first commit

backend/app/services/qr.py

@@ -0,0 +1,16 @@
+import base64
+import io
+import json
+
+import qrcode
+
+
+def build_qr_payload(qr_token: str) -> str:
+    return json.dumps({"v": 1, "token": qr_token}, separators=(",", ":"))
+
+
+def qr_png_base64(data: str) -> str:
+    image = qrcode.make(data, box_size=8, border=2)
+    buffer = io.BytesIO()
+    image.save(buffer, format="PNG")
+    return base64.b64encode(buffer.getvalue()).decode("ascii")