Question

我已经搜索了很多关于如何同步运行AFNetworking 2.0的示例和教程，并且只找到了AFNetworking 1.0的解决方案。我找到了什么：Can AFNetworking return data synchronously (inside a block)?

我的例子：

- (User *)getUserWithUsername: (NSString *) username andPassword: (NSString *) password {

    NSDictionary *params = @{@"email": username, @"password": password};


    [[DCAPIClient sharedClient] POST:@"login" parameters:params success:^(NSURLSessionDataTask * __unused task, id JSONResult) {
        NSLog(@"JSON %@", JSONResult);
        BOOL errorCode = [JSONResult objectForKey:@"error"];
        if (!errorCode) {
            self.username = [JSONResult objectForKey:@"name"];            
            // Fill the attributes
            // self.email = .. a
         } else {
            // error with login show alert
         }

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

     // this does not work
     //[[[DCAPIClient sharedClient] operationQueue] waitUntilAllOperationsAreFinished];


     if (self.username == nil) {
         return nil;
     }

     return self;

}

但这不起作用，因为首先调用if (self.username == nil)。

如何让AFNetworking 2.0 lib同步运行，我可以返回响应？

DCAPIClient：AFHTTPSessionManager

+ (instancetype)sharedClient {
    static DCAPIClient *_sharedClient = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _sharedClient = [[DCAPIClient alloc] initWithBaseURL:[NSURL URLWithString:DCAPIBaseURLString]];
        _sharedClient.responseSerializer = [AFJSONResponseSerializer serializer];
    });

    return _sharedClient;
}

Answer 1

仇恨者会讨厌，但有时你只是希望你的HTTP调用是同步的。

为此，您可以使用AFNetworking-Synchronous库。它为AFHTTPRequestOperationManager添加了一个方便的类别，其中包含syncGET和syncPOST等同步方法，这些方法在内部使用AFNetworking的waitUntilFinished来实现同步调用。

Answer 2

我不确定你为什么这样做，但一个解决方案是使用回调块。像这样：

- (void)getUserWithUsername: (NSString *) username andPassword: (NSString *) password success:(void (^)(User *user))success failure:(void (^)(NSError *error))failure
{
    NSDictionary *params = @{@"email": username, @"password": password};

    __weak __typeof(self)weakSelf = self;    

    [[DCAPIClient sharedClient] POST:@"login" parameters:params success:^(NSURLSessionDataTask * __unused task, id JSONResult) {

        BOOL errorCode = [JSONResult objectForKey:@"error"];
        if (!errorCode) {
            weakSelf.username = [JSONResult objectForKey:@"name"];

            if (weakSelf.username == nil) {
                failure(nil);
            }else{
                success(weakSelf)
            }
        } else {
            failure(nil);
        }

    } failure:^(NSURLSessionDataTask *__unused task, NSError *error) {
         failure(error);
    }];
}

Answer 3

您不应该使本机异步方法同步，而是使您的调用站点异步。

也就是说，您的方法变为异步并提供完成处理程序：

- (void) userWithUsername:(NSString *)username 
                 password:(NSString *)password 
               completion:(completion_handler_t)completion;

其中completion_handler_t是一个类型定义，可以像这样在头文件中声明：

typedef void (^completion_handler_t)(User*, NSError*);

请注意，使用typedef是可选的，可能会使您的代码更易于理解。

然后您可以按如下方式使用它：

[self userWithUsername:username 
              password:password 
            completion:^(User* user, NSError*error){
    // Check error; do something with user
    ...
}];

您可以按如下所示实现它：

- (void) userWithUsername:(NSString *)username 
                 password:(NSString *)password 
               completion:(completion_handler_t)completion
{
    NSDictionary *params = @{@"email": username, @"password": password};
    [[DCAPIClient sharedClient] POST:@"login" parameters:params   
        success:^(NSURLSessionDataTask * __unused task, id JSONResult) {
            NSLog(@"JSON %@", JSONResult);
            BOOL errorCode = [JSONResult objectForKey:@"error"];
            if (!errorCode) {
                self.username = [JSONResult objectForKey:@"name"];            
                // Fill the attributes
                // self.email = .. a
                if (completion) {
                    completion(theUser, nil);  // completion(self, nil)?? 
                }
            } else {
                if (completion) {
                    completion(nil, error);
                }
            }

        } failure:^(NSURLSessionDataTask *__unused task, NSError *error) {
             if (completion) {
                 completion(nil, error);
             }
        }];
}

如何同步使用AFNetworking 2.0

3 个答案: