Function errorHandlingMiddleware

backend/src/middlewares/error.ts:35–119

(
  error: Error,
  req: ExpressRequestWithContext,
  res: Response,
  _next: NextFunction,
)

};

async function errorHandlingMiddleware(
  error: Error,
  req: ExpressRequestWithContext,
  res: Response,
  _next: NextFunction,
): Promise<void> {
  try {
    const monkeyError = error as MonkeyError;
    let status = 500;
    const data: { errorId?: string; uid: string } = {
      errorId: monkeyError.errorId ?? uuidv4(),
      uid: monkeyError.uid ?? req.ctx?.decodedToken?.uid,
    };
    let message = "Unknown error";

    if (/ECONNREFUSED.*27017/i.test(error.message)) {
      message = "Could not connect to the database. It may be down.";
    } else if (error instanceof URIError || error instanceof SyntaxError) {
      status = 400;
      message = "Unprocessable request";
    } else if (error instanceof MonkeyError) {
      message = error.message;
      status = error.status;
    } else {
      message = `Oops! Our monkeys dropped their bananas. Please try again later. - ${data.errorId}`;
    }

    await incrementBadAuth(req, res, status);

    if (status >= 400 && status < 500) {
      recordClientErrorByVersion(req.headers["x-client-version"] as string);
    }

    if (!isDevEnvironment() && status >= 500 && status !== 503) {
      recordServerErrorByVersion(version);

      const { uid, errorId } = data as {
        uid: string;
        errorId: string;
      };

      try {
        await addLog(
          "system_error",
          `${status} ${errorId} ${error.message} ${error.stack}`,
          uid,
        );
        await db.collection<DBError>("errors").insertOne({
          _id: errorId,
          timestamp: Date.now(),
          status: status,
          uid,
          message: error.message,
          stack: error.stack,
          endpoint: req.originalUrl,
          method: req.method,
          url: req.url,
        });