Vapor 3.0 middleware

MyMiddleware.swift

import Vapor

public final class MyMiddleware: Middleware {
    public init() {
    }

    public func respond(to req: Request, chainingTo next: Responder) throws -> Future<Response> {
        return try next.respond(to: req).map { res in
            if req.http.headers.contains(name: "X-NYA-N") {
                res.http.headers.add(name: "X-NYA-N", value: "RESPONSE")
            }
            return res
        }
    }
}

routes.swift

import Vapor

public func routes(_ router: Router) throws {
    let myMiddlewaredRoutes = router.grouped(MyMiddleware())
    let homeController = HomeController()
    myMiddlewaredRoutes.get(use: homeController.index)
}