Add file helper

server/filesystem/filesystem.go

@@ -50,29 +50,36 @@ func (fs *Filesystem) Path() string {
 	return fs.root
 }
 
+// Returns a reader for a file instance.
+func (fs *Filesystem) File(p string) (*os.File, os.FileInfo, error) {
+	cleaned, err := fs.SafePath(p)
+	if err != nil {
+		return nil, nil, err
+	}
+	st, err := os.Stat(cleaned)
+	if err != nil {
+		return nil, nil, err
+	}
+	if st.IsDir() {
+		return nil, nil, &Error{code: ErrCodeIsDirectory}
+	}
+	f, err := os.Open(cleaned)
+	if err != nil {
+		return nil, nil, err
+	}
+	return f, st, nil
+}
+
 // Reads a file on the system and returns it as a byte representation in a file
 // reader. This is not the most memory efficient usage since it will be reading the
 // entirety of the file into memory.
 func (fs *Filesystem) Readfile(p string, w io.Writer) error {
-	cleaned, err := fs.SafePath(p)
+	file, _, err := fs.File(p)
 	if err != nil {
 		return err
 	}
-
-	if st, err := os.Stat(cleaned); err != nil {
-		return err
-	} else if st.IsDir() {
-		return &Error{code: ErrCodeIsDirectory}
-	}
-
-	f, err := os.Open(cleaned)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	_, err = bufio.NewReader(f).WriteTo(w)
-
+	defer file.Close()
+	_, err = bufio.NewReader(file).WriteTo(w)
 	return err
 }