Middleware
Middleware, FUNCTIONS, (req, res, next), ACCESS, karti, HAIN — next(), CALL, karके, PIPELINE, ke, AGLE, MIDDLEWARE, ko, CONTROL, PASS, kiya, jaata hai. AGAR, next() CALL, nahi, hota, REQUEST, "HANG" ho, jaayegi.
Middleware, GLOBALLY, (app.use()), YA, SPECIFIC, ROUTES, PAR, (app.get("/admin", authMiddleware, handler)) APPLY, ki, ja, sakti, hai — LOGGING, AUTH, VALIDATION, JAISE, CROSS-CUTTING, CONCERNS, ke, liye, IDEAL, hai.
function logger(req, res, next) {
console.log(`${req.method} ${req.url}`);
next(); // agle middleware/handler ko, CONTROL, PASS
}
function requireAuth(req, res, next) {
if (!req.headers.authorization) {
return res.status(401).json({ error: "Unauthorized" });
}
next();
}
app.use(logger); // SAARE routes ke liye
app.get("/admin", requireAuth, (req, res) => res.send("Admin panel"));- Middleware = (req, res, next) function, request-response, pipeline, mein
- next() call, karna, ZAROORI, hai — WARNA, request, "hang" ho, jaati, hai
- Global (app.use) ya, route-specific, DONO, tareeke, se, APPLY, ho, sakti hai
helmet, SECURITY-RELATED, HTTP, HEADERS, SET, karta hai. morgan, HTTP, REQUEST, LOGGING, karta hai. compression, GZIP, COMPRESSION, ke, saath, RESPONSES, SEND, karta hai — SAB, app.use() se, EASILY, ADD, ho, jaate, HAIN.
const helmet = require("helmet");
const morgan = require("morgan");
app.use(helmet());
app.use(morgan("combined"));AGAR, express.json() MIDDLEWARE, EK, ROUTE, HANDLER, ke, BAAD, DEFINE, kiya, jaata hai (JO, req.body, USE, karta hai), req.body, undefined, HOGA — MIDDLEWARE, ORDER, TOP-TO-BOTTOM, STRICTLY, FOLLOW, hota hai.