From 79452e7472245e561ebedd937002b51eb57e9dba Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Sat, 21 May 2022 10:18:00 -0600
Subject: [PATCH] Re-arrange routes so that cache only applies to blog routes

---
 srv/src/http/api.go        | 88 ++++++++++++++++++++++----------------
 srv/src/http/middleware.go |  1 +
 2 files changed, 53 insertions(+), 36 deletions(-)

diff --git a/srv/src/http/api.go b/srv/src/http/api.go
index ebc1de2..3cb4ba5 100644
--- a/srv/src/http/api.go
+++ b/srv/src/http/api.go
@@ -161,7 +161,32 @@ func (a *api) Shutdown(ctx context.Context) error {
 	return nil
 }
 
-func (a *api) handler() http.Handler {
+func (a *api) apiHandler() http.Handler {
+	mux := http.NewServeMux()
+	mux.Handle("/pow/challenge", a.newPowChallengeHandler())
+	mux.Handle("/pow/check",
+		a.requirePowMiddleware(
+			http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {}),
+		),
+	)
+
+	mux.Handle("/mailinglist/subscribe", a.requirePowMiddleware(a.mailingListSubscribeHandler()))
+	mux.Handle("/mailinglist/finalize", a.mailingListFinalizeHandler())
+	mux.Handle("/mailinglist/unsubscribe", a.mailingListUnsubscribeHandler())
+
+	mux.Handle("/chat/global/", http.StripPrefix("/chat/global", newChatHandler(
+		a.params.GlobalRoom,
+		a.params.UserIDCalculator,
+		a.requirePowMiddleware,
+	)))
+
+	// disallowGetMiddleware is used rather than a MethodMux because it has an
+	// exception for websockets, which is needed for chat.
+	return disallowGetMiddleware(mux)
+
+}
+
+func (a *api) blogHandler() http.Handler {
 
 	cache, err := lru.New(5000)
 
@@ -172,32 +197,6 @@ func (a *api) handler() http.Handler {
 
 	mux := http.NewServeMux()
 
-	{
-		apiMux := http.NewServeMux()
-		apiMux.Handle("/pow/challenge", a.newPowChallengeHandler())
-		apiMux.Handle("/pow/check",
-			a.requirePowMiddleware(
-				http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {}),
-			),
-		)
-
-		apiMux.Handle("/mailinglist/subscribe", a.requirePowMiddleware(a.mailingListSubscribeHandler()))
-		apiMux.Handle("/mailinglist/finalize", a.mailingListFinalizeHandler())
-		apiMux.Handle("/mailinglist/unsubscribe", a.mailingListUnsubscribeHandler())
-
-		apiMux.Handle("/chat/global/", http.StripPrefix("/chat/global", newChatHandler(
-			a.params.GlobalRoom,
-			a.params.UserIDCalculator,
-			a.requirePowMiddleware,
-		)))
-
-		mux.Handle("/api/", http.StripPrefix("/api",
-			// disallowGetMiddleware is used rather than a MethodMux because it
-			// has an exception for websockets, which is needed for chat.
-			disallowGetMiddleware(apiMux),
-		))
-	}
-
 	mux.Handle("/posts/", http.StripPrefix("/posts",
 		apiutil.MethodMux(map[string]http.Handler{
 			"GET":     a.renderPostHandler(),
@@ -220,19 +219,36 @@ func (a *api) handler() http.Handler {
 	mux.Handle("/feed.xml", a.renderFeedHandler())
 	mux.Handle("/", a.renderIndexHandler())
 
-	globalHandler := http.Handler(mux)
-
-	globalHandler = apiutil.MethodMux(map[string]http.Handler{
+	h := apiutil.MethodMux(map[string]http.Handler{
 		"GET": applyMiddlewares(
-			globalHandler,
-			logReqMiddleware,
+			mux,
+			logReqMiddleware, // only log GETs on cache miss
 			cacheMiddleware(cache),
-			setCSRFMiddleware,
 		),
 		"*": applyMiddlewares(
-			globalHandler,
+			mux,
 			purgeCacheOnOKMiddleware(cache),
 			authMiddleware(a.auther),
+		),
+	})
+
+	return h
+}
+
+func (a *api) handler() http.Handler {
+
+	mux := http.NewServeMux()
+
+	mux.Handle("/api/", http.StripPrefix("/api", a.apiHandler()))
+	mux.Handle("/", a.blogHandler())
+
+	h := apiutil.MethodMux(map[string]http.Handler{
+		"GET": applyMiddlewares(
+			mux,
+			setCSRFMiddleware,
+		),
+		"*": applyMiddlewares(
+			mux,
 			checkCSRFMiddleware,
 			addResponseHeadersMiddleware(map[string]string{
 				"Cache-Control": "no-store, max-age=0",
@@ -243,7 +259,7 @@ func (a *api) handler() http.Handler {
 		),
 	})
 
-	globalHandler = setLoggerMiddleware(a.params.Logger)(globalHandler)
+	h = setLoggerMiddleware(a.params.Logger)(h)
 
-	return globalHandler
+	return h
 }
diff --git a/srv/src/http/middleware.go b/srv/src/http/middleware.go
index 7296a35..943bc05 100644
--- a/srv/src/http/middleware.go
+++ b/srv/src/http/middleware.go
@@ -182,6 +182,7 @@ func purgeCacheOnOKMiddleware(cache *lru.Cache) middleware {
 			h.ServeHTTP(wrw, r)
 
 			if wrw.statusCode == 200 {
+				apiutil.GetRequestLogger(r).Info(r.Context(), "purging cache!")
 				cache.Purge()
 			}
 		})