由于格式不断出现错误，提示“无法读取数据”

Question

基本上，我是在我的swift应用中创建一个登录视图控制器，用于验证和登录用户。

这是应用程序通过POST HTTP请求进行请求和处理的方式：

import Foundation

enum MyResult<T, E: Error> {

    case success(T)
    case failure(E)
}

class NetworkingService {

    let baseUrl = "https://example/example/login.php"

    func handleResponse(for request: URLRequest,
                        completion: @escaping (Result<User, Error>) -> Void) {

        let session = URLSession.shared

        let task = session.dataTask(with: request) { (data, response, error) in

            DispatchQueue.main.async {

                guard let unwrappedResponse = response as? HTTPURLResponse else {
                    completion(.failure(NetworkingError.badResponse))
                    return
                }

                print(unwrappedResponse.statusCode)

                switch unwrappedResponse.statusCode {

                case 200 ..< 300:
                    print("success")

                default:
                    print("failure")
                }

                if let unwrappedError = error {
                    completion(.failure(unwrappedError))
                    return
                }

                if let unwrappedData = data {

                    do {
                        let json = try JSONSerialization.jsonObject(with: unwrappedData, options: [])
                        print(json)

                        if let user = try? JSONDecoder().decode(User.self, from: unwrappedData) {
                            completion(.success(user))

                        } else {
                            let errorResponse = try JSONDecoder().decode(ErrorResponse.self, from: unwrappedData)
                            completion(.failure(errorResponse))
                        }

                    } catch {
                        completion(.failure(error))
                    }
                }
            }
        }

        task.resume()
    }

    func request(endpoint: String,
                 parameters: [String: Any],
                 completion: @escaping (Result<User, Error>) -> Void) {

        guard let url = URL(string: baseUrl + endpoint) else {
            completion(.failure(NetworkingError.badUrl))
            return
        }

        var request = URLRequest(url: url)

        var components = URLComponents()

        var queryItems = [URLQueryItem]()

        for (key, value) in parameters {

            let queryItem = URLQueryItem(name: key, value: String(describing: value))
            queryItems.append(queryItem)
        }

        components.queryItems = queryItems


        let queryItemData = components.query?.data(using: .utf8)

        request.httpBody = queryItemData
        request.httpMethod = "POST"
        request.addValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")

        handleResponse(for: request, completion: completion)
    }

    func request(endpoint: String,
                 loginObject: Login,
                 completion: @escaping (Result<User, Error>) -> Void) {

        guard let url = URL(string: baseUrl + endpoint) else {
            completion(.failure(NetworkingError.badUrl))
            return
        }

        var request = URLRequest(url: url)

        do {
            let loginData = try JSONEncoder().encode(loginObject)
            request.httpBody = loginData

        } catch {
            completion(.failure(NetworkingError.badEncoding))
        }

        request.httpMethod = "POST"
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")

        handleResponse(for: request, completion: completion)
    }


}

enum NetworkingError: Error {
    case badUrl
    case badResponse
    case badEncoding
}

结构如下：

import UIKit

struct User: Decodable {
    let id: Int
    let name: String
    let username: String
}

因为我正在使用mySQL数据库，所以我使用php脚本来生成从输入中获取参数的JSON。

这是JSON的样子：

[
    {
        "id": "3",
        "name": "KevinName",
        "username": "kName"
    }
]

状态码返回成功200，但没有数据加载到应用程序中，并且出现错误

  

由于格式不正确，无法读取数据

我相信它与创建JSON的PHP脚本有关

<?php


$con=mysqli_connect("localhost","username","password","db");

// Check connection
if (mysqli_connect_errno())
{
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// This SQL statement selects ALL from the table 'Equipment'

$username = $_POST['username'];
$password = $_POST['password'];

$sql = "SELECT id, driver_name, username FROM table1 WHERE (username = '$username') and password = '$password' ";


if ($result = mysqli_query($con, $sql))
{
    // Create temporary connection
    $resultArray = array();
    $tempArray = array();

    // Look through each row
    while($row = $result->fetch_object())
    {

        $tempArray = $row;
        array_push($resultArray, $tempArray);
    }


    echo json_encode($resultArray);
}

mysqli_close($con);



?>