feat: add middleware utils

Author: cyber-hari

src/utils/middleware.utils.ts

@@ -0,0 +1,232 @@
+import { randomUUID } from "crypto";
+import { Config } from "../config";
+import { uuid } from "./id.utils";
+import { HttpStatusCodes } from "./http-status-codes";
+import { ErrorResponse } from "./response.utils";
+import { Env } from "./env.utils";
+
+/**
+ * Type definitions for Express-compatible middleware
+ */
+export type Request = {
+  headers: Record<string, string | string[] | undefined>;
+  method: string;
+  url: string;
+  ip?: string;
+  body?: any;
+  query?: Record<string, any>;
+  params?: Record<string, any>;
+  [key: string]: any;
+};
+
+export type Response = {
+  status: (code: number) => Response;
+  json: (data: any) => void;
+  send: (data: any) => void;
+  setHeader: (name: string, value: string | string[]) => void;
+  end: (data?: any) => void;
+  on: (event: string, callback: (...args: any[]) => void) => void;
+  [key: string]: any;
+};
+
+export type NextFunction = (err?: Error | any) => void;
+
+export type Middleware = (
+  req: Request,
+  res: Response,
+  next: NextFunction,
+) => void | Promise<void>;
+
+/**
+ * Attaches a unique request ID to each request.
+ * Useful for request tracing and correlation between logs.
+ *
+ * @param {object} [options] - Configuration options
+ * @param {string} [options.headerName='X-Request-ID'] - Header name for request ID
+ * @param {boolean} [options.exposeHeader=true] - Whether to expose the header in response
+ * @returns {Middleware} Express-compatible middleware
+ */
+export function requestId(options?: {
+  headerName?: string;
+  exposeHeader?: boolean;
+}): Middleware {
+  const headerName = options?.headerName || "X-Request-ID";
+  const exposeHeader = options?.exposeHeader !== false;
+
+  return (req, res, next) => {
+    // Use existing request ID from header or generate a new one
+    const existingId = req.headers[headerName.toLowerCase()];
+    const id = (existingId as string) || randomUUID();
+
+    // Attach ID to request object
+    req.id = id;
+
+    // Add ID to response headers
+    if (exposeHeader) {
+      res.setHeader(headerName, id);
+    }
+
+    next();
+  };
+}
+
+/**
+ * Measures request processing time and logs or adds it to response headers.
+ *
+ * @param {object} [options] - Configuration options
+ * @param {boolean} [options.addHeader=true] - Whether to add X-Response-Time header
+ * @param {boolean} [options.logOnComplete=false] - Whether to log timing info
+ * @returns {Middleware} Express-compatible middleware
+ */
+export function responseTime(options?: {
+  addHeader?: boolean;
+  logOnComplete?: boolean;
+}): Middleware {
+  const addHeader = options?.addHeader !== false;
+  const logOnComplete = options?.logOnComplete === true;
+
+  return (req, res, next) => {
+    const start = process.hrtime();
+
+    // Function to calculate elapsed time
+    const calculateDuration = (): number => {
+      const diff = process.hrtime(start);
+      return diff[0] * 1e3 + diff[1] * 1e-6; // Convert to ms
+    };
+
+    // Handle response completion
+    res.on("finish", () => {
+      const duration = calculateDuration();
+
+      if (addHeader) {
+        res.setHeader("X-Response-Time", `${duration.toFixed(2)}ms`);
+      }
+
+      if (logOnComplete) {
+        const { method, url } = req;
+        // eslint-disable-next-line no-console
+        console.info(`${method} ${url} - ${duration.toFixed(2)}ms`);
+      }
+    });
+
+    next();
+  };
+}
+
+/**
+ * Request timeout middleware.
+ * Aborts requests that take too long to process.
+ *
+ * @param {number} [timeoutMs=30000] - Timeout in milliseconds
+ * @returns {Middleware} Express-compatible middleware
+ */
+export function timeout(timeoutMs: number = Config.Http.timeout): Middleware {
+  return (req, res, next) => {
+    // Set timeout for the request
+    const timer = setTimeout(() => {
+      res.status(408).json({
+        error: true,
+        message: "Request timeout",
+        status: 408,
+        timestamp: new Date().toISOString(),
+      });
+    }, timeoutMs);
+
+    // Clear timeout when response is sent
+    res.on("finish", () => {
+      clearTimeout(timer);
+    });
+
+    next();
+  };
+}
+
+/**
+ * Creates a standardized error response object for API errors.
+ *
+ * @param {string} message - Error message
+ * @param {Request} req - Express request object
+ * @param {any} error - Original error object
+ * @param {object} [options] - Additional options
+ * @param {boolean} [options.includeDetails=false] - Whether to include error details in non-production
+ * @returns {object} Formatted error response
+ */
+const createErrorResponse = (
+  message: string,
+  req: Request,
+  error: any,
+  options?: { includeDetails?: boolean },
+) => {
+  const isDev = Env.isDev();
+  const includeDetails = options?.includeDetails && isDev;
+
+  const response: Record<string, any> = {
+    error: true,
+    message,
+    timestamp: new Date().toISOString(),
+    requestId: error?.requestId || req.id || uuid(),
+    path: req.originalUrl || req.url,
+  };
+
+  // Include error code if present
+  if (error?.code) {
+    response.code = error.code;
+  }
+
+  // Include stack trace in development mode if requested
+  if (includeDetails && error?.stack) {
+    response.stack = error.stack.split("\n").map((line: string) => line.trim());
+  }
+
+  return response;
+};
+
+/**
+ * Global error handling middleware with enhanced features.
+ *
+ * @param {object} [options] - Error handler options
+ * @param {boolean} [options.logErrors=true] - Whether to log errors
+ * @param {boolean} [options.includeDetails=false] - Whether to include error details in non-production
+ * @param {Function} [options.logger=console.error] - Custom logging function
+ * @returns {(err: any, req: Request, res: Response, next: NextFunction) => void} Error middleware
+ */
+export function errorHandler(options?: {
+  logErrors?: boolean;
+  includeDetails?: boolean;
+  logger?: (message: string, error: any) => void;
+}) {
+  const logErrors = options?.logErrors !== false;
+  const includeDetails = options?.includeDetails === true;
+  // eslint-disable-next-line no-console
+  const logger = options?.logger || console.error;
+
+  return (err: any, req: Request, res: Response, _next: NextFunction) => {
+    // Determine status code
+    const status =
+      err?.status || err?.statusCode || HttpStatusCodes.INTERNAL_SERVER_ERROR;
+
+    // Log error if enabled
+    if (logErrors) {
+      const logMessage = `[ERROR] ${req.method} ${req.originalUrl || req.url}: ${err.message || "Unknown error"}`;
+      logger(logMessage, err);
+    }
+
+    // Handle ErrorResponse instances (our custom error class)
+    if (err instanceof ErrorResponse) {
+      return res.status(status).json({
+        error: err.error,
+        message: err.message,
+        timestamp: err.timestamp,
+        requestId: err.requestId || req.id || uuid(),
+        path: req.originalUrl || req.url,
+      });
+    }
+
+    // Handle any other errors
+    return res.status(status).json(
+      createErrorResponse(err?.message || "Internal Server Error", req, err, {
+        includeDetails,
+      }),
+    );
+  };
+}