What technology is PHP Composer? Let's take a look

What technology is PHP Composer?

If you are a programmer, you are likely to find that the wheel of technology updates is spinning so hard that you can't keep up, such as user authentication, database management, routing and other technologies. There are many mature frameworks in PHP to deal with these problems, so you would think that these frameworks should be easy to use, right?

If you manually install and use Zend, or Laravel or Symfony, you will find that it is not an easy task. Each technology has its own various dependency packages, so in the end things will be a mess. .

The role of Composer appears at this time. Composer is a dependency management tool for PHP. It manages all the dependencies your PHP project needs. In other words, Composer will pull all the code libraries and dependencies required for your PHP project from the Internet and put them together for management.

This method of dependency management for projects is not a new concept. In fact, Composer was inspired by npm's Node.js and Bundler's Ruby.

I believe you should know something about PEAR. PEAR is a PHP library management tool that has been around for many years. However, many programmers don't like using PEAR for many reasons, firstly, it's outdated, and secondly, PEAR requires you to install the entire system rather than on a per-project basis. That said, if you have a project that relies on a slightly older library, things can get tricky. To learn more about the history of PHP package management tools, you can read Packages: The Way Forward for PHP.

How to install Composer

The installation of Composer is very simple and can be completed with a few lines of commands. I use OS X, but it's the same for any *nix system.

Please open the command line window and run the following command:

$ curl -s https://getcomposer.org/installer | php

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

The first line of command is to download the composer.phar file to your computer. The second line of command moves the composer.phar file into your bin directory so that you can access it globally on your computer.

Now run the following command:

$ composer

If you successfully installed Composer, this command will return you a valid command Parameter list, and usage description.

How to install Composer on Windows

If you want to install Composer on Windows system, you can find the installation method on the official website, http://getcomposer.org/.

How to use Composer?

Now that Composer has been installed on our computer, we can start using it to import the code libraries needed in the project. Composer requires a configuration file, which is a JSON file. We put it in the root directory of the project.

For example, if we want to use Slim Framework, we can create the following composer.json file:

{  
"require": {  
"slim/slim": "2.*"  
}  
}  
想通过Composer安装 Slim，你只需要简单的使用下面的命令：
 $ composer install

Now Slim will be automatically downloaded and installed to vendor/slim/slim Under contents.

Is not it simple!

Automatic loading

Now, suppose your project depends on many different code libraries, and you want to be able to load these libraries automatically. Fortunately, Composer has a file that can perform this task. It can automatically download all the libraries your project depends on into the project.

If you want to use Composer's autoloader, you only need to include a line in the relative index file or startup file:

 require ‘vendor/autoload.php’;

In this way, when adding new dependency packages to the project Don't worry anymore.

For example:

// Autoload  
require ‘vendor/autoload.php’;
// 实例或 Slim 应用  
$app = new \Slim\Slim();
// 定义 HTTP GET 路径 
$app->get(‘/hello/:name’, function ($name) {  
echo "Hello, $name";  
});
// 运行 Slim 应用  
$app->run();

Conclusion

Using package management tools in PHP projects is the right direction. Programming languages ​​like Ruby have shown us the convenience of using dependency management tools in projects, saving a lot of development and configuration time for developers.

A large number of popular frameworks have also begun to reference Composer, and more developers are using Composer in their projects.

As a PHP developer, Composer will be your best partner. With the increase in usage, Composer will definitely become the basic library of PHP.

With the increase of good tools like Composer, PHP will become more and more easy to use. Composer has solved a lot of big problems for the PHP community, and there's no reason why we shouldn't use it.

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