add opt.validate functions peerIn, peerOut

[jamesgibson14]

I am adding some validate functions to the base gun code. This will give users custom ability to validate incoming / outgoing traffic, and in the case of validate.dataIn, control whether or not data is stored in the local graph.

[jamesgibson14]

To use just add a validate object to the gun option and any or all of the 2 validate functions and return truthy values to allow or falsy to deny.

//for a nodejs server:
const validate = {
    peerIn( raw, peer, gunRoot ){
        const peerIsRelay = !!peer.url
        console.log( `PEER_IN: peerIsRelay ${ peerIsRelay }, ${ peer.wire._socket.remoteAddress }, ${JSON.stringify( peer.id )} - ${raw}\n\r` )
        //must return a truthy for gun to accept a message
        return true
    },
    peerOut( raw, peer, wireMessage ){
        const peerIsRelay = !peer.wire._socket || !!peer.wire._url
        console.log( `PEER_OUT: peerIsRelay ${ peerIsRelay }, ${JSON.stringify( peer.wire?.headers?.host || peer.wire?._url )} - ${raw} \n\r` ) 
        //must return a truthy for gun to send message
        return true
    },
}
const gunConfig = {
    axe: false, 
    web: config.server.listen(config.port), 
    peers: process.env?.PEERS?.split(',') || [],
    validate,
}
var gun = Gun( gunConfig );

[jamesgibson14]

peer.wire._socket.remoteAddress could be used to whitelist messages by IP address, or the raw messages could be check for certain gun paths or public keys to allow or deny.

[jamesgibson14]

@amark it was hard to pick the exact spots to add these validation function, I tried to add them at the lowest level possible so messages could be dropped before much processing has been done. Any feedback to improve it would be great.

[jamesgibson14]

I removed validate.dataIn, since on.in and on.put events work just as well.

[amark]

Oh sorry, GitHub's email notification system has been broken for me for a while.

Thanks for contributing :)

I disagree with how tho:

1) for instance, ws already has an earlier place to do this: the upgrade header from the HTTP to WebSocket handshake, or even verifyClient callback: https://github.com/websockets/ws/blob/master/doc/ws.md

2) if this were to be in GUN, not HTTP/ws, then it should be wrapped as an adapter (especially anything that is non-uniform between browser/NodeJS) like this contributor did https://github.com/amark/gun/blob/master/lib/verify.js very similarly to you, tho note, it reuses (1), tho in my opinion API-wise would be more consistent with the actual ws API so there is less "magic" going on. I'm guessing this may have been something you'd have wanted, but couldn't find it because its poorly documented as a contributor adapter?

Is there something about the above 2 comments that would not solve what you are needing to do?

Thank you for jumping in and helping tho! Want to contribute more in other ways too?