Authorization

const crypto = require("crypto");

const API_PUBLIC_KEY = "your_public_key";
const API_PRIVATE_KEY = "your_private_key";
const CHANNEL_AUTH_ENDPOINT = "https://api.futuur.com/v2.0/pusher/auth/";

async function authorizeChannel(socketId, channelName) {
  const timestamp = String(Math.floor(Date.now() / 1000));
  const paramsToSign = {
    Key: API_PUBLIC_KEY,
    Timestamp: timestamp,
    channel_name: channelName,
    socket_id: socketId,
  };
  const rawToSign = new URLSearchParams(
    Object.entries(paramsToSign).sort(([a], [b]) => a.localeCompare(b)),
  ).toString();
  const signature = crypto
    .createHmac("sha512", API_PRIVATE_KEY)
    .update(rawToSign)
    .digest("hex");

  const response = await fetch(CHANNEL_AUTH_ENDPOINT, {
    method: "POST",
    headers: {
      Key: API_PUBLIC_KEY,
      Timestamp: timestamp,
      HMAC: signature,
      "Content-Type": "application/x-www-form-urlencoded",
    },
    body: new URLSearchParams({
      socket_id: socketId,
      channel_name: channelName,
    }),
  });

  if (!response.ok) {
    throw new Error("Forbidden");
  }

  return response.json(); // { auth: "..." }
}

const Pusher = require("pusher-js");

const pusher = new Pusher("9011f7eac38e825792d5", {
  cluster: "us2",
  channelAuthorization: {
    customHandler: ({ socketId, channelName }, callback) => {
      authorizeChannel(socketId, channelName)
        .then((authResponse) => callback(null, authResponse))
        .catch((err) => callback(err, null));
    },
  },
});

const channel = pusher.subscribe("private-user-1");