http-message VS Nyholm PSR-7

There is a package within The PHP League that allows validation of an OpenAPI specification: league/openapi-psr7-validator. This package validates requests and responses to the PSR-7 specification.

PSR-7, the standard for requests and responses

Guzzle implements PSR-7: HTTP message interfaces (but apparently not yet PSR-18: HTTP Client, or at least they don't mention it). That means it's possible to use it in third-party libraries/frameworks and easy to replace with similar tools.

The Yii HTTP Application provides the Application::class, as well as the events and handlers needed to interact with HTTP. The package is implemented using PSR-7 and PSR-15 standards.

[PSR Http Message.](https://github.com/php-fig/http-message) This repository holds all interfaces/classes/traits related to [PSR-7](http://www.php-fig.org/psr/psr-7/).

PSR Http Message. This repository holds all interfaces/classes/traits related to PSR-7.

Since the library is designed to be easily integrated with different frameworks, it relies on the usage of PSR-7 compliant HTTP messages. To fulfill this requirement, I'll be using the nyholm/psr7 package.

Sounds good for the future given that PHP-FIG seems uninterested in maintaining the related code repo https://github.com/php-fig/http-message/pull/95

As the documentation states, this package only performs the conversion, so we would need a PSR-7 and a PSR-17 implementation to convert the objects to and from PSR-7. We can use the library the documentation recommends, nyholm/psr7, but there are others.

The following example shows how to create configuration for the HTTP factories, using the nyholm/psr7 package:

Since the library is designed to be easily integrated with different frameworks, it relies on the usage of PSR-7 compliant HTTP messages. To fulfill this requirement, I'll be using the nyholm/psr7 package.

If you go strict PSR-7, as you see in nyholm/psr7, Tobias uses traits to add the functionality of the extended RequestInterface and MessageInterface:

The Symfony folks thought of this, however, and provided a bridge that converts HttpFoundation objects to PSR-7 ones. The bridge simply needs a PSR-7 and PSR-17 factory, for which they suggest to use Tobias Nyholm's PSR-7 implementation.

“In theory, theory and practice are the same. In practice, they are not.” (Dr. Albert Einstein). I believe same goes for packages, too. A good example is the [comparison](https://github.com/Nyholm/psr7) of some PSR-7 implementations.

The point is why would I pull in code in the first place that is not needed? If it is optional, then why is it not a separate package? Same with all of the bloated HTTP requests and response objects that frameworks and other libs usually use. I really like https://github.com/Nyholm/psr7 for that reason, it has a table in it's readme.md that is pretty much enough to know why I like it. If something specific is needed it can be decorated or extended on project level.