fix: apply Phase 1-2 correctness and constant extraction from PR #273

- Replace datetime.utcnow() with datetime.now(timezone.utc) in 4 files
- Extract duplicate literals to constants in 5 files
  - models.py: "files.id" → _FILES_ID_FK
  - upload_to_email.py: "logo.png" → _LOGO_FILENAME
  - general.py: "%B %d, %Y" → _DATE_DISPLAY_FORMAT
  - files.py: "File not found" → _FILE_NOT_FOUND
  - upload_to_google_drive.py: Google token URL → _GOOGLE_TOKEN_URL

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/tasks/monitor_stalled_steps.py

@@ -6,7 +6,7 @@ that have been stuck in "in_progress" state for too long and mark them as failed
 """
 
 import logging
-from datetime import datetime
+from datetime import datetime, timezone
 
 from app.celery_app import celery
 from app.database import SessionLocal
@@ -37,12 +37,12 @@ def monitor_stalled_steps():
 
             if stalled_count > 0:
                 logger.warning(
-                    f"[{datetime.utcnow().isoformat()}] "
+                    f"[{datetime.now(timezone.utc).isoformat()}] "
                     f"Recovered {stalled_count} stalled step(s). "
                     f"Marked as failed due to timeout."
                 )
             else:
-                logger.debug(f"[{datetime.utcnow().isoformat()}] No stalled steps found.")
+                logger.debug(f"[{datetime.now(timezone.utc).isoformat()}] No stalled steps found.")
 
             return {"recovered": stalled_count}
 

app/tasks/upload_to_email.py

@@ -20,6 +20,9 @@ from app.utils import log_task_progress
 
 logger = logging.getLogger(__name__)
 
+# Constants
+_LOGO_FILENAME = "logo.png"
+
 
 def get_email_template(template_name="default.html"):
     """
@@ -87,16 +90,16 @@ def attach_logo(msg):
     """Attach the DocuElevate logo to the email with proper Content-ID."""
     try:
         # Try to find logo in workdir first (for customization)
-        custom_logo_path = os.path.join(settings.workdir, "templates", "email", "logo.png")
+        custom_logo_path = os.path.join(settings.workdir, "templates", "email", _LOGO_FILENAME)
         if os.path.exists(custom_logo_path):
             logo_path = custom_logo_path
         else:
             # Use built-in logo
             app_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-            logo_path = os.path.join(app_dir, "static", "logo.png")
+            logo_path = os.path.join(app_dir, "static", _LOGO_FILENAME)
             # Fallback to logo in frontend/static if app/static doesn't exist
             if not os.path.exists(logo_path):
-                logo_path = os.path.join(app_dir, "..", "frontend", "static", "logo.png")
+                logo_path = os.path.join(app_dir, "..", "frontend", "static", _LOGO_FILENAME)
 
         if os.path.exists(logo_path):
             with open(logo_path, "rb") as img:
@@ -106,7 +109,7 @@ def attach_logo(msg):
             mimetype = "image/svg+xml" if logo_path.endswith(".svg") else "image/png"
             logo_attach = MIMEImage(logo_data, mimetype)
             logo_attach.add_header("Content-ID", "<logo>")
-            logo_attach.add_header("Content-Disposition", "inline", filename="logo.png")
+            logo_attach.add_header("Content-Disposition", "inline", filename=_LOGO_FILENAME)
             msg.attach(logo_attach)
             logger.info(f"Logo attached from {logo_path}")
             return True

app/tasks/upload_to_google_drive.py

@@ -20,6 +20,9 @@ from app.utils import log_task_progress
 
 logger = logging.getLogger(__name__)
 
+# Google OAuth constants
+_GOOGLE_TOKEN_URL = "https://oauth2.googleapis.com/token"
+
 
 def get_drive_service_oauth():
     """
@@ -40,7 +43,7 @@ def get_drive_service_oauth():
         credentials = OAuthCredentials(
             None,  # No access token initially, will be refreshed
             refresh_token=settings.google_drive_refresh_token,
-            token_uri="https://oauth2.googleapis.com/token",
+            token_uri=_GOOGLE_TOKEN_URL,
             client_id=settings.google_drive_client_id,
             client_secret=settings.google_drive_client_secret,
             # Use only drive.file scope