PHP将json $ _POST数据转换为数组

Question

我有这样的json数据：

 "[\n  {\n    \"sort\" : 0,\n    \"wishlistid\" : 0,\n    \"item\" : \"Test\",\n    \"userid\" : 11\n  }\n]"

我是通过Alamofire通话从Swift那里获得的：

 func saveWishList(_ cellHolder: Array<WishListClass>, completion: @escaping (_ result: Bool) -> Void)
{

    //Define Array of Dictionary

    var jsonArrayOfDictionaries = [[String: Any]]()

    //For each item in the cellHolder

    for i in 0..<cellHolder.count {

        //Define Dictionary for grading data

        var jsonDict = [String: Any]()

        jsonDict["userid"] = cellHolder[i].userid

        jsonDict["wishlistid"] = cellHolder[i].wishlistid

        jsonDict["item"] = cellHolder[i].item

        jsonDict["sort"] = cellHolder[i].sort

        jsonArrayOfDictionaries.append(jsonDict)

        jsonDict = [String: Any]()

    }

    let jsonData: Data? = try? JSONSerialization.data(withJSONObject: jsonArrayOfDictionaries, options: .prettyPrinted)

    let json = String(data: jsonData!, encoding: String.Encoding.utf8)

    let parameters: Parameters = [
        "wishList" : json!
    ]

    Alamofire.request(webservice + "?action=postuserwishlist", method: HTTPMethod.post, parameters: parameters, encoding: URLEncoding.httpBody, headers: [:]).responseJSON { response in

        if(response.error == nil)
        {
            if let result = response.result.value {

                let jsonData = result

                print(jsonData)

                completion(false)

            }
        }

    }
}

现在我正在尝试检索发布到php数组中的json。...

所以我的问题是我将如何在PHP中做到这一点？我期望在PHP中使用键和值组成一个数组。