Use timezone-aware timestamps and update tests

backend/app/auth.py

@@ -11,6 +11,7 @@ from sqlalchemy import select
 from app.config import settings
 from app.database import get_db
 from app.models.user import User
+from app.utils import utc_now
 
 # Password hashing
 pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
@@ -33,9 +34,9 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
     """Create a JWT access token"""
     to_encode = data.copy()
     if expires_delta:
-        expire = datetime.utcnow() + expires_delta
+        expire = utc_now() + expires_delta
     else:
-        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+        expire = utc_now() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
 
     to_encode.update({"exp": expire, "type": "access"})
     encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
@@ -45,7 +46,7 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
 def create_refresh_token(data: dict) -> str:
     """Create a JWT refresh token"""
     to_encode = data.copy()
-    expire = datetime.utcnow() + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)
+    expire = utc_now() + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)
     to_encode.update({"exp": expire, "type": "refresh"})
     encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
     return encoded_jwt

backend/app/models/device.py

@@ -4,6 +4,7 @@ from typing import Optional
 from sqlalchemy import Column, Integer, String, Boolean, DateTime, Float, JSON, ForeignKey, Text
 from sqlalchemy.orm import relationship
 from app.database import Base
+from app.utils import utc_now
 
 
 class Device(Base):
@@ -59,8 +60,8 @@ class Device(Base):
     owner = relationship("User", back_populates="devices")
 
     # Timestamps
-    created_at = Column(DateTime, default=datetime.utcnow)
-    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    created_at = Column(DateTime, default=utc_now)
+    updated_at = Column(DateTime, default=utc_now, onupdate=utc_now)
 
     # Relations
     metrics = relationship("DeviceMetric", back_populates="device", cascade="all, delete-orphan")
@@ -76,7 +77,7 @@ class DeviceMetric(Base):
     device_id = Column(Integer, ForeignKey("devices.id", ondelete="CASCADE"), nullable=False)
 
     # Metric data
-    timestamp = Column(DateTime, default=datetime.utcnow, index=True)
+    timestamp = Column(DateTime, default=utc_now, index=True)
     cpu_usage = Column(Float)
     ram_usage = Column(Float)
     disk_usage = Column(Float)
@@ -100,7 +101,7 @@ class DeviceLog(Base):
     device_id = Column(Integer, ForeignKey("devices.id", ondelete="CASCADE"), nullable=False)
 
     # Log data
-    timestamp = Column(DateTime, default=datetime.utcnow, index=True)
+    timestamp = Column(DateTime, default=utc_now, index=True)
     level = Column(String(20), nullable=False)  # info, warning, error, critical
     category = Column(String(50))  # system, network, service, hardware
     message = Column(Text, nullable=False)

backend/app/routers/ai_chat.py

@@ -10,6 +10,7 @@ from app.database import get_db
 from app.models.user import User
 from app.models.ai_chat import Conversation, Message, MessageRole
 from app.auth import get_current_active_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/ai-chat", tags=["AI Chat"])
 
@@ -188,7 +189,7 @@ async def send_message(
 
     # Update conversation
     conversation.message_count += 2
-    conversation.updated_at = datetime.utcnow()
+    conversation.updated_at = utc_now()
 
     if not conversation.title or conversation.title == "New Conversation":
         # Auto-generate title from first message

backend/app/routers/api_health.py

@@ -13,6 +13,8 @@ import asyncio
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/health", tags=["health"])
@@ -47,7 +49,7 @@ async def check_api_status(name: str, check_func) -> Dict[str, Any]:
             "name": name,
             "status": "connected" if result.get("connected") else "not_configured",
             "message": result.get("message", ""),
-            "last_checked": datetime.utcnow().isoformat(),
+            "last_checked": utc_now().isoformat(),
             "configuration": {
                 k: v for k, v in result.items()
                 if k.endswith("_configured") or k == "connected"
@@ -60,7 +62,7 @@ async def check_api_status(name: str, check_func) -> Dict[str, Any]:
             "name": name,
             "status": "error",
             "message": f"Health check failed: {str(e)}",
-            "last_checked": datetime.utcnow().isoformat(),
+            "last_checked": utc_now().isoformat(),
             "configuration": {},
             "error": str(e)
         }
@@ -154,7 +156,7 @@ async def check_all_apis():
 
     return SystemHealthStatus(
         status=overall_status,
-        timestamp=datetime.utcnow().isoformat(),
+        timestamp=utc_now().isoformat(),
         total_apis=total_apis,
         connected_apis=connected_count,
         not_configured_apis=not_configured_count,

backend/app/routers/auth.py

@@ -17,7 +17,7 @@ from app.auth import (
 )
 from app.services.blockchain import BlockchainService
 from app.services.crypto import wallet_crypto, WalletKeyEncryptionError
-from datetime import datetime
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/auth", tags=["Authentication"])
 
@@ -82,7 +82,7 @@ async def register(user_data: UserCreate, db: AsyncSession = Depends(get_db)):
         wallet_address=wallet_address,
         wallet_private_key=encrypted_private_key,
         balance=100.0,  # Starting bonus
-        created_at=datetime.utcnow()
+        created_at=utc_now()
     )
 
     db.add(user)
@@ -131,7 +131,7 @@ async def login(
         )
 
     # Update last login
-    user.last_login = datetime.utcnow()
+    user.last_login = utc_now()
     await db.commit()
 
     # Create tokens

backend/app/routers/browser.py

@@ -12,7 +12,6 @@ from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
 from typing import List, Optional
-from datetime import datetime
 import httpx
 from urllib.parse import urlparse, quote
 import hashlib
@@ -21,6 +20,7 @@ from ..database import get_db
 from ..auth import get_current_user
 from ..models import User
 from pydantic import BaseModel, HttpUrl
+from ..utils import utc_now
 
 router = APIRouter(prefix="/api/browser", tags=["browser"])
 
@@ -142,7 +142,7 @@ async def add_bookmark(
         "title": bookmark.title,
         "url": bookmark.url,
         "folder": bookmark.folder,
-        "created_at": datetime.utcnow().isoformat()
+        "created_at": utc_now().isoformat()
     }
 
     return {
@@ -208,10 +208,10 @@ async def add_history_entry(
 ):
     """Add a history entry"""
     new_entry = {
-        "id": hashlib.md5(f"{entry.url}{datetime.utcnow()}".encode()).hexdigest()[:8],
+        "id": hashlib.md5(f"{entry.url}{utc_now()}".encode()).hexdigest()[:8],
         "url": entry.url,
         "title": entry.title,
-        "visited_at": datetime.utcnow().isoformat()
+        "visited_at": utc_now().isoformat()
     }
 
     return {
@@ -232,7 +232,7 @@ async def clear_history(
 @router.get("/search")
 async def web_search(
     q: str = Query(..., min_length=1, description="Search query"),
-    engine: str = Query("duckduckgo", regex="^(duckduckgo|google|bing)$"),
+    engine: str = Query("duckduckgo", pattern="^(duckduckgo|google|bing)$"),
     current_user: User = Depends(get_current_user)
 ):
     """
@@ -397,7 +397,7 @@ async def open_new_tab(
     """Open a new tab"""
     return {
         "tab": {
-            "id": hashlib.md5(f"{url}{datetime.utcnow()}".encode()).hexdigest()[:8],
+            "id": hashlib.md5(f"{url}{utc_now()}".encode()).hexdigest()[:8],
             "url": url,
             "title": "Loading...",
             "active": True

backend/app/routers/dashboard.py

@@ -19,6 +19,7 @@ from ..database import get_db
 from ..auth import get_current_user
 from ..models import User, Device, Email, Post, Video, File, Conversation, Block, Transaction
 from pydantic import BaseModel
+from ..utils import utc_now
 
 router = APIRouter(prefix="/api/dashboard", tags=["dashboard"])
 
@@ -201,7 +202,7 @@ async def get_dashboard_overview(
         },
         "services": services,
         "system_health": system_health,
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }
 
 
@@ -356,7 +357,7 @@ async def get_recent_activity(
             "icon": "📧",
             "action": "Received new email",
             "description": "Meeting reminder from Sarah",
-            "timestamp": (datetime.utcnow() - timedelta(minutes=5)).isoformat()
+            "timestamp": (utc_now() - timedelta(minutes=5)).isoformat()
         },
         {
             "id": 2,
@@ -364,7 +365,7 @@ async def get_recent_activity(
             "icon": "⛓️",
             "action": "Transaction completed",
             "description": "Sent 10 RoadCoins to wallet abc123",
-            "timestamp": (datetime.utcnow() - timedelta(minutes=15)).isoformat()
+            "timestamp": (utc_now() - timedelta(minutes=15)).isoformat()
         },
         {
             "id": 3,
@@ -372,7 +373,7 @@ async def get_recent_activity(
             "icon": "⛏️",
             "action": "Block mined",
             "description": "Mined block #1234, earned 50 RoadCoins",
-            "timestamp": (datetime.utcnow() - timedelta(hours=1)).isoformat()
+            "timestamp": (utc_now() - timedelta(hours=1)).isoformat()
         },
         {
             "id": 4,
@@ -380,7 +381,7 @@ async def get_recent_activity(
             "icon": "🥧",
             "action": "Device connected",
             "description": "Raspberry Pi 4 - Living Room came online",
-            "timestamp": (datetime.utcnow() - timedelta(hours=2)).isoformat()
+            "timestamp": (utc_now() - timedelta(hours=2)).isoformat()
         },
         {
             "id": 5,
@@ -388,7 +389,7 @@ async def get_recent_activity(
             "icon": "🌐",
             "action": "New like",
             "description": "Mike liked your post",
-            "timestamp": (datetime.utcnow() - timedelta(hours=3)).isoformat()
+            "timestamp": (utc_now() - timedelta(hours=3)).isoformat()
         }
     ]
 

backend/app/routers/devices.py

@@ -10,6 +10,7 @@ from app.database import get_db
 from app.models.device import Device, DeviceMetric, DeviceLog
 from app.models.user import User
 from app.routers.auth import get_current_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/devices", tags=["devices"])
 
@@ -239,7 +240,7 @@ async def update_device(
     if device_data.description is not None:
         device.description = device_data.description
 
-    device.updated_at = datetime.utcnow()
+    device.updated_at = utc_now()
 
     await db.commit()
     await db.refresh(device)
@@ -265,7 +266,7 @@ async def device_heartbeat(
     # Update device status
     device.is_online = True
     device.status = "online"
-    device.last_seen = datetime.utcnow()
+    device.last_seen = utc_now()
 
     # Update system info if provided
     if heartbeat_data.ip_address:
@@ -308,7 +309,7 @@ async def device_heartbeat(
     # Save metric snapshot
     metric = DeviceMetric(
         device_id=device.id,
-        timestamp=datetime.utcnow(),
+        timestamp=utc_now(),
         cpu_usage=heartbeat_data.cpu_usage_percent,
         ram_usage=heartbeat_data.ram_usage_percent,
         disk_usage=heartbeat_data.disk_usage_percent,
@@ -392,7 +393,7 @@ async def ssh_connect(
         "device_id": device_id,
         "ip_address": device.ip_address,
         "hostname": device.hostname,
-        "connection_token": f"ssh_token_{device_id}_{datetime.utcnow().timestamp()}",
+        "connection_token": f"ssh_token_{device_id}_{utc_now().timestamp()}",
         "status": "connected",
         "message": f"SSH connection established to {device.hostname or device.ip_address}"
     }
@@ -448,7 +449,7 @@ async def ssh_execute_command(
         "command": command_data.command,
         "output": output,
         "exit_code": 0,
-        "executed_at": datetime.utcnow().isoformat()
+        "executed_at": utc_now().isoformat()
     }
 
 
@@ -511,7 +512,7 @@ async def deploy_to_device(
         "deploy_path": deploy_config.deploy_path,
         "steps": deployment_steps,
         "status": "success",
-        "deployed_at": datetime.utcnow().isoformat(),
+        "deployed_at": utc_now().isoformat(),
         "message": "Deployment completed successfully"
     }
 

backend/app/routers/discord.py

@@ -12,6 +12,8 @@ import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/discord", tags=["discord"])
@@ -304,5 +306,5 @@ async def discord_health_check():
         "service": "discord",
         "status": "operational" if DISCORD_BOT_TOKEN else "not_configured",
         "webhook_status": "operational" if DISCORD_WEBHOOK_URL else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/email.py

@@ -10,6 +10,7 @@ from app.database import get_db
 from app.models.user import User
 from app.models.email import Email, EmailFolder, EmailFolderType
 from app.auth import get_current_active_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/email", tags=["Email"])
 
@@ -154,7 +155,7 @@ async def send_email(
         bcc=",".join(email_data.bcc) if email_data.bcc else None,
         is_read=False,
         is_draft=False,
-        sent_at=datetime.utcnow()
+        sent_at=utc_now()
     )
 
     db.add(email)
@@ -193,7 +194,7 @@ async def get_email(
     # Mark as read if recipient is viewing
     if email.recipient_id == current_user.id and not email.is_read:
         email.is_read = True
-        email.read_at = datetime.utcnow()
+        email.read_at = utc_now()
         await db.commit()
 
     return email

backend/app/routers/files.py

@@ -11,6 +11,7 @@ from app.database import get_db
 from app.models.user import User
 from app.models.file import File, Folder
 from app.auth import get_current_active_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/files", tags=["Files"])
 
@@ -217,7 +218,7 @@ async def get_file(
         )
 
     # Update last accessed
-    file.last_accessed = datetime.utcnow()
+    file.last_accessed = utc_now()
     await db.commit()
 
     return file

backend/app/routers/games.py

@@ -19,6 +19,7 @@ import random
 from ..database import get_db
 from ..auth import get_current_user
 from ..models import User
+from ..utils import utc_now
 
 router = APIRouter(prefix="/api/games", tags=["games"])
 
@@ -62,7 +63,7 @@ async def list_cities(
                 "money": 45000,
                 "level": 5,
                 "created_at": "2024-01-01T00:00:00Z",
-                "updated_at": datetime.utcnow().isoformat()
+                "updated_at": utc_now().isoformat()
             }
         ]
     }

backend/app/routers/github.py

@@ -186,7 +186,7 @@ async def list_commits(
 async def list_pull_requests(
     owner: str,
     repo: str,
-    state: str = Query("open", regex="^(open|closed|all)$"),
+    state: str = Query("open", pattern="^(open|closed|all)$"),
     page: int = Query(1, ge=1),
     per_page: int = Query(30, ge=1, le=100),
     current_user: User = Depends(get_current_user)
@@ -220,7 +220,7 @@ async def list_pull_requests(
 async def list_issues(
     owner: str,
     repo: str,
-    state: str = Query("open", regex="^(open|closed|all)$"),
+    state: str = Query("open", pattern="^(open|closed|all)$"),
     page: int = Query(1, ge=1),
     per_page: int = Query(30, ge=1, le=100),
     current_user: User = Depends(get_current_user)

backend/app/routers/huggingface.py

@@ -37,7 +37,7 @@ class InferenceRequest(BaseModel):
 async def list_models(
     search: Optional[str] = Query(None),
     filter_task: Optional[str] = Query(None, alias="task"),
-    sort: str = Query("downloads", regex="^(downloads|likes|trending)$"),
+    sort: str = Query("downloads", pattern="^(downloads|likes|trending)$"),
     limit: int = Query(20, ge=1, le=100),
     current_user: User = Depends(get_current_user)
 ):
@@ -146,7 +146,7 @@ async def run_inference(
 @router.get("/datasets")
 async def list_datasets(
     search: Optional[str] = Query(None),
-    sort: str = Query("downloads", regex="^(downloads|likes|trending)$"),
+    sort: str = Query("downloads", pattern="^(downloads|likes|trending)$"),
     limit: int = Query(20, ge=1, le=100),
     current_user: User = Depends(get_current_user)
 ):
@@ -194,7 +194,7 @@ async def get_dataset_info(
 @router.get("/spaces")
 async def list_spaces(
     search: Optional[str] = Query(None),
-    sort: str = Query("likes", regex="^(likes|trending)$"),
+    sort: str = Query("likes", pattern="^(likes|trending)$"),
     limit: int = Query(20, ge=1, le=100),
     current_user: User = Depends(get_current_user)
 ):

backend/app/routers/miner.py

@@ -13,6 +13,7 @@ from app.database import get_db
 from app.models.blockchain import Block, Wallet
 from app.models.user import User
 from app.routers.auth import get_current_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/miner", tags=["miner"])
 
@@ -97,7 +98,7 @@ async def get_miner_status(
     """Get current miner status and performance metrics."""
     uptime_seconds = 0
     if miner_state.started_at:
-        uptime_seconds = int((datetime.utcnow() - miner_state.started_at).total_seconds())
+        uptime_seconds = int((utc_now() - miner_state.started_at).total_seconds())
 
     # Simulate some variance in hashrate
     current_hashrate = miner_state.hashrate_mhs
@@ -242,7 +243,7 @@ async def control_miner(
             raise HTTPException(status_code=400, detail="Miner is already running")
 
         miner_state.is_mining = True
-        miner_state.started_at = datetime.utcnow()
+        miner_state.started_at = utc_now()
         miner_state.hashrate_mhs = random.uniform(38.0, 45.0)  # Simulate hashrate
 
         if control.pool_url:
@@ -268,7 +269,7 @@ async def control_miner(
         miner_state.is_mining = False
         await asyncio.sleep(1)
         miner_state.is_mining = True
-        miner_state.started_at = datetime.utcnow()
+        miner_state.started_at = utc_now()
         miner_state.hashrate_mhs = random.uniform(38.0, 45.0)
 
         background_tasks.add_task(simulate_mining)
@@ -314,5 +315,5 @@ async def get_pool_info(
         "pool_fee": "1%",
         "min_payout": 10.0,
         "payment_interval_hours": 24,
-        "last_block_found": (datetime.utcnow() - timedelta(minutes=random.randint(5, 120))).isoformat(),
+        "last_block_found": (utc_now() - timedelta(minutes=random.randint(5, 120))).isoformat(),
     }

backend/app/routers/railway.py

@@ -13,6 +13,8 @@ import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/railway", tags=["railway"])
@@ -389,5 +391,5 @@ async def railway_health_check():
     return {
         "service": "railway",
         "status": "operational" if RAILWAY_TOKEN else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/sentry.py

@@ -13,6 +13,8 @@ import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/sentry", tags=["sentry"])
@@ -376,5 +378,5 @@ async def sentry_health_check():
     return {
         "service": "sentry",
         "status": "operational" if SENTRY_AUTH_TOKEN else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/slack.py

@@ -7,11 +7,12 @@ Provides endpoints for sending messages, managing channels, and interacting with
 from fastapi import APIRouter, HTTPException, status
 from pydantic import BaseModel
 from typing import List, Optional, Dict, Any
-from datetime import datetime
 import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/slack", tags=["slack"])
@@ -277,5 +278,5 @@ async def slack_health_check():
         "service": "slack",
         "status": "operational" if SLACK_BOT_TOKEN else "not_configured",
         "webhook_status": "operational" if SLACK_WEBHOOK_URL else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/stripe.py

@@ -8,11 +8,12 @@ Stripe is a payment processing platform for online businesses.
 from fastapi import APIRouter, HTTPException, status
 from pydantic import BaseModel, EmailStr
 from typing import List, Optional, Dict, Any
-from datetime import datetime
 import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/stripe", tags=["stripe"])
@@ -324,5 +325,5 @@ async def stripe_health_check():
     return {
         "service": "stripe",
         "status": "operational" if STRIPE_SECRET_KEY else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/twilio.py

@@ -14,6 +14,8 @@ import base64
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/twilio", tags=["twilio"])
@@ -255,5 +257,5 @@ async def twilio_health_check():
     return {
         "service": "twilio",
         "status": "operational" if (TWILIO_ACCOUNT_SID and TWILIO_AUTH_TOKEN) else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/vercel.py

@@ -13,6 +13,8 @@ import httpx
 import os
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/api/vercel", tags=["vercel"])
@@ -420,5 +422,5 @@ async def vercel_health_check():
     return {
         "service": "vercel",
         "status": "operational" if VERCEL_TOKEN else "not_configured",
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": utc_now().isoformat()
     }

backend/app/routers/video.py

@@ -10,6 +10,7 @@ from app.database import get_db
 from app.models.user import User
 from app.models.video import Video, VideoView, VideoLike
 from app.auth import get_current_active_user
+from app.utils import utc_now
 
 router = APIRouter(prefix="/api/videos", tags=["Videos"])
 
@@ -117,7 +118,7 @@ async def upload_video(
         category=video_data.category,
         tags=video_data.tags,
         is_public=True,
-        published_at=datetime.utcnow()
+        published_at=utc_now()
     )
 
     db.add(video)

backend/app/routers/vscode.py

@@ -12,11 +12,11 @@ from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
 from typing import List, Optional
-from datetime import datetime
 
 from ..database import get_db
 from ..auth import get_current_user
 from ..models import User, File, Folder
+from ..utils import utc_now
 from pydantic import BaseModel
 
 router = APIRouter(prefix="/api/vscode", tags=["vscode"])
@@ -120,7 +120,7 @@ async def update_file_content(
         raise HTTPException(status_code=404, detail="File not found")
 
     # In a real implementation, save to S3 or file system
-    file.updated_at = datetime.utcnow()
+    file.updated_at = utc_now()
     file.size = len(content.encode('utf-8'))
 
     await db.commit()

backend/app/services/api_manager.py

@@ -12,6 +12,8 @@ import httpx
 from enum import Enum
 import logging
 
+from app.utils import utc_now
+
 logger = logging.getLogger(__name__)
 
 
@@ -93,23 +95,23 @@ class APIClient:
             if response.status_code < 500:
                 self.status = APIStatus.CONNECTED
                 self.error_message = None
-                self.last_check = datetime.utcnow()
+                self.last_check = utc_now()
                 return True
             else:
                 self.status = APIStatus.ERROR
                 self.error_message = f"Server error: {response.status_code}"
-                self.last_check = datetime.utcnow()
+                self.last_check = utc_now()
                 return False
 
         except httpx.TimeoutException:
             self.status = APIStatus.ERROR
             self.error_message = "Connection timeout"
-            self.last_check = datetime.utcnow()
+            self.last_check = utc_now()
             return False
         except Exception as e:
             self.status = APIStatus.ERROR
             self.error_message = str(e)
-            self.last_check = datetime.utcnow()
+            self.last_check = utc_now()
             logger.error(f"Health check failed for {self.name}: {e}")
             return False
 

backend/app/services/blockchain.py

@@ -1,7 +1,6 @@
 """Blockchain service"""
 import hashlib
 import json
-from datetime import datetime
 from typing import List, Optional
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, desc
@@ -9,6 +8,7 @@ from app.models.blockchain import Block, Transaction, Wallet
 from app.models.user import User
 from app.config import settings
 from app.services.crypto import wallet_crypto, WalletKeyDecryptionError
+from app.utils import utc_now
 import secrets
 
 
@@ -31,7 +31,7 @@ class BlockchainService:
         if existing:
             return existing
 
-        timestamp = datetime.utcnow()
+        timestamp = utc_now()
         genesis_hash = BlockchainService.calculate_hash(0, str(timestamp), "0", [], 0)
 
         genesis_block = Block(
@@ -69,7 +69,7 @@ class BlockchainService:
             latest_block = await BlockchainService.create_genesis_block(db)
 
         new_index = latest_block.index + 1
-        timestamp = datetime.utcnow()
+        timestamp = utc_now()
         previous_hash = latest_block.hash
         difficulty = settings.BLOCKCHAIN_DIFFICULTY
 
@@ -117,7 +117,7 @@ class BlockchainService:
             tx.block_index = new_block.index
             tx.is_confirmed = True
             tx.confirmations = 1
-            tx.confirmed_at = datetime.utcnow()
+            tx.confirmed_at = utc_now()
 
         # Reward miner
         user.balance += settings.MINING_REWARD
@@ -152,7 +152,7 @@ class BlockchainService:
             ) from exc
 
         # Generate transaction hash
-        tx_data = f"{from_address}{to_address}{amount}{datetime.utcnow()}"
+        tx_data = f"{from_address}{to_address}{amount}{utc_now()}"
         transaction_hash = hashlib.sha256(tx_data.encode()).hexdigest()
 
         # Sign transaction (simplified)

backend/app/utils/__init__.py

@@ -0,0 +1,4 @@
+"""Utility helpers for the BlackRoad backend."""
+
+from .datetime import utc_now  # noqa: F401
+

backend/app/utils/datetime.py

@@ -0,0 +1,9 @@
+"""Datetime utilities."""
+
+from datetime import datetime, timezone
+
+
+def utc_now() -> datetime:
+    """Return a timezone-aware UTC datetime."""
+    return datetime.now(timezone.utc)
+