How to create libp2p modular protocols and API?

[0x20CB]

Hello,

I am looking to extend on libp2p and would like to know how to achieve custom protocols that can modularly be added to libp2p. For example, if I would like to create a crate for a custom protocol and let others use it.

Could you create an example or detail out how it would be done.

Thank you.

[drHuangMHT]

The definition of a custom protocol can be as simple as copy-paste a existing protocol implementation and then change its PROTOCOL_NAME(of type StreamProtocol), because that's what's differentiate one protocol from another during protocol negotiation.
You may make a copy of ping protocol here, it can be regarded as a minimum example of a working protocol. Start from here and and tinker with the data being sent over its negotiated substream, work your way up. You may also leave your thoughts about the features you want to have in your protocol, and we can give you some hints and such.
If you get confused about rust-libp2p application model and architecture, don't hesitate to ask, but you may open a discussion thread next time if it's about how to work with rust-libp2p.