PHP
What is Composer?
Learn that Composer is a PHP package manager and what it provides.
What does Composer do?
Composer is a tool that manages external libraries (packages) in PHP projects. When a project needs a logging library like Monolog or an HTTP client like GuzzleHttp, you install them with a single Composer command instead of downloading files by hand and wiring up paths.
Composer also resolves relations between dependencies: if a package needs another, it installs that too automatically. This is called dependency management.
The vendor/ folder and Packagist
When Composer installs, it puts all packages into the vendor/ folder at the project root. You never touch this folder by hand; Composer manages the packages. Packages are published on a public repository called Packagist; Composer searches and downloads from there.
You do not put vendor/ under version control; when another developer runs composer install, the same packages are installed automatically.
Exercise Print the dependency list
Define a $deps array: "monolog/monolog" => "3.5", "guzzlehttp/guzzle" => "7.8", "symfony/console" => "6.4". Print each line in the form monolog/monolog: 3.5.
Show example solution
" . $ver . "\n"; }.
Example solution:
<?php
$deps = ["monolog/monolog" => "3.5", "guzzlehttp/guzzle" => "7.8", "symfony/console" => "6.4"];
foreach ($deps as $pkg => $ver) {
echo $pkg . ": " . $ver . "\n";
}
Test yourself
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What is Composer's main job?
- It manages PHP dependencies
- It speeds up PHP code
- It backs up databases
- It captures browser requests
Show answer
It manages PHP dependencies — Correct. Composer installs and manages package dependencies.
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Complete the Composer command
<?php
// Composer command to install a package
$cfg = ["cmd" => "____ monolog/monolog"];
echo $cfg["cmd"] . "\n";
Show answer
<?php
// Composer command to install a package
$cfg = ["cmd" => "composer require monolog/monolog"];
echo $cfg["cmd"] . "\n";
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Match the Composer concepts
- Composer
- Package manager
- vendor/
- Packages location
- Packagist
- Public repository
- require
- Adds a package
Next lesson: The composer.json file
