fix: Ensure all datetime operations return timezone-aware objects (#268)

Signed-off-by: Joe P <joe@basicmemory.com>
Co-authored-by: Claude <noreply@anthropic.com>

src/basic_memory/api/routers/resource_router.py

@@ -188,7 +188,7 @@ async def write_resource(
                     "content_type": content_type,
                     "file_path": file_path,
                     "checksum": checksum,
-                    "updated_at": datetime.fromtimestamp(file_stats.st_mtime),
+                    "updated_at": datetime.fromtimestamp(file_stats.st_mtime).astimezone(),
                 },
             )
             status_code = 200
@@ -200,8 +200,8 @@ async def write_resource(
                 content_type=content_type,
                 file_path=file_path,
                 checksum=checksum,
-                created_at=datetime.fromtimestamp(file_stats.st_ctime),
-                updated_at=datetime.fromtimestamp(file_stats.st_mtime),
+                created_at=datetime.fromtimestamp(file_stats.st_ctime).astimezone(),
+                updated_at=datetime.fromtimestamp(file_stats.st_mtime).astimezone(),
             )
             entity = await entity_repository.add(entity)
             status_code = 201

src/basic_memory/importers/chatgpt_importer.py

@@ -93,7 +93,7 @@ class ChatGPTImporter(Importer[ChatImportResult]):
                 break
 
         # Generate permalink
-        date_prefix = datetime.fromtimestamp(created_at).strftime("%Y%m%d")
+        date_prefix = datetime.fromtimestamp(created_at).astimezone().strftime("%Y%m%d")
         clean_title = clean_filename(conversation["title"])
 
         # Format content

src/basic_memory/importers/utils.py

@@ -43,13 +43,13 @@ def format_timestamp(timestamp: Any) -> str:  # pragma: no cover
         except ValueError:
             try:
                 # Try unix timestamp as string
-                timestamp = datetime.fromtimestamp(float(timestamp))
+                timestamp = datetime.fromtimestamp(float(timestamp)).astimezone()
             except ValueError:
                 # Return as is if we can't parse it
                 return timestamp
     elif isinstance(timestamp, (int, float)):
         # Unix timestamp
-        timestamp = datetime.fromtimestamp(timestamp)
+        timestamp = datetime.fromtimestamp(timestamp).astimezone()
 
     if isinstance(timestamp, datetime):
         return timestamp.strftime("%Y-%m-%d %H:%M:%S")

src/basic_memory/markdown/entity_parser.py

@@ -130,6 +130,6 @@ class EntityParser:
             content=post.content,
             observations=entity_content.observations,
             relations=entity_content.relations,
-            created=datetime.fromtimestamp(file_stats.st_ctime),
-            modified=datetime.fromtimestamp(file_stats.st_mtime),
+            created=datetime.fromtimestamp(file_stats.st_ctime).astimezone(),
+            modified=datetime.fromtimestamp(file_stats.st_mtime).astimezone(),
         )

src/basic_memory/mcp/tools/build_context.py

@@ -1,6 +1,6 @@
 """Build context tool for Basic Memory MCP server."""
 
-from typing import Optional, Union
+from typing import Optional
 
 from loguru import logger
 
@@ -111,7 +111,7 @@ async def build_context(
             metadata=MemoryMetadata(
                 depth=depth or 1,
                 timeframe=timeframe,
-                generated_at=datetime.now(),
+                generated_at=datetime.now().astimezone(),
                 primary_count=0,
                 related_count=0,
                 uri=migration_status,  # Include status in metadata

src/basic_memory/models/knowledge.py

@@ -1,6 +1,7 @@
 """Knowledge graph models."""
 
-from datetime import datetime
+from datetime import datetime, timezone
+from basic_memory.utils import ensure_timezone_aware
 from typing import Optional
 
 from sqlalchemy import (
@@ -73,8 +74,8 @@ class Entity(Base):
     checksum: Mapped[Optional[str]] = mapped_column(String, nullable=True)
 
     # Metadata and tracking
-    created_at: Mapped[datetime] = mapped_column(DateTime)
-    updated_at: Mapped[datetime] = mapped_column(DateTime)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now().astimezone())
+    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now().astimezone(), onupdate=lambda: datetime.now().astimezone())
 
     # Relationships
     project = relationship("Project", back_populates="entities")
@@ -103,6 +104,16 @@ class Entity(Base):
     def is_markdown(self):
         """Check if the entity is a markdown file."""
         return self.content_type == "text/markdown"
+    
+    def __getattribute__(self, name):
+        """Override attribute access to ensure datetime fields are timezone-aware."""
+        value = super().__getattribute__(name)
+        
+        # Ensure datetime fields are timezone-aware
+        if name in ('created_at', 'updated_at') and isinstance(value, datetime):
+            return ensure_timezone_aware(value)
+        
+        return value
 
     def __repr__(self) -> str:
         return f"Entity(id={self.id}, name='{self.title}', type='{self.entity_type}'"

src/basic_memory/models/project.py

@@ -52,9 +52,9 @@ class Project(Base):
     is_default: Mapped[Optional[bool]] = mapped_column(Boolean, default=None, nullable=True)
 
     # Timestamps
-    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(UTC))
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(UTC))
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, default=lambda: datetime.now(UTC), onupdate=lambda: datetime.now(UTC)
+        DateTime(timezone=True), default=lambda: datetime.now(UTC), onupdate=lambda: datetime.now(UTC)
     )
 
     # Define relationships to entities, observations, and relations

src/basic_memory/schemas/base.py

@@ -13,7 +13,7 @@ Key Concepts:
 
 import mimetypes
 import re
-from datetime import datetime, time
+from datetime import datetime, time, timezone
 from pathlib import Path
 from typing import List, Optional, Annotated, Dict
 
@@ -53,22 +53,28 @@ def parse_timeframe(timeframe: str) -> datetime:
         timeframe: Natural language timeframe like 'today', '1d', '1 week ago', etc.
 
     Returns:
-        datetime: The parsed datetime for the start of the timeframe
+        datetime: The parsed datetime for the start of the timeframe, timezone-aware in local system timezone
 
     Examples:
-        parse_timeframe('today') -> 2025-06-05 00:00:00 (start of today)
-        parse_timeframe('1d') -> 2025-06-04 14:50:00 (24 hours ago)
-        parse_timeframe('1 week ago') -> 2025-05-29 14:50:00 (1 week ago)
+        parse_timeframe('today') -> 2025-06-05 00:00:00-07:00 (start of today with local timezone)
+        parse_timeframe('1d') -> 2025-06-04 14:50:00-07:00 (24 hours ago with local timezone)
+        parse_timeframe('1 week ago') -> 2025-05-29 14:50:00-07:00 (1 week ago with local timezone)
     """
     if timeframe.lower() == "today":
-        # Return start of today (00:00:00)
-        return datetime.combine(datetime.now().date(), time.min)
+        # Return start of today (00:00:00) in local timezone
+        naive_dt = datetime.combine(datetime.now().date(), time.min)
+        return naive_dt.astimezone()
     else:
         # Use dateparser for other formats
         parsed = parse(timeframe)
         if not parsed:
             raise ValueError(f"Could not parse timeframe: {timeframe}")
-        return parsed
+        
+        # If the parsed datetime is naive, make it timezone-aware in local system timezone
+        if parsed.tzinfo is None:
+            return parsed.astimezone()
+        else:
+            return parsed
 
 
 def validate_timeframe(timeframe: str) -> str:
@@ -85,7 +91,7 @@ def validate_timeframe(timeframe: str) -> str:
     parsed = parse_timeframe(timeframe)
 
     # Convert to duration
-    now = datetime.now()
+    now = datetime.now().astimezone()
     if parsed > now:
         raise ValueError("Timeframe cannot be in the future")
 

src/basic_memory/sync/sync_service.py

@@ -357,8 +357,8 @@ class SyncService:
 
             # get file timestamps
             file_stats = self.file_service.file_stats(path)
-            created = datetime.fromtimestamp(file_stats.st_ctime)
-            modified = datetime.fromtimestamp(file_stats.st_mtime)
+            created = datetime.fromtimestamp(file_stats.st_ctime).astimezone()
+            modified = datetime.fromtimestamp(file_stats.st_mtime).astimezone()
 
             # get mime type
             content_type = self.file_service.content_type(path)

src/basic_memory/utils.py

@@ -5,6 +5,7 @@ import os
 import logging
 import re
 import sys
+from datetime import datetime
 from pathlib import Path
 from typing import Optional, Protocol, Union, runtime_checkable, List
 
@@ -318,4 +319,24 @@ def validate_project_path(path: str, project_path: Path) -> bool:
         resolved = (project_path / path).resolve()
         return resolved.is_relative_to(project_path.resolve())
     except (ValueError, OSError):
-        return False
+        return False
+
+
+def ensure_timezone_aware(dt: datetime) -> datetime:
+    """Ensure a datetime is timezone-aware using system timezone.
+    
+    If the datetime is naive, convert it to timezone-aware using the system's local timezone.
+    If it's already timezone-aware, return it unchanged.
+    
+    Args:
+        dt: The datetime to ensure is timezone-aware
+        
+    Returns:
+        A timezone-aware datetime
+    """
+    if dt.tzinfo is None:
+        # Naive datetime - assume it's in local time and add timezone
+        return dt.astimezone()
+    else:
+        # Already timezone-aware
+        return dt