Added prefix filtering to TagLine.tags() and Message.tags_from_file()

chatmastermind/message.py

@@ -219,9 +219,12 @@ class Message():
                    file_path=data.get(cls.file_yaml_key, None))
 
     @classmethod
-    def tags_from_file(cls: Type[MessageInst], file_path: pathlib.Path) -> set[Tag]:
+    def tags_from_file(cls: Type[MessageInst],
+                       file_path: pathlib.Path,
+                       prefix: Optional[str] = None) -> set[Tag]:
         """
-        Return only the tags from the given Message file.
+        Return only the tags from the given Message file,
+        optionally filtered based on prefix.
         """
         if not file_path.exists():
             raise MessageError(f"Message file '{file_path}' does not exist")
@@ -229,11 +232,14 @@ class Message():
             raise MessageError(f"File type '{file_path.suffix}' is not supported")
         if file_path.suffix == '.txt':
             with open(file_path, "r") as fd:
-                tags = TagLine(fd.readline()).tags()
+                tags = TagLine(fd.readline()).tags(prefix)
         else:  # '.yaml'
             with open(file_path, "r") as fd:
                 data = yaml.load(fd, Loader=yaml.FullLoader)
-                tags = set(sorted(data[cls.tags_yaml_key]))
+                if prefix and len(prefix) > 0:
+                    tags = set(sorted([t.strip() for t in data[cls.tags_yaml_key] if t.startswith(prefix)]))
+                else:
+                    tags = set(sorted(data[cls.tags_yaml_key]))
         return tags
 
     @classmethod