Cleaned up middleware/route handlers

handler/static.go

@@ -0,0 +1,53 @@
+package handler
+
+import (
+	"net/http"
+	"os"
+)
+
+// Wrapper for default FileSystem
+type justFilesFilesystem struct {
+	fs http.FileSystem
+}
+
+// Wrapper for default File
+type neuteredReaddirFile struct {
+	http.File
+}
+
+// Modifies the behavior of FileSystem.Open to return the neutered version of File
+func (fs justFilesFilesystem) Open(name string) (http.File, error) {
+	f, err := fs.fs.Open(name)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if the requested path is a directory
+	// and explicitly return an error to trigger a 404
+	fileInfo, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	if fileInfo.IsDir() {
+		return nil, os.ErrNotExist
+	}
+
+	return neuteredReaddirFile{f}, nil
+}
+
+// Overrides the Readdir method of File to always return nil
+func (f neuteredReaddirFile) Readdir(count int) ([]os.FileInfo, error) {
+	return nil, nil
+}
+
+// Handles requests for static files, without allowing access to the
+// directory viewer and returning 404 if an exact file is not found
+func StaticFS(staticFS *http.FileSystem) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			nfs := justFilesFilesystem{*staticFS}
+			fs := http.FileServer(nfs)
+			fs.ServeHTTP(w, r)
+		},
+	)
+}