Alamofire网络调用不在后台线程中运行 [英] Alamofire network calls not being run in background thread

问题描述

据我了解，默认情况下，Alamofire请求在后台线程中运行。

It is my understanding that by default, Alamofire requests run in a background thread.

当我尝试运行此代码时：

When I tried running this code:

let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

        Alamofire.request(productsEndPoint, method: .get)
            .responseJSON { response in
                // check for errors
                guard response.result.error == nil else {
                    // got an error in getting the data, need to handle it
                    print("Inside error guard")
                    print(response.result.error!)
                    return
                }

                // make sure we got some JSON since that's what we expect
                guard let json = response.result.value as? [String: Any] else {
                    print("didn't get products as JSON from API")
                    print("Error: \(response.result.error)")
                    return
                }

                // get and print the title
                guard let products = json["products"] as? [[String: Any]] else {
                    print("Could not get products from JSON")
                    return
                }
                print(products)

        }

在网络呼叫的所有项目都已完成打印之前，UI没有响应;所以我尝试将GCD与Alamofire一起使用：

The UI was unresponsive until all the items from the network call have finished printing; so I tried using GCD with Alamofire:

let queue = DispatchQueue(label: "com.test.api", qos: .background, attributes: .concurrent)

    queue.async {

        let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

        Alamofire.request(productsEndPoint, method: .get)
            .responseJSON { response in
                // check for errors
                guard response.result.error == nil else {
                    // got an error in getting the data, need to handle it
                    print("Inside error guard")
                    print(response.result.error!)
                    return
                }

                // make sure we got some JSON since that's what we expect
                guard let json = response.result.value as? [String: Any] else {
                    print("didn't get products as JSON from API")
                    print("Error: \(response.result.error)")
                    return
                }

                // get and print the title
                guard let products = json["products"] as? [[String: Any]] else {
                    print("Could not get products from JSON")
                    return
                }
                print(products)

        }
    }

并且UI仍然没有像以前那样没有响应。

and the UI is still unresponsive as it was before.

我在这里做错了什么，或者Alamofire的错误在哪里？

Am I doing anything wrong here, or does the fault lie with Alamofire?

推荐答案

默认情况下，Alamofire在后台线程上运行我错了。它实际上默认在主队列上运行。我在Alamofire的Github页面上打开了一个问题，这里已经解决了这个问题： https://github.com / Alamofire / Alamofire / issues / 1922

I was wrong about Alamofire running on a background thread by default. It actually runs on the main queue by default. I've opened an issue on Alamofire's Github page and it's been solved here: https://github.com/Alamofire/Alamofire/issues/1922

解决我的问题的正确方法是指定我希望我的请求运行的队列类型.responseJSON方法中的队列参数（

The correct way to solve my problem was to specify what kind of queue I want my request to be run on using the "queue" parameter on the .responseJSON method (

.responseJSON(queue: queue) { response in
...
}

）

这是我的代码的完整更正版本：

This is the entire, corrected version of my code:

let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

    let queue = DispatchQueue(label: "com.test.api", qos: .background, attributes: .concurrent)

    Alamofire.request(productsEndPoint, method: .get)
        .responseJSON(queue: queue) { response in
            // check for errors
            guard response.result.error == nil else {
                // got an error in getting the data, need to handle it
                print("Inside error guard")
                print(response.result.error!)
                return
            }

            // make sure we got some JSON since that's what we expect
            guard let json = response.result.value as? [String: Any] else {
                print("didn't get products as JSON from API")
                print("Error: \(response.result.error)")
                return
            }

            // get and print the title
            guard let products = json["products"] as? [[String: Any]] else {
                print("Could not get products from JSON")
                return
            }
            print(products)
     }

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