@ledgerhq/live-common
Version:
Common ground for the Ledger Live apps
65 lines • 2.75 kB
JavaScript
import { AppNotFound, backupAppStorage, getAppStorageInfo, } from "@ledgerhq/device-core";
import { Observable, catchError, from, of, switchMap } from "rxjs";
import { BackupAppDataError, BackupAppDataEventType } from "./types";
/**
* Backs up the application data for a specific app on a Ledger device.
* @param transport - The transport object used to communicate with the Ledger device.
* @param appName - The name of the application to backup.
* @returns An observable that emits BackupAppDataEvent according to the backup process.
* @throws {BackupAppDataError}
*/
export function backupAppData(transport, appName) {
const obs = new Observable(subscriber => {
const sub = from(getAppStorageInfo(transport, appName))
.pipe(switchMap(async (appDataInfo) => {
subscriber.next({ type: BackupAppDataEventType.AppDataInfoFetched, data: appDataInfo });
const dataSize = appDataInfo.size;
// Check if there is any data to backup
if (dataSize === 0) {
subscriber.next({ type: BackupAppDataEventType.NoAppDataToBackup });
subscriber.complete();
return;
}
// Backup app data by chunks
let appData = Buffer.from([]);
let offset = 0;
while (offset < dataSize) {
const chunk = await backupAppStorage(transport);
// Make sure that the process advances
if (chunk.length === 0) {
subscriber.error(new BackupAppDataError("Chunk data is empty"));
return;
}
appData = Buffer.concat([appData, chunk]);
offset += chunk.length;
subscriber.next({
type: BackupAppDataEventType.Progress,
data: Number((offset / dataSize).toFixed(2)),
});
}
// Check data size
if (appData.length !== dataSize) {
subscriber.error(new BackupAppDataError("App data size mismatch"));
return;
}
subscriber.next({
type: BackupAppDataEventType.AppDataBackedUp,
data: appData.toString("base64"),
});
subscriber.complete();
}), catchError(e => {
if (e instanceof AppNotFound) {
subscriber.next({ type: BackupAppDataEventType.NoAppDataToBackup });
subscriber.complete();
return of(null);
}
throw e;
}))
.subscribe();
return () => {
sub.unsubscribe();
};
});
return obs;
}
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