer.json, this command installs all the necessary packages. If another developer joins your project, they can run composer install to get all the required packages.

composer update

This command updates all your packages to the latest versions that are allowed by your composer.json file.

composer dump-autoload

This command generates a class map that allows PHP to automatically include your classes without manually including files.