ios - afnetworking通过for循环发送请求,如何保证接收到数据的顺序和发送请求的顺序一致?

Question

利用AFNetworking进行网络请求,要发送的参数在一个数组里,每次取数组中的一条数据设置参数发送请求,

我通过for循环遍历数组并设置参数发送请求,将网络请求返回的数据添加到一个新的数组中,

发现不是每次请求返回的数据的顺序是一样的,功能需求返回数据的排序必须跟发送请求的顺序是一样的,

求问有什么方法保证前一次请求返回数据之后再发送下一次请求?

非常感谢,万分感谢!!!!

/**
 *  加载订单数据,设置控件位置
 */
- (void)loadOrderData {
        NSString *userID = [[NSUserDefaults standardUserDefaults] stringForKey:@"GOId"];
        NSDictionary *dict = @{
                               @"GOId" : userID,
                               };
        // 将字典转为json
        NSDictionary *params = [ELHOCToJson ocToJson:dict];
        
        NSString *URL = [NSString stringWithFormat:@"%@RealtimeOrder_getROListCon12345.action", ELHBaseURL];
        
        
        __weak typeof(self) weakSelf = self;
        [self.manager POST:URL parameters:params success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
            
            weakSelf.ELHOrderArray = [ELHOrderModel mj_objectArrayWithKeyValuesArray:responseObject];
            

            dispatch_queue_t conCurrentQueue = dispatch_queue_create("order", NULL);
            // 获取订单编号
            for (int i = 0; i < weakSelf.ELHOrderArray.count; i++) {
                ELHOrderModel *model = weakSelf.ELHOrderArray[i];
                
                [weakSelf.ELHOrderNumArray addObject:model.ROBM];
                dispatch_barrier_async(conCurrentQueue, ^{
                        // 加载订单详情列表
                        [self loadOrderDetailData:model.ROBM];    // 问题可能就出在这个for循环里,发送请求的顺序应该是按顺序发送的,但是返回数据的时间可能就不一样了,所以造成了数据顺序错乱的问题,求问如何解决此问题?
                    });
            }
            
            
       
            
            // 刷新数据
            [orderVC.tableView reloadData];
            
        } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
            NSLog(@"%@", error);
        }];
    
}



/**
 *   加载订单详情列表
 */
- (void)loadOrderDetailData:(NSString *)ROBM {
    NSDictionary *dict = @{
                           @"ROBM" : ROBM,
                           };
    
    // 字典转json
    NSDictionary *params = [ELHOCToJson ocToJson:dict];
    
    NSString *URL = [NSString stringWithFormat:@"%@OrderPrice_getOPListByROBM.action", ELHBaseURL];
    
    __weak typeof(self) weakSelf = self;
    [self.manager POST:URL parameters:params success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {       
    
        // 将获取到的订单详情数据逐个添加到数组中
        [weakSelf.ELHOrderDetailArray addObject:[ELHOrderDetailModel mj_objectArrayWithKeyValuesArray:responseObject]];
        ELHOrderTableViewController *orderVC = weakSelf.childViewControllers.firstObject;
        
        orderVC.orderDetailArray = weakSelf.ELHOrderDetailArray;
        
        // 刷新数据
        [orderVC.tableView reloadData];
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        NSLog(@"%@", error);
    }];
}

Answer 1

I found a compromise, which is to use the dispatch_group_async function in the callback of afnetworking for sequence control.
The code is as follows:

[self.manager POST:URL parameters:params success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
//            NSLog(@"%@", responseObject);
            // 字典数组转模型数组
            weakSelf.ELHOrderArray = [ELHOrderModel mj_objectArrayWithKeyValuesArray:responseObject];

            

            
            // 获取订单编号
            for (int i = 0; i < weakSelf.ELHOrderArray.count; i++) {
                ELHOrderModel *model = weakSelf.ELHOrderArray[i];
                
                // 将订单编号存入一个数组,亦可以不存直接进行获取订单列表操作,加这一步因为项目需求
                [weakSelf.ELHOrderNumArray addObject:model.ROBM];
                

            }
            
            
            
            /**
             *  根据上面获取到的订单编号数组,遍历数组 获取 订单列表
             */
            NSMutableArray *tempArray = [NSMutableArray arrayWithArray:weakSelf.ELHOrderNumArray]; // 创建临时数组用于存放接收到的数据,确保临时数组的长度和你请求到的数据的组数是一样的,这样才能保证你"第几个请求返回的数据放在数组的第几个位置", 这句代码 [tempArray setObject:responseDict atIndexedSubscript:i]; 实现该功能
            if (weakSelf.ELHOrderNumArray != nil) {
                dispatch_queue_t queue = dispatch_queue_create("order", DISPATCH_QUEUE_CONCURRENT);
                dispatch_group_t group = dispatch_group_create();
                
                for (int i = 0; i < weakSelf.ELHOrderNumArray.count ; i++) {
                    dispatch_group_async(group, queue, ^{
                        NSString *urlStr = [NSString stringWithFormat:@"%@OrderPrice_getOPListByROBM.action", ELHBaseURL];
                        NSURL *url = [NSURL URLWithString:urlStr];
                        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
                        request.HTTPMethod = @"POST";
                        request.HTTPBody = [[NSString stringWithFormat:@"jo={ROBM=%@}", weakSelf.ELHOrderNumArray[i]] dataUsingEncoding:NSUTF8StringEncoding];
                        NSURLResponse *response;
                        NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

                        NSDictionary *responseDict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
                        // 第几个请求返回的数据放在数组的第几个位置
                        [tempArray setObject:responseDict atIndexedSubscript:i];

                    });
                }
                
                dispatch_group_notify(group, dispatch_get_main_queue(), ^{
                    // 将所有请求到的数据按顺序放到一个数组中,之后进行别的操作刷新数据就可以了
                    [self.ELHOrderDetailArray addObjectsFromArray:[ELHOrderDetailModel mj_objectArrayWithKeyValuesArray:tempArray]]; 

                    ......
                    
                    [self.tableView reloadData];

                });
                
            }
    
            
        } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
            NSLog(@"%@", error);
        }];

Answer 2

After reading the document, operationQueue is used to handle delegate callbacks. NSURLSessionConfiguration's HTTPMaximumConnectionsPerHost can guarantee Only one request is initiated under the same domain name at a time, the code is as follows: operationQueue 是用来处理 delegate 回调的, NSURLSessionConfiguration 的 HTTPMaximumConnectionsPerHost 可以保证同一域名下每次只发起一个请求, 代码如下:

NSURLSessionConfiguration *configure = [NSURLSessionConfiguration defaultSessionConfiguration];
configure.HTTPMaximumConnectionsPerHost = 1;

AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc] initWithSessionConfiguration:configure];
manager.operationQueue.maxConcurrentOperationCount = 1;

不过 AFNetworking 使用了并行队列 url_session_manager_processing_queue() 处理数据, 由于不能保证这个队列的先后性, 所以其实也不能够确保回调的串行性

----------------------------------------原答案-----------------------------
把 manger 里 queue 的 maxConcurrentOperationCount 设置成 1.

还有你这里的 dispatch_barrier_async 我不知道你是想干嘛, 保证串行? 你这个 for rrreee

However, AFNetworking uses a parallel queue url_session_manager_processing_queue() to process data. Since the sequence of this queue cannot be guaranteed, the seriality of callbacks cannot be guaranteed. #🎜🎜# #🎜🎜#----------------------------------------Original answer---- ------------------------
Put the of queue in manger maxConcurrentOperationCount is set to 1.#🎜🎜# #🎜🎜#And your dispatch_barrier_async here, I don’t know what you want to do, ensure seriality? Your for loop is inherently serial#🎜🎜 #

Answer 3

First suspend the sending queue, and then when the for loop generates requests, add dependencies between the requests and put them in the queue.

Answer 4

There is still no way to determine the order of the returned data, I feel...

Answer 5

I also encountered this problem. Did you solve it? How did you do it