如何从Unity连接到数据库

Z时代
2024-01-10
分类：问答

我正在尝试通过Unity连接到MS SQL数据库。但是，当我尝试打开连接时，出现IOException：连接丢失。

我已经从Unity \ Editor \ Data \ Mono \ lib \ mono \

2.0导入了System.Data.dll。我正在使用以下代码：

 using UnityEngine;
 using System.Collections;
 using System.Data.Sql;
 using System.Data.SqlClient;
 public class SQL_Controller : MonoBehaviour {
     string conString = "Server=myaddress.com,port;" +
             "Database=databasename;" +
             "User ID=username;" +
             "Password=password;";
     public string GetStringFromSQL()
     {
         LoadConfig();
         string result = "";
         SqlConnection connection = new SqlConnection(conString);
         connection.Open();
         Debug.Log(connection.State);
         SqlCommand Command = connection.CreateCommand();
         Command.CommandText = "select * from Artykuly2";
         SqlDataReader ThisReader = Command.ExecuteReader();
         while (ThisReader.Read())
         {
             result = ThisReader.GetString(0);
         }
         ThisReader.Close();
         connection.Close();
         return result;
     }
 }

这是我得到的错误：

IOException: Connection lost
Mono.Data.Tds.Protocol.TdsComm.GetPhysicalPacketHeader ()
Mono.Data.Tds.Protocol.TdsComm.GetPhysicalPacket ()
Mono.Data.Tds.Protocol.TdsComm.GetByte ()
Mono.Data.Tds.Protocol.Tds.ProcessSubPacket ()
Mono.Data.Tds.Protocol.Tds.NextResult ()
Mono.Data.Tds.Protocol.Tds.SkipToEnd ()
Rethrow as TdsInternalException: Server closed the connection.
Mono.Data.Tds.Protocol.Tds.SkipToEnd ()
Mono.Data.Tds.Protocol.Tds70.Connect (Mono.Data.Tds.Protocol.TdsConnectionParameters connectionParameters)
Mono.Data.Tds.Protocol.Tds80.Connect (Mono.Data.Tds.Protocol.TdsConnectionParameters connectionParameters)

请忽略此方法的任何安全风险，我需要进行此测试，安全性将在稍后发布。感谢您的时间。

回答：

请忽略此方法的任何安全风险

不要这样做 。安全性是在安全保护之前还是之后都没有关系。您将结束重新编写整个代码的过程，因为在您的应用程序中进行了硬编码，可以

反编译和检索。现在以正确的方式进行连接，这样您就不必重新编写整个应用程序。

使用php，perl或您喜欢的任何语言在服务器上运行数据库命令，但这应该在服务器上完成。

在Unity中，使用WWW或UnityWebRequest类与该脚本进行通信，然后就可以从Unity向服务器发送和接收信息。有很多例子了那里。即使这样，您仍然需要实现自己的安全性，但这比您现在拥有的要好得多。

您还可以使用json接收多个数据。

下面是一个完整的例子这个统一维基。它显示了如何使用服务器端的php和客户端的Unity

+ C＃与Unity中的数据库进行交互。

：

用PDO添加分数 ：

<?php
        // Configuration
        $hostname = 'localhot';
        $username = 'yourusername';
        $password = 'yourpassword';
        $database = 'yourdatabase';
        $secretKey = "mySecretKey"; // Change this value to match the value stored in the client javascript below
        try {
            $dbh = new PDO('mysql:host='. $hostname .';dbname='. $database, $username, $password);
        } catch(PDOException $e) {
            echo '<h1>An error has ocurred.</h1><pre>', $e->getMessage() ,'</pre>';
        }
        $realHash = md5($_GET['name'] . $_GET['score'] . $secretKey); 
        if($realHash == $hash) { 
            $sth = $dbh->prepare('INSERT INTO scores VALUES (null, :name, :score)');
            try {
                $sth->execute($_GET);
            } catch(Exception $e) {
                echo '<h1>An error has ocurred.</h1><pre>', $e->getMessage() ,'</pre>';
            }
        } 
?>

使用PDO检索得分 ：

<?php
    // Configuration
    $hostname = 'localhost';
    $username = 'yourusername';
    $password = 'yourpassword';
    $database = 'yourdatabase';
    try {
        $dbh = new PDO('mysql:host='. $hostname .';dbname='. $database, $username, $password);
    } catch(PDOException $e) {
        echo '<h1>An error has occurred.</h1><pre>', $e->getMessage() ,'</pre>';
    }
    $sth = $dbh->query('SELECT * FROM scores ORDER BY score DESC LIMIT 5');
    $sth->setFetchMode(PDO::FETCH_ASSOC);
    $result = $sth->fetchAll();
    if(count($result) > 0) {
        foreach($result as $r) {
            echo $r['name'], "\t", $r['score'], "\n";
        }
    }
?>

在服务器上启用跨域策略 ：

该文件应命名为“ crossdomain.xml”，并放置在Web服务器的根目录中。Unity要求您要通过WWW请求访问的网站具有跨域策略。

<?xml version="1.0"?>
<cross-domain-policy>
<allow-access-from domain="*"/>
</cross-domain-policy>

：

来自Unity的客户端代码连接到服务器，与PDO交互，并根据调用的函数添加或检索分数。对该客户端代码进行了少许修改，以使用最新的Unity版本进行编译。

private string secretKey = "mySecretKey"; // Edit this value and make sure it's the same as the one stored on the server
public string addScoreURL = "http://localhost/unity_test/addscore.php?"; //be sure to add a ? to your url
public string highscoreURL = "http://localhost/unity_test/display.php";
//Text to display the result on
public Text statusText;
void Start()
{
    StartCoroutine(GetScores());
}
// remember to use StartCoroutine when calling this function!
IEnumerator PostScores(string name, int score)
{
    //This connects to a server side php script that will add the name and score to a MySQL DB.
    // Supply it with a string representing the players name and the players score.
    string hash = Md5Sum(name + score + secretKey);
    string post_url = addScoreURL + "name=" + WWW.EscapeURL(name) + "&score=" + score + "&hash=" + hash;
    // Post the URL to the site and create a download object to get the result.
    WWW hs_post = new WWW(post_url);
    yield return hs_post; // Wait until the download is done
    if (hs_post.error != null)
    {
        print("There was an error posting the high score: " + hs_post.error);
    }
}
// Get the scores from the MySQL DB to display in a GUIText.
// remember to use StartCoroutine when calling this function!
IEnumerator GetScores()
{
    statusText.text = "Loading Scores";
    WWW hs_get = new WWW(highscoreURL);
    yield return hs_get;
    if (hs_get.error != null)
    {
        print("There was an error getting the high score: " + hs_get.error);
    }
    else
    {
        statusText.text = hs_get.text; // this is a GUIText that will display the scores in game.
    }
}
public string Md5Sum(string strToEncrypt)
{
    System.Text.UTF8Encoding ue = new System.Text.UTF8Encoding();
    byte[] bytes = ue.GetBytes(strToEncrypt);
    // encrypt bytes
    System.Security.Cryptography.MD5CryptoServiceProvider md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
    byte[] hashBytes = md5.ComputeHash(bytes);
    // Convert the encrypted bytes back to a string (base 16)
    string hashString = "";
    for (int i = 0; i < hashBytes.Length; i++)
    {
        hashString += System.Convert.ToString(hashBytes[i], 16).PadLeft(2, '0');
    }
    return hashString.PadLeft(32, '0');
}