Middleware

Running Code Before Requests Complete

💡 Middleware, EK, "SECURITY, CHECKPOINT" hai, ENTRY, GATE, PAR — HAR, REQUEST, ko, ACTUAL, PAGE/ROUTE, tak, PAHUNCHNE, se, PEHLE, ISME, se, GUZARNA, PADТA, hai — REDIRECT, REWRITE, YA, HEADERS, MODIFY, ki, ja, sakti, HAIN.

middleware.js (PROJECT, ROOT, mein) DEFINE, kiya, jaata hai — YE, matching_config, mein, DEFINE, ki, gayi, SAARI, requests, ke, liye, RUN, hota hai, EDGE, RUNTIME, PAR (bahut, FAST).

Middleware, aksar, AUTHENTICATION, (UNAUTHENTICATED, users, ko, login, page, PAR, REDIRECT, karna), LOCALIZATION, aur, A/B, TESTING, ke, liye, USE, hota hai.

// middleware.js:
import { NextResponse } from "next/server";

export function middleware(request) {
  const token = request.cookies.get("token");
  if (!token && request.nextUrl.pathname.startsWith("/dashboard")) {
    return NextResponse.redirect(new URL("/login", request.url));
  }
  return NextResponse.next();
}

export const config = {
  matcher: ["/dashboard/:path*"],
};

🛡️

Middleware, EK, "SECURITY, CHECKPOINT" hai, ENTRY, GATE, PAR — HAR, REQUEST, ko, ACTUAL, PAGE/ROUTE, tak, PAHUNCHNE, se, PEHLE, ISME, se, GUZARNA, PADТA, hai — REDIRECT, REWRITE, YA, HEADERS, MODIFY, ki, ja, sakti, HAIN.

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⚡ Quick Recap

middleware.js = SAARI, matching, requests, ke, liye, request, complete, hone, se, PEHLE, RUN, hota, hai
Edge Runtime, PAR, RUN, hota, hai — EXTREMELY, FAST
Authentication, localization, A/B, testing, ke, liye, COMMON, use-cases

On this page (2 subtopics)

NextResponse.redirect(), BROWSER, ka, URL, CHANGE, karta hai (VISIBLE, redirect). NextResponse.rewrite(), URL, BAR, mein, DIKHТE, HUE, URL, ko, SAME, RAKHТE, hue, INTERNALLY, EK, DIFFERENT, page, SERVE, karta hai — jaise, A/B, TESTING, ke, liye.

return NextResponse.rewrite(new URL("/variant-b", request.url));

matcher config, mein, REGEX-jaise, PATTERNS, USE, kiye, ja, sakte, HAIN — jaise, "/((?!api|_next/static).*)" SAARE, routes, PAR, MATCH, karega, EXCEPT, API, routes, aur, STATIC, files.

💡Tip: Middleware, ko, SIRF, ZAROORI, routes, PAR, hi, RUN, karna, chahiye — EK, TOO-BROAD, matcher, se, UNNECESSARY, latency, HAR, request, PAR, ADD, ho, sakti, hai.

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Middleware

Rewrites vs Redirects in Middleware

Middleware Matcher Configuration