This code snippet is a middleware function that extracts the subdomain from the request's hostname and rewrites the URL if the subdomain is "www" or exists. Otherwise, it allows the request to proceed to the next middleware.

URL Subdomain Rewriting Middleware.md

URL Subdomain Rewriting Middleware

Preview:

import { type NextRequest, NextResponse } from "next/server";

export const config = {
  matcher: ["/((?!api/|_next/|_static/|_vercel|[\\w-]+\\.\\w+).*)"],
};

export default function middleware(req: NextRequest) {
  const url = req.nextUrl;
  const headers = req.headers;
  const hostname = req.headers.get("host");
  const domainParts = hostname?.split(".") as string[];
  const searchParams = url.searchParams.toString();
  let subdomain = null;

  const pathWithSearchParams = `${url.pathname}${
    searchParams.length > 0 ? `?${searchParams}` : ""
  }`;

  // if localhost then 1 else 2
  const isLocalhost = headers.get("host")?.includes("localhost") ? 1 : 2;

  if (domainParts?.length > isLocalhost) {
    subdomain = domainParts[0]; // assuming subdomain is the first part
  }

  if (subdomain === "www") {
    const rewriteUrl = new URL(`/${pathWithSearchParams}`, req.url);
    return NextResponse.rewrite(rewriteUrl);
  }

  if (subdomain) {
    const rewriteUrl = new URL(`/${subdomain}${pathWithSearchParams}`, req.url);
    return NextResponse.rewrite(rewriteUrl);
  }

  return NextResponse.next();
}

Associated Context
Type	Code Snippet ( .ts )
Associated Tags	NextRequest NextResponse config middleware url headers hostname domainParts isLocalhost subdomain Framework: Next.js reactjs js Server-side rendering URL rewriting Middleware Routing Subdomains HTTP headers Localhost Rewriting URLs Domain parsing
💡 Smart Description	This code snippet defines a middleware function that handles the next/server request. It checks if there is a subdomain in the response headers and returns it as an HTTP redirect URL, or null for any domain part of this request. If not, This code snippet is a middleware function that extracts the subdomain from the request's hostname and rewrites the URL if the subdomain is "www" or exists. Otherwise, it allows the request to proceed to the next middleware.
🔎 Suggested Searches	Next js middleware for forwarding requests
Related Links	https://www.geeksforgeeks.org/ https://www.geeksforgeeks.org/typescript-class/ https://www.geeksforgeeks.org/data-structures/linked-list/ https://www.npmjs.com/package/@nestjs/config https://www.npmjs.com/package/@typescript-eslint/parser https://www.npmjs.com/package/tsconfig-paths https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes https://developer.mozilla.org/en-US/docs/Web/API/URL/URL https://developer.mozilla.org/en-US/docs/Web/API/URL https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/length https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split https://developer.mozilla.org/en-US/docs/Web/API/Headers/get
Related People	Sumanta Kabiraj
Sensitive Information	No Sensitive Information Detected
Shareable Link	https://sumanta.pieces.cloud/?p=3cff4babaf