The php-fig/http-message repository contains common interface definitions for HTTP messages as defined by PSR-7. It provides a set of PHP interfaces for HTTP request and response objects, allowing for interoperability between different HTTP client libraries and frameworks.

Pros

• Standardizes HTTP message interfaces across PHP projects
• Improves interoperability between different PHP HTTP libraries and frameworks
• Encourages consistent API design for HTTP-related functionality
• Backed by the PHP Framework Interop Group (PHP-FIG), ensuring wide adoption

Cons

• Requires implementation by libraries and frameworks to be useful
• Some developers argue that the interfaces are too complex or verbose
• Doesn't provide concrete implementations, only interfaces
• May require additional effort to integrate with existing codebases

Code Examples

1. Creating a ServerRequest object:

use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\UriInterface;

$request = new ServerRequest(
    'GET',
    Uri::fromString('https://example.com/api'),
    ['Content-Type' => 'application/json'],
    '{"key": "value"}',
    '1.1',
    ['REMOTE_ADDR' => '127.0.0.1']
);

2. Modifying a Response object:

use Psr\Http\Message\ResponseInterface;

$response = $response
    ->withStatus(200)
    ->withHeader('Content-Type', 'application/json')
    ->withBody(stream_for('{"result": "success"}'));

3. Using a StreamInterface:

use Psr\Http\Message\StreamInterface;

$stream = $streamFactory->createStream('Hello, World!');
$content = $stream->getContents();
$stream->rewind();
$size = $stream->getSize();

Getting Started

To use PSR-7 interfaces in your project:

1. Install the package via Composer:

   composer require psr/http-message
   

2. Use the interfaces in your code:

   use Psr\Http\Message\RequestInterface;
   use Psr\Http\Message\ResponseInterface;
   
   class MyHttpClient
   {
       public function sendRequest(RequestInterface $request): ResponseInterface
       {
           // Implementation here
       }
   }
   

3. Implement the interfaces or use a library that provides concrete implementations (e.g., Guzzle, Laminas Diactoros, or Slim).