<!--
    tagline: Script are callbacks that are called before/after installing packages
-->

# Scripts

## What is a script?

A script, in Composer's terms, can either be a PHP callback (defined as a
static method) or any command-line executable command. Scripts are useful
for executing a package's custom code or package-specific commands during
the Composer execution process.

As of Composer 2.5 scripts can also be Symfony Console Command classes,
which allows you to easily run them including passing options. This is
however not recommended for handling events.

> **Note:** Only scripts defined in the root package's `composer.json` are
> executed. If a dependency of the root package specifies its own scripts,
> Composer does not execute those additional scripts.

## Event names

Composer fires the following named events during its execution process:

### Command Events

- **pre-install-cmd**: occurs before the `install` command is executed with a
  lock file present.
- **post-install-cmd**: occurs after the `install` command has been executed
  with a lock file present.
- **pre-update-cmd**: occurs before the `update` command is executed, or before
  the `install` command is executed without a lock file present.
- **post-update-cmd**: occurs after the `update` command has been executed, or
  after the `install` command has been executed without a lock file present.
- **pre-status-cmd**: occurs before the `status` command is executed.
- **post-status-cmd**: occurs after the `status` command has been executed.
- **pre-archive-cmd**: occurs before the `archive` command is executed.
- **post-archive-cmd**: occurs after the `archive` command has been executed.
- **pre-autoload-dump**: occurs before the autoloader is dumped, either during
  `install`/`update`, or via the `dump-autoload` command.
- **post-autoload-dump**: occurs after the autoloader has been dumped, either
  during `install`/`update`, or via the `dump-autoload` command.
- **post-root-package-install**: occurs after the root package has been
  installed during the `create-project` command (but before its
  dependencies are installed).
- **post-create-project-cmd**: occurs after the `create-project` command has
  been executed.

### Installer Events

- **pre-operations-exec**: occurs before the install/upgrade/.. operations
  are executed when installing a lock file. Plugins that need to hook into
  this event will need to be installed globally to be usable, as otherwise
  they would not be loaded yet when a fresh install of a project happens.

### Package Events

- **pre-package-install**: occurs before a package is installed.
- **post-package-install**: occurs after a package has been installed.
- **pre-package-update**: occurs before a package is updated.
- **post-package-update**: occurs after a package has been updated.
- **pre-package-uninstall**: occurs before a package is uninstalled.
- **post-package-uninstall**: occurs after a package has been uninstalled.

### Plugin Events

- **init**: occurs after a Composer instance is done being initialized.
- **command**: occurs before any Composer Command is executed on the CLI. It
  provides you with access to the input and output objects of the program.
- **pre-file-download**: occurs before files are downloaded and allows
  you to manipulate the `HttpDownloader` object prior to downloading files
  based on the URL to be downloaded.
- **post-file-download**: occurs after package dist files are downloaded and
  allows you to perform additional checks on the file if required.
- **pre-command-run**: occurs before a command is executed and allows you to
  manipulate the `InputInterface` object's options and arguments to tweak
  a command's behavior.
- **pre-pool-create**: occurs before the Pool of packages is created, and lets
  you filter the list of packages that is going to enter the Solver.

> **Note:** Composer makes no assumptions about the state of your dependencies
> prior to `install` or `update`. Therefore, you should not specify scripts
> that require Composer-managed dependencies in the `pre-update-cmd` or
> `pre-install-cmd` event hooks. If you need to execute scripts prior to
> `install` or `update` please make sure they are self-contained within your
> root package.

## Defining scripts

The root JSON object in `composer.json` should have a property called
`"scripts"`, which contains pairs of named events and each event's
corresponding scripts. An event's scripts can be defined as either a string
(only for a single script) or an array (for single or multiple scripts.)

For any given event:

- Scripts execute in the order defined when their corresponding event is fired.
- An array of scripts wired to a single event can contain both PHP callbacks
and command-line executable commands.
- PHP classes and commands containing defined callbacks must be autoloadable
via Composer's autoload functionality.
- Callbacks can only autoload classes from psr-0, psr-4 and classmap
definitions. If a defined callback relies on functions defined outside of a
class, the callback itself is responsible for loading the file containing these
functions.

Script definition example:

```json
{
    "scripts": {
        "post-update-cmd": "MyVendor\\MyClass::postUpdate",
        "post-package-install": [
            "MyVendor\\MyClass::postPackageInstall"
        ],
        "post-install-cmd": [
            "MyVendor\\MyClass::warmCache",
            "phpunit -c app/"
        ],
        "post-autoload-dump": [
            "MyVendor\\MyClass::postAutoloadDump"
        ],
        "post-create-project-cmd": [
            "php -r \"copy('config/local-example.php', 'config/local.php');\""
        ]
    }
}
```

Using the previous definition example, here's the class `MyVendor\MyClass`
that might be used to execute the PHP callbacks:

```php
<?php

namespace MyVendor;

use Composer\Script\Event;
use Composer\Installer\PackageEvent;

class MyClass
{
    public static function postUpdate(Event $event)
    {
        $composer = $event->getComposer();
        // do stuff
    }

    public static function postAutoloadDump(Event $event)
    {
        $vendorDir = $event->getComposer()->getConfig()->get('vendor-dir');
        require $vendorDir . '/autoload.php';

        some_function_from_an_autoloaded_file();
    }

    public static function postPackageInstall(PackageEvent $event)
    {
        $installedPackage = $event->getOperation()->getPackage();
        // do stuff
    }

    public static function warmCache(Event $event)
    {
        // make cache toasty
    }
}
```

**Note:** During a Composer `install` or `update` command run, a variable named
`COMPOSER_DEV_MODE` will be added to the environment. If the command was run
with the `--no-dev` flag, this variable will be set to 0, otherwise it will be
set to 1. The variable is also available while `dump-autoload` runs, and it
will be set to the same as the last `install` or `update` was run in.

## Event classes

When an event is fired, your PHP callback receives as first argument a
`Composer\EventDispatcher\Event` object. This object has a `getName()` method
that lets you retrieve the event name.

Depending on the [script types](#event-names) you will get various event
subclasses containing various getters with relevant data and associated
objects:

- Base class: [`Composer\EventDispatcher\Event`](https://github.com/composer/composer/blob/main/src/Composer/EventDispatcher/Event.php)
- Command Events: [`Composer\Script\Event`](https://github.com/composer/composer/blob/main/src/Composer/Script/Event.php)
- Installer Events: [`Composer\Installer\InstallerEvent`](https://github.com/composer/composer/blob/main/src/Composer/Installer/InstallerEvent.php)
- Package Events: [`Composer\Installer\PackageEvent`](https://github.com/composer/composer/blob/main/src/Composer/Installer/PackageEvent.php)
- Plugin Events:
  - init: [`Composer\EventDispatcher\Event`](https://github.com/composer/composer/blob/main/src/Composer/EventDispatcher/Event.php)
  - command: [`Composer\Plugin\CommandEvent`](https://github.com/composer/composer/blob/main/src/Composer/Plugin/CommandEvent.php)
  - pre-file-download: [`Composer\Plugin\PreFileDownloadEvent`](https://github.com/composer/composer/blob/main/src/Composer/Plugin/PreFileDownloadEvent.php)
  - post-file-download: [`Composer\Plugin\PostFileDownloadEvent`](https://github.com/composer/composer/blob/main/src/Composer/Plugin/PostFileDownloadEvent.php)

## Running scripts manually

If you would like to run the scripts for an event manually, the syntax is:

```shell
php composer.phar run-script [--dev] [--no-dev] script
```

For example `composer run-script post-install-cmd` will run any
**post-install-cmd** scripts and [plugins](plugins.md) that have been defined.

You can also give additional arguments to the script handler by appending `--`
followed by the handler arguments. e.g.
`composer run-script post-install-cmd -- --check` will pass`--check` along to
the script handler. Those arguments are received as CLI arg by CLI handlers,
and can be retrieved as an array via `$event->getArguments()` by PHP handlers.

## Writing custom commands

If you add custom scripts that do not fit one of the predefined event name
above, you can either run them with run-script or also run them as native
Composer commands. For example the handler defined below is executable by
running `composer test`:

```json
{
    "scripts": {
        "test": "phpunit",
        "do-something": "MyVendor\\MyClass::doSomething"
        "my-cmd": "MyVendor\\MyCommand"
    }
}
```

Similar to the `run-script` command you can give additional arguments to scripts,
e.g. `composer test -- --filter <pattern>` will pass `--filter <pattern>` along
to the `phpunit` script.

Using a PHP method via `composer do-something arg` lets you execute a
`static function doSomething(\Composer\Script\Event $event)` and `arg` becomes
available in `$event->getArguments()`. This however does not let you easily pass
custom options in the form of `--flags`.

Using a [symfony/console](https://packagist.org/packages/symfony/console) `Command`
class you can define and access arguments and options more easily.

For example with the command below you can then simply call `composer my-cmd
--arbitrary-flag` without even the need for a `--` separator. To be detected
as symfony/console commands the class name must end with `Command` and extend
symfony's `Command` class. Also note that this will run using Composer's built-in
symfony/console version which may not match the one you have required in your
project, and may change between Composer minor releases. If you need more
safety guarantees you should rather use your own binary file that runs your own
symfony/console version in isolation in its own process then.

```php
<?php

namespace MyVendor;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class MyCommand extends Command
{
    protected function configure(): void
    {
        $this->setDefinition([
            new InputOption('arbitrary-flag', null, InputOption::VALUE_NONE, 'Example flag'),
            new InputArgument('foo', InputArgument::OPTIONAL, 'Optional arg'),
        ]);
    }

    public function execute(InputInterface $input, OutputInterface $output): int
    {
        if ($input->getOption('arbitrary-flag')) {
            $output->writeln('The flag was used')
        }

        return 0;
    }
}
```

> **Note:** Before executing scripts, Composer's bin-dir is temporarily pushed
> on top of the PATH environment variable so that binaries of dependencies
> are directly accessible. In this example no matter if the `phpunit` binary is
> actually in `vendor/bin/phpunit` or `bin/phpunit` it will be found and executed.


## Managing the process timeout

Although Composer is not intended to manage long-running processes and other
such aspects of PHP projects, it can sometimes be handy to disable the process
timeout on custom commands. This timeout defaults to 300 seconds and can be
overridden in a variety of ways depending on the desired effect:

- disable it for all commands using the config key `process-timeout`,
- disable it for the current or future invocations of composer using the
  environment variable `COMPOSER_PROCESS_TIMEOUT`,
- for a specific invocation using the `--timeout` flag of the `run-script` command,
- using a static helper for specific scripts.

To disable the timeout for specific scripts with the static helper directly in
composer.json:

```json
{
    "scripts": {
        "test": [
            "Composer\\Config::disableProcessTimeout",
            "phpunit"
        ]
    }
}
```

To disable the timeout for every script on a given project, you can use the
composer.json configuration:

```json
{
    "config": {
        "process-timeout": 0
    }
}
```

It's also possible to set the global environment variable to disable the timeout
of all following scripts in the current terminal environment:

```shell
export COMPOSER_PROCESS_TIMEOUT=0
```

To disable the timeout of a single script call, you must use the `run-script` composer
command and specify the `--timeout` parameter:

```shell
php composer.phar run-script --timeout=0 test
```

## Referencing scripts

To enable script re-use and avoid duplicates, you can call a script from another
one by prefixing the command name with `@`:

```json
{
    "scripts": {
        "test": [
            "@clearCache",
            "phpunit"
        ],
        "clearCache": "rm -rf cache/*"
    }
}
```

You can also refer a script and pass it new arguments:

```json
{
    "scripts": {
        "tests": "phpunit",
        "testsVerbose": "@tests -vvv"
    }
}
```

## Calling Composer commands

To call Composer commands, you can use `@composer` which will automatically
resolve to whatever composer.phar is currently being used:

```json
{
    "scripts": {
        "test": [
            "@composer install",
            "phpunit"
        ]
    }
}
```

One limitation of this is that you can not call multiple composer commands in
a row like `@composer install && @composer foo`. You must split them up in a
JSON array of commands.

## Executing PHP scripts

To execute PHP scripts, you can use `@php` which will automatically
resolve to whatever php process is currently being used:

```json
{
    "scripts": {
        "test": [
            "@php script.php",
            "phpunit"
        ]
    }
}
```

One limitation of this is that you can not call multiple commands in
a row like `@php install && @php foo`. You must split them up in a
JSON array of commands.

You can also call a shell/bash script, which will have the path to
the PHP executable available in it as a `PHP_BINARY` env var.

## Setting environment variables

To set an environment variable in a cross-platform way, you can use `@putenv`:

```json
{
    "scripts": {
        "install-phpstan": [
            "@putenv COMPOSER=phpstan-composer.json",
            "composer install --prefer-dist"
        ]
    }
}
```

## Custom descriptions.

You can set custom script descriptions with the following in your `composer.json`:

```json
{
    "scripts-descriptions": {
        "test": "Run all tests!"
    }
}
```

The descriptions are used in `composer list` or `composer run -l` commands to
describe what the scripts do when the command is run.

> **Note:** You can only set custom descriptions of custom commands.
