Add new build_and_cache_graph in utils.py

src/backend/langflow/api/utils.py

@@ -1,13 +1,16 @@
 import warnings
 from pathlib import Path
-from typing import TYPE_CHECKING, List
+from typing import TYPE_CHECKING, List, Optional
 
 from fastapi import HTTPException
 from langchain_core.documents import Document
+from langflow.graph.graph.base import Graph
+from langflow.services.chat.service import ChatService
+from langflow.services.database.models.flow import Flow
+from langflow.services.store.schema import StoreComponentCreate
 from platformdirs import user_cache_dir
 from pydantic import BaseModel
-
-from langflow.services.store.schema import StoreComponentCreate
+from sqlmodel import Session
 
 if TYPE_CHECKING:
     from langflow.services.database.models.flow.model import Flow
@@ -17,7 +20,9 @@ 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):
@@ -27,7 +32,11 @@ 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
@@ -48,7 +57,9 @@ 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
@@ -58,7 +69,9 @@ 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
@@ -93,7 +106,11 @@ 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):
@@ -133,7 +150,9 @@ 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
 
@@ -164,7 +183,9 @@ 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. "
@@ -206,3 +227,22 @@ def serialize_field(value):
     elif isinstance(value, str):
         return {"result": value}
     return value
+
+
+def build_and_cache_graph(
+    flow_id: str,
+    session: Session,
+    chat_service: "ChatService",
+    graph: Optional[Graph] = None,
+):
+    """Build and cache the graph."""
+    flow: Flow = session.get(Flow, flow_id)
+    if not flow or not flow.data:
+        raise ValueError("Invalid flow ID")
+    other_graph = Graph.from_payload(flow.data)
+    if graph is None:
+        graph = other_graph
+    else:
+        graph = graph.update(other_graph)
+    chat_service.set_cache(flow_id, graph)
+    return graph