feat: add cache config

README.md

@@ -6,6 +6,7 @@ GSS (Go serve SPA) is a containerized web server for single-page applications wr
 
 - Optimized for single-page apps.
 - Automatically serves pre-compressed brotli and gzip files if available.
+- Sensible default cache configuration.
 - Docker-based.
 - Configurable via YAML.
 - Lightweight.

gss.go

@@ -129,68 +129,78 @@ func (a *app) serveSPA() http.HandlerFunc {
 			reqFile = filepath.Join(a.Config.Dir, "index.html")
 		}
 
-		serveCompressedFile := func(encoding, extension string) {
-			serve := func(mimeType string) {
+		serveFile := func(mimeType string) {
+			files, err := filepath.Glob(a.Config.Dir + "/*")
+			if err != nil {
+				log.Error().Msgf("Error getting files to serve: %v", err)
+			}
+
+			encodings := r.Header.Get("Accept-Encoding")
+			brotli := "br"
+			brotliExt := ".br"
+			gzip := "gzip"
+			gzipExt := ".gz"
+			serveCompressed := func(encoding, extension string) {
 				w.Header().Set("Content-Encoding", encoding)
 				w.Header().Set("Content-Type", mimeType)
 
 				http.ServeFile(w, r, reqFile+extension)
 			}
 
-			switch filepath.Ext(reqFile) {
-			case ".html":
-				serve("text/html")
-			case ".css":
-				serve("text/css")
-			case ".js":
-				serve("application/javascript")
-			case ".svg":
-				serve("image/svg+xml")
-			default:
-				http.ServeFile(w, r, reqFile)
-			}
-		}
-
-		encodings := r.Header.Get("Accept-Encoding")
-		files, err := filepath.Glob(a.Config.Dir + "/*")
-		if err != nil {
-			log.Error().Msgf("Error getting files to serve: %v", err)
-		}
+			if strings.Contains(encodings, brotli) {
+				for _, f := range files {
+					if f == reqFile+brotliExt {
+						serveCompressed(brotli, brotliExt)
 
-		brotli := "br"
-		brotliExt := ".br"
+						return
+					}
+				}
+			}
 
-		if strings.Contains(encodings, brotli) {
-			for _, f := range files {
-				if f == reqFile+brotliExt {
-					serveCompressedFile(brotli, brotliExt)
+			if strings.Contains(encodings, gzip) {
+				for _, f := range files {
+					if f == reqFile+gzipExt {
+						serveCompressed(gzip, gzipExt)
 
-					return
+						return
+					}
 				}
 			}
+
+			// If the request does not accept compressed files, or the directory does not contain compressed files,
+			// serve the file as is.
+			http.ServeFile(w, r, reqFile)
 		}
 
-		gzip := "gzip"
-		gzipExt := ".gz"
+		switch filepath.Ext(reqFile) {
+		case ".html":
+			w.Header().Set("Cache-Control", "no-cache")
 
-		if strings.Contains(encodings, gzip) {
-			for _, f := range files {
-				if f == reqFile+gzipExt {
-					serveCompressedFile(gzip, gzipExt)
+			serveFile("text/html")
+		case ".css":
+			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
 
-					return
-				}
-			}
-		}
+			serveFile("text/css")
+		case ".js":
+			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
 
-		// If the request does not accept compressed files, or the directory does not contain compressed files,
-		// serve the file as is.
-		http.ServeFile(w, r, reqFile)
+			serveFile("application/javascript")
+		case ".svg":
+			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
+
+			serveFile("image/svg+xml")
+		default:
+			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
+
+			http.ServeFile(w, r, reqFile)
+		}
 	}
 }
 
 func (a *app) setHeaders(h http.Handler) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Vary", "Accept-Encoding")
+
 		for k, v := range a.Config.Headers {
 			w.Header().Set(k, v)
 		}

gss_test.go

@@ -114,12 +114,12 @@ func TestGSS(t *testing.T) {
 
 		app := newApp(cfg).init()
 		w := httptest.NewRecorder()
-		r := httptest.NewRequest(http.MethodGet, "/main.css", nil)
+		r := httptest.NewRequest(http.MethodGet, "/main.68aa49f7.css", nil)
 
 		app.Server.Handler.ServeHTTP(w, r)
 
-		assert.Equal(t, http.StatusOK, w.Code)
-		assert.Equal(t, "/main.css", r.RequestURI)
+		assert.Equal(t, http.StatusOK, w.Result().StatusCode)
+		assert.Equal(t, "/main.68aa49f7.css", r.RequestURI)
 		assert.Contains(t, w.Header().Get("Content-Type"), "css")
 	})
 
@@ -135,12 +135,12 @@ func TestGSS(t *testing.T) {
 
 		app := newApp(cfg).init()
 		w := httptest.NewRecorder()
-		r := httptest.NewRequest(http.MethodGet, "/main.js", nil)
+		r := httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js", nil)
 
 		app.Server.Handler.ServeHTTP(w, r)
 
-		assert.Equal(t, http.StatusOK, w.Code)
-		assert.Equal(t, "/main.js", r.RequestURI)
+		assert.Equal(t, http.StatusOK, w.Result().StatusCode)
+		assert.Equal(t, "/main.8d3db4ef.js", r.RequestURI)
 		assert.Contains(t, w.Header().Get("Content-Type"), "javascript")
 	})
 
@@ -156,12 +156,12 @@ func TestGSS(t *testing.T) {
 
 		app := newApp(cfg).init()
 		w := httptest.NewRecorder()
-		r := httptest.NewRequest(http.MethodGet, "/main.js.LICENSE.txt", nil)
+		r := httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js.LICENSE.txt", nil)
 
 		app.Server.Handler.ServeHTTP(w, r)
 
-		assert.Equal(t, http.StatusOK, w.Code)
-		assert.Equal(t, "/main.js.LICENSE.txt", r.RequestURI)
+		assert.Equal(t, http.StatusOK, w.Result().StatusCode)
+		assert.Equal(t, "/main.8d3db4ef.js.LICENSE.txt", r.RequestURI)
 	})
 
 	t.Run("serves brotli files succesfully", func(t *testing.T) {
@@ -176,7 +176,7 @@ func TestGSS(t *testing.T) {
 
 		app := newApp(cfg).init()
 		w := httptest.NewRecorder()
-		r := httptest.NewRequest(http.MethodGet, "/main.js", nil)
+		r := httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js", nil)
 
 		r.Header.Add("Accept-Encoding", "br")
 
@@ -198,7 +198,7 @@ func TestGSS(t *testing.T) {
 
 		app := newApp(cfg).init()
 		w := httptest.NewRecorder()
-		r := httptest.NewRequest(http.MethodGet, "/main.js", nil)
+		r := httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js", nil)
 
 		r.Header.Add("Accept-Encoding", "gzip")
 
@@ -247,4 +247,55 @@ func TestGSS(t *testing.T) {
 
 		assert.Equal(t, http.StatusNotFound, w.Code)
 	})
+
+	t.Run("serves a cached response for a fresh resource", func(t *testing.T) {
+		t.Parallel()
+
+		cfg := &config{
+			Dir: "test/web/dist",
+		}
+		cfg, err := cfg.validate()
+
+		assert.NoError(t, err)
+
+		app := newApp(cfg).init()
+
+		t.Run("HTML files should have Cache-Control: no-cache", func(t *testing.T) {
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest(http.MethodGet, "/", nil)
+
+			app.Server.Handler.ServeHTTP(w, r)
+
+			last := w.Header().Get("Last-Modified")
+
+			w = httptest.NewRecorder()
+			r = httptest.NewRequest(http.MethodGet, "/", nil)
+
+			r.Header.Set("If-Modified-Since", last)
+
+			app.Server.Handler.ServeHTTP(w, r)
+
+			assert.Equal(t, http.StatusNotModified, w.Code)
+			assert.Equal(t, w.Header().Get("Cache-Control"), "no-cache")
+		})
+
+		t.Run("other files should have Cache-Control: public, max-age=31536000, immutable", func(t *testing.T) {
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js", nil)
+
+			app.Server.Handler.ServeHTTP(w, r)
+
+			last := w.Header().Get("Last-Modified")
+
+			w = httptest.NewRecorder()
+			r = httptest.NewRequest(http.MethodGet, "/main.8d3db4ef.js", nil)
+
+			r.Header.Set("If-Modified-Since", last)
+
+			app.Server.Handler.ServeHTTP(w, r)
+
+			assert.Equal(t, http.StatusNotModified, w.Code)
+			assert.Equal(t, w.Header().Get("Cache-Control"), "public, max-age=31536000, immutable")
+		})
+	})
 }

test/web/dist/index.html

@@ -1 +1 @@
-<!doctype html><html lang="en"><head><meta charset="UTF-8"/><title>Project Title</title><meta name="viewport" content="width=device-width,initial-scale=1"/><script defer="defer" src="main.js"></script><link href="main.css" rel="stylesheet"></head><body><noscript>JavaScript is needed to run this app.</noscript><div id="root"></div></body></html>
+<!doctype html><html lang="en"><head><meta charset="UTF-8"/><title>Project Title</title><meta name="viewport" content="width=device-width,initial-scale=1"/><script defer="defer" src="main.8d3db4ef.js"></script><link href="main.68aa49f7.css" rel="stylesheet"></head><body><noscript>JavaScript is needed to run this app.</noscript><div id="root"></div></body></html>

test/web/webpack.config.js

@@ -9,6 +9,7 @@ module.exports = {
   mode: "production",
   entry: "./src/index.jsx",
   output: {
+    filename: "[name].[contenthash:8].js",
     path: path.join(__dirname, "/dist"),
   },
   module: {
@@ -43,7 +44,9 @@ module.exports = {
       },
       template: "./src/index.html",
     }),
-    new MiniCssExtractPlugin(),
+    new MiniCssExtractPlugin({
+      filename: "[name].[contenthash:8].css",
+    }),
     new CompressionPlugin(),
     new CompressionPlugin({
       algorithm: "brotliCompress",