rollbar/src/server/middleware/rollbarExpressMiddleware.js

Effortlessly track and debug errors in your JavaScript applications with Rollbar. This package includes advanced error tracking features and an intuitive interface to help you identify and fix issues more quickly.

import { AsyncLocalStorage } from 'node:async_hooks';

export function extractSessionId(headerValue) {
  if (!headerValue) {
    return null;
  }
  const rawValue = Array.isArray(headerValue)
    ? headerValue.join(',')
    : headerValue;
  if (typeof rawValue !== 'string') {
    return null;
  }
  const entries = rawValue.split(',');
  for (const entry of entries) {
    const trimmed = entry.trim();
    if (!trimmed) {
      continue;
    }
    const equalsIndex = trimmed.indexOf('=');
    if (equalsIndex === -1) {
      continue;
    }
    const key = trimmed.slice(0, equalsIndex).trim();
    if (key !== 'rollbar.session.id') {
      continue;
    }
    const value = trimmed.slice(equalsIndex + 1).trim();
    if (!value) {
      return null;
    }
    try {
      return decodeURIComponent(value);
    } catch (_e) {
      return value;
    }
  }
  return null;
}

function getBaggageHeader(req) {
  if (!req) {
    return null;
  }
  if (typeof req.get === 'function') {
    return req.get('baggage');
  }
  return req.headers?.baggage || null;
}

export default function rollbarExpressMiddleware(rollbar) {
  const storage = rollbar?.client.asyncLocalStorage || new AsyncLocalStorage();
  if (rollbar) {
    rollbar.client.asyncLocalStorage = storage;
  }

  return function rollbarExpressMiddlewareHandler(req, _res, next) {
    const sessionId = extractSessionId(getBaggageHeader(req));
    if (!sessionId) {
      return next();
    }
    return storage.run({ sessionId }, () => next());
  };
}