Disable cache for static and media files, serve template assets directly from memory

cache.go

@@ -49,7 +49,7 @@ func cacheMiddleware(next http.Handler) http.Handler {
 			}
 			setCacheHeaders(w, cache)
 			// check conditional request
-			if ifNoneMatchHeader := r.Header.Get("If-None-Match"); ifNoneMatchHeader != "" && ifNoneMatchHeader == cache.hash {
+			if ifNoneMatchHeader := r.Header.Get("If-None-Match"); ifNoneMatchHeader != "" && ifNoneMatchHeader == cache.eTag {
 				// send 304
 				w.WriteHeader(http.StatusNotModified)
 				return
@@ -78,8 +78,7 @@ func cacheKey(r *http.Request) string {
 }
 
 func setCacheHeaders(w http.ResponseWriter, cache *cacheItem) {
-	w.Header().Del(cacheInternalExpirationHeader)
-	w.Header().Set("ETag", cache.hash)
+	w.Header().Set("ETag", cache.eTag)
 	w.Header().Set("Last-Modified", cache.creationTime.UTC().Format(http.TimeFormat))
 	if w.Header().Get("Cache-Control") == "" {
 		if cache.expiration != 0 {
@@ -93,7 +92,7 @@ func setCacheHeaders(w http.ResponseWriter, cache *cacheItem) {
 type cacheItem struct {
 	expiration   int
 	creationTime time.Time
-	hash         string
+	eTag         string
 	code         int
 	header       http.Header
 	body         []byte
@@ -126,20 +125,29 @@ func getCache(key string, next http.Handler, r *http.Request) (item *cacheItem)
 		result := recorder.Result()
 		body, _ := ioutil.ReadAll(result.Body)
 		_ = result.Body.Close()
-		h := sha256.New()
-		_, _ = io.Copy(h, bytes.NewReader(body))
-		hash := fmt.Sprintf("%x", h.Sum(nil))
-		exp, _ := strconv.Atoi(result.Header.Get(cacheInternalExpirationHeader))
+		eTag := result.Header.Get("ETag")
+		if eTag == "" {
+			h := sha256.New()
+			_, _ = io.Copy(h, bytes.NewReader(body))
+			eTag = fmt.Sprintf("%x", h.Sum(nil))
+		}
 		lastMod := time.Now()
 		if lm := result.Header.Get("Last-Modified"); lm != "" {
 			if parsedTime, te := dateparse.ParseLocal(lm); te == nil {
 				lastMod = parsedTime
 			}
 		}
+		exp, _ := strconv.Atoi(result.Header.Get(cacheInternalExpirationHeader))
+		// Remove problematic headers
+		result.Header.Del(cacheInternalExpirationHeader)
+		result.Header.Del("Accept-Ranges")
+		result.Header.Del("ETag")
+		result.Header.Del("Last-Modified")
+		// Create cache item
 		item = &cacheItem{
 			expiration:   exp,
 			creationTime: lastMod,
-			hash:         hash,
+			eTag:         eTag,
 			code:         result.StatusCode,
 			header:       result.Header,
 			body:         body,

http.go

@@ -172,16 +172,16 @@ func buildHandler() (http.Handler, error) {
 
 	// Assets
 	for _, path := range allAssetPaths() {
-		r.With(cacheMiddleware).Get(path, serveAsset)
+		r.Get(path, serveAsset)
 	}
 
 	// Static files
 	for _, path := range allStaticPaths() {
-		r.With(cacheMiddleware).Get(path, serveStaticFile)
+		r.Get(path, serveStaticFile)
 	}
 
 	// Media files
-	r.With(cacheMiddleware).Get(`/m/{file:[0-9a-fA-F]+(\.[0-9a-zA-Z]+)?}`, serveMediaFile)
+	r.Get(`/m/{file:[0-9a-fA-F]+(\.[0-9a-zA-Z]+)?}`, serveMediaFile)
 
 	// Short paths
 	r.With(cacheMiddleware).Get("/s/{id:[0-9a-fA-F]+}", redirectToLongPath)

render.go

@@ -130,7 +130,7 @@ func initRendering() error {
 			}
 			return d.Before(b)
 		},
-		"asset":  assetFile,
+		"asset":  assetFileName,
 		"string": getTemplateStringVariant,
 		"include": func(templateName string, data ...interface{}) (template.HTML, error) {
 			if len(data) == 1 {

templateAssets.go

@@ -4,6 +4,7 @@ import (
 	"crypto/sha1"
 	"fmt"
 	"io/ioutil"
+	"mime"
 	"net/http"
 	"os"
 	"path"
@@ -13,23 +14,23 @@ import (
 
 const assetsFolder = "templates/assets"
 
-var compiledAssetsFolder string
-var assetFiles map[string]string
+var assetFileNames map[string]string = map[string]string{}
+var assetFiles map[string]*assetFile = map[string]*assetFile{}
+
+type assetFile struct {
+	contentType string
+	body        []byte
+}
 
 func initTemplateAssets() (err error) {
-	compiledAssetsFolder, err = ioutil.TempDir("", "goblog-assets-*")
-	if err != nil {
-		return
-	}
-	assetFiles = map[string]string{}
 	err = filepath.Walk(assetsFolder, func(path string, info os.FileInfo, err error) error {
 		if info.Mode().IsRegular() {
-			compiled, err := compileAssets(path)
+			compiled, err := compileAsset(path)
 			if err != nil {
 				return err
 			}
 			if compiled != "" {
-				assetFiles[strings.TrimPrefix(path, assetsFolder+"/")] = compiled
+				assetFileNames[strings.TrimPrefix(path, assetsFolder+"/")] = compiled
 			}
 		}
 		return nil
@@ -40,7 +41,7 @@ func initTemplateAssets() (err error) {
 	return nil
 }
 
-func compileAssets(name string) (compiledFileName string, err error) {
+func compileAsset(name string) (compiledFileName string, err error) {
 	originalContent, err := ioutil.ReadFile(name)
 	if err != nil {
 		return
@@ -67,21 +68,21 @@ func compileAssets(name string) (compiledFileName string, err error) {
 	sha.Write(compiledContent)
 	hash := fmt.Sprintf("%x", sha.Sum(nil))
 	compiledFileName = hash + compiledExt
-	err = ioutil.WriteFile(path.Join(compiledAssetsFolder, compiledFileName), compiledContent, 0644)
-	if err != nil {
-		return
+	assetFiles[compiledFileName] = &assetFile{
+		contentType: mime.TypeByExtension(compiledExt),
+		body:        compiledContent,
 	}
 	return
 }
 
 // Function for templates
-func assetFile(fileName string) string {
-	return "/" + assetFiles[fileName]
+func assetFileName(fileName string) string {
+	return "/" + assetFileNames[fileName]
 }
 
 func allAssetPaths() []string {
 	var paths []string
-	for _, name := range assetFiles {
+	for _, name := range assetFileNames {
 		paths = append(paths, "/"+name)
 	}
 	return paths
@@ -89,6 +90,13 @@ func allAssetPaths() []string {
 
 // Gets only called by registered paths
 func serveAsset(w http.ResponseWriter, r *http.Request) {
-	w.Header().Add("Cache-Control", "public,max-age=31536000,immutable")
-	http.ServeFile(w, r, filepath.Join(compiledAssetsFolder, r.URL.Path))
+	f := strings.TrimPrefix(r.URL.Path, "/")
+	af, ok := assetFiles[f]
+	if !ok {
+		serve404(w, r)
+		return
+	}
+	w.Header().Set("Cache-Control", "public,max-age=31536000,immutable")
+	w.Header().Set(contentType, af.contentType)
+	w.Write(af.body)
 }