将块传递给AFNetworking方法? [英] Passing blocks to a AFNetworking method?

问题描述

-(void )getDataFromServer: (NSMutableDictionary *)dict
 {

 NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@/doSomething",MainURL ]];
 [AFJSONRequestOperation addAcceptableContentTypes:[NSSet setWithObject:@"text/html"]];

 AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:url];
 NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST" path:nil parameters:dict];

 AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
 success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON)
 {
     _myArray = JSON;
     [_myTableView reloadData]; //Or do some other stuff that are related to the current `ViewController`
 }
 failure:^(NSURLRequest *request , NSURLResponse *response , NSError *error , id JSON)
 {
     NSLog(@"request: %@",request);
     NSLog(@"Failed: %@",[error localizedDescription]);
 }];

 [httpClient enqueueHTTPRequestOperation:operation];
 }

我在其中一个应用程序中的7个不同位置使用了上面的代码.确切的代码块在ViewControllers的7中重复.我通常要做的是将要使用的方法放在NSObject类中，并在需要时分配和使用它，但是由于上述方法是Async并使用块，因此我不能仅将JSON返回到ViewController谁打电话给它，并且必须复制&将上述方法粘贴到我需要的每个ViewController中.

I'm using the above code in 7 different places in one of my apps. The exact chunk of code is duplicated in 7 of my ViewControllers. What I normally used to do is to put the method I want to use in a NSObject class and allocate and use it when ever I need but because the above is Async and using blocks I can't just return the JSON to the ViewController who called it and have to copy & paste the above method in every ViewController I need it in.

我的目标是将以上内容仅放在应用程序的一个位置，仍然可以从应用程序周围的不同ViewControllers调用它，并获取所需的数据. 我想避免使用诸如NSNotification或KVO之类的观察器，而是寻找一种更优雅的解决方案. 经过一番阅读后，我注意到有可能绕过障碍物.以上是可行的解决方案吗?一个代码示例将不胜感激.

My goal is to have the above in only one place in my app and still be able to call it from different ViewControllers around my app and get the data I need. I'd like to avoid using an observer such as NSNotification or KVO and looking for a more elegant solution. After some reading I noticed the possibility to pass blocks around. Is that a possible solution with the above? A code example would be appreciated.

推荐答案

将API调用的特征化为类似

Factorize the API call to something like

+ (void)getDataFromServerWithParameters:(NSMutableDictionary *)params completion:(void (^)(id JSON))completion failure:(void (^)(NSError * error))failure {
     NSString * path = @"resources/123";
     NSMutableURLRequest *request = [self.httpClient requestWithMethod:@"POST" path:path parameters:params];
     AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
        if (completion)
            completion(JSON);
     } failure:^(NSURLRequest *request , NSURLResponse *response , NSError *error , id JSON) {
        if (failure)
            failure(error);
     }];

     [httpClient enqueueHTTPRequestOperation:operation];
 }

您可以将此方法放置在XYAPI之类的实用工具类中，并只需从您的控制器中调用它，例如

You can place this method in a utility class like XYAPI and just invoke it from your controllers like

 [XYAPI getDataFromServer:params completion:^(id JSON){
     // do something, for instance reload the table with a new data source
     _myArray = JSON;
     [_myTableView reloadData];
 } failure:^(NSError * error) {
    // do something
 }];

此外，您无需在每次请求时都生成新的AFHTTPClient.在XYAPI类中配置并使用共享的.像

Also you don't need to spawn a new AFHTTPClient at every request. Configure and use a shared one in the XYAPI class. Something like

+ (AFHTTPClient *)httpClient {
    static AFHTTPClient * client = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        client = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"http://foo.com/api/v1/"]];
        [AFJSONRequestOperation addAcceptableContentTypes:[NSSet setWithObject:@"text/html"]];
    });
    return client;
}

请注意，以上示例中已经使用了此实现.
在类方法的上下文中，self是类本身，因此self.httpClient确实在运行时解析为[XYAPI httpClient].

Note that this implementation is already used in the above example.
self in the context of a class method is the class itself, so self.httpClient is indeed resolved at runtime as [XYAPI httpClient].

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