webkernel/lifecycle

Composer Runtime Metadata

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Composer's generated autoloader makes Composer\InstalledVersions available to application code. Use it when code needs an installed package's identity or location without assuming a dependency-directory layout.

Package lookup

<?php declare(strict_types=1);

use Composer\InstalledVersions;

require __DIR__ . '/vendor/autoload.php';

if (InstalledVersions::isInstalled('acme/billing')) {
    $package_path = InstalledVersions::getInstallPath('acme/billing');
}

Lifecycle's webkernel_package() wraps this lookup for the webkernel/* namespace and adds canonicalization and a per-package cache.

base_path() uses root package metadata during initialization.

Useful APIs

API	Question
`isInstalled()`	Is this package or provided package available?
`getPrettyVersion()`, `getVersion()`	Which version is recorded?
`getReference()`	Which source/dist reference is recorded?
`getInstallPath()`	Where is the package installed?
`getInstalledPackagesByType()`	Which installed packages have a given type?

Install paths can contain symlinks or relative segments. Some package kinds have no physical install directory. A missing package lookup can throw OutOfBoundsException; a registered metapackage can return null for its path. Handle those cases before opening files.

API availability

composer-plugin-api and composer-runtime-api describe different boundaries. Lifecycle's manifest requires the plugin API to integrate with Composer. A library that relies on a particular runtime utility should declare the runtime API version it needs. See Composer's official runtime utilities for version availability and method details.

Build-time discovery

Package metadata lookup is useful during manifest generation. Read the installed package set during Composer/build work, generate the application-specific result and let requests consume that result. The existence of a runtime metadata API does not require scanning the package set during every HTTP request.

Next step

Read Built-in Workers for how Lifecycle uses its own Composer events.