The library currently supportsPSR-18 HTTP Clients,PSR-17 HTTP Factories,PSR-14 Event Dispatchers,PSR-11 Containers,PSR-6 Caches andPSR-3 Logs.

This is largely intended for inclusion in libraries like SDKs that wish to support PSR interfaces without requiring hard dependencies on specific implementations or demanding extra configuration by users.

• Requirements
• Installation
  • Meta-Packages
  • PSR-18 HTTP Clients
  • PSR-17 HTTP Factories
  • PSR-14 Event Dispatchers
  • PSR-11 Containers
  • PSR-6 Caches
  • PSR-3 Logs
• Handling Failures
• Exceptions
• Singletons
• Mocking Priority
• Preferring an Implementation
• Using a Specific Implementation

• PHP 8.2+
• Composer 2.0+

The discovery of a particular interface requires the presence of a compatible implementation in the host application. This library does not install any implementations for you.

You should install the appropriate dependencies from the list below for the PSRs you wish to have discovery support for.

Thepsr-discovery/all meta-package includes all of the discovery suite packages. If you're looking for an all-in-one solution, this is the one you want.

Installation:

composer require psr-discovery/all

See the following sections for more information on the individual usage of each package.

Installation:

composer require psr-discovery/http-client-implementations

Usage:

usePsrDiscovery\Discover;$httpClient = Discover::httpClient();

Please see thepsr-discovery/http-client-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

Installation:

composer require psr-discovery/http-factory-implementations

Usage:

usePsrDiscovery\Discover;// Returns a PSR-17 RequestFactoryInterface instance$requestFactory = Discover::httpRequestFactory();// Returns a PSR-17 ResponseFactoryInterface instance$responseFactory = Discover::httpResponseFactory();// Returns a PSR-17 StreamFactoryInterface instance$streamFactory = Discover::httpStreamFactory();// Returns a PSR-17 UploadedFileFactoryInterface instance$uploadedFileFactory = Discover::httpUploadedFileFactory();// Returns a PSR-17 UriFactoryInterface instance$uriFactory = Discover::httpUriFactory();// Returns a PSR-7 RequestInterface instance$request =$requestFactory->createRequest('GET','https://example.com');

Please see thepsr-discovery/http-factory-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

Installation:

composer require psr-discovery/event-dispatcher-implementations

Usage:

usePsrDiscovery\Discover;$eventDispatcher = Discover::eventDispatcher();

Please see thepsr-discovery/event-dispatcher-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

Installation:

composer require psr-discovery/container-implementations

Usage:

usePsrDiscovery\Discover;$container = Discover::container();

Please see thepsr-discovery/container-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

Installation:

composer require psr-discovery/cache-implementations

Usage:

usePsrDiscovery\Discover;$cache = Discover::cache();

Please see thepsr-discovery/cache-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

Installation:

composer require psr-discovery/log-implementations

Usage:

usePsrDiscovery\Discover;$log = Discover::log();

Please see thepsr-discovery/log-implementations repository for a list of the supported implementations. If a particular implementation is missing you'd like to see, please open a pull request adding support.

If the library is unable to discover a suitable implementation, the relevant discovery method will simply returnnull. This allows you to handle the failure gracefully, for example by falling back to a default implementation.

Example:

usePsrDiscovery\Discover;$httpClient = Discover::httpClient();if ($httpClient ===null) {// No suitable HTTP Client implementation was discovered.// Fall back to a default implementation.$httpClient =newDefaultHttpClient();}

The library will expose aPsrDiscovery\Exceptions\SupportPackageNotFoundException when a discovery method is called, but the required support package is not installed.

By default, the discovery methods will always return a new instance of the discovered implementation. If you wish to use a singleton instance instead, simply passtrue to the$singleton parameter of the discovery method.

Example:

usePsrDiscovery\Discover;// $httpClient1 !== $httpClient2 (default)$httpClient1 = Discover::httpClient();$httpClient2 = Discover::httpClient();// $httpClient1 === $httpClient2$httpClient1 = Discover::httpClient(singleton:true);$httpClient2 = Discover::httpClient(singleton:true);

This library will give priority to searching for an available PSR mocking library, likepsr-mock/http-client-implementation orphp-http/mock-client.

The expectation is that these mocking libraries will always be installed as development dependencies, and therefore if they are available, they are intended to be used.

If you wish to prefer a specific implementation over others, you can use theprefer() on any installed discovery support libraries.

Example usingpsr-discovery/http-factories-implementations:

usePsrDiscovery\Discover;usePsrDiscovery\Implementations\Psr17\RequestFactories;// Prefer the a specific implementation of PSR-17 over others.RequestFactories::prefer('nyholm/psr7');// Return an instance of Nyholm\Psr7\Factory\Psr17Factory,// or the next available from the list of candidates,// Returns null if none are discovered.$factory = Discover::httpRequestFactory();

This will cause the discovery method to return the preferred implementation if it is available, otherwise, it will fall back to the default behavior.

Note that assigning a preferred implementation will give it priority over the default preference of mocking libraries.

If you wish to force a specific implementation and ignore the rest of the discovery candidates, you can use theuse() on any installed discovery support libraries.

Example usingpsr-discovery/http-factories-implementations:

usePsrDiscovery\Discover;usePsrDiscovery\Implementations\Psr17\RequestFactories;// Only discover a specific implementation of PSR-17.RequestFactories::use('nyholm/psr7');// Return an instance of Nyholm\Psr7\Factory\Psr17Factory,// or null if it is not available.$factory = Discover::httpRequestFactory();

This will cause the discovery method to return the preferred implementation if it is available, otherwise, it will returnnull.

This library is not produced or endorsed by, or otherwise affiliated with, the PHP-FIG.

Repositories