Question

我有一种方法可以使用AFNetworking调用enqueueBatchOfHTTPRequestOperations将文件列表从Web服务器下载到iPad。每隔一段时间我就会得到一次失败的操作（通常是文件较大时）。从历史上看，我单独下载了每个文件，只需再次调用操作，直到达到一定的重试次数。

我重构了代码以使用enqueueBatchOfHTTPRequestOperations。这很好但我不知道如何获取有关“特定”操作失败的通知，如果失败，我不知道如何将它们重新添加到队列中。

以下是我用来下载“n”个文件的代码：

    NSMutableArray *operationsArray = [[NSMutableArray alloc]init];
for (MINPageDefinition *currPage in [[MINPageStore sharedInstance] pageArray])
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *serverLibraryURL = [defaults objectForKey:kRootURL];
    serverLibraryURL = [serverLibraryURL stringByAppendingPathComponent:kPageDefinitionsDirectory];
    serverLibraryURL = [serverLibraryURL stringByAppendingPathComponent:currPage.pageImageName];

    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:serverLibraryURL]];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    operation.outputStream = [NSOutputStream outputStreamToFileAtPath:currPage.pageImageURL append:NO];

    [operationsArray addObject:operation];
}
if ([operationsArray count] > 0)
{
    AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@""]];
    void (^progressBlock)(NSUInteger numberOfCompletedOperations, NSUInteger totalNumberOfOperations) = ^(NSUInteger numberOfCompletedOperations, NSUInteger totalNumberOfOperations) {
        NSLog(@"%d proccesses completed out of %d", numberOfCompletedOperations, totalNumberOfOperations);
    };
    void (^completionBlock)(NSArray *operations) = ^(NSArray *operations) {
        NSLog(@"All operations completed");
    };
    [client enqueueBatchOfHTTPRequestOperations:operationsArray
                                  progressBlock:progressBlock
                                completionBlock:completionBlock];
}

之前，我有一个执行操作的方法。失败时，失败块将递归调用自身。如果操作失败，如何修改此代码以重试“n”次？

Answer 1

检查以下代码@justLearningAgain

[[WfServices sharedClient] GET:kGetAddress parameters:dicParam  success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"RESPONSE ::: %@",responseObject);
  }failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    }];


+ (WfServices *)sharedClient
{
    static WfServices * _sharedClient = nil;
    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{
        _sharedClient = [[WfServices alloc] initWithBaseURL:[NSURL URLWithString:kWFBaseURLString]];
    });

    return _sharedClient;
}

Answer 2

难道你不能在那个操作的故障块中再次将单个失败的操作排入队列吗？

[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
     [[APIClient sharedClient] enqueueHTTPRequestOperation:operation];
}];

[APIClient sharedClient]是对AFHTTPClient子类的引用（单例或不单例）。

Answer 3

我认为AFNetworking Auto-Retry可能会有所帮助。

或者您可以在AFHTTPClient中覆盖以下方法。

考虑resumeTasksArray =您需要重新添加到队列的操作数组。

NSMutableArray *resumeTasksArray; before @implementation AFHTTPClient 

- (AFHTTPRequestOperation *)HTTPRequestOperationWithRequest:(NSURLRequest *)request
                                                success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                                                failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure {

void(^authFailBlock)(AFHTTPRequestOperation *opr, NSError *err) = ^(AFHTTPRequestOperation *opr, NSError *err){
    [resumeTasksArray addObject:request];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
        //now, queue up and execute the original task
        for (NSURLRequest *previousRequest in resumeTasksArray) {
            NSLog(@"^^^^^^^^^^^^^^^^^^^^^^^^^^^^Resume Task URL - %@", previousRequest.URL);
            NSMutableURLRequest *newRequest = [previousRequest mutableCopy];
            [newRequest setValue:[NSString stringWithFormat:@"Bearer %@", AppSingleton.access_token] forHTTPHeaderField:@"Authorization"];
            AFHTTPRequestOperation *opera10n = [[AFHTTPRequestOperation alloc]initWithRequest:newRequest];
            opera10n.responseSerializer = self.responseSerializer;
            [opera10n setCompletionBlockWithSuccess:success failure:failure];
            if (![[self.operationQueue operations] containsObject:opera10n]) {
                [[self operationQueue] addOperation:opera10n];
                [opera10n start];
            }
        }
        [resumeTasksArray removeAllObjects];
    });
};
AFHTTPRequestOperation *operation = [super HTTPRequestOperationWithRequest:request success:success failure:authFailBlock];
return operation;
}

如何在AFNetworking使用enqueueBatchOfHTTPRequestOperations失败时重新添加操作

3 个答案: