Maui中的Android使用https时信任所有证书

前言

最近使用Maui+blazor写了一个Android app，需要调用webapi接口，同时需要用websock与服务器通信，在使用http和https中遇到一些问题

http

Android默认禁止http,想要使用http需要在Platforms\Android目录下找到AndroidManifest.xml文件，然后在application节点中添加android:UsesCleartextTraffic="true" 如图

或者在MainApplication类中的Application特性中添加UsesCleartextTraffic = true

    [Application(UsesCleartextTraffic =true)]
    public class MainApplication : MauiApplication
    {
        public MainApplication(IntPtr handle, JniHandleOwnership ownership)
            : base(handle, ownership)
        {
        }

        protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();

    }

https

使用https时因为需要证书，目前没有证书，就在iis中创建了个自签名证书（webapi发布到了iis),这时想要调用api接口需要信任证书，官网上给的解决方案如下

    public class HttpsClientHandlerService
    {
        public HttpMessageHandler GetPlatformMessageHandler()
        {
#if ANDROID
            var handler = new Xamarin.Android.Net.AndroidMessageHandler
            {
                ServerCertificateCustomValidationCallback = (message, cert, chain, errors) =>
            {
                if (cert != null && cert.Issuer.Equals("CN=LAPTOP-CL5H1EIT"))
                    return true;
                return errors == System.Net.Security.SslPolicyErrors.None;
            }
            };
            return handler;
#elif IOS
        var handler = new NSUrlSessionHandler
        {
            TrustOverrideForUrl = IsHttpsLocalhost
        };
        return handler;
#else
            throw new PlatformNotSupportedException("Only Android and iOS supported.");
#endif
        }

#if IOS
    public bool IsHttpsLocalhost(NSUrlSessionHandler sender, string url, Security.SecTrust trust)
    {
        return url.StartsWith("https://localhost");
    }
#endif
    }

     builder.Services.AddScoped(sp => new HttpClient(new HttpsClientHandlerService().GetPlatformMessageHandler()) { BaseAddress = new Uri("https://192.168.6.13") });

先在一个类中创建一个反回httpmessagehandle
的方法，在实例化httpclient时传入，这时在请求接口时cert参数会获取证书的信息，这里做了一下判断，也可以直接返回true

websocket

在websocket使用wss请求连接如下

ClientWebSocket webSocket = new ClientWebSocket();

        webSocket.Options.RemoteCertificateValidationCallback = (message,cain,cailn,error) => true;
        await webSocket.ConnectAsync(new Uri("wss://192.168.6.13/pumpsys/Websocket/GetWebsocketConnection"), disposalTokenSource.Token);
        await SendMessageAsync();
        await ReceiveLoop();

和使用httpclient调用接口差不多，在option中有个remotecertificatevalidationcallback的委托，
他在请求连接时也会返回证书信息在cain参数中