defined-realtime-websocket

Defined.fi Realtime Websocket SDK

TypeScript library for interacting with Defined.fi's realtime websockets.

This library is isomorphic, working on both client and server. Client uses the built-in browser WebSocket, and server will default to the ws package.

Installation

defined-realtime-websocket can be used both client-side and server-side.

To install defined-realtime-websocket, use:

npm install defined-realtime-websocket
# or yarn add defined-realtime-websocket
# or pnpm i defined-realtime-websocke

Usage

If you’re new to Defined.fi's API, or need an API key, checkout their docs to get started

Configuration

Import and instantiate the client with your defined API key. If you don't have an API key, you can request one in Defined.fi's Discord

import { DefinedRealtimeClient } from 'defined-realtime-websocket';

const DEFINED_API_KEY = '1234...7890';

const definedWs = new DefinedRealtimeClient(MY_DEFINED_API_KEY);

That's it for set up.

Now let's subscribe to a realtime update of some kind.

First we'll need an subscription handler to handle incoming websocket messages and updates. A subscription handler is just a JavaScript object with three functions attached to it: next(nextVal => void), error(err => void), and complete(() => void). This is based off the Apollo and other GraphQL subscription event sink patterns.

const subscriptionHandler = {
  next: (nextVal) {
    // Save the incoming websocket data somewhere in your application
  },
  error: (err) {
    // Handle a websocket error in your application
  },
  complete: () {
    // The subscription is done/complete and there will be no more events sent.
  }
}

Available Subscriptions

subscribeToTokenPriceUpdates

Latest price data.

const unsub = definedWs.subscribeToTokenPriceUpdates(
  subscriptionHandler,
  // Optional filter object
  {
    contractAddress: '0x1234...',
    chainId: 1,
  }
);

subscribeToTokenChartUpdates

Data you need to update your charts. (Supports TradingView format output).

const unsub = definedWs.subscribeToTokenChartUpdates(
  subscriptionHandler,
  // Optional filter object
  {
    contractAddress: '0x1234...',
    chainId: 1,
  }
);

subscribeToTokenSwapUpdates

Latest transaction events.

const unsub = definedWs.subscribeToTokenSwapUpdates(
  subscriptionHandler,
  // Optional filter object
  {
    contractAddress: '0x1234...',
    chainId: 1,
  }
);

subscribeToNftSales

Latest nft transaction events.

const unsub = definedWs.subscribeToNftSales(
  subscriptionHandler,
  // Optional filter object
  {
    contractAddress: '0x1234...',
    chainId: 1,
  }
);

subscribe

If the pre-built subscriptions don't work, you can always use own custom GQL.

Create your own GQL subscription.

// Custom GQL for $LINK mainnet price updates
const customGql = `
subscription UpdatePrice($address: String, $networkId: Int) {
  onUpdatePrice(address: "0x514910771af9ca656af840dff83e8264ecf986ca", networkId: 1) {
    address
    networkId
    priceUsd
    timestamp
  }
}`;

// Add the typing
interface TokenPricingGqlData {
  onUpdatePrice: {
    timestamp: number;
    priceUsd: number;
    networkId: number;
    address: string;
  };
}

// Subscribe to the custom GQL and add in the type for full type-safety
const unsub = definedWs.subscribe<TokenPricingGqlData>(
  customGql,
  subscriptionHandler
);

Full example

Let's get all realtime trades for the Milady NFT collection.

import { DefinedRealtimeClient } from 'defined-realtime-websocket';

const definedWs = new DefinedRealtimeClient(API_KEY);

await definedWs.subscribeToNftSales(
  // Filter (optional)
  {
    // Milady
    contractAddress: '0x5af0d9827e0c53e4799bb226655a1de152a425a5',
    // Mainnet
    chainId: 1,
  },
  // Subscription handle / event sink
  {
    next(nftTxData) {
      console.log(nftTxData.onCreateNftEvents.address)
    },
    error(_) {
      // noop
    },
    complete: () {
      // noop
    },
  }
);

License

MIT. Do whatever.

Contributing

Gladly accept PRs and feedback via GitHub.