Swift 如何从 Alamofire 返回值

正如马特所指出的，Alamofire通过"完成处理程序"模式异步返回数据，因此您必须执行同样的操作.您不能立即将该值设置为return，而是希望将方法更改为不返回任何内容，而是使用完成处理程序闭包模式.

如今，这可能看起来像:

func getOrders(completionHandler: @escaping (Result<[String: Any]>) -> Void) {
    performRequest("orders", completion: completionHandler)
}

func performRequest(_ section: String, completion: @escaping (Result<[String: Any]>) -> Void) {
    let url = baseURL.appendingPathComponent(section)
    let params = ["consumer_key": "key", "consumer_secret": "secret"]

    Alamofire.request(url, parameters: params)
        .authenticate(user: consumerKey, password: consumerSecret)
        .responseJSON { response in
            switch response.result {
            case .success(let value as [String: Any]):
                completion(.success(value))

            case .failure(let error):
                completion(.failure(error))

            default:
                fatalError("received non-dictionary JSON response")
            }
    }
}

然后，当你想调用它时，你可以使用这个completion闭包参数(如果你想的话，在尾随闭包中):

api.getOrders { result in
    switch result {
    case .failure(let error):
        print(error)

    case .success(let value):
        // use `value` here
    }
}

// but don't try to use the `error` or `value`, as the above closure
// has not yet been called
//