Fix parsing svg content

custom_components/oasis_mini/pyoasismini/__init__.py

@@ -1,5 +1,7 @@
 """Oasis Mini API client."""
 
+from __future__ import annotations
+
 import asyncio
 import logging
 from typing import Any, Awaitable, Final
@@ -9,7 +11,7 @@ from aiohttp import ClientResponseError, ClientSession
 import async_timeout
 
 from .const import TRACKS
-from .utils import _bit_to_bool
+from .utils import _bit_to_bool, decrypt_svg_content
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -33,7 +35,6 @@ AUTOPLAY_MAP = {
     "4": "30 minutes",
 }
 
-
 LED_EFFECTS: Final[dict[str, str]] = {
     "0": "Solid",
     "1": "Rainbow",
@@ -112,6 +113,7 @@ class OasisMini:
         """Return the drawing progress percent."""
         if not (self.track and (svg_content := self.track.get("svg_content"))):
             return None
+        svg_content = decrypt_svg_content(svg_content)
         paths = svg_content.split("L")
         total = self.track.get("reduced_svg_content", {}).get("1", len(paths))
         percent = (100 * self.progress) / total

custom_components/oasis_mini/pyoasismini/utils.py

@@ -1,11 +1,17 @@
 """Oasis Mini utils."""
 
+from __future__ import annotations
+
+import base64
 import logging
 import math
 from xml.etree.ElementTree import Element, SubElement, tostring
 
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+
 _LOGGER = logging.getLogger(__name__)
 
+APP_KEY = "5joW8W4Usk4xUXu5bIIgGiHloQmzMZUMgz6NWQnNI04="
 
 BACKGROUND_FILL = ("#CCC9C4", "#28292E")
 COLOR_DARK = ("#28292E", "#F4F5F8")
@@ -25,6 +31,7 @@ def draw_svg(track: dict, progress: int, model_id: str) -> str | None:
     if track and (svg_content := track.get("svg_content")):
         try:
             if progress is not None:
+                svg_content = decrypt_svg_content(svg_content)
                 paths = svg_content.split("L")
                 total = track.get("reduced_svg_content", {}).get(model_id, len(paths))
                 percent = min((100 * progress) / total, 100)
@@ -137,3 +144,28 @@ def draw_svg(track: dict, progress: int, model_id: str) -> str | None:
         except Exception as e:
             _LOGGER.exception(e)
     return None
+
+
+def decrypt_svg_content(svg_content: dict[str, str]):
+    """Decrypt SVG content using AES CBC mode."""
+    if decrypted := svg_content.get("decrypted"):
+        return decrypted
+
+    # decode base64-encoded data
+    key = base64.b64decode(APP_KEY)
+    iv = base64.b64decode(svg_content["iv"])
+    ciphertext = base64.b64decode(svg_content["content"])
+
+    # create the cipher and decrypt the ciphertext
+    cipher = Cipher(algorithms.AES(key), modes.CBC(iv))
+    decryptor = cipher.decryptor()
+    decrypted = decryptor.update(ciphertext) + decryptor.finalize()
+
+    # remove PKCS7 padding
+    pad_len = decrypted[-1]
+    decrypted = decrypted[:-pad_len].decode("utf-8")
+
+    # save decrypted data so we don't have to do this each time
+    svg_content["decrypted"] = decrypted
+
+    return decrypted