Remove HeadResponder (#3147)

The HEAD method is identical to GET except that the server must not send content in the response (RFC 9110, section 9.3.2).

The previous default behaviour of returning 200 OK to every HEAD request to a constant route is not standard-compliant.

The new behaviour is to always forward the request to the GET route, unless the developer explicitly configured a custom HEAD route.

Sources/Vapor/Responder/DefaultResponder.swift

@@ -39,26 +39,6 @@ internal struct DefaultResponder: Responder {
                 }
             }
 
-            // If the route isn't explicitly a HEAD route,
-            // and it's made up solely of .constant components,
-            // register a HEAD route with the same path
-            if route.method == .GET &&
-                route.path.allSatisfy({ component in
-                    if case .constant(_) = component { return true }
-                    return false
-            }) {
-                let headRoute = Route(
-                    method: .HEAD,
-                    path: route.path,
-                    responder: middleware.makeResponder(chainingTo: HeadResponder()),
-                    requestType: route.requestType,
-                    responseType: route.responseType)
-
-                let headCachedRoute = CachedRoute(route: headRoute, responder: middleware.makeResponder(chainingTo: HeadResponder()))
-
-                router.register(headCachedRoute, at: [.constant(HTTPMethod.HEAD.string)] + path)
-            }
-
             router.register(cached, at: [.constant(route.method.string)] + path)
         }
         self.router = router
@@ -155,12 +135,6 @@ internal struct DefaultResponder: Responder {
     }
 }
 
-private struct HeadResponder: Responder {
-    func respond(to request: Request) -> EventLoopFuture<Response> {
-        request.eventLoop.makeSucceededFuture(.init(status: .ok))
-    }
-}
-
 private struct NotFoundResponder: Responder {
     func respond(to request: Request) -> EventLoopFuture<Response> {
         request.eventLoop.makeFailedFuture(RouteNotFound())

Tests/VaporTests/RouteTests.swift

@@ -229,38 +229,23 @@ final class RouteTests: XCTestCase {
         }
     }
 
-    func testHeadRequestWithConstantPathReturnsOK() throws {
+    func testHeadRequestForwardedToGet() throws {
         let app = Application(.testing)
         defer { app.shutdown() }
 
         app.get("hello") { req -> String in
-            return "hi"
-        }
-
-        try app.testable(method: .running(port: 0)).test(.HEAD, "/hello") { res in
-            XCTAssertEqual(res.status, .ok)
-            XCTAssertEqual(res.headers.first(name: .contentLength), "0")
-            XCTAssertEqual(res.body.readableBytes, 0)
-        }
-    }
-
-    func testHeadRequestWithParameterForwardedToGet() throws {
-        let app = Application(.testing)
-        defer { app.shutdown() }
-
-        app.get("hello", ":name") { req -> String in
             XCTAssertEqual(req.method, .HEAD)
             return "hi"
         }
 
-        try app.testable(method: .running(port: 0)).test(.HEAD, "/hello/joe") { res in
+        try app.testable(method: .running(port: 0)).test(.HEAD, "/hello") { res in
             XCTAssertEqual(res.status, .ok)
             XCTAssertEqual(res.headers.first(name: .contentLength), "2")
             XCTAssertEqual(res.body.readableBytes, 0)
         }
     }
 
-    func testExplicitHeadRouteHandlerOverridesGeneratedHandler() throws {
+    func testExplicitHeadRouteOverridesForwardingToGet() throws {
         let app = Application(.testing)
         defer { app.shutdown() }