ssb-keyring/models/po-box.js

A persistence store for encryption keys for scuttlebutt. It's purpose is to make easy to answer box2 encryption/ decryption questions.

const pull = require('pull-stream')
const { read } = require('pull-level')

const { toBuffer, isPOBoxId } = require('../util')

const POBOX = 'pobox'

module.exports = function POBox (db, dm) {
  let cache // Map: groupId => group.info

  const api = {
    load (cb) {
      readPersisted((err, map) => {
        if (err) return cb(err)
        cache = map
        cb(null)
      })
    },

    add (poBoxId, info, cb) {
      if (!cache) throw new Error('keyring not ready')
      if (cache.has(poBoxId)) {
        if (cb) cb()
        return false
      }
      if (!isPOBoxId(poBoxId)) return cb(new Error(`expected a poBoxId, got ${poBoxId}`))
      if (!info.key) return cb(new Error('expected info.key'))
      // TODO <<< store public/secret keys in BFE format, along with ID in BFE format ???

      try {
        // 32 bytes, where 32 === sodium-universal's crypto_scalarmult_SCALARBYTES
        info.key = toBuffer(info.key, 32)
      } catch (e) { return cb(e) }

      cache.set(poBoxId, info)
      db.put([POBOX, poBoxId, Date.now()], info, cb)
      return true
      // TODO store entity poBox is associated with too?
      // - groupId (so only reindex the group lobby feed?
      // - fusionId
    },
    has (poboxId) {
      if (!cache) throw new Error('keyring not ready')
      return cache.has(poboxId)
    },
    get (poboxId) {
      if (!cache) throw new Error('keyring not ready')
      return cache.get(poboxId)
    },
    list () {
      if (!cache) throw new Error('keyring not ready')
      return Array.from(cache.keys())
    }
  }

  return api

  function readPersisted (cb) {
    pull(
      read(db, {
        lt: [POBOX + '~', undefined, undefined], // "group~" is just above "group" in charwise sort
        gt: [POBOX, null, null]
      }),
      pull.map(({ key, value: info }) => {
        const [_, poBoxId, createdAt] = key // eslint-disable-line
        return [poBoxId, info]
      }),
      pull.collect((err, pairs) => {
        if (err) return cb(err)
        cb(null, new Map(pairs))
      })
    )
  }
}