带委托的NSURLSession在主线程上不起作用

如何解决带委托的NSURLSession在主线程上不起作用

我希望在主线程上调用NSURLSession的委托。当我将[NSOperationQueue mainQueue]传递给delegateQueue时，没有调用该代表团。

    @interface NSURLSessionTests : XCTestCase<NSURLSessionDataDelegate>
    {
        @private
        dispatch_semaphore_t _semaphore;
    }
    @end

    @implementation NSURLSessionTests

    - (void)testWithRequest{
        NSMutableuRLRequest *request = [NSMutableuRLRequest requestWithURL:[NSURL URLWithString: @"http://example.com/"]];
        
        NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
        NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration
                                                              delegate:self
                                                        delegateQueue:[NSOperationQueue mainQueue]];
        NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request];
        
        _semaphore = dispatch_semaphore_create(0);
        [dataTask resume];
        
        NSLog(@"Start: %@",dataTask);
        
        dispatch_semaphore_wait(_semaphore,disPATCH_TIME_FOREVER);
    }

    # pragma mark NSURLSessionDataDelegate

    - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask
                                    didReceiveResponse:(NSURLResponse *)response
                                      completionHandler:(void (^)(NSURLSessionResponsedisposition disposition))completionHandler {
        NSLog(@"didReceiveResponse: %@",NSThread.currentThread);
        NSLog(@"%@",response);
        completionHandler(NSURLSessionResponseAllow);
    }

    - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
    {
        NSLog(@"didReceiveData: %@",data);
    }

    - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
    {
        NSLog(@"didCompleteWithError: %@",error);
        dispatch_semaphore_signal(_semaphore);
    }
    @end

执行结果如下。

Test Suite 'Selected tests' started at 2020-10-19 16:53:56.013
Test Suite 'Tests.xctest' started at 2020-10-19 16:53:56.014
Test Suite 'NSURLSessionTests' started at 2020-10-19 16:53:56.014
Test Case '-[NSURLSessionTests testWithRequest]' started.
2020-10-19 16:53:56.016936+0900 xctest[91856:6495007] Start: LocalDataTask <A9DFF949-ED27-4C5E-8E15-93113442D876>.<1>

这里很冷。没有调用所有委托方法。

如果我将nil传递给delegateQueue，它将按预期工作。

        NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration
                                                          delegate:self
                                                     delegateQueue:nil];

但不在主线程上。

Test Suite 'Selected tests' started at 2020-10-19 17:10:03.227
Test Suite 'Tests.xctest' started at 2020-10-19 17:10:03.228
Test Suite 'NSURLSessionTests' started at 2020-10-19 17:10:03.228
Test Case '-[NSURLSessionTests testWithRequest]' started.
2020-10-19 17:10:03.230845+0900 xctest[91910:6506707] Start: LocalDataTask <44C2D9FA-09D3-4C25-9129-B164D451836D>.<1>
2020-10-19 17:10:03.629414+0900 xctest[91910:6506750] didReceiveResponse: <NSThread: 0x7f8d2281f480>{number = 2,name = (null)}
2020-10-19 17:10:03.629867+0900 xctest[91910:6506750] <NSHTTPURLResponse: 0x7f8d20f333e0> { URL: http://example.com/ } { Status Code: 200,Headers {
    ...
} }
2020-10-19 17:10:03.630215+0900 xctest[91910:6506750] didReceiveData: <NSThread: 0x7f8d2281f480>{number = 2,name = (null)}
2020-10-19 17:10:03.630459+0900 xctest[91910:6506750] #NSData 1KB(1256)
2020-10-19 17:10:03.630940+0900 xctest[91910:6506750] didCompleteWithError: <NSThread: 0x7f8d2281f480>{number = 2,name = (null)}
2020-10-19 17:10:03.631095+0900 xctest[91910:6506750] (null)
Test Case '-[NSURLSessionTests testWithRequest]' passed (0.403 seconds).
Test Suite 'NSURLSessionTests' passed at 2020-10-19 17:10:03.632.
  Executed 1 test,with 0 failures (0 unexpected) in 0.403 (0.404) seconds
Test Suite 'Tests.xctest' passed at 2020-10-19 17:10:03.633.
  Executed 1 test,with 0 failures (0 unexpected) in 0.403 (0.405) seconds
Test Suite 'Selected tests' passed at 2020-10-19 17:10:03.633.
  Executed 1 test,with 0 failures (0 unexpected) in 0.403 (0.406) seconds
Program ended with exit code: 0

为什么不使用[NSOperationQueue mainQueue]来调用代表团？我如何在主线程上工作？

2020/10/23编辑

如前所述，当我改为XCTestExpectation而不是dispatch_semaphore_t时，Xctest代码起作用了。

@interface NSURLSessionTests : XCTestCase<NSURLSessionDataDelegate>
{
    @private
    XCTestExpectation *_expection;
}
@end

@implementation NSURLSessionTests
- (void)testWithRequest{
    _expection = [self expectationWithDescription:@"UIDocument is opened."];
    
    NSMutableuRLRequest *request = [NSMutableuRLRequest requestWithURL:[NSURL URLWithString: @"http://example.com/"]];
    
...
    
    [dataTask resume];
    [self waitForExpectations:[NSArray arrayWithObject:_expection] timeout:12.0];
}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"didCompleteWithError: %@",NSThread.currentThread);
    NSLog(@"%@",error);
    [_expection fulfill];
}
@end

但是我的应用代码仍然无法正常工作。当我检查应用程序代码时，发现正在等待HTTP请求结束。

- (void)startSync
{
    FcLicenseChecker *license = [FcLicenseChecker sharedInstance];
    if(!license.isCheckRunning)
    {
        [license execute];
    }
    
    [license waitUntilCheckFinished];
...

@implementation FcLicenseChecker

- (void)waitUntilCheckFinished
{
    while (_isCheckRunning)
    {
        [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.1]];
    }
}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
  ...
  _isCheckRunning = NO;
}

它正在waitUntilCheckFinished中肆虐，而没有代表团的来信。

我认为使用[NSRunLoop currentRunLoop] runUntilDate等待结束的方式适用于NSURLConnection的委派，但不适用于NSURLSession。

我认为更改为在didCompleteWithError中启动下一个进程而不是等待结束是可行的，但是这非常困难，因为有很多代码使用此类。

有没有办法等到NSURLSession结束？