测量AFNetworking HTTP GET中的响应时间

Question

我正在尝试使用AFNetworking下载文件时测量每个GET请求所花费的时间.我正在循环中重复下载文件.我遇到的问题是我测量总时间的方式,它给出了比实际更大的总时间.例如,对于50次下载,它提供72秒,但实际上它只花了大约5秒.我还怀疑5秒太低而不能下载50次(每个文件的下载大小为581 kb).

在这种情况下,如何有效地测量时间？我需要时间从请求被解雇到收到响应.

我下载文件的方法:

- (void) HTTPGetRequest
{    
    startTime = CACurrentMediaTime(); // Start measuring time

    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:http://myServer];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"GET"
                                                            path:@"/download/Text581KB.txt"
                                                      parameters:nil];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];

    // Save downloaded file
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:@"Text581KB.txt"]];
    operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];

    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        double elapsedTime = (CACurrentMediaTime() - startTime); // Measuring time
        totalTime += elapsedTime; // Measuring total time HERE!
        [results setString:[NSString stringWithFormat: @"Current Transaction Time: %f sec\nTotal Time: %f sec", elapsedTime, totalTime]];
        [_resultLabel performSelectorOnMainThread:@selector(setText:) withObject:results waitUntilDone:NO];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];

    [operation setDownloadProgressBlock:^(NSUInteger bytesWritten, long long totalBytesWritten, long long totalBytesExpectedToWrite) {  ((int)totalBytesExpectedToWrite));
        totalDownloadSize += totalBytesExpectedToWrite;
        [_DataTransferredLabel setText:[NSString stringWithFormat:@"Total Download Size: %@", [self getFileSize:totalDownloadSize/1024]]];
    }];

    [operation setCacheResponseBlock:^NSCachedURLResponse *(NSURLConnection *connection, NSCachedURLResponse *cachedResponse) {
        return nil;
    }];
    [operationQueue addOperation:operation];
}

我在viewDidLoad中创建了一个NSOperationQueue:

operationQueue = [NSOperationQueue new];
[operationQueue setMaxConcurrentOperationCount:1]; // using this as I was suspecting downloads were happening in parallel & thus 50 downloads finishing in a few secs

我正在调用HTTPGetRequest方法,如下所示:

- (IBAction)startDownload:(UIButton *)sender {
    totalCount = [[_countText text] longLongValue]; // get # of times to download
    long currentCount = 1;
    completedCount = 0;
    totalTime = 0;
    totalDownloadSize = 0;
    while (currentCount <= totalCount)
    {
        [self HTTPGetRequest];
        [results setString:@""];
        currentCount++;

    }

Answer 1

使用AFHTTPRequestOperationLogger.