Swift HTTP Post请求DataSingEncoding使字符串变形

Question

$username = $_POST['username'];
$password = $_POST['password'];
if (!empty($username) && !empty($password)) {
    $encrypted_password = md5($password);
    $user -> login($username,$encrypted_password);
} else {
    $json['error'] = 'You must fill all fields!';
    echo json_encode($json);
    mysqli_close($this->connection);
}

{"error":"You must fill all fields!"}

但是在iOS中，当我们对字符串进行编码时，它会将发送给php脚本的整个字符串转换为：

Optional(<75736572 6e616d65 3d612670 61737377 6f72643d 61>)

因为php脚本希望数据如下所示：

username=xyz&password=xyz

它当然不起作用。

SWIFT代码：

let username = UsernameTextField.text ?? ""
        let password = PasswordTextField.text ?? ""
        
        if(username.isEmpty || password.isEmpty) {return; }
        
        
        
        let request = NSMutableURLRequest (URL: NSURL(string: "http://myip/loginregister.php")!)
        request.HTTPMethod = "POST"
        request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField:"Content-Type")
        let postString = "username=\(username)&password=\(password)"
        request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)
        let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { data, response, error in
            guard error == nil && data != nil else {
                // check for fundamental networking error
                print("error=\(error)")
                return
            }
            
            let data = postString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
            
            
            do {
                if let json = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? NSDictionary {
                    let success = json["success"] as? Int                                 
                    print("Success: \(success)")
                } else {
                    let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)   
                    print("Error could not parse JSON: \(jsonStr)")
                }
            } catch let parseError {
                print(parseError)                                                      `JSONObjectWithData`
                let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
                print("Error could not parse JSON: '\(jsonStr)'")
            }
        }
        
        task.resume()

错误消息：

Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}
Error could not parse JSON: 'Optional(username=a&password=a)'

Answer 1

a）你扔掉服务器的答案...

b）熟悉调试器并检查PostString的内容；它从来都不是有效的JSON，因此不能期望转换成功。

c）不要把发送和接收部分混在一起，而是解决一个又一个问题。