memegoat/backend/src/common/middlewares/http-logger.middleware.ts

import { createHash } from "node:crypto";
import { Injectable, Logger, NestMiddleware } from "@nestjs/common";
import { NextFunction, Request, Response } from "express";

@Injectable()
export class HTTPLoggerMiddleware implements NestMiddleware {
	private readonly logger = new Logger("HTTP");

	use(request: Request, response: Response, next: NextFunction): void {
		const { method, originalUrl, ip } = request;
		const userAgent = request.get("user-agent") || "";
		const startTime = Date.now();

		response.on("finish", () => {
			const { statusCode } = response;
			const contentLength = response.get("content-length");
			const duration = Date.now() - startTime;

			const hashedIp = createHash("sha256")
				.update(ip as string)
				.digest("hex");
			const message = `${method} ${originalUrl} ${statusCode} ${contentLength || 0} - ${userAgent} ${hashedIp} +${duration}ms`;

			if (statusCode >= 500) {
				return this.logger.error(message);
			}

			if (statusCode >= 400) {
				return this.logger.warn(message);
			}

			return this.logger.log(message);
		});

		next();
	}
}