Define an actual middleware type, use that to set up API routes

srv/src/http/api.go

@@ -166,24 +166,6 @@ func (a *api) handler() http.Handler {
 		return a.requirePowMiddleware(h)
 	}
 
-	formMiddleware := func(h http.Handler) http.Handler {
-		wh := checkCSRFMiddleware(h)
-		wh = logReqMiddleware(wh)
-		wh = addResponseHeaders(map[string]string{
-			"Cache-Control": "no-store, max-age=0",
-			"Pragma":        "no-cache",
-			"Expires":       "0",
-		}, wh)
-
-		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
-			if r.Method != "GET" {
-				wh.ServeHTTP(rw, r)
-			} else {
-				h.ServeHTTP(rw, r)
-			}
-		})
-	}
-
 	mux := http.NewServeMux()
 
 	{
@@ -215,17 +197,17 @@ func (a *api) handler() http.Handler {
 	mux.Handle("/posts/", http.StripPrefix("/posts",
 		apiutil.MethodMux(map[string]http.Handler{
 			"GET":     a.renderPostHandler(),
-			"POST":    authMiddleware(a.auther, a.postPostHandler()),
-			"DELETE":  authMiddleware(a.auther, a.deletePostHandler()),
-			"PREVIEW": authMiddleware(a.auther, a.previewPostHandler()),
+			"POST":    a.postPostHandler(),
+			"DELETE":  a.deletePostHandler(),
+			"PREVIEW": a.previewPostHandler(),
 		}),
 	))
 
 	mux.Handle("/assets/", http.StripPrefix("/assets",
 		apiutil.MethodMux(map[string]http.Handler{
 			"GET":    a.getPostAssetHandler(),
-			"POST":   authMiddleware(a.auther, a.postPostAssetHandler()),
-			"DELETE": authMiddleware(a.auther, a.deletePostAssetHandler()),
+			"POST":   a.postPostAssetHandler(),
+			"DELETE": a.deletePostAssetHandler(),
 		}),
 	))
 
@@ -234,10 +216,28 @@ func (a *api) handler() http.Handler {
 	mux.Handle("/feed.xml", a.renderFeedHandler())
 	mux.Handle("/", a.renderIndexHandler())
 
-	var globalHandler http.Handler = mux
-	globalHandler = formMiddleware(globalHandler)
-	globalHandler = setCSRFMiddleware(globalHandler)
-	globalHandler = setLoggerMiddleware(a.params.Logger, globalHandler)
+	globalHandler := http.Handler(mux)
+
+	globalHandler = apiutil.MethodMux(map[string]http.Handler{
+		"GET": applyMiddlewares(
+			globalHandler,
+			logReqMiddleware,
+			setCSRFMiddleware,
+		),
+		"*": applyMiddlewares(
+			globalHandler,
+			authMiddleware(a.auther),
+			checkCSRFMiddleware,
+			addResponseHeadersMiddleware(map[string]string{
+				"Cache-Control": "no-store, max-age=0",
+				"Pragma":        "no-cache",
+				"Expires":       "0",
+			}),
+			logReqMiddleware,
+		),
+	})
+
+	globalHandler = setLoggerMiddleware(a.params.Logger)(globalHandler)
 
 	return globalHandler
 }

srv/src/http/apiutil/apiutil.go

@@ -117,6 +117,9 @@ func RandStr(numBytes int) string {
 //
 // If no Handler is defined for a method then a 405 Method Not Allowed error is
 // returned.
+//
+// If the method "*" is defined then all methods not defined will be directed to
+// that handler, and 405 Method Not Allowed is never returned.
 func MethodMux(handlers map[string]http.Handler) http.Handler {
 
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
@@ -128,13 +131,16 @@ func MethodMux(handlers map[string]http.Handler) http.Handler {
 			method = formMethod
 		}
 
-		handler, ok := handlers[method]
-
-		if !ok {
-			http.Error(rw, "Method not allowed", http.StatusMethodNotAllowed)
+		if handler, ok := handlers[method]; ok {
+			handler.ServeHTTP(rw, r)
 			return
 		}
 
+		if handler, ok := handlers["*"]; ok {
 			handler.ServeHTTP(rw, r)
+			return
+		}
+
+		http.Error(rw, "Method not allowed", http.StatusMethodNotAllowed)
 	})
 }

srv/src/http/auth.go

@@ -65,7 +65,7 @@ func (a *auther) Allowed(ctx context.Context, username, password string) bool {
 	return err == nil
 }
 
-func authMiddleware(auther Auther, h http.Handler) http.Handler {
+func authMiddleware(auther Auther) middleware {
 
 	respondUnauthorized := func(rw http.ResponseWriter, r *http.Request) {
 		rw.Header().Set("WWW-Authenticate", `Basic realm="NOPE"`)
@@ -73,6 +73,7 @@ func authMiddleware(auther Auther, h http.Handler) http.Handler {
 		apiutil.GetRequestLogger(r).WarnString(r.Context(), "unauthorized")
 	}
 
+	return func(h http.Handler) http.Handler {
 		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
 			username, password, ok := r.BasicAuth()
@@ -90,3 +91,4 @@ func authMiddleware(auther Auther, h http.Handler) http.Handler {
 			h.ServeHTTP(rw, r)
 		})
 	}
+}

srv/src/http/middleware.go

@@ -10,7 +10,17 @@ import (
 	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
 )
 
-func addResponseHeaders(headers map[string]string, h http.Handler) http.Handler {
+type middleware func(http.Handler) http.Handler
+
+func applyMiddlewares(h http.Handler, middlewares ...middleware) http.Handler {
+	for _, m := range middlewares {
+		h = m(h)
+	}
+	return h
+}
+
+func addResponseHeadersMiddleware(headers map[string]string) middleware {
+	return func(h http.Handler) http.Handler {
 		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 			for k, v := range headers {
 				rw.Header().Set(k, v)
@@ -18,19 +28,21 @@ func addResponseHeaders(headers map[string]string, h http.Handler) http.Handler
 			h.ServeHTTP(rw, r)
 		})
 	}
+}
 
-func setLoggerMiddleware(logger *mlog.Logger, h http.Handler) http.Handler {
+func setLoggerMiddleware(logger *mlog.Logger) middleware {
+	return func(h http.Handler) http.Handler {
 		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
-		type reqInfoKey string
+			type logCtxKey string
 
 			ip, _, _ := net.SplitHostPort(r.RemoteAddr)
 
 			ctx := r.Context()
 			ctx = mctx.Annotate(ctx,
-			reqInfoKey("remote_ip"), ip,
-			reqInfoKey("url"), r.URL,
-			reqInfoKey("method"), r.Method,
+				logCtxKey("remote_ip"), ip,
+				logCtxKey("url"), r.URL,
+				logCtxKey("method"), r.Method,
 			)
 
 			r = r.WithContext(ctx)
@@ -38,6 +50,7 @@ func setLoggerMiddleware(logger *mlog.Logger, h http.Handler) http.Handler {
 			h.ServeHTTP(rw, r)
 		})
 	}
+}
 
 type logResponseWriter struct {
 	http.ResponseWriter