Websocket connection is throwing error 403 on the second attempt

Developer API
1

I’m creating a web socket connection with upstox to fetch real time market data using the following code -

// Import required modules
import { ApiClient, WebsocketApi } from "upstox-js-sdk";
import { WebSocket } from "ws";
import pkg from "protobufjs";
const {load} = pkg;

// Initialize global variables
let protobufRoot = null;
let defaultClient = ApiClient.instance;
let apiVersion = "2.0";
let OAUTH2 = defaultClient.authentications["OAUTH2"];

// Function to authorize the market data feed
const getMarketFeedUrl = async () => {
  return new Promise((resolve, reject) => {
    let apiInstance = new WebsocketApi(); // Create new Websocket API instance

    // Call the getMarketDataFeedAuthorize function from the API
    apiInstance.getMarketDataFeedAuthorize(
      apiVersion,
      (error, data, response) => {
        if (error) reject(error); // If there's an error, reject the promise
        else resolve(data.data.authorizedRedirectUri); // Else, resolve the promise with the authorized URL
      }
    );
  });
};

// Function to establish WebSocket connection
const connectWebSocket = async (wsUrl, instrumentKeys, callback) => {
  return new Promise((resolve, reject) => {
    const ws = new WebSocket(wsUrl, {
      headers: {
        "Api-Version": apiVersion,
        Authorization: "Bearer " + OAUTH2.accessToken,
      },
      followRedirects: true,
    });

    // WebSocket event handlers
    ws.on("open", () => {
      console.log("connected");
      resolve(ws); // Resolve the promise once connected

      // Set a timeout to send a subscription message after 1 second
      setTimeout(() => {
        const data = {
          guid: "someguid",
          method: "sub",
          data: {
            mode: "full",
            instrumentKeys: instrumentKeys,
          },
        };
        ws.send(Buffer.from(JSON.stringify(data)));
      }, 1000);
    });

    ws.on("close", () => {
      console.log("disconnected");
    });

    ws.on("message", (data) => {
      const decodedData = decodeProfobuf(data);
      const information = Object.keys(decodedData.feeds).map(
        (key) => ({
          instrumentKey: key,
          ltp: decodedData.feeds[key]?.ff?.indexFF?.ltpc?.ltp,
          open1D: decodedData.feeds[key]?.ff?.indexFF?.marketOHLC?.ohlc[0].open,
          close1D: decodedData.feeds[key]?.ff?.indexFF?.marketOHLC?.ohlc[0].close
        })
      );
      callback(JSON.stringify(information));
    });

    ws.on("error", (error) => {
      console.log("error:", error);
      reject(error); // Reject the promise on error
    });
  });
};

// Function to initialize the protobuf part
const initProtobuf = async () => {
  protobufRoot = await load("./utils/MarketDataFeed.proto");
  console.log("Protobuf part initialization complete");
};

// Function to decode protobuf message
const decodeProfobuf = (buffer) => {
  if (!protobufRoot) {
    console.warn("Protobuf part not initialized yet!");
    return null;
  }

  const FeedResponse = protobufRoot.lookupType(
    "com.upstox.marketdatafeeder.rpc.proto.FeedResponse"
  );
  return FeedResponse.decode(buffer);
};

// Initialize the protobuf part and establish the WebSocket connection
export const getMarketDataFeed = (async (accessToken, instrumentKeys, callback) => {
  OAUTH2.accessToken = accessToken;
  try {
    await initProtobuf(); // Initialize protobuf
    const wsUrl = await getMarketFeedUrl(); // Get the market feed URL
    const ws = await connectWebSocket(wsUrl, instrumentKeys, callback); // Connect to the WebSocket
  }
  catch (error) {
    console.error("An error occurred:", error);
  }
});

I’m calling the method getMarketDataFeed to initialize the protobuf, establish a web socket connection to fetch real time market data. The callback passed to the method is the following -

(data) => {
    socket.emit('market data', data);
}

The first time I call this method (when the application is brought up), everything seems fine. The second time onwards, I start getting the following error -

error: Error: Unexpected 
server response: 403

at ClientRequest.<anonymous>
at ClientRequest.emit (node:events:514:28)    
    at HTTPParser.parserOnIncomingClient [as onIncoming] (node:_http_client:700:27)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:119:17)       
    at TLSSocket.socketOnData (node:_http_client:541:22)
    at TLSSocket.emit (node:events:514:28)        
    at addChunk (node:internal/streams/readable:324:12)
    at readableAddChunk (node:internal/streams/readable:297:9)
    at Readable.push (node:internal/streams/readable:234:10)
    at TLSWrap.onStreamRead (node:internal/stream_base_commons:190:23)

I don’t see anything wrong in the code. Can you please help me with this?

2

The code used to establish a web socket connection is taken from here → upstox-nodejs/examples/websocket/market_data/websocket_client.js at master · upstox/upstox-nodejs · GitHub

Just the method getMarketDataFeed was added which establishes the web socket connection when invoked.

3

The redirect URL obtained for the WebSocket is valid for a single connection only. To reconnect to the WebSocket, you must generate a new redirect URL.

For convenience, please refer to the new streamer functions available in Node.js on our GitHub page.
Nodejs SDK

4

The issue was that the existing web socket connection was not being closed before establishing a new one. Thanks Ketan for your response.

1 Like
5

@Anish_Bhagavatula Thank you for the update confirming the issue is resolved.