订阅ReactiveCocoa中的信号以进行网络呼叫的正确选择是什么？ [英] What is a correct alternative for subscribing to signals in ReactiveCocoa for network calls?

问题描述

我是 ReactiveCocoa 的新手，并且在阅读了ReactiveCocoa的最佳做法之后这里我知道我需要避免显式订阅和处置但是在所有关于网络的教程和 ReactiveCocoa 中我看到了相同的模式：创建信号（make GET 或 POST 请求服务器，解析结果， sendNext ， sendCompleted ） - > subcsribeNext （做UI内容或其他结果） - > subscribeError 。因此，我们认为这里有一个明确的订阅，这是不好的。

是否有更正确和概念上纯粹的方法来做这个常见的事情？ rac_liftSelector：withSignals：或类似的东西？或者当我们处理网络电话和 AFNetworking 时，我们应该始终使用这种标准订阅模式吗？详细解释将非常有用。

I'm new to ReactiveCocoa world and after reading best practices of ReactiveCocoa here I knew that I need to "avoid explicit subscriptions and disposal" but in all tutorials about network and ReactiveCocoa I saw the same pattern : create signal (make GET or POST request to server, parse result, sendNext, sendCompleted) -> subcsribeNext (do UI stuff or something other with the result) -> subscribeError. So as we see there is an explicit subscription here, which is not good, I think.

Are there some more correct and conceptually pure ways of doing this common thing? rac_liftSelector:withSignals: or something like this? Or when we deal with network calls and AFNetworking we should always use this standard subscription pattern? Detailed explanation will be very helpful.

编辑：

在我的应用程序中，我主要是取电话，其中一些是是依赖的，其他人是单身（绝大多数），如登录或 fetchWhatever ，或 postWhatever 。我使用相同的模式构建的所有API调用（ self - 是我的 API管理器 NVMAPI 类 AFHTTPSessionManager 子类）：

EDITS:

In my application I have mainly fetching calls, some of them are dependent and others are single (vast majority) like login or fetchWhatever, or postWhatever. All API calls I construct with the same pattern like this (self - is my API manager NVMAPI class which is AFHTTPSessionManager subclass):

    -(RACSignal*)loginUserWithEmail:(NSString *)email andPassword:(NSString *)password
     {
        __block NSURLSessionDataTask* task;
        return [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        task = [self GET:kUserLoginEndpoint
          parameters:@{@"email": email, @"password": password}
             success:^(NSURLSessionDataTask *task, id responseObject) {
                     NVMUser* user = [[NVMUser alloc] initWithDictionary:responseObject[@"user"]];
                   [subscriber sendNext:user];
                   [subscriber sendCompleted];
             } failure:^(NSURLSessionDataTask *task, NSError *error) {
                 [subscriber sendError:error];
             }];
    return [RACDisposable disposableWithBlock:^{
        [task cancel];
    }];
       }] replayLazily];
        }

我不使用 MVVM 并使用简单的MVC。这里我如何在视图控制器中进行API调用和创建信号：

I don't use MVVM and use simple MVC. Here how I make API calls and create signals in view controllers:

[SVProgressHUD showWithStatus:@"Processing..." maskType:SVProgressHUDMaskTypeBlack];
[[[NVMAPI api] loginUserWithEmail:self.emailTextField.text
                               andPassword:self.passwordTextField.text]    
 subscribeNext:^(id x) {
                [self.activeUser setupWithUser:x];
                [SVProgressHUD dismiss];
                [self performSegueWithIdentifier:kLoginSeque sender:self];
 } 
     error:^(NSError *error) {
             [SVProgressHUD dismiss];
             [self showAlertWithText:error.localizedDescription title:@"Error"];
 }];

我使用的所有信号都是这样的： fetchComments ， postStatus 等。如果我有从属调用，我使用 flattenMap 。所以我很感兴趣 - 它是一种创建信号和使用它们的正确方法（简单的 subscribeNext ）？或者这可以通过一些更正确和优雅的方式来实现？

编辑2：

我看到订阅的主要问题 - 我不知道如何使用它们实现tableview的分页。我有 fetchComment 方法，带有加载分页注释 - 每个页面包含15条注释。我不能同时使用 subcribeNext 或 RAC（）绑定，对吗？我该如何管理这种模式？

All signals I use the same way like: fetchComments, postStatus, etc. If I have dependent calls I use flattenMap. So I'm interested - is it a right approach for creating signals and for using them (simple subscribeNext)? Or this can be achieved with some more correct and elegant way?

EDIT 2:

Main problem with subscriptions which I see - I don't know how to implement pagination for tableview with them. I have fetchComment method with load paginated comments - each page contain 15 comments. I can't use neither subcribeNext nor RAC() binding for this, right?How can I manage this pattern?

推荐答案

网络呼叫并不特殊，您可以像编写任何其他信号一样编写发出网络请求的信号。

Network calls aren't special, you can compose signals that issue network requests the same way you would compose any other signal.

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