DownloadManager: download a file to cache partition

Question

I am using the public api of class DownloadManager, I am able to download files to sdcard, so-called external storage. However, when I tried to download a file to other places, like /cache partition, it throw a security exception which says "Destination must be on external storage".

Does anyone know how to bypass this limitation and write downloaded file to /cache partition ?

Thanks a lot.

score 3 · Answer 1 · answered May 29 '15 at 05:37

3

If you're developing a system app, there is a hidden function on DownloadManager.Request named setDestinationToSystemCache()

It requires these permissions:

android.permission.ACCESS_DOWNLOAD_MANAGER
android.permission.ACCESS_DOWNLOAD_MANAGER_ADVANCED"
android.permission.ACCESS_CACHE_FILESYSTEM

answered May 29 '15 at 05:37

Brian R

31
5

`android.permission.ACCESS_CACHE_FILESYSTEM` is only granted to system apps. – Onur-Andros Ozbek Oct 12 '18 at 15:38

score 1 · Answer 2 · answered Jan 21 '11 at 19:25

1

Actually I found a way to download files to /cache partition. In the DownloadManager class, there is an api setDestinationUri(), call this function with parameter "null", the android would download files to /cache partition. Moreover, if the parameter is not null, the uri must start with "/mnt/sdcard/..." otherwise an exception would be thrown.

answered Jan 21 '11 at 19:25

Jimmy

573
4
9
14

4

Don't use /mnt/sdcard - call Environment.getExternalStorageDirectory() instead. /mnt/sdcard isn't guaranteed. – James Moore Jul 31 '11 at 15:40
2

He didn't say he is using "/mnt/sdcard". – tasomaniac May 23 '13 at 13:04

DownloadManager: download a file to cache partition

2 Answers2