Oc/swift Technology Download File (breakpoint continuation AFN download file alamofire Download File native download) (source code)

I always feel that what I write is not technology , But feelings , One tutorial after another is the trace of one's own journey . Success with expertise is the most replicable , I hope my path will make you less detours , I hope I can help you erase the dust of knowledge , I hope I can help you clarify the context of knowledge , I hope there will be you and me on the top of technology in the future .

Preface

Recently downloaded to be a music player , I have a problem downloading music , Download when the network is too laggy mp3 music , On the way to download request time out. Then you can't download . I don't know how to relink and continue downloading , Use it at the beginning Alamofire The interceptor of reactivates the download , Find and download again , That's not good , The best thing is to continue downloading , Later, you can continue downloading after disconnecting the network by using breakpoint continuous transmission .

The content written below is not very perfect , But for fear of forgetting, I'd better record it first , Optimize again when free .

Before we begin , First, let's talk about how to download resources for testing , You can use Google browser , Check a downloaded resource online to download , During the download process, you can click , Look at the picture below .

In this way, the download address can be tested .

On the subject

Alamofire 5.4.4 Download the file

Alamofire Download File source code

It's OK to use this download method if the network is smooth , If the network card is downloaded, the download will fail if there is a link timeout .
Even if setting an extended timeout is useless .

AF.sessionConfiguration.timeoutIntervalForRequest = 3600

Alamofire Interceptor ( Re Download )

Later, I searched the Internet , think Alamofire The request has an interceptor , When the link fails , Interceptors can be used to intercept , Then download again .

But there will be a problem , Even if the relink succeeds, it will be downloaded again , Only the previous record of disconnecting money is gone , Need to download again , In this case , If no one disconnects while downloading , Download again , Become a dead cycle , Never download successfully .

The final solution is to continue with the breakpoint of the original sound …

Breakpoint continuation

Breakpoint continuation source code

Breakpoint continuation uses native URLSession To achieve , You can start downloading , Stop downloading , Downloading again will continue to download on the basis of the previous one . If there is an error in the download , You can save the downloaded content , Then try again and link again to continue downloading .

Let's talk about the core code ：
1. If there is a problem during the download process, you can try to re link the download path to continue downloading

2. You can stop downloading while downloading

3. Then click the start button to continue downloading

Use AFN Download the file

AFURLSessionManager

AFURLSessionManager Source link

use AFN Download available AFURLSessionManager Class to create objects to download .

The method of the following picture is in AFN On the basis of another layer of packaging , Then call this method from outside to directly pass URL You can download .


Use ：

The following picture is the download effect. I have tried it without problem ：

AFHTTPSessionManager

AFHTTPSessionManager Source code address

AFN You can also use AFHTTPSessionManager Class to create an object to download

Use ：

The following picture is the download effect. I have tried it without problem