EPNS JavaScript SDK.

Getting started

Install

yarn add epns-sdk

Use

import {Query, ChannelSubscription} from 'epns-sdk'
import * as ethers from 'ethers'

;(async () => {
  const SUBGRAPH_URL = 'https://api.thegraph.com/subgraphs/name/vbstreetz/epns'
  const ROPSTEN_CONTRACT_ADDRESS = '0xb02E99b9634bD21A8e3E36cc7adb673287A8FeaC'
  const CHANNEL_ADDRESS = '0x..channel..address'
  const query = new Query(SUBGRAPH_URL)
  console.log(await query.getChannels())
  const channel = await query.getChannel(CHANNEL_ADDRESS)

  const provider = new ethers.providers.Web3Provider(window.ethereum)
  const channelSubscription = new ChannelSubscription(
    ROPSTEN_CONTRACT_ADDRESS,
    provider.getSigner(), CHANNEL_ADDRESS
  )
  console.log('subscribed to %s: %s', (channel.name, await channelSubscription.getIsSubscribed())
  channelSubscription.onChange(subscribed => console.log({subscribed}))
  button.onclick = () => await channel.toggle()
})()

API

The SDK provides the following clients:

• Query: ran queries against an EPNS subgraph.
• ChannelSubscription: subscribe and/ manage the subscription to a channel.
• ChannelOwner: send out channel notifications, get stats etc.
• Channels: subscribe to channel creations + updates.
• Notifications: subscribe to notifications.

Query

new Query(subGraphUrl: string)

Make a new Query client to use to run queries against an EPNS subgraph at subGraphUrl.

query.getChannels(page?: number, count?: number): Promise<Array>

Get a list of channels. To get all channels, invoke: query.getChannels(). To retrieve a paginated list of channels, pass in the page and count query parameters, e.g. query.getChannels(1, 3).

query.getChannel(channelAddress: string): Promise

Get channel info for channelAddress.

query.getNotifications(userAddress: string): Promise<Array>

Get a list of a userAddress's notifications. Pass in the optional page and count to get a paginated list of the notifications.

query.getNotification(id: string): Promise

Fetch notification info matching id.

query.getIsSubscribed(channelAddress: string, userAddress: string): Promise

Get whether userAddress is subscribed to channelAddress.

query.request(query: string, variables: any): Promise

Execute a query (with variables) against subgraphUrl.

ChannelSubscription

new ChannelSubscription(contractAddress: string, signer: ethers.Signer, channelAddress: string)

Make a new ChannelSubscription client for signer and channelAddress at contractAddress.

channelSubscription.subscribe(): Promise<ethers.Transaction>

Subscribe to channel.

channelSubscription.unsubscribe(): Promise<ethers.Transaction>

Cancel subscription.

channelSubscription.toggle(): Promise

Toggle subscription state of the user.

channelSubscription.getIsSubscribed(): Promise

Get whether user address is subscribed to channel.

channelSubscription.onChange(fn: Function): Function

Subscribe to changes in the subscription state of user address and invoke fn(subscribed: boolean). Returns a function to stop listening to the changes.

ChannelOwner

new ChannelOwner(contractAddress: string, signer: ethers.Signer, channelAddress: string)

Make a new ChannelOwner client to manage the channel owned by signer.

channelOwner.getStats(): Promise

Get detailed channel stats as an owner.

channelOwner.notify(type: string, msg: string, recipientAddress?: string, sub?: string, cta?: string, img?: string): Promise<ethers.Transaction>

Send out a notification.

Channels

new Channels(contractAddress: string, signer: ethers.Signer)

Make a new Channels client to subscribe to channel events.

channels.onAdd(fn: Function): Function

Invoke fn whenever a new channel is added. Returns a function to cancel listening to new channel additions.

Notifications

new Notifications(contractAddress: string, signer: ethers.Signer)

Make a new Notifications client to subscribe to notifications sent to signer.

notifications.onReceive(fn: Function): Function

Invoke fn for every notification sent to signer. Returns a function to cancel listening to new notifications.

License

MIT