如何在Android上使用Xamarin启用NTLM和TLS 1.2？

Question

我正在使用Android上的Xamarin客户端应用程序，我需要TLS 1.2和NTLM。

到目前为止，我一直在使用常规System.Net.HttpClientHandler和它工作得很好 - 它看起来像这样：

new System.Net.Http.HttpClientHandler() 
     { 
      Credentials = credentials 
     }; 

但现在我有一个新的客户，我需要TLS 1.2。所以我做了针对Android的代码：

new Xamarin.Android.Net.AndroidClientHandler() 
     { 
      Credentials = credentials 
     }; 

与环境变量：

XA_HTTP_CLIENT_HANDLER_TYPE=Xamarin.Android.Net.AndroidClientHandler 

现在，这种AndroidClientHandler工作尽可能的证书去。但我也需要NTLM才能工作。对我来说，似乎AndroidClientHandler只支持Basic和Digest身份验证方案（请参阅Xamarin.Android.Net.AuthenticationScheme）。

我也尝试过使用ModernHttpClient，但在我看来，它使用Mono的方式与System.Net.Http.HttpClientHandler一样，所以TLS 1.2在那里也不起作用。

在我看来，这应该是一个很常见的情况，但我仍然无法在网上找到相关示例。我希望我只是错过了一些明显的东西。你们怎么解决这个问题？

Answer 1

我相信这将是有益的你读通过：

https://github.com/xamarin/xamarin-android/blob/0c3597869bc4493895e755bda8a26f778e4fe9e0/src/Mono.Android/Xamarin.Android.Net/AndroidClientHandler.cs#L40-L56

/// <para> 
/// The class supports pre-authentication of requests albeit in a slightly "manual" way. Namely, whenever a request to a server requiring authentication 
/// is made and no authentication credentials are provided in the <see cref="PreAuthenticationData"/> property (which is usually the case on the first 
/// request), the <see cref="RequestNeedsAuthorization"/> property will return <c>true</c> and the <see cref="RequestedAuthentication"/> property will 
/// contain all the authentication information gathered from the server. The application must then fill in the blanks (i.e. the credentials) and re-send 
/// the request configured to perform pre-authentication. The reason for this manual process is that the underlying Java HTTP client API supports only a 
/// single, VM-wide, authentication handler which cannot be configured to handle credentials for several requests. AndroidClientHandler, therefore, implements 
/// the authentication in managed .NET code. Message handler supports both Basic and Digest authentication. If an authentication scheme that's not supported 
/// by AndroidClientHandler is requested by the server, the application can provide its own authentication module (<see cref="AuthenticationData"/>, 
/// <see cref="PreAuthenticationData"/>) to handle the protocol authorization.</para> 
/// <para>AndroidClientHandler also supports requests to servers with "invalid" (e.g. self-signed) SSL certificates. Since this process is a bit convoluted using 
/// the Java APIs, AndroidClientHandler defines two ways to handle the situation. First, easier, is to store the necessary certificates (either CA or server certificates) 
/// in the <see cref="TrustedCerts"/> collection or, after deriving a custom class from AndroidClientHandler, by overriding one or more methods provided for this purpose 
/// (<see cref="ConfigureTrustManagerFactory"/>, <see cref="ConfigureKeyManagerFactory"/> and <see cref="ConfigureKeyStore"/>). The former method should be sufficient 
/// for most use cases, the latter allows the application to provide fully customized key store, trust manager and key manager, if needed. Note that the instance of 
/// AndroidClientHandler configured to accept an "invalid" certificate from the particular server will most likely fail to validate certificates from other servers (even 
/// if they use a certificate with a fully validated trust chain) unless you store the CA certificates from your Android system in <see cref="TrustedCerts"/> along with 
/// the self-signed certificate(s).</para> 

这基本上说：它支持Basic和Digest认证。如果服务器请求的AndroidClientHandler中不支持认证方案，则应用程序可以提供它自己的认证模块来处理协议授权。

然后，我们可以看到，RequestedAuthentication属性将列出的关于服务器：支持的每个方案

https://github.com/xamarin/xamarin-android/blob/0c3597869bc4493895e755bda8a26f778e4fe9e0/src/Mono.Android/Xamarin.Android.Net/AndroidClientHandler.cs#L116-L124

/// <summary> 
/// If the website requires authentication, this property will contain data about each scheme supported 
/// by the server after the response. Note that unauthorized request will return a valid response - you 
/// need to check the status code and and (re)configure AndroidClientHandler instance accordingly by providing 
/// both the credentials and the authentication scheme by setting the <see cref="PreAuthenticationData"/> 
/// property. If AndroidClientHandler is not able to detect the kind of authentication scheme it will store an 
/// instance of <see cref="AuthenticationData"/> with its <see cref="AuthenticationData.Scheme"/> property 
/// set to <c>AuthenticationScheme.Unsupported</c> and the application will be responsible for providing an 
/// instance of <see cref="IAndroidAuthenticationModule"/> which handles this kind of authorization scheme 
/// (<see cref="AuthenticationData.AuthModule"/> 
/// </summary> 

这就告诉我们，如果返回Unsupported作为我们AuthenticationScheme，然后我们需要提交我们自己的IAndroidAuthenticationModule来应对挑战。

这里是AuthenticationScheme的枚举：

https://github.com/xamarin/xamarin-android/blob/24f2aec113857b5c583e14959b9af08ad45b22b1/src/Mono.Android/Xamarin.Android.Net/AuthenticationScheme.cs

namespace Xamarin.Android.Net 
{ 
    /// <summary> 
    /// Authentication schemes supported by <see cref="AndroidClientHandler"/> 
    /// </summary> 
    public enum AuthenticationScheme 
    { 
     /// <summary> 
     /// Default value used in <see cref="AuthenticationData.Scheme"/> 
     /// </summary> 
     None, 

     /// <summary> 
     /// <see cref="AndroidClientHandler"/> doesn't support this scheme, the application must provide its own value. See <see cref="AuthenticationData.Scheme"/> 
     /// </summary> 
     Unsupported, 

     /// <summary> 
     /// The HTTP Basic authentication scheme 
     /// </summary> 
     Basic, 

     /// <summary> 
     /// The HTTP Digest authentication scheme 
     /// </summary> 
     Digest 
    } 
} 

因此，我们必须通过具体的实现扩展这个接口来实现自定义IAndroidAuthenticationModule：

https://github.com/xamarin/xamarin-android/blob/24f2aec113857b5c583e14959b9af08ad45b22b1/src/Mono.Android/Xamarin.Android.Net/IAndroidAuthenticationModule.cs

然后你会将该实现传递给AuthenticationData.AuthModule属性：

https://github.com/xamarin/xamarin-android/blob/24f2aec113857b5c583e14959b9af08ad45b22b1/src/Mono.Android/Xamarin.Android.Net/AuthenticationData.cs#L37

你会再传递到主客户端的PreAuthenticationData财产。

https://github.com/xamarin/xamarin-android/blob/0c3597869bc4493895e755bda8a26f778e4fe9e0/src/Mono.Android/Xamarin.Android.Net/AndroidClientHandler.cs#L113

我希望这有助于！