move default Content-Type from middleware to function

Author: jlarfors

server.go

@@ -61,7 +61,6 @@ func Run(ctx context.Context, site Site) error {
 
 	router := chi.NewRouter()
 	router.Use(middleware.Logger)
-	router.Use(setDefaultContentType) // Needs to come before compress.
 	router.Use(middleware.Compress(5))
 	router.Get("/", func(w http.ResponseWriter, r *http.Request) {
 		pageInfo := PageInfo{
@@ -563,6 +562,7 @@ func Run(ctx context.Context, site Site) error {
 		return fmt.Errorf("getting static sub-embed: %w", err)
 	}
 	router.Get("/static/*", func(w http.ResponseWriter, r *http.Request) {
+		setDefaultContentType(w, r)
 		fs := http.StripPrefix("/static", http.FileServer(http.FS(sub)))
 		fs.ServeHTTP(w, r)
 	})
@@ -781,46 +781,35 @@ func shortHash(hash string) string {
 	return hash
 }
 
-// setDefaultContentType sets the Content-Type header for files with an
-// extension.
+// setDefaultContentType sets a default Content-Type header.
 // This is in order for the compress middleware to work correctly.
 // For explicit paths in the router, the Content-Type *should* be set manually.
-// Hence this is for files that are embedded, or otherwise not explicitly
-// defined.
-// It does not matter if the Content-Type is not set by this function: it just
-// means things like the compress middleware will not work.
-func setDefaultContentType(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		// Ignore if Content-Type is already set.
-		if r.Header.Get("Content-Type") != "" {
-			next.ServeHTTP(w, r)
-			return
-		}
-		// Ignore if the request is not for a file (i.e. it has an extension).
-		ext := path.Ext(r.URL.Path)
-		if ext == "" {
-			next.ServeHTTP(w, r)
-			return
-		}
-		// Automatically set Content-Type for files with an extension.
-		switch ext {
-		case ".css":
-			w.Header().Set("Content-Type", "text/css")
-		case ".js":
-			w.Header().Set("Content-Type", "text/javascript")
-		case ".json":
-			w.Header().Set("Content-Type", "application/json")
-		case ".xml":
-			w.Header().Set("Content-Type", "application/xml")
-		case ".png":
-			w.Header().Set("Content-Type", "image/png")
-		case ".svg":
-			w.Header().Set("Content-Type", "image/svg+xml")
-		case ".jpg", ".jpeg":
-			w.Header().Set("Content-Type", "image/jpeg")
-		default:
-			// Ignore if the extension is not recognised.
-		}
-		next.ServeHTTP(w, r)
-	})
+// Hence this is for files that are embedded, or where the Content-Type cannot
+// be explicitly set.
+func setDefaultContentType(w http.ResponseWriter, r *http.Request) {
+	// Ignore if Content-Type is already set.
+	if w.Header().Get("Content-Type") != "" {
+		return
+	}
+	// Ignore if the request is not for a file (i.e. it has an extension).
+	ext := path.Ext(r.URL.Path)
+	// Automatically set Content-Type for files with an extension.
+	switch ext {
+	case ".css":
+		w.Header().Set("Content-Type", "text/css")
+	case ".js":
+		w.Header().Set("Content-Type", "text/javascript")
+	case ".json":
+		w.Header().Set("Content-Type", "application/json")
+	case ".xml":
+		w.Header().Set("Content-Type", "application/xml")
+	case ".png":
+		w.Header().Set("Content-Type", "image/png")
+	case ".svg":
+		w.Header().Set("Content-Type", "image/svg+xml")
+	case ".jpg", ".jpeg":
+		w.Header().Set("Content-Type", "image/jpeg")
+	default:
+		// Ignore if the extension is not recognised.
+	}
 }