ionic-native/file plugin writing to the downloads folder

[DanielLeushuis]

I'm submitting a bug report
[x ] bug report
[ ] feature request
[ ] support request => Please do not submit support requests here, use one of these channels: https://forum.ionicframework.com/ or https://ionicworldwide.herokuapp.com/

Current behavior:
When using the ionic-native/file plugin the application cannot create, move or copy a file to the Downloads folder on Android, error code 9 with message INVALID_MODIFICATION_ERR is thrown. Tried file paths: file:///storage/emulated/0/Download and file:///mnt/sdcard/Download. Writing to the app specific folders is possible (for example externalApplicationStorageDirectory). I do request READ_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE upon startup (which shows the modal for approving). After restarting the app creating, moving or copying a file to the Downloads folder can be done without a problem.

Expected behavior:
Writing to the Downloads folder should be possible after requesting the permission so without restarting the application

Steps to reproduce:

1. Request permissions for READ_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE
2. Write to the Downloads folder: cordova.file.externalRootDirectory + "Download"
3. Receive INVALID_MODIFICATION_ERR

Related code:

let keystoreData = JSON.stringify((this.currentWallet as ILocalWallet).keyStore);
let options: IWriteOptions = {replace: true};
let storageLocation = cordova.file.externalRootDirectory + "Download"; 
console.log("Trying to save file to: " + storageLocation);
this.fileNative.writeFile(storageLocation, filename, keystoreData, options).then(data => {
    console.log("Write file succes! Saved to location: " + storageLocation + filename);
    console.log(JSON.stringify(data));
    let toast = this.toastCtrl.create({
        message: 'Successfully saved keystore to downloads folder!',
        duration: 2000,
        position: "bottom"
    });
    toast.present(toast);
 }).catch(error => {
    console.log("Error!");
    console.log(JSON.stringify(error));
    let toast = this.toastCtrl.create({
        message: 'Please restart the application to save the file to your downloads folder.',
        position: "bottom",
        showCloseButton: true,
        closeButtonText: 'Ok'
    });
    toast.present(toast);
});

Ionic info: (run ionic info from a terminal/cmd prompt and paste output below):

cli packages: (/Users/danielleushuis/.nvm/versions/node/v8.11.2/lib/node_modules)

    @ionic/cli-utils  : 1.19.2
    ionic (Ionic CLI) : 3.20.0

global packages:

    cordova (Cordova CLI) : 8.0.0

local packages:

    @ionic/app-scripts : 3.1.9
    Cordova Platforms  : android 7.0.0 browser 5.0.3
    Ionic Framework    : ionic-angular 3.9.2

System:

    Node  : v8.11.2
    npm   : 5.6.0
    OS    : macOS High Sierra
    Xcode : Xcode 9.4.1 Build version 9F2000

Environment Variables:

    ANDROID_HOME : not set

Misc:

    backend : pro

[phoenixsampras]

This is critical and urgent

[SavageCore]

If anyone ends up here from Google you need to add android:requestLegacyExternalStorage="true" to the application tag in AndroidManifest.xml

I could not write to Download at all irrespective of app restart.

It is explained in Capacitor Filesystem docs