composer/doc/04-schema.md

# composer.json

This chapter will explain all of the options available in `composer.json`.

## JSON schema

We have a [JSON schema](http://json-schema.org) that documents the format and
can also be used to validate your `composer.json`. In fact, it is used by the
`validate` command. You can find it at: [`Resources/composer-
schema.json`](https://github.com/composer/composer/blob/master/res
/composer-schema.json).

## Package root

The root of the package definition is a JSON object.

## name

The name of the package. It consists of vendor name and project name,
separated by `/`.

Examples:

* monolog/monolog
* igorw/event-source

Required for published packages (libraries).

## description

A short description of the package. Usually this is just one line long.

Optional but recommended.

## version

The version of the package.

This must follow the format of `X.Y.Z` with an optional suffix of `-dev`,
`alphaN`, `-betaN` or `-RCN`.

Examples:

    1.0.0
    1.0.2
    1.1.0
    0.2.5
    1.0.0-dev
    1.0.0-beta2
    1.0.0-RC5

Optional if the package repository can infer the version from somewhere, such
as the VCS tag name in the VCS repository. In that case it is also recommended
to omit it.

## type

The type of the package. It defaults to `library`.

Package types are used for custom installation logic. If you have a package
that needs some special logic, you can define a custom type. This could be a
`symfony-bundle`, a `wordpress-plugin` or a `typo3-module`. These will all be
specific to certain projects, and they will need to provide an installer
capable of installing packages of that type.

Out of the box, composer supports two types:

* **library:** This is the default. It will simply copy the files to `vendor`.
* **composer-installer:** A package of type `composer-installer` provides an
installer for other packages that have a custom type. Symfony could supply a
`symfony/bundle-installer` package, which every bundle would depend on.
Whenever you install a bundle, it will fetch the installer and register it, in
order to be able to install the bundle.

Only use a custom type if you need custom logic during installation. It is
recommended to omit this field and have it just default to `library`.

## keywords

An array of keywords that the package is related to. These can be used for
searching and filtering.

Examples:

    logging
    events
    database
    redis
    templating

Optional.

## homepage

An URL to the website of the project.

Optional.

## time

Release date of the version.

Must be in `YYYY-MM-DD` or `YYYY-MM-DD HH:MM:SS` format.

Optional.

## license

The license of the package. This can be either a string or an array of strings.

The recommended notation for the most common licenses is:

    MIT
    BSD-2
    BSD-3
    BSD-4
    GPLv2
    GPLv3
    LGPLv2
    LGPLv3
    Apache2
    WTFPL

Optional, but it is highly recommended to supply this.

## authors

The authors of the package. This is an array of objects.

Each author object can have following properties:

* **name:** The author's name. Usually his real name.
* **email:** The author's email address.
* **homepage:** An URL to the author's website.

An example:

```json
{
    "authors": [
        {
            "name": "Nils Adermann",
            "email": "naderman@naderman.de",
            "homepage": "http://www.naderman.de"
        },
        {
            "name": "Jordi Boggiano",
            "email": "j.boggiano@seld.be",
            "homepage": "http://seld.be"
        }
    ]
}
```

Optional, but highly recommended.

## Link types

Each of these takes an object which maps package names to version constraints.

* **require:** Packages required by this package.
* **recommend:** Recommended packages, installed by default.
* **suggest:**  Suggested packages. These are displayed after installation,
  but not installed by default.
* **conflict:** Mark this version of this package as conflicting with other
  packages.
* **replace:** Packages that can be replaced by this package. This is useful
  for large repositories with subtree splits. It allows the main package to
  replace all of it's child packages.
* **provide:** List of other packages that are provided by this package. This
  is mostly useful for common interfaces. A package could depend on some virtual
  `logger` package, any library that provides this logger, would simply list it
  in `provide`.

Example:

```json
{
    "require": {
        "monolog/monolog": "1.0.*"
    }
}
```

Optional.

## autoload

Autoload mapping for a PHP autoloader.

Currently only [PSR-0](https://github.com/php-fig/fig-
standards/blob/master/accepted/PSR-0.md) autoloading is supported. Under the
`psr-0` key you define a mapping from namespaces to paths, relative to the
package root.

Example:

```json
{
    "autoload": {
        "psr-0": { "Monolog": "src/" }
    }
}
```

Optional, but it is highly recommended that you follow PSR-0 and use this.

## target-dir

Defines the installation target.

In case the package root is below the namespace declaration you cannot
autoload properly. `target-dir` solves this problem.

An example is Symfony. There are individual packages for the components. The
Yaml component is under `Symfony\Component\Yaml`. The package root is that
`Yaml` directory. To make autoloading possible, we need to make sure that it
is not installed into `vendor/symfony/yaml`, but instead into
`vendor/symfony/yaml/Symfony/Component/Yaml`, so that the autoloader can load
it from `vendor/symfony/yaml`.

To do that, `autoload` and `target-dir` are defined as follows:

```json
{
    "autoload": {
        "psr-0": { "Symfony\\Component\\Yaml": "" }
    },
    "target-dir": "Symfony/Component/Yaml"
}
```

Optional.

## repositories

Custom package repositories to use.

By default composer just uses the packagist repository. By specifying
repositories you can get packages from elsewhere.

Repositories are not resolved recursively. You can only add them to your main
`composer.json`. Repository declarations of dependencies' `composer.json`s are
ignored.

Following repository types are supported:

* **composer:** A composer repository is simply a `packages.json` file served
  via HTTP that contains a list of `composer.json` objects with additional
  `dist` and/or `source` information.
* **vcs:** The version control system repository can fetch packages from git,
  svn and hg repositories. Note the distinction between package repository and
  version control repository.
* **pear:** With this you can import any pear repository into your composer
  project.
* **package:** If you depend on a project that does not have any support for
  composer whatsoever you can define the package inline using a `package`
  repository. You basically just inline the `composer.json` object.

For more information on any of these, see [Repositories].

Example:

```json
{
    "repositories": [
        {
            "type": "composer",
            "url": "http://packages.example.com"
        },
        {
            "type": "vcs",
            "url": "https://github.com/Seldaek/monolog"
        },
        {
            "type": "pear",
            "url": "http://pear2.php.net"
        },
        {
            "type": "package",
            "package": {
                "name": "smarty/smarty",
                "version": "3.1.7",
                "dist": {
                    "url": "http://www.smarty.net/files/Smarty-3.1.7.zip",
                    "type": "zip"
                },
                "source": {
                    "url": "http://smarty-php.googlecode.com/svn/",
                    "type": "svn",
                    "reference": "tags/Smarty_3_1_7/distribution/"
                }
            }
        }
    ]
}
```

> **Note:** Order is significant here. Repositories added later will take
precedence. This also means that custom repositories can override packages
that exist on packagist.

You can also disable the packagist repository by setting `packagist` to
`false`.

```json
{
    "repositories": [
        {
            "packagist": false
        }
    ]
}
```

## config

A set of configuration options. It is only used for projects.

The following options are supported:

* **vendor-dir:** Defaults to `vendor`. You can install dependencies into a
  different directory if you want to.
* **bin-dir:** Defaults to `vendor/bin`. If a project includes binaries, they
  will be symlinked into this directory.

Example:

```json
{
    "config": {
        "bin-dir": "bin"
    }
}
```

## scripts

Composer allows you to hook into various parts of the installation process through the use of scripts.

These events are supported:

* **pre-install-cmd:** Occurs before the install command is executed, contains
  one or more Class::method callables.
* **post-install-cmd:** Occurs after the install command is executed, contains
  one or more Class::method callables.
* **pre-update-cmd:** Occurs before the update command is executed, contains
  one or more Class::method callables.
* **post-update-cmd:** Occurs after the update command is executed, contains
  one or more Class::method callables.
* **pre-package-install:** Occurs before a package is installed, contains one
  or more Class::method callables.
* **post-package-install:** Occurs after a package is installed, contains one
  or more Class::method callables.
* **pre-package-update:** Occurs before a package is updated, contains one or
  more Class::method callables.
* **post-package-update:** Occurs after a package is updated, contains one or
  more Class::method callables.
* **pre-package-uninstall:** Occurs before a package has been uninstalled,
  contains one or more Class::method callables.
* **post-package-uninstall:** Occurs after a package has been uninstalled,
  contains one or more Class::method callables.

For each of these events you can provide a static method on a class that will
handle it.

Example:

```json
{
    "scripts": {
        "post-install-cmd": [
            "Acme\\ScriptHandler::doSomething"
        ]
    }
}
```

The event handler receives a `Composer\Script\Event` object as an argument,
which gives you access to the `Composer\Composer` instance through the
`getComposer` method.

```php
namespace Acme;

use Composer\Script\Event;

class ScriptHandler
{
    static public function doSomething(Event $event)
    {
        // custom logic
    }
}
```

## extra

Arbitrary extra data for consumption by `scripts`.

This can be virtually anything. To access it from within a script event
handler, you can do:

```php
$extra = $event->getComposer()->getPackage()->getExtra();
```

Optional.

## bin

A set of files that should be treated as binaries and symlinked into the `bin-
dir` (from config).

See [articles/bin.md] for more details.

Optional.