feat: Add PSR-7 middleware support for HTTP transports

[CodeWithKyrian]

Adds PSR-7 compatible middleware support to both HttpServerTransport and StreamableHttpServerTransport.

[nadar]

@CodeWithKyrian would be nice to have this relased.

[alebedev80]

@CodeWithKyrian when it will be released finally?

[CodeWithKyrian]

HI @nadar and @alebedev80 , quick update on this.

So I’ve paused active development on this package because I’m now working with the PHP Foundation, Anthropic, and the Symfony team on the official MCP PHP SDK. A lot of the ideas and design decisions from this package made their way into the official one, so the transition shouldn’t feel foreign. The APIs are very very similar as this package was a base for it.

Some features (like this particular PR) aren’t in the official SDK yet, but I do plan to bring that in. Also, since this package was built around ReactPHP, I’m working on a ReactPHP transport option for the official SDK so folks depending on async http-based transports won’t get stuck.

This weekend I’m going to tidy up a few things here, merge pending PRs, fix some issues, and tag one final release (or one of the final releases I guess). After that, this package will be archived and I’ll recommend moving to the official SDK going forward.

Thanks for the patience🙏🏽