README
datastore-pubsub
provides an implementation of an api for pubsub to be used as a datastore with TieredDatastore
Table of Contents
Install
npm install datastore-pubsub
Usage
import { PubsubDatastore } from 'datastore-pubsub'
const dsPubsub = new PubsubDatastore(pubsub, datastore, peerId, validator)
API
Setup
new PubsubDatastore(pubsub, datastore, peerId, validator, subscriptionKeyFn)
Creates a DatastorePubsub instance.
Arguments:
pubsub
(Object): implementation of a pubsub (must have publish and subscribe functions), such as libp2p/pubsub.datastore
(Object): datastore compliant with interface-datastore, such as datastore-fs.peerId
(PeerId
Instance): peer identifier object.validator
(Object): containing validate function and select function.subscriptionKeyFn
(function): function to manipulate the key topic received according to the needs, as well as to block the message received to be published.
Note: validator
object must be composed by two functions, validate (record: uint8Array, peerId: PeerId) => boolean
and select (received: uint8Array, current: uint8Array) => boolean
. validate
aims to verify if a new record received by pubsub is valid to be stored locally by the node. If it is valid and the node already has a local record stored, select
is the function provided to be responsible for deciding which record is the best (newer) between the already stored and the received through pubsub. A validator
example can be found at: TODO (js-ipns)
const dsPubsub = new DatastorePubsub(pubsub, datastore, peerId, validator)
Get
const buf = await dsPubsub.get(key)
Try to subscribe a topic with Pubsub and receive the current local value if available.
Arguments:
key
(Uint8Array): a key representing a unique identifier of the object to subscribe.
Returns Promise<Uint8Array>
containing the most recent known record stored.
Put
await dsPubsub.put(key, val)
Publishes a value through pubsub.
Arguments:
key
(Uint8Array): a key representing a unique identifier of the object to publish.val
(Uint8Array): value to be propagated.
Returns Promise<void>
Unsubscribe
await dsPubsub.unsubscribe(key)
Unsubscribe a previously subscribe value.
Arguments:
key
(Uint8Array): a key representing a unique identifier of the object to publish.
Returns Promise<void>
Contribute
Feel free to join in. All welcome. Open an issue!
This repository falls under the IPFS Code of Conduct.
License
Copyright (c) Protocol Labs, Inc. under the MIT License. See LICENSE file for details.