API provides an advanced file download functionality that persists beyond app termination, runs in the background and continues even when the user closed/suspended the application. The plugin includes progress updates and primarily designed for long-term transfer operations for resources like video, music, and large images.
Sample usage
var fileName = "PointerEventsCordovaPlugin.wmv",
uriString = "http://media.ch9.ms/ch9/8c03/f4fe2512-59e5-4a07-bded-124b06ac8c03/PointerEventsCordovaPlugin.wmv";
// open target file for download
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function(fileSystem) {
fileSystem.root.getFile(fileName, { create: true }, function (targetFile) {
var onSuccess, onError, onProgress; // plugin callbacks to track operation execution status and progress
var downloader = new BackgroundTransfer.BackgroundDownloader();
// Create a new download operation.
var download = downloader.createDownload(uriString, targetFile);
// Start the download and persist the promise to be able to cancel the download.
app.downloadPromise = download.startAsync().then(onSuccess, onError, onProgress);
});
});Internal vs External (SD card) storage on Android
External Storage
resolve cordova.file.externalDataDirectory directory in runtime
window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, function(dirEntry) {
dirEntry.getFile(fileName, { create: true }, function (targetFile) {
...
})
}, function(error) {...})Note, that device can be without external storage. In this case cordova.file.externalDataDirectory will be null so it should be checked before usage.
Internal Storage
resolve cordova.file.dataDirectory directory in runtime
window.resolveLocalFileSystemURL(cordova.file.dataDirectory, function(dirEntry) {
dirEntry.getFile(fileName, { create: true }, function (targetFile) {
...
})
}, function(error) {...})Read File Plugin quirks for more details:
https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-file/#android-quirks.
https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-file/#configuring-the-plugin-optiona
Supported platforms
Windows8
Windows Phone8
iOS 7.0 or later
Android
Quirks
If a download operation was completed when the application was in the background, onSuccess callback is called when the application become active.
If a download operation was completed when the application was closed, onSuccess callback is called right after the first startAsync() is called for the same uri, as if the file has been downloaded immediately.
A new download operation for the same uri resumes a pending download instead of triggering a new one. If no pending downloads found for the uri specified, a new download is started, the target file will be automatically overwritten once donwload is completed.
On Android temporary downloading file is created on external storage (limitation of DownloadManager), so if there is no external storage the downloading will fail.
