Fetching Real-time OHLC

We now use the new Price Index Streams to fetch pre-aggregated OHLC data directly from Bitquery's GraphQL WebSocket API. This removes the need to manually calculate candlesticks from raw trade data.

To learn more about streaming data via graphQL, visit Bitquery subscriptions.

Imports and Configuration

import { createClient } from "graphql-ws";
import config from "./configs.json";

• createClient: From the graphql-ws library, used to subscribe to GraphQL streams.
• config: A local file storing your Bitquery API token.

let client;
const BITQUERY_ENDPOINT = 'wss://streaming.bitquery.io/eap?token=' + config.authtoken;

Subscription Query

const subscriptionQuery = `
subscription {
  Trading {
    Tokens(
      where: {
        Token: {
          Network: {is: "Solana"},
          Address: {is: "6ft9XJZX7wYEH1aywspW5TiXDcshGc2W2SqBHN9SLAEJ"}
        },
        Interval: {Time: {Duration: {eq: 1}}}
      }
    ) {
      Block {
        Time
      }
      Price {
        Ohlc {
          Open
          High
          Low
          Close
        }
      }
      Volume {
        Base
      }
    }
  }
}
`;

• This query subscribes to pre-aggregated 1-minute OHLC bars for a token on the Solana network.

• It includes:

  • Block time (Block.Time)
  • OHLC prices (Open, High, Low, Close)
  • Trade volume (Volume.Base)

---

Subscribing to the Stream

export function subscribeToWebSocket(onRealtimeCallback) {
  client = createClient({ url: BITQUERY_ENDPOINT });

  const onNext = (data) => {
    const tokenData = data.data?.Trading?.Tokens?.[0];
    if (!tokenData) return;

    const bar = {
      time: new Date(tokenData.Block.Time).getTime(),
      open: tokenData.Price.Ohlc.Open,
      high: tokenData.Price.Ohlc.High,
      low: tokenData.Price.Ohlc.Low,
      close: tokenData.Price.Ohlc.Close,
      volume: tokenData.Volume.Base,
    };

    onRealtimeCallback(bar); // Emit finalized 1-minute OHLC bar
  };

  client.subscribe(
    { query: subscriptionQuery },
    { next: onNext, error: console.error }
  );
}

• subscribeToWebSocket:

  • Connects to Bitquery using graphql-ws.
  • On each received message, extracts the finalized OHLC bar and passes it to your onRealtimeCallback.

Unsubscribing from the Stream

export function unsubscribeFromWebSocket() {
  if (client) {
    client.dispose();
  }
}

• unsubscribeFromWebSocket: Terminates the WebSocket connection to stop receiving data.