恢复从iOS和Android上使用Corona sdk编写的移动应用程序下载大文件的下载

Question

I need to download large audio files from a web server from within a corona sdk app, and have been looking at using network.download() or possibly network.request() for this purpose.

Because much of the user base will be in areas that have poor or intermittent network coverage, I would like to improve robustness of the download process by allowing for resuming download from where it left off if the network drops out. From the documentation neither network.download or network.request functions seem to support this directly, but is there a way that I can use either of these functions to achieve what I'm looking for? If not, is there another technique I can use?

My app will eventually be for both iOS and Android , but for now I am developing the iOS version first. Therefore, I am ok with having to use a different solution for each platform if there is not an easy solution that covers both platforms. However, I would prefer not to have to use native code if possible as I don't currently have an Enterprise subscription for Corona.

Answer 1

I don't think you can do this using Corona without native plugins.

One way to go around this problem is to split the large files in smaller ones, and I don't mean creating multiple audio files just splitting the large audio files in smaller files.

Then you can download one chunk at a time and when one fails, by getting an error in the handler or waiting a reasonable timeout and then checking to see if the file is present in the file system, you can start downloading it again.

After all chunks are download you can recreate the large file by using the ltn library.

You can read some more about the ltn12 library here and I think you need to take a close look to the Pumps method.

Answer 2

On your server-side, create a simple program that splits an audio file in multiple sub-files of the max size you would like to specify. On your client-side, create a function that collides multiple chunks in one single audio files.

For example if you would like to limit your file size to 1MB, create a server side program that splits any audio file above 1MB in chunks: a 4.5MB file would be split in part1 1MB, part2 1MB, part3 1MB, part4 1MB, part5 0.5MB. Glue the chunks together in one single file in your lua code when you have fetched that with network.request.