Swift：尝试将元组传递给回调函数时得到 "ambiguous expression"

Question

我有这个 class 用于根据我的后端对用户进行身份验证。

class BackendService {


class func performLogin(#email: String, password: String, success:((res: NSHTTPURLResponse, json: JSON, statusCode: HTTPStatus))->(), failure: (NSError)->()) {

    let loginURL = baseURL + "/login"
    let parameters = ["email": email, "password": password]

    Alamofire.request(.POST, loginURL, parameters: parameters).responseJSON { (req, res, json, err) in

        if(err != nil) {
            let response = (error: err!)
            failure(response)
        }
        else {


            if let httpStatus = HTTPStatus(rawValue: res!.statusCode) {
                let response = (res: res, json: JSON(json!) , statusCode: httpStatus)
                success(response)
            }
        }
    }

}

在 success(response) 我得到 Type of expression is ambiguous without more context。有任何想法吗？

有没有更好、更快捷的方式来编写这个class？

Answer 1

它没有编译的原因是你在成功元组声明周围有一组额外的括号。如果你删除它们，那么它将编译。这是您的函数的更新版本，其中包含尽可能少的编译更改。

You need to make sure you have baseURL defined somewhere.

class func performLogin(#email: String, password: String, success:(res: NSHTTPURLResponse, json: JSON, statusCode: HTTPStatus)->(), failure: (NSError)->()) {

    let loginURL = baseURL + "/login"
    let parameters = ["email": email, "password": password]

    Alamofire.request(.POST, loginURL, parameters: parameters).responseJSON { (req, res, json, err) in

        if (err != nil) {
            let response = (error: err!)
            failure(response)
        }
        else {
            if let httpStatus = HTTPStatus(rawValue: res!.statusCode) {
                let response = (res: res!, json: JSON(json!), statusCode: httpStatus)
                success(response)
            }
        }
    }
}

这是您的原始函数的更新版本，它当然更干净，但还不完全安全。一个好的经验法则是感叹号越多，风险越大。

typealias LoginSuccessHandler = (NSHTTPURLResponse, JSON, HTTPStatus) -> Void
typealias LoginFailureHandler = (NSError) -> Void

class func performLogin(#email: String, password: String, success: LoginSuccessHandler?, failure: LoginFailureHandler?) {
    let loginURL = baseURL + "/login"
    let parameters = ["email": email, "password": password]

    Alamofire.request(.POST, loginURL, parameters: parameters).responseJSON { request, response, json, error in
        if let error = error {
            failure?(error)
        } else {
            if let httpStatus = HTTPStatus(rawValue: response!.statusCode) {
                success?(response!, JSON(json!), httpStatus)
            }
        }
    }
}

您真的应该看看 Alamofire.Request class 中内置的 @mattt 令人敬畏的验证逻辑。这样您就可以完全消除对 HTTPStatus 枚举的需要。

public func validate() -> Self
public func validate(contentType array: [String]) -> Self
public func validate(statusCode array: [Int]) -> Self
public func validate(statusCode range: Range<Int>) -> Self
public func validate(validation: Validation) -> Self

Swift：尝试将元组传递给回调函数时得到 "ambiguous expression"

Swift: Getting "ambiguous expression" when try to pass tuple to callback function

ios

swift

alamofire