Format exception message

src/backend/langflow/api/utils.py

@@ -22,7 +22,9 @@ API_WORDS = ["api", "key", "token"]
 
 
 def has_api_terms(word: str):
-    return "api" in word and ("key" in word or ("token" in word and "tokens" not in word))
+    return "api" in word and (
+        "key" in word or ("token" in word and "tokens" not in word)
+    )
 
 
 def remove_api_keys(flow: dict):
@@ -32,7 +34,11 @@ def remove_api_keys(flow: dict):
             node_data = node.get("data").get("node")
             template = node_data.get("template")
             for value in template.values():
-                if isinstance(value, dict) and has_api_terms(value["name"]) and value.get("password"):
+                if (
+                    isinstance(value, dict)
+                    and has_api_terms(value["name"])
+                    and value.get("password")
+                ):
                     value["value"] = None
 
     return flow
@@ -53,7 +59,9 @@ def build_input_keys_response(langchain_object, artifacts):
             input_keys_response["input_keys"][key] = value
     # If the object has memory, that memory will have a memory_variables attribute
     # memory variables should be removed from the input keys
-    if hasattr(langchain_object, "memory") and hasattr(langchain_object.memory, "memory_variables"):
+    if hasattr(langchain_object, "memory") and hasattr(
+        langchain_object.memory, "memory_variables"
+    ):
         # Remove memory variables from input keys
         input_keys_response["input_keys"] = {
             key: value
@@ -63,7 +71,9 @@ def build_input_keys_response(langchain_object, artifacts):
         # Add memory variables to memory_keys
         input_keys_response["memory_keys"] = langchain_object.memory.memory_variables
 
-    if hasattr(langchain_object, "prompt") and hasattr(langchain_object.prompt, "template"):
+    if hasattr(langchain_object, "prompt") and hasattr(
+        langchain_object.prompt, "template"
+    ):
         input_keys_response["template"] = langchain_object.prompt.template
 
     return input_keys_response
@@ -98,7 +108,11 @@ def raw_frontend_data_is_valid(raw_frontend_data):
 def is_valid_data(frontend_node, raw_frontend_data):
     """Check if the data is valid for processing."""
 
-    return frontend_node and "template" in frontend_node and raw_frontend_data_is_valid(raw_frontend_data)
+    return (
+        frontend_node
+        and "template" in frontend_node
+        and raw_frontend_data_is_valid(raw_frontend_data)
+    )
 
 
 def update_template_values(frontend_template, raw_template):
@@ -138,7 +152,9 @@ def get_file_path_value(file_path):
     # If the path is not in the cache dir, return empty string
     # This is to prevent access to files outside the cache dir
     # If the path is not a file, return empty string
-    if not path.exists() or not str(path).startswith(user_cache_dir("langflow", "langflow")):
+    if not path.exists() or not str(path).startswith(
+        user_cache_dir("langflow", "langflow")
+    ):
         return ""
     return file_path
 
@@ -169,7 +185,9 @@ async def check_langflow_version(component: StoreComponentCreate):
 
     langflow_version = get_lf_version_from_pypi()
     if langflow_version is None:
-        raise HTTPException(status_code=500, detail="Unable to verify the latest version of Langflow")
+        raise HTTPException(
+            status_code=500, detail="Unable to verify the latest version of Langflow"
+        )
     elif langflow_version != component.last_tested_version:
         warnings.warn(
             f"Your version of Langflow ({component.last_tested_version}) is outdated. "
@@ -230,3 +248,25 @@ def build_and_cache_graph(
         graph = graph.update(other_graph)
     chat_service.set_cache(flow_id, graph)
     return graph
+
+
+def format_syntax_error_message(exc: SyntaxError) -> str:
+    """Format a SyntaxError message for returning to the frontend."""
+    return f"Syntax error in code. Error on line {exc.lineno}: {exc.text.strip()}"
+
+
+def get_causing_exception(exc: Exception) -> Exception:
+    """Get the causing exception from an exception."""
+    if hasattr(exc, "__cause__") and exc.__cause__:
+        return get_causing_exception(exc.__cause__)
+    return exc
+
+
+def format_exception_message(exc: Exception) -> str:
+    """Format an exception message for returning to the frontend."""
+    # We need to check if the __cause__ is a SyntaxError
+    # If it is, we need to return the message of the SyntaxError
+    causing_exception = get_causing_exception(exc)
+    if isinstance(causing_exception, SyntaxError):
+        return format_syntax_error_message(causing_exception)
+    return str(exc)

src/backend/langflow/api/v1/chat.py

@@ -14,7 +14,11 @@ from fastapi.responses import StreamingResponse
 from loguru import logger
 from sqlmodel import Session
 
-from langflow.api.utils import build_and_cache_graph, format_elapsed_time
+from langflow.api.utils import (
+    build_and_cache_graph,
+    format_elapsed_time,
+    format_exception_message,
+)
 from langflow.api.v1.schemas import (
     ResultData,
     StreamData,
@@ -45,9 +49,13 @@ async def chat(
         user = await get_current_user_for_websocket(websocket, db)
         await websocket.accept()
         if not user:
-            await websocket.close(code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized")
+            await websocket.close(
+                code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized"
+            )
         elif not user.is_active:
-            await websocket.close(code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized")
+            await websocket.close(
+                code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized"
+            )
 
         if client_id in chat_service.cache_service:
             await chat_service.handle_websocket(client_id, websocket)
@@ -63,7 +71,9 @@ async def chat(
         logger.error(f"Error in chat websocket: {exc}")
         messsage = exc.detail if isinstance(exc, HTTPException) else str(exc)
         if "Could not validate credentials" in str(exc):
-            await websocket.close(code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized")
+            await websocket.close(
+                code=status.WS_1008_POLICY_VIOLATION, reason="Unauthorized"
+            )
         else:
             await websocket.close(code=status.WS_1011_INTERNAL_ERROR, reason=messsage)
 
@@ -133,8 +143,12 @@ async def build_vertex(
         cache = chat_service.get_cache(flow_id)
         if not cache:
             # If there's no cache
-            logger.warning(f"No cache found for {flow_id}. Building graph starting at {vertex_id}")
-            graph = build_and_cache_graph(flow_id=flow_id, session=next(get_session()), chat_service=chat_service)
+            logger.warning(
+                f"No cache found for {flow_id}. Building graph starting at {vertex_id}"
+            )
+            graph = build_and_cache_graph(
+                flow_id=flow_id, session=next(get_session()), chat_service=chat_service
+            )
         else:
             graph = cache.get("result")
         result_dict = {}
@@ -165,7 +179,8 @@ async def build_vertex(
                 raise ValueError(f"No result found for vertex {vertex_id}")
 
         except Exception as exc:
-            params = str(exc)
+            #
+            params = format_exception_message(exc)
             valid = False
             result_dict = ResultData(results={})
             artifacts = {}