Installing packages from Packagist
Learn to search for and install packages from Packagist.
What is Packagist?
Packagist is the main repository for PHP packages. Composer searches and downloads from here. A package name has the vendor/project form; for example monolog/monolog is a logging library, guzzlehttp/guzzle is an HTTP client.
When you run composer require monolog/monolog, Composer finds the package on Packagist, downloads it into vendor/ and adds it to the autoload. Afterwards you can import classes with use.
Using a package
After you install a package with composer require, calling require_once vendor/autoload.php makes its classes usable. For example with Monolog installed, write new Monolog\Logger("app") to create a logger.
With GuzzleHttp installed, send HTTP requests with new GuzzleHttp\Client(). Since the Composer autoloader loads namespaces automatically, you do not write file paths; use is enough.
Exercise Monolog Logger simulation
Mimic the Logger class of the Monolog package. Define namespace Monolog;; inside it add a Logger class. Add a public string $name property and public function __construct(string $name) that assigns $this->name = $name. public function info(string $msg): string should return "[" . $this->name . "] " . $msg.
Create an instance with $log = new \Monolog\Logger("app"), call info("Started") and print its output.
Show example solution
string { return "[" . $this->name . "] " . $msg; } }. Print with $log = new \Monolog\Logger("app"); echo $log->info("Started") . "\n";.
Example solution:
<?php
namespace Monolog;
class Logger {
public string $name;
public function __construct(string $name) {
$this->name = $name;
}
public function info(string $msg): string {
return "[" . $this->name . "] " . $msg;
}
}
$log = new \Monolog\Logger("app");
echo $log->info("Started") . "\n";Test yourself
-
Complete the package name
<?php // Monolog package name $cfg = ["name" => "____"]; echo $cfg["name"] . "\n";Show answer
<?php // Monolog package name $cfg = ["name" => "monolog/monolog"]; echo $cfg["name"] . "\n"; -
Match the Packagist concepts
- Packagist
- Package repository
- monolog/monolog
- Logging library
- guzzlehttp/guzzle
- HTTP client
- vendor/project
- Package name form
-
What does the guzzlehttp/guzzle package do?
- It sends HTTP requests
- It logs events
- It runs database queries
- It compresses files
Show answer
It sends HTTP requests — Correct. GuzzleHttp is an HTTP client library.