Refactor the restore backup implementation to RestoreBackupJob

plugins/CuraDrive/src/RestoreBackupJob.py

@@ -0,0 +1,89 @@
+import base64
+import hashlib
+import threading
+from tempfile import NamedTemporaryFile
+from typing import Optional, Any, Dict
+
+from PyQt5.QtNetwork import QNetworkReply, QNetworkRequest
+
+from UM.Job import Job
+from UM.Logger import Logger
+from UM.PackageManager import catalog
+from UM.TaskManagement.HttpRequestManager import HttpRequestManager
+from cura.CuraApplication import CuraApplication
+
+
+class RestoreBackupJob(Job):
+    """Downloads a backup and overwrites local configuration with the backup.
+
+     When `Job.finished` emits, `restore_backup_error_message` will either be `""` (no error) or an error message
+     """
+
+    DISK_WRITE_BUFFER_SIZE = 512 * 1024
+    DEFAULT_ERROR_MESSAGE = catalog.i18nc("@info:backup_status", "There was an error trying to restore your backup.")
+
+    def __init__(self, backup: Dict[str, Any]) -> None:
+        """ Create a new restore Job. start the job by calling start()
+
+        :param backup: A dict containing a backup spec
+        """
+
+        super().__init__()
+        self._job_done = threading.Event()
+
+        self._backup = backup
+        self.restore_backup_error_message = ""
+
+    def run(self):
+
+        HttpRequestManager.getInstance().get(
+            url = self._backup.get("download_url"),
+            callback = self._onRestoreRequestCompleted,
+            error_callback = self._onRestoreRequestCompleted
+        )
+
+        self._job_done.wait()
+
+    def _onRestoreRequestCompleted(self, reply: QNetworkReply, error: Optional["QNetworkReply.NetworkError"] = None):
+        if not HttpRequestManager.replyIndicatesSuccess(reply, error):
+            Logger.warning("Requesting backup failed, response code %s while trying to connect to %s",
+                           reply.attribute(QNetworkRequest.HttpStatusCodeAttribute), reply.url())
+            self.restore_backup_error_message = self.DEFAULT_ERROR_MESSAGE
+            self._job_done.set()
+            return
+
+        # We store the file in a temporary path fist to ensure integrity.
+        temporary_backup_file = NamedTemporaryFile(delete = False)
+        with open(temporary_backup_file.name, "wb") as write_backup:
+            app = CuraApplication.getInstance()
+            bytes_read = reply.read(self.DISK_WRITE_BUFFER_SIZE)
+            while bytes_read:
+                write_backup.write(bytes_read)
+                bytes_read = reply.read(self.DISK_WRITE_BUFFER_SIZE)
+                app.processEvents()
+
+        if not self._verifyMd5Hash(temporary_backup_file.name, self._backup.get("md5_hash", "")):
+            # Don't restore the backup if the MD5 hashes do not match.
+            # This can happen if the download was interrupted.
+            Logger.log("w", "Remote and local MD5 hashes do not match, not restoring backup.")
+            self.restore_backup_error_message = self.DEFAULT_ERROR_MESSAGE
+
+        # Tell Cura to place the backup back in the user data folder.
+        with open(temporary_backup_file.name, "rb") as read_backup:
+            cura_api = CuraApplication.getInstance().getCuraAPI()
+            cura_api.backups.restoreBackup(read_backup.read(), self._backup.get("metadata", {}))
+
+        self._job_done.set()
+
+    @staticmethod
+    def _verifyMd5Hash(file_path: str, known_hash: str) -> bool:
+        """Verify the MD5 hash of a file.
+
+        :param file_path: Full path to the file.
+        :param known_hash: The known MD5 hash of the file.
+        :return: Success or not.
+        """
+
+        with open(file_path, "rb") as read_backup:
+            local_md5_hash = base64.b64encode(hashlib.md5(read_backup.read()).digest(), altchars = b"_-").decode("utf-8")
+            return known_hash == local_md5_hash