如何从Http响应中提取GET值？

Question

我在桌面应用程序中嵌入了一个http服务器，用于捕获来自OAuth2重定向的响应。下面的方法拾取消息并将其转换为字符串：

private void ReceiveCallback(IAsyncResult ar)
{
    var client = (Socket)ar.AsyncState;
    var size = client.EndReceive(ar);
    var received = new byte[size];

    Array.Copy(Buffer, received, size);
    var data = Encoding.ASCII.GetString(received);

    OnCallback(data);
}

onCallback方法是一个将数据传递给另一个类的事件。成功进行身份验证调用后,数据内容如下所示：

var response = new HttpResponseMessage();
response.Content = new StringContent(message);

Answer 1

class Program
{
    public static void Main()
    {
        string input = "GET /?code=CODE_I_NEED_APPEARS_HERE& HTTP/1.1 Host: localhost:8321 Connection: keep-alive Cache-Control: max-age=0 Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8 Accept-Encoding: gzip, deflate, br Accept-Language: en-US,en;q=0.9";
        string output = GetCode(input);
        Console.WriteLine(output);
        Console.ReadLine();
    }

    private static readonly Regex Pattern = new Regex(@"code=([^&\s]+)", RegexOptions.Compiled);

    public static string GetCode(string input)
    {
        var value = Pattern.Match(input);
        return value.Groups[1].Value;
    }
}

输出应该是代码参数的值