Add MessageHistoryComponent to retrieve stored messages

src/backend/langflow/components/helpers/MessageHistory.py

@@ -0,0 +1,46 @@
+from typing import List, Optional
+
+from langflow import CustomComponent
+from langflow.memory import get_messages
+from langflow.schema import Record
+
+
+class MessageHistoryComponent(CustomComponent):
+    display_name = "Message History"
+    description = "Used to retrieve stored messages."
+
+    def build_config(self):
+        return {
+            "sender": {
+                "options": ["Machine", "User", "Machine and User"],
+                "display_name": "Sender Type",
+            },
+            "sender_name": {"display_name": "Sender Name"},
+            "n_messages": {
+                "display_name": "Number of Messages",
+                "info": "Number of messages to retrieve.",
+            },
+            "session_id": {
+                "display_name": "Session ID",
+                "info": "Session ID of the chat history.",
+                "input_types": ["Text"],
+            },
+        }
+
+    def build(
+        self,
+        sender: Optional[str] = None,
+        sender_name: Optional[str] = None,
+        session_id: Optional[str] = None,
+        n_messages: int = 5,
+    ) -> List[Record]:
+        if sender == "Machine and User":
+            sender = None
+        messages = get_messages(
+            sender=sender,
+            sender_name=sender_name,
+            session_id=session_id,
+            limit=n_messages,
+        )
+        self.status = messages
+        return messages