metis-desk/apps/server/src/app.ts

import { randomUUID } from "node:crypto";

import type { HttpErrorResponseDTO } from "@metis/core/common";
import { registerCoreRoutes } from "@metis/core/module";
import type { Application, ErrorRequestHandler, RequestHandler } from "express";
import express from "express";
import helmet from "helmet";

import type { HttpLogger } from "./infrastructure/http/http-logger";
import { logHttpRequest } from "./infrastructure/http/http-logger";

export function createApp(
  logger: HttpLogger = logHttpRequest,
  identity?: { middleware: RequestHandler; register: (app: Application) => void }
) {
  const app = express();
  app.disable("x-powered-by");
  app.use(helmet());
  app.use((request, response, next) => {
    const requestId = randomUUID();
    const startedAt = performance.now();
    response.setHeader("x-request-id", requestId);
    response.setHeader("cache-control", "no-store");
    response.once("finish", () => {
      logger({
        event: "http_request",
        requestId,
        method: request.method,
        statusCode: response.statusCode,
        durationMs: Math.round((performance.now() - startedAt) * 100) / 100,
      });
    });
    next();
  });

  app.use(express.json({ limit: "64kb" }));
  if (identity) {
    app.use(identity.middleware);
    identity.register(app);
  }
  registerCoreRoutes(app);

  app.use((_request, response) => {
    const error: HttpErrorResponseDTO = {
      code: "NOT_FOUND",
      requestId: response.getHeader("x-request-id")?.toString() ?? "",
    };
    response.status(404).json(error);
  });
  const errorHandler: ErrorRequestHandler = (_error: unknown, _request, response, next) => {
    if (response.headersSent) {
      next(_error);
      return;
    }
    const error: HttpErrorResponseDTO = {
      code: "INTERNAL_ERROR",
      requestId: response.getHeader("x-request-id")?.toString() ?? "",
    };
    response.status(500).json(error);
  };
  app.use(errorHandler);
  return app;
}