04/16 Updated with domain settings in .env file

app.py

@@ -294,8 +294,10 @@ def update_existing_qr_codes():
     """Update existing QR codes with missing URLs or images at startup.
 
     Regenerates qr_url slugs without needing a request context.
-    For qr_code_image, constructs the base URL from FLASK_HOST/FLASK_PORT
-    config so this can run safely outside any HTTP request.
+    For qr_code_image, uses QR_BASE_URL (from .env) as the authoritative base
+    URL so that generated links always match the public-facing domain.
+    Falls back to FLASK_HOST/FLASK_PORT construction only when QR_BASE_URL is
+    not configured (development environments without a reverse proxy).
     """
     from extensions import db as _db, logger_handler as lh
     from utils.helpers import generate_qr_code, get_qr_styling, generate_qr_url
@@ -306,14 +308,19 @@ def update_existing_qr_codes():
         if not qr_codes:
             return
 
-        # Build a base URL that does not require an active request context.
-        host = os.environ.get('FLASK_HOST', '0.0.0.0')
-        # 0.0.0.0 is a bind address, not a reachable hostname — default to localhost
-        if host in ('0.0.0.0', ''):
-            host = 'localhost'
-        port = os.environ.get('FLASK_PORT', '5000')
-        scheme = 'https' if _Cfg.SESSION_COOKIE_SECURE else 'http'
-        base_url = f"{scheme}://{host}:{port}/"
+        # Prefer the explicit QR_BASE_URL env var (required behind a reverse proxy).
+        # Fall back to FLASK_HOST/PORT for local/dev environments.
+        qr_base_url = os.environ.get('QR_BASE_URL', '').rstrip('/')
+        if qr_base_url:
+            base_url = qr_base_url + '/'
+        else:
+            host = os.environ.get('FLASK_HOST', '0.0.0.0')
+            # 0.0.0.0 is a bind address, not a reachable hostname — default to localhost
+            if host in ('0.0.0.0', ''):
+                host = 'localhost'
+            port = os.environ.get('FLASK_PORT', '5000')
+            scheme = 'https' if _Cfg.SESSION_COOKIE_SECURE else 'http'
+            base_url = f"{scheme}://{host}:{port}/"
 
         updated_count = 0
         for qr_code in qr_codes: