datastore-pubsub

Responsible for providing an interface-datastore compliant api to pubsub

Table of contents

• Install
  • Browser <script> tag
• Usage
• API
  • Setup
  • Get
  • Put
  • Unsubscribe
• API Docs
• License
• Contribute

Install

$ npm i datastore-pubsub

Browser <script> tag

Loading this module through a script tag will make it's exports available as DatastorePubsub in the global namespace.

<script src="https://unpkg.com/datastore-pubsub/dist/index.min.js"></script>

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>

API Docs

• https://ipfs.github.io/js-datastore-pubsub

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

Contributions welcome! Please check out the issues.

Also see our contributing document for more information on how we work, and about contributing in general.

Please be aware that all interactions related to this repo are subject to the IPFS Code of Conduct.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.