Add ability to persist and load nodes

[make-github-pseudonymous-again]

Continuing holepunchto/hyperdht#4.

[make-github-pseudonymous-again]

Something like the following:

class DHT extends EventEmitter {

  ...

  toJSON () {
    return {
      nodes: this.nodes.toArray(),
    }
  }

  addNodes (nodes) {
    for (const node of nodes) {
      const { id , token , to } = node
      const peer = {
        host: node.host,
        port: node.port,
      }
      this._addNode(id, peer, token, to)
    }
  }

}

[mafintosh]

Yep! I wouldn't call it toJSON though as the ids are binary. Just toArray() or toNodesArray() is fine

[make-github-pseudonymous-again]

What about the next and prev properties leaking from the tos should we throw them away?
Same for tick.
We could still have a convenience function to output some JSON. Stringify the ids?

[mafintosh]

Good idea stripping the private info. A map of that array to { id, port, ip, referrer: { ip, port, id } } should be enough.

I'm soft -1 on stringify'ing the ids. I think that is the responsibility of whoever is serialising. Alternatively addNodes should deserialise them from hex if they are strings.

[make-github-pseudonymous-again]

What should be in the referrer ?

class DHT extends EventEmitter {

  ...

  getNodes () {
    return this.nodes.toArray().map(
      ({id, host, port, roundtripToken, to}) => ({
        id,
        host,
        port,
        referrer: { ? }
      })
    )
  }

  addNodes (nodes) {
    for (const node of nodes) {
      const { id , token , to } = node
      const peer = { host , port } = node
      this._addNode(id, peer, token, to)
    }
  }


}

[mafintosh]

@aureooms node.referrer is set on the node. not all nodes have this

[make-github-pseudonymous-again]

@aureooms node.referrer is set on the node. not all nodes have this

@mafintosh I see.

[make-github-pseudonymous-again]

What should we do with referrer in addNodes? Should we even care about token and to being given?

class DHT extends EventEmitter {

  ...

  getNodes () {
    return this.nodes.toArray().map(
      ({id, host, port, referrer }) => ({
        id,
        host,
        port,
        referrer: referrer === null ? null : {
          id: referrer.id,
          host: referrer.host,
          port: referrer.port,
        }
      })
    )
  }

  addNodes (nodes) {
    for (const node of nodes) {
      const { id , token , to } = node
      const peer = { host , port } = node
      this._addNode(id, peer, token, to)
    }
  }

}

[mafintosh]

We don't care about token/to.

Actually we don't persist the referrer in the nodes table, so disregard that for now.

[make-github-pseudonymous-again]

Final iteration?

class DHT extends EventEmitter {

  ...

  getNodes () {
    return this.nodes.toArray().map(
      ({id, host, port, referrer }) => ({
        id,
        host,
        port,
        referrer: referrer === null ? null : {
          id: referrer.id,
          host: referrer.host,
          port: referrer.port,
        }
      })
    )
  }

  addNodes (nodes) {
    for (const { id , host , port } of nodes) {
      this._addNode(id, { host , port })
    }
  }

}

[mafintosh]

just skip the referrer on export for now, other than that looks good to me. can you open a PR?

[make-github-pseudonymous-again]

Yes!

[make-github-pseudonymous-again]

PR at #22. I added some tests. Could not get rid of the setTimeout for some reason. Had to trigger some command on a for it to add b as a node.