swift - Moya - 使用 NSOperation 链式请求

Question

我有几个需要链接的请求。我可以这样做

provider.request(.apples) { (result) in
        switch result {
        case .success(let response):

           provider.request(.oranges) { (result) in
                switch result {
                case .success(let response):

                   ...couple of other fruits

                case .failure(let error):
                  print(error)
        }
    }

        case .failure(let error):
            print(error)
        }
    }

但我想使用 NSOperation 将它们链接起来。

我该怎么做？

Answer 1

我是 Swift 的初学者，但是通过代码我了解到您正在请求“苹果”。如果该请求成功，则再次请求“橙子”，如果成功，则请求其他水果，依此类推。

是的，您可以使用 NSOperation 链接它们，请参阅我对以下问题的回答，我在其中概述了 2 种不同的方法。

Do NSOperations and their completionBlocks run concurrently?

注意:这里有几种情况:1)是否只有“apples”请求成功才需要请求“oranges”，只有“oranges:请求成功”才能请求其他水果？在这种情况下，您可以引用上述问题中的答案。示例流程如下:

RequestFruitOperation *requestApplesOperation = [[RequestFruitOperation alloc] initWithFruitType:Apples];

[requestApplesOperation setCompletionBlock:^{
    if(requestApplesOperation.success){
        //add oranges
        RequestFruitOperation *requestOrangesOperation = [[RequestFruitOperation alloc] initWithFruitType:Oranges];
        [requestOrangesOperation setCompletionBlock:^{
            if(requestOrangesOperation.success) {
                //add mangoes
                RequestFruitOperation *requestMangosOperation = [[RequestFruitOperation alloc] initWithFruitType:Mangos];
                [operationQueue addOperation:requestMangosOperation];
            }
        }];
        [operationQueue addOperation:requestOrangesOperation];
    }

}
 [operationQueue addOperation:requestApplesOperation];

2) 如果您可以并行请求“苹果”、“橘子”和“其他水果”，而无需等待彼此成功，那么您就不需要将它们链接在一起。您可以只将操作添加到队列中。

RequestFruitOperation *requestApplesOperation = [[RequestFruitOperation alloc] initWithFruitType:Apples];
[operationQueue addOperation:requestApplesOperation];

RequestFruitOperation *requestOrangesOperation = [[RequestFruitOperation alloc] Oranges];
[operationQueue addOperation:requestOrangesOperation];

RequestFruitOperation *requestMangosOperation = [[RequestFruitOperation alloc] Mangos];
[operationQueue addOperation:requestMangosOperation];