iOS：这是从服务器下载大文件的最佳方法

Question

I have a zip file which contains db. i need to download that zip file when the user open the app at first time.So am using

NSData *urlData =[NSData dataWithContentsOfURL:urlToRequest];

to download a file in GCD mode. Since it's working fine,am not getting any errors.

But, is it ok to download a large File using the above method or we have to use NSURLConnection for large file download. Please advice.

Answer 1

You should use NSURLSession => NSURLSessionDownloadTask api

What is wrong with below for large file download

[NSData dataWithContentsOfURL:urlToRequest];

• Since, you are having large file to download which take huge time, thus more chances of connection break or any other interruption, which won't be resumed from last downloaded progress
• In case of a Large file, user should be provide an ability to pause and resume, above won't support that.
• Background downloading is also not supported
• Progress Status is not supported, which is very important for users, so as to keep them waiting on your app.

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Now, NSURLSession => NSURLSessionDownloadTask supports all of the above.

Follow this nice tutorial:

NSURLSession Tutorial: