M http.go → http.go

@@ -141,6 +141,11 @@ log.Println(err)
 			renderError(w, InternalServerErrorMsg, 500)
 			return
 		}
+		newName := filepath.Clean(r.Form.Get("rename"))
+		if newName != fileName {
+			newPath := path.Join(c.FilesDirectory, authUser, newName)
+			os.Rename(filePath, newPath)
+		}
 		http.Redirect(w, r, "/my_site", 303)
 	}
 }

M templates/edit_file.html → templates/edit_file.html

@@ -1,6 +1,8 @@
 {{template "header" .}}
 <h2>Editing {{.FileName}}</h2>
 <form id="edit-form" action="/edit/{{.FileName}}" method="POST">
+ <label for="rename">Rename:</label>
+   <input type="text" value="{{.FileName}}" id="rename" name="rename">
   <textarea rows="20" name="file_text" id="editor">{{.FileText}}</textarea>
   <br>
   <input type="submit" value="Save file" class="button">

M utils.go → utils.go

@@ -45,6 +45,9 @@ func checkIfValidFile(filename string, fileBytes []byte) error {
 	if len(filename) == 0 {
 		return fmt.Errorf("Please enter a filename")
 	}
+	if len(filename) > 256 { // arbitrarily chosen
+		return fmt.Errorf("Filename is too long")
+	}
 	ext := strings.ToLower(path.Ext(filename))
 	found := false
 	for _, mimetype := range c.OkExtensions {