```

Refactor datetime handling to use utc_now utility

Replaced multiple occurrences of `datetime.now(timezone.utc)` with
a single `utc_now` utility function across various modules. This
enhances code consistency and reusability, and reduces redundancy.

No behavioral changes are intended; only the implementation detail
is modified to leverage the utility function for getting the current
UTC datetime.

Fixes #1234
```

src/backend/base/langflow/api/v1/flows.py

@@ -19,6 +19,7 @@ from langflow.services.database.models.folder.model import Folder
 from langflow.services.database.models.user.model import User
 from langflow.services.deps import get_session, get_settings_service
 from langflow.services.settings.service import SettingsService
+from langflow.utils.util import utc_now
 
 # build router
 router = APIRouter(prefix="/flows", tags=["Flows"])
@@ -52,7 +53,7 @@ def create_flow(
                 flow.name = f"{flow.name} (1)"
 
         db_flow = Flow.model_validate(flow, from_attributes=True)
-        db_flow.updated_at = datetime.now(timezone.utc)
+        db_flow.updated_at = utc_now()
 
         if db_flow.folder_id is None:
             # Make sure flows always have a folder
@@ -188,7 +189,7 @@ def update_flow(
                 setattr(db_flow, key, value)
         webhook_component = get_webhook_component_in_flow(db_flow.data)
         db_flow.webhook = webhook_component is not None
-        db_flow.updated_at = datetime.now(timezone.utc)
+        db_flow.updated_at = utc_now()
         if db_flow.folder_id is None:
             default_folder = session.exec(select(Folder).where(Folder.name == DEFAULT_FOLDER_NAME)).first()
             if default_folder:

src/backend/base/langflow/api/v1/schemas.py

@@ -14,6 +14,7 @@ from langflow.services.database.models.api_key.model import ApiKeyRead
 from langflow.services.database.models.base import orjson_dumps
 from langflow.services.database.models.flow import FlowCreate, FlowRead
 from langflow.services.database.models.user import UserRead
+from langflow.utils.util import utc_now
 
 
 class BuildStatus(Enum):
@@ -263,7 +264,7 @@ class VertexBuildResponse(BaseModel):
     """JSON string of the params."""
     data: ResultDataResponse
     """Mapping of vertex ids to result dict containing the param name and result value."""
-    timestamp: Optional[datetime] = Field(default_factory=lambda: datetime.now(timezone.utc))
+    timestamp: Optional[datetime] = Field(default_factory=lambda: utc_now())
     """Timestamp of the build."""
 
 

src/backend/base/langflow/api/v1/variable.py

@@ -9,6 +9,7 @@ from langflow.services.auth.utils import get_current_active_user
 from langflow.services.database.models.user.model import User
 from langflow.services.database.models.variable import Variable, VariableCreate, VariableRead, VariableUpdate
 from langflow.services.deps import get_session, get_settings_service
+from langflow.utils.util import utc_now
 
 router = APIRouter(prefix="/variables", tags=["Variables"])
 
@@ -89,7 +90,7 @@ def update_variable(
         variable_data = variable.model_dump(exclude_unset=True)
         for key, value in variable_data.items():
             setattr(db_variable, key, value)
-        db_variable.updated_at = datetime.now(timezone.utc)
+        db_variable.updated_at = utc_now()
         session.commit()
         session.refresh(db_variable)
         return db_variable

src/backend/base/langflow/schema/message.py

@@ -8,7 +8,7 @@ from pydantic import BeforeValidator, ConfigDict, Field, field_serializer
 
 from langflow.schema.data import Data
 from langflow.schema.image import Image, get_file_paths, is_image_file
-
+from langflow.utils.util import utc_now
 
 def _timestamp_to_str(timestamp: datetime) -> str:
     return timestamp.strftime("%Y-%m-%d %H:%M:%S")
@@ -24,7 +24,7 @@ class Message(Data):
     files: Optional[list[str | Image]] = Field(default=[])
     session_id: Optional[str] = Field(default="")
     timestamp: Annotated[str, BeforeValidator(_timestamp_to_str)] = Field(
-        default=datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
+        default=utc_now(stringify=True)
     )
     flow_id: Optional[str] = None
 
@@ -41,7 +41,7 @@ class Message(Data):
         self,
     ) -> BaseMessage:
         """
-        Converts the Data to a BaseMessage.
+        Converts the Data into a BaseMessage.
 
         Returns:
             BaseMessage: The converted BaseMessage.

src/backend/base/langflow/services/auth/utils.py

@@ -16,6 +16,8 @@ from langflow.services.database.models.api_key.model import ApiKey
 from langflow.services.database.models.user.crud import get_user_by_id, get_user_by_username, update_user_last_login_at
 from langflow.services.database.models.user.model import User
 from langflow.services.deps import get_session, get_settings_service
+from langflow.utils.util import utc_now
+
 
 oauth2_login = OAuth2PasswordBearer(tokenUrl="api/v1/login", auto_error=False)
 
@@ -112,7 +114,7 @@ async def get_current_user_by_jwt(
         token_type: str = payload.get("type")
         if expires := payload.get("exp", None):
             expires_datetime = datetime.fromtimestamp(expires, timezone.utc)
-            if datetime.now(timezone.utc) > expires_datetime:
+            if utc_now() > expires_datetime:
                 logger.info("Token expired for user")
                 raise HTTPException(
                     status_code=status.HTTP_401_UNAUTHORIZED,
@@ -189,7 +191,7 @@ def create_token(data: dict, expires_delta: timedelta):
     settings_service = get_settings_service()
 
     to_encode = data.copy()
-    expire = datetime.now(timezone.utc) + expires_delta
+    expire = utc_now() + expires_delta
     to_encode["exp"] = expire
 
     return jwt.encode(

src/backend/base/langflow/services/database/models/api_key/model.py

@@ -5,14 +5,13 @@ from uuid import UUID, uuid4
 from pydantic import field_validator
 from sqlmodel import Column, DateTime, Field, Relationship, SQLModel, func
 
+from langflow.utils.util import utc_now
+
+
 if TYPE_CHECKING:
     from langflow.services.database.models.user import User
 
 
-def utc_now():
-    return datetime.now(timezone.utc)
-
-
 class ApiKeyBase(SQLModel):
     name: Optional[str] = Field(index=True, nullable=True, default=None)
     last_used_at: Optional[datetime] = Field(default=None, nullable=True)

src/backend/base/langflow/services/database/models/flow/model.py

@@ -14,6 +14,7 @@ from sqlalchemy import UniqueConstraint
 from sqlmodel import JSON, Column, Field, Relationship, SQLModel
 
 from langflow.schema import Data
+from langflow.utils.util import utc_now
 
 if TYPE_CHECKING:
     from langflow.services.database.models.folder import Folder
@@ -27,7 +28,7 @@ class FlowBase(SQLModel):
     icon_bg_color: Optional[str] = Field(default=None, nullable=True)
     data: Optional[Dict] = Field(default=None, nullable=True)
     is_component: Optional[bool] = Field(default=False, nullable=True)
-    updated_at: Optional[datetime] = Field(default_factory=lambda: datetime.now(timezone.utc), nullable=True)
+    updated_at: Optional[datetime] = Field(default_factory=lambda: utc_now(), nullable=True)
     webhook: Optional[bool] = Field(default=False, nullable=True, description="Can be used on the webhook endpoint")
     endpoint_name: Optional[str] = Field(default=None, nullable=True, index=True)
 

src/backend/base/langflow/services/database/models/user/crud.py

@@ -9,6 +9,7 @@ from sqlmodel import Session, select
 
 from langflow.services.database.models.user.model import User, UserUpdate
 from langflow.services.deps import get_session
+from langflow.utils.util import utc_now
 
 
 def get_user_by_username(db: Session, username: str) -> Union[User, None]:
@@ -37,7 +38,7 @@ def update_user(user_db: Optional[User], user: UserUpdate, db: Session = Depends
     if not changed:
         raise HTTPException(status_code=status.HTTP_304_NOT_MODIFIED, detail="Nothing to update")
 
-    user_db.updated_at = datetime.now(timezone.utc)
+    user_db.updated_at = utc_now()
     flag_modified(user_db, "updated_at")
 
     try:
@@ -51,7 +52,7 @@ def update_user(user_db: Optional[User], user: UserUpdate, db: Session = Depends
 
 def update_user_last_login_at(user_id: UUID, db: Session = Depends(get_session)):
     try:
-        user_data = UserUpdate(last_login_at=datetime.now(timezone.utc))  # type: ignore
+        user_data = UserUpdate(last_login_at=utc_now())  # type: ignore
         user = get_user_by_id(db, user_id)
         return update_user(user, user_data, db)
     except Exception:

src/backend/base/langflow/services/database/models/user/model.py

@@ -4,6 +4,8 @@ from uuid import UUID, uuid4
 
 from sqlmodel import Field, Relationship, SQLModel
 
+from langflow.utils.util import utc_now
+
 if TYPE_CHECKING:
     from langflow.services.database.models.api_key import ApiKey
     from langflow.services.database.models.variable import Variable
@@ -18,8 +20,8 @@ class User(SQLModel, table=True):
     profile_image: Optional[str] = Field(default=None, nullable=True)
     is_active: bool = Field(default=False)
     is_superuser: bool = Field(default=False)
-    create_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
-    updated_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
+    create_at: datetime = Field(default_factory=lambda: utc_now())
+    updated_at: datetime = Field(default_factory=lambda: utc_now())
     last_login_at: Optional[datetime] = Field(default=None, nullable=True)
     api_keys: list["ApiKey"] = Relationship(
         back_populates="user",

src/backend/base/langflow/services/database/models/variable/model.py

@@ -4,14 +4,13 @@ from uuid import UUID, uuid4
 
 from sqlmodel import JSON, Column, DateTime, Field, Relationship, SQLModel, func
 
+from langflow.utils.util import utc_now
+
+
 if TYPE_CHECKING:
     from langflow.services.database.models.user.model import User
 
 
-def utc_now():
-    return datetime.now(timezone.utc)
-
-
 class VariableBase(SQLModel):
     name: str = Field(description="Name of the variable")
     value: str = Field(description="Encrypted value of the variable")

src/backend/base/langflow/utils/util.py

@@ -4,6 +4,7 @@ import re
 from functools import wraps
 from pathlib import Path
 from typing import Any, Dict, List, Optional, Union
+from datetime import datetime, timezone
 
 from docstring_parser import parse
 
@@ -14,6 +15,13 @@ from langflow.utils import constants
 from langflow.utils.logger import logger
 
 
+
+def utc_now(stringify=False):
+    if stringify:
+        return datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
+    return datetime.now(timezone.utc)
+
+
 def unescape_string(s: str):
     # Replace escaped new line characters with actual new line characters
     return s.replace("\\n", "\n")