Implement pause/resume in file downloading

Question

I\'m trying to implement pause/resume in my download manager, I search the web and read several articles and change my code according them but resume seems not working corre

Answer 1

I think you just need to delete the input.skip(downloadedSize) line. Setting the HTTP header for byte range means the server will skip sending those bytes.

Say you have a file that's 20 bytes long consisting of "aaaaabbbbbcccccffffffffd", and suppose the transfer is paused after downloading 5 bytes. Then the Range header will cause the server to send "bbbbbcccccffffffffd", you should read all of this content and append it to the file -- no skip(). But the skip() call in your code will skip "bbbbb" leaving "cccccffffffffd" to be downloaded. If you've already downloaded at least 50% of the file, then skip() will exhaust all of the input and nothing will happen.

Also, all of the things in stringy05's post apply. You should make sure the server supports HTTP/1.1, make sure the Range header is supported for the resource (dynamically generated content may not support it), and make sure the resource isn't modified using etag and modification date.