Alamofire RequestRetrier，调用主操作队列上的完成块可以吗？

Question

我一直想知道从主队列上的请求重试调用完成块是否可以，因为函数调用是在 session.rootQueue

上进行的

func retry(_ request: Request, for session: Session, dueTo error: Error, completion: @escaping (RetryResult) -> Void) {
    
        OperationQueue.main.addOperation { [weak self] in
            
            guard let self = self else {
                completion(.doNotRetryWithError(e))
                return
            }
            self.handleError(e, completion: completion)
            
        }
        
    }
    
}

docu 没有明确说明，但如果我没记错的话，通常期望在与函数调用相同的队列中调用完成块

public protocol RequestRetrier {
    /// Determines whether the `Request` should be retried by calling the `completion` closure.
    ///
    /// This operation is fully asynchronous. Any amount of time can be taken to determine whether the request needs
    /// to be retried. The one requirement is that the completion closure is called to ensure the request is properly
    /// cleaned up after.
    ///
    /// - Parameters:
    ///   - request:    `Request` that failed due to the provided `Error`.
    ///   - session:    `Session` that produced the `Request`.
    ///   - error:      `Error` encountered while executing the `Request`.
    ///   - completion: Completion closure to be executed when a retry decision has been determined.
    func retry(_ request: Request, for session: Session, dueTo error: Error, completion: @escaping (RetryResult) -> Void)

所以我的问题是，应该在哪个队列上调用完成？

Answer 1

是的，它是安全的，因为调用重试器的内部实现会立即回调到 Alamofire 的 rootQueue。

从 Alamofire 5.4.4 开始：

retrier.retry(request, for: self, dueTo: error) { retryResult in
    self.rootQueue.async {
        guard let retryResultError = retryResult.error else { completion(retryResult); return }

        let retryError = AFError.requestRetryFailed(retryError: retryResultError, originalError:
error)
        completion(.doNotRetryWithError(retryError))
    }
}

Alamofire RequestRetrier，调用主操作队列上的完成块可以吗？

Alamofire RequestRetrier, is it ok to call the completion block on the main operation queue?

grand-central-dispatch

swift

alamofire