A field guide to developing with secure-scuttlebutt
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README.md

ssb field guide

A field guide to developing with ssb

Further reading:

ssb

The database layer is secure-scuttlebutt.

A database of unforgeable append-only feeds, optimized for efficient replication for peer to peer protocols

The database is implemented with flumedb. Your data is probably stored in a file at ~/.ssb/flume/log.offset. This is an append only log that has your messages and probably your friends and foafs messages as well.

Also in ~/.ssb/flume you will see some JSON files. These are materialized views of the database log (flume views). friends.json is a view of people within two hops in your foaf graph.

feeds

A feed is a signed append-only sequence of messages. Each identity has exactly one feed. Your ssb log contains many feeds (one for each identity that you are gossiping), all mixed together. Each message in a feed has a field sequence that is an increasing number. That way you can tell peers the latest sequence that you have, and then request or send newer messages.

sbot

scuttlebot (or sbot) provides network services on top of secure-scuttlebutt (the database).

The gossip and replication server for Secure Scuttlebutt - a distributed social network

See also:

client

A client is an application that uses sbot with various plugins as a backend. Each peer on the network corresponds to one database and one sbot instance, and the same sbot may be shared by several clients (see ssb-party). All of these processes are probably running on one machine.

ssb-client

ssb-client can be used to connect to an sbot running in a separate process. There are some important configuration bits that your application needs, caps.shs and caps.sign. Your client needs shs, and sbot needs sign. These determine which network your app connects to. By setting these you can do tests and development on a separate network. SHS stands for secret handshake. There is a whitepaper about it too.

Setting caps.shs makes gossip connections not occur with peers that have a different shs key.

Setting caps.sign makes messages to be considered invalid that were created with a different sign key.

If you only set the shs key, messages could leak out of your network if someone in the network changes their shs key, or adds messages manually. Setting the sign key ensures that the messages will not be able to be published (or validated) on the main ssb network, only on a network where that same sign key is used.

shs and sign should be base64 encoded random strings

var crypto = require('crypto')
crypto.randomBytes(32).toString('base64')
var Client = require('ssb-client')
var path = require('path')
var home = require('os-homedir')
var getKeys = require('ssb-keys').loadOrCreateSync

var SSB_PATH = path.join(home(), '.ssb')
var keys = getKeys(path.join(SSB_PATH, 'secret'))

Client(keys, {
    path: SSB_PATH,
    caps: {
        shs: 'abc'
    }
}, (err, sbot, config) => {
    // `sbot` here is an rpc client for a local sbot server 
})

start an sbot

The client depends on an sbot using the same caps.shs as the client. You can pass it in as an argument

$ sbot server -- --caps.shs="abc" --caps.sign="123"

See also ssb-minimal

sbot plugins

Plugins expose methods via rpc to interact with an sbot. A plugin will typically read data from the ssb log, then create a view of that data that is saved somewhere, so it doesn't need to be recalculated from the beginning.

An example is ssb-contacts. This uses flumeview-reduce to persist it's state, but you could use any persistence.

Plugins have an interface used by secret-stack. For plugin authors this means you need a few fields in your module. exports.manifest is familiar if you have used muxrpc. The manifest is used to tell remote clients what functions your service is exposing via rpc.

exports.name = 'contacts'
exports.version = require('./package.json').version
exports.manifest = {
    stream: 'source',
    get: 'async'
}
exports.init = function (ssb, config) { /* ... */ }