URLConnection 没有完成获取 InputStream

Question

我创建到身份验证服务器 (OAuth 2.0) 的连接以获取令牌。执行此操作的方法如下：

public static async Task<String> GetToken(string username, string password)
        {
            String response = null;

            await Task.Run(() =>
            {
                URL url = new URL(Configuration.Configuration.baseURL + Configuration.Configuration.tokenPath);
                HttpURLConnection urlConnection = (HttpURLConnection)url.OpenConnection();
                urlConnection.DoOutput = true;
                urlConnection.DoInput = true;
                urlConnection.RequestMethod = "POST";
                urlConnection.SetRequestProperty("Content-Type", "application/x-www-form-urlencoded");

                var content = new FormUrlEncodedContent(new[]
                {
                    new KeyValuePair<string, string>("grant_type", "password"),
                    new KeyValuePair<string, string>("username", username),
                    new KeyValuePair<string, string>("password", password),
                    new KeyValuePair<string, string>("client_id", "widas_servicebar"),
                    new KeyValuePair<string, string>("scope", Configuration.Configuration.scopes)
                });

                //var content = new Dictionary<string, string>();
                //content.Add("grant_type", "password");
                //content.Add("username", username);
                //content.Add("password", password);
                //content.Add("client_id", "widas_servicebar");
                //content.Add("scope", Configuration.Configuration.scopes);

                using (var streamWriter = new StreamWriter(urlConnection.OutputStream))
                {
                    streamWriter.Write(content);
                    streamWriter.Flush();
                    streamWriter.Close();
                }

                urlConnection.Connect();
                var stream = urlConnection.InputStream;
                using (var streamReader = new StreamReader(stream))
                {
                    response = streamReader.ReadToEnd();                    
                    return response;
                }
            });
            return response;
        }

不幸的是，当我调试代码时，它总是卡在 var stream = urlConnection.InputStream; 并且从那里不再发生任何事情（我尝试等待 15 分钟并使用 Postman，请求在 200-500 毫秒内得到响应）。

我对其他一些方法使用了几乎相同的代码，这些方法也建立了与服务器（内容服务器）的连接并且这些方法正常工作。

我的代码中是否有任何错误或者输入流永远不会结束的原因是什么？

如果重要的话：我正在构建一个 Xamarin.Android 项目。

Answer 1

以防万一您不知道：有一个名为 Xamarin.Auth 的 Xamarin 组件可提供 OAuth 身份验证。您不必手动实施它：

Xamnarin.Forms教程：https://developer.xamarin.com/guides/xamarin-forms/web-services/authentication/oauth/

NuGet：https://www.nuget.org/packages/Xamarin.Auth/

Answer 2

我让它工作了。似乎我尝试使用的东西并没有像我想象的那样起作用。现在的工作代码如下所示：

public static async Task<String> GetToken(string username, string password)
        {
            String response = null;

            await Task.Run(() =>
            {
                URL url = new URL(Configuration.Configuration.baseURL + Configuration.Configuration.tokenPath);
                HttpURLConnection urlConnection = (HttpURLConnection)url.OpenConnection();
                urlConnection.DoOutput = true;
                urlConnection.DoInput = true;
                urlConnection.RequestMethod = "POST";
                urlConnection.SetRequestProperty("Content-Type", "application/x-www-form-urlencoded");                            

                var content = new Dictionary<string, string>();
                content.Add("grant_type", "password");
                content.Add("username", username);
                content.Add("password", password);
                content.Add("client_id", "widas_servicebar");
                content.Add("scope", Configuration.Configuration.scopes);

                Stream os = urlConnection.OutputStream;
                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
                writer.Write(getQuery(content));
                writer.Flush();
                writer.Close();
                os.Close();

                urlConnection.Connect();
                //var debug = urlConnection.ErrorStream;
                var stream = urlConnection.InputStream;

                using (var streamReader = new StreamReader(stream))
                {
                    response = streamReader.ReadToEnd();                    
                }
                return response;
            });
            return response;
        }

getQuery 方法如下所示：

private static String getQuery(Dictionary<string, string> dictionary)
        {
            StringBuilder result = new StringBuilder();
            bool first = true;

            foreach (KeyValuePair<string, string> entry in dictionary)
            {      
                if (first)
                {
                    first = false;
                }          
                result.Append(URLEncoder.Encode(entry.Key, "UTF-8"));
                result.Append("=");
                result.Append(URLEncoder.Encode(entry.Value, "UTF-8"));
                result.Append("&");
            }

            return result.ToString();
        }

URLConnection 没有完成获取 InputStream

URLConnection does not finish getting InputStream

android

httpurlconnection

oauth-2.0

xamarin