Support local update file for OTA

Support local update file for Matter OTA updates. The otaUrl must use
the file:/// URL scheme. The path is relative to the OTA provider
directory.

matter_server/server/device_controller.py

@@ -972,13 +972,15 @@ async def update_node(self, node_id: int, software_version: int | str) -> None:
 
         # Add update to the OTA provider
         ota_provider = ExternalOtaProvider(
-            self.server.vendor_id, self._ota_provider_dir / f"{node_id}"
+            self.server.vendor_id,
+            self._ota_provider_dir,
+            self._ota_provider_dir / f"{node_id}",
         )
 
         await ota_provider.initialize()
 
         node_logger.info("Downloading update from '%s'", update["otaUrl"])
-        await ota_provider.download_update(update)
+        await ota_provider.fetch_update(update)
 
         self._attribute_update_callbacks.setdefault(node_id, []).append(
             ota_provider.check_update_state

matter_server/server/ota/provider.py

@@ -65,9 +65,12 @@ class ExternalOtaProvider:
 
     ENDPOINT_ID: Final[int] = 0
 
-    def __init__(self, vendor_id: int, ota_provider_dir: Path) -> None:
+    def __init__(
+        self, vendor_id: int, ota_provider_base_dir: Path, ota_provider_dir: Path
+    ) -> None:
         """Initialize the OTA provider."""
         self._vendor_id: int = vendor_id
+        self._ota_provider_base_dir: Path = ota_provider_base_dir
         self._ota_provider_dir: Path = ota_provider_dir
         self._ota_file_path: Path | None = None
         self._ota_provider_proc: Process | None = None
@@ -261,10 +264,11 @@ async def stop(self) -> None:
         self._ota_provider_proc = None
         self._ota_provider_task = None
 
-    async def download_update(self, update_desc: dict) -> None:
-        """Download update file from OTA Path and add it to the OTA provider."""
+    async def _download_update(
+        self, url: str, checksum_alg: hashlib._Hash | None
+    ) -> Path:
+        """Download update file from OTA URL."""
 
-        url = update_desc["otaUrl"]
         parsed_url = urlparse(url)
         file_name = unquote(Path(parsed_url.path).name)
 
@@ -273,20 +277,6 @@ async def download_update(self, update_desc: dict) -> None:
         file_path = self._ota_provider_dir / file_name
 
         try:
-            checksum_alg = None
-            if (
-                "otaChecksum" in update_desc
-                and "otaChecksumType" in update_desc
-                and update_desc["otaChecksumType"] in CHECHKSUM_TYPES
-            ):
-                checksum_alg = hashlib.new(
-                    CHECHKSUM_TYPES[update_desc["otaChecksumType"]]
-                )
-            else:
-                LOGGER.warning(
-                    "No OTA checksum type or not supported, OTA will not be checked."
-                )
-
             async with ClientSession(raise_for_status=True) as session:
                 # fetch the paa certificates list
                 LOGGER.debug("Download update from '%s'.", url)
@@ -300,20 +290,6 @@ async def download_update(self, update_desc: dict) -> None:
                             if checksum_alg:
                                 checksum_alg.update(chunk)
 
-                # Download finished, check checksum if necessary
-                if checksum_alg:
-                    checksum = b64encode(checksum_alg.digest()).decode("ascii")
-                    checksum_expected = update_desc["otaChecksum"].strip()
-                    if checksum != checksum_expected:
-                        LOGGER.error(
-                            "Checksum mismatch for file '%s', expected: '%s', got: '%s'",
-                            file_name,
-                            checksum_expected,
-                            checksum,
-                        )
-                        await loop.run_in_executor(None, file_path.unlink)
-                        raise UpdateError("Checksum mismatch!")
-
                 LOGGER.info(
                     "Update file '%s' downloaded to '%s'",
                     file_name,
@@ -326,6 +302,55 @@ async def download_update(self, update_desc: dict) -> None:
             )
             raise UpdateError("Fetching software version failed") from err
 
+        return file_path
+
+    async def fetch_update(self, update_desc: dict) -> None:
+        """Fetch update file from OTA URL."""
+        url = update_desc["otaUrl"]
+        parsed_url = urlparse(url)
+        file_name = unquote(Path(parsed_url.path).name)
+
+        loop = asyncio.get_running_loop()
+
+        checksum_alg = None
+        if (
+            "otaChecksum" in update_desc
+            and "otaChecksumType" in update_desc
+            and update_desc["otaChecksumType"] in CHECHKSUM_TYPES
+        ):
+            checksum_alg = hashlib.new(CHECHKSUM_TYPES[update_desc["otaChecksumType"]])
+        else:
+            LOGGER.warning(
+                "No OTA checksum type or not supported, OTA will not be checked."
+            )
+
+        if parsed_url.scheme in ["http", "https"]:
+            file_path = await self._download_update(url, checksum_alg)
+        elif parsed_url.scheme in ["file"]:
+            file_path = self._ota_provider_base_dir / Path(parsed_url.path[1:])
+            if not file_path.exists():
+                logging.warning("Local update file not found: %s", file_path)
+                raise UpdateError("Local update file not found")
+            if checksum_alg:
+                checksum_alg.update(
+                    await loop.run_in_executor(None, file_path.read_bytes)
+                )
+        else:
+            raise UpdateError("Unsupported OTA URL scheme")
+
+        # Download finished, check checksum if necessary
+        if checksum_alg:
+            checksum_expected = update_desc["otaChecksum"].strip()
+            checksum = b64encode(checksum_alg.digest()).decode("ascii")
+            if checksum != checksum_expected:
+                LOGGER.error(
+                    "Checksum mismatch for file '%s', expected: '%s', got: '%s'",
+                    file_name,
+                    checksum_expected,
+                    checksum,
+                )
+                raise UpdateError("Checksum mismatch!")
+
         self._ota_file_path = file_path
 
     async def check_update_state(