參考文章：
URLProtocol 注冊方式的細(xì)節(jié)問題
NSURLProtocol的基本使用

NSURLProtocol registerClass:

    NSURLSession *session = [NSURLSession sharedSession];
    [[session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSLog(@"data.length:%ld",data.length);
    }] resume];

[NSURLSession sharedSession]會按照NSURLProtocol registerClass:注冊的類遍歷,后注冊的先遍歷.(只有一個可以接受響應(yīng))

NSURLSessionConfiguration.protocolClasses

    NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
    config.protocolClasses = @[[WYTURLProtocol class]];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:config];
    [[session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSLog(@"data.length:%ld",data.length);
    }] resume];

[NSURLSessionConfiguration defaultSessionConfiguration]創(chuàng)建的config不受NSURLProtocol registerClass:注冊的影響,需要配置config.protocolClasses

支持后臺下載的session,不支持配置WYTURLProtocol

NSURLSessionConfiguration *config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:@"NSURLProtocol_Test"];
    // Custom NSURLProtocol subclasses are not available to background sessions.
    // 支持后臺下載的session,不支持配置WYTURLProtocol,設(shè)置protocolClasses不會生效
    config.protocolClasses = @[[WYTURLProtocol class]];

HTTPBody丟失問題

據(jù)蘋果官方說明，因?yàn)檎埱髤?shù)可能會很大，為了保證性能，請求參數(shù)是沒有被攔截掉的，就是post的HTTPBody是沒有的