# Dependency Management (Composer)

In short, [Composer ](https://getcomposer.org/)is a dependency manager for PHP. If you’ve worked with npm for NodeJS, Maven for Java or NuGet for C#, the principle should be familiar. Basically, Composer lets us define a *composer.json* file in our project root which contains a list of dependencies for the project. Using commands such as *composer install* we can then automagically add those dependencies to our project.

By default, Composer pulls the dependencies from [Packagist ](https://packagist.org/)which is also where you can find the [open-source modules](https://packagist.org/packages/deep-web-solutions/) of our framework. You can also define your own package sources, such as GitHub or a private packages repository. You can read more about how that works and how a composer.json file looks like by reading [this article](https://getcomposer.org/doc/02-libraries.md) of the official documentation.

Composer also has another ground-breaking advantage — it generates an autoloader for your project. You probably know this already, but in PHP you need to call *include* or *require* before using the contents of a file. It can become tedious (and it’s definitely error-prone) to do that for all the files in your project, especially as your plugin grows. Moreover, if you want to only load classes conditionally, that becomes a nightmare!

An [autoloader ](https://www.php.net/manual/en/language.oop5.autoload.php)lets you define a function that loads PHP files containing classes only when the class is used. That basically guarantees the conditional loading. Moreover, the Composer autoloader also supports loading simple files containing plain PHP functions (albeit non-conditionally).

{% hint style="info" %}
By using the PSR-4 autoloading standard for our project structure and Composer for loading dependencies and generating an autoloader, it’s **virtually impossible** to cause a “function/class does not exist” runtime error in production!
{% endhint %}

 [Here is an example](https://github.com/deep-web-solutions/wordpress-framework-bootstrapper/blob/master/composer.json) of a *composer.json* file that is actually used by the first module of the framework, the Bootstrapper. The relevant entries are “autoload” and “autoload-dev”. The autoloader is then the only file that we need to *require* as one of the first things the module does in [*bootstrap.php*](https://github.com/deep-web-solutions/wordpress-framework-bootstrapper/blob/master/bootstrap.php).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://framework.deep-web-solutions.com/key-concepts-and-dev-tools/dependency-management-composer.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.