datastore-pubsub

Responsible for providing an interface-datastore compliant api to pubsub

Table of contents

• Install
• Usage
• API
  • • Setup
    • Get
    • Put
    • Unsubscribe
• Contribute
• License
• Contribute

Install

$ npm i 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

Licensed under either of

• Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
• MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)

Contribute

Feel free to join in. All welcome. Open an issue!

This repository falls under the IPFS Code of Conduct.