swift - Alamofire的请求数量一个接一个

Question

我有许多请求，我想在没有嵌套意大利面条代码的情况下一个接一个地调用。

我已经用串行调度队列试过了

let queue = dispatch_queue_create("label", DISPATCH_QUEUE_SERIAL)

Alamofire.request(Router.Countries).responseString { (response:Response<String, NSError>) in
            print(1)
        }

Alamofire.request(Router.Countries).responseString { (response:Response<String, NSError>) in
            print(2)
        }

Alamofire.request(Router.Countries).responseString { (response:Response<String, NSError>) in
            print(3)
        }

但不幸的是，这不起作用。此输出可以是 1,3,2 或 3,1,2 或任何其他组合。

一个接一个地获得输出 1,2,3 的最佳方法是什么。

Answer 1

好的，我最终编写了自己的实现。

我创建了一个 RequestChain 类，它以 Alamofire.Request 作为参数

class RequestChain {
    typealias CompletionHandler = (success:Bool, errorResult:ErrorResult?) -> Void

    struct ErrorResult {
        let request:Request?
        let error:ErrorType?
    }

    private var requests:[Request] = []

    init(requests:[Request]) {
        self.requests = requests
    }

    func start(completionHandler:CompletionHandler) {
        if let request = requests.first {
            request.response(completionHandler: { (_, _, _, error) in
                if error != nil {
                    completionHandler(success: false, errorResult: ErrorResult(request: request, error: error))
                    return
                }
                self.requests.removeFirst()
                self.start(completionHandler)
            })
            request.resume()
        }else {
            completionHandler(success: true, errorResult: nil)
            return
        }

    }
}

我是这样用的

let r1 = Alamofire.request(Router.Countries).responseArray(keyPath: "endpoints") { (response: Response<[CountryModel],NSError>) in
    print("1")
}

let r2 = Alamofire.request(Router.Countries).responseArray(keyPath: "endpoints") { (response: Response<[CountryModel],NSError>) in
    print("2")
}

let r3 = Alamofire.request(Router.Countries).responseArray(keyPath: "endpoints") { (response: Response<[CountryModel],NSError>) in
    print("3")
}

let chain = RequestChain(requests: [r1,r2,r3])

chain.start { (success, errorResult) in
    if success {
        print("all have been success")
    }else {
        print("failed with error \(errorResult?.error) for request \(errorResult?.request)")
    }


}

重要的是你告诉经理不要立即执行请求

    let manager = Manager.sharedInstance
    manager.startRequestsImmediately = false

希望对别人有帮助