Sep 16 - Optimize code, part 1

app.py

@@ -48,6 +48,14 @@ def create_app() -> Flask:
     cfg = get_config()
     app.config.from_object(cfg)
 
+    # Real client IP behind Nginx: ProxyFix takes it from the X-Forwarded-For
+    # entry appended by our own proxy (TRUSTED_PROXY_COUNT hops), never from the
+    # first, client-supplied entry. The login rate limiter depends on it.
+    _trusted_proxies = app.config.get('TRUSTED_PROXY_COUNT', 1)
+    if _trusted_proxies > 0:
+        from werkzeug.middleware.proxy_fix import ProxyFix
+        app.wsgi_app = ProxyFix(app.wsgi_app, x_for=_trusted_proxies)
+
     # Guard against deployment with the insecure default SECRET_KEY
     import sys
     if not app.debug and app.config.get('SECRET_KEY') == 'change-me-in-production':
@@ -324,6 +332,20 @@ def create_app() -> Flask:
         """Handle internal server errors with user-friendly page"""
         return render_template('errors/500.html'), 500
 
+    @app.errorhandler(413)
+    def request_too_large(error):
+        """Request over MAX_CONTENT_LENGTH, or a form field over MAX_FORM_MEMORY_SIZE"""
+        from flask import jsonify
+        message = 'The upload is too large. / El archivo es demasiado grande.'
+        if (request.path.startswith(('/qr/', '/api/'))
+                or request.headers.get('X-Requested-With') == 'XMLHttpRequest'):
+            return jsonify({'success': False, 'message': message}), 413
+        flash(message, 'error')
+        referrer = request.referrer or ''
+        if not referrer.startswith(request.host_url):
+            referrer = url_for('dashboard.dashboard')
+        return redirect(referrer)
+
     # ------------------------------------------------------------------
     # Startup initialization (runs under gunicorn and flask run alike)
     # ------------------------------------------------------------------
@@ -395,22 +417,24 @@ 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}/"
+        # Public base URL for QR images generated here. There is no request at
+        # startup, so it can only come from QR_BASE_URL (e.g.
+        # https://qr.govservicesinc.com). Without it no image is generated: the
+        # old FLASK_HOST/FLASK_PORT fallback printed http://localhost:5000/...
+        # into QR codes that no phone can open. Routes still build images from
+        # the request when a QR code is created or its styling is edited.
+        base_url = (_Cfg.QR_BASE_URL or '').rstrip('/')
+        base_url = f"{base_url}/" if base_url else ''
+        if not base_url:
+            lh.logger.info("Startup: QR_BASE_URL not set — missing QR images are not generated at startup")
 
         updated_count = 0
         for qr_code in qr_codes:
-            if not qr_code.qr_url or not qr_code.qr_code_image:
+            if not qr_code.qr_url or (not qr_code.qr_code_image and base_url):
                 try:
                     if not qr_code.qr_url:
                         qr_code.qr_url = generate_qr_url(qr_code.name, qr_code.id)
-                    if not qr_code.qr_code_image:
+                    if not qr_code.qr_code_image and base_url:
                         qr_data = f"{base_url}qr/{qr_code.qr_url}"
                         styling = get_qr_styling(qr_code)
                         qr_code.qr_code_image = generate_qr_code(