Dio (HttpClient) cannot set a self-signed trust certificate about dio

[AlexV525]

1. We no longer provide support to dio: <5.0.0.
2. Do some search: https://www.mongodb.com/docs/atlas/device-sdks/sdk/flutter/troubleshooting/#connect-to-app-services-using-android-7-or-older

[ac169]

1. We no longer provide support to .dio: <5.0.0
2. Do some search: https://www.mongodb.com/docs/atlas/device-sdks/sdk/flutter/troubleshooting/#connect-to-app-services-using-android-7-or-older

dio: ^5.0.0 was also tested and the problem remains! I have doubts that the signature algorithm for the certificate format does not support IP certificates, and the support is not perfect! But there is no documentation

According to the example, the following error is displayed:

DioException [unknown]: null
Error: HandshakeException: Handshake error in client (OS Error: 
	CERTIFICATE_VERIFY_FAILED: Hostname mismatch(../../third_party/boringssl/src/ssl/handshake.cc:393))

[ac169]

Previously, the IP certificate was deployed on the HTTP server, now replace the certificate with the domain name certificate! Create a new test code in the test directory.

dio.httpClientAdapter = IOHttpClientAdapter(
      createHttpClient: () {
        SecurityContext securityContext =
            SecurityContext(withTrustedRoots: true);
        **securityContext.setTrustedCertificates('assets/ca-cert.crt'); or
        securityContext.useCertificateChainBytes(File('assets/ca-cert.crt').readAsBytesSync());**
        final client = HttpClient(
          context: securityContext,
        );
        client.badCertificateCallback = (cert, host, port) => true;

        return client;
      },
    );

This code will work in a separate test file with setTrustedCertificates and useCertificateChainBytes Settings. But placing the code in the project indicates that the certificate file is not found

I/flutter ( 6689): Error: FileSystemException: Cannot open file, path = 'assets/ca-cert.crt' (OS Error: No such file or directory, errno = 2)

[ac169]

1. Dio (HttpClient) certificate authentication The support for IP certificate authentication is not perfect.

2. Using File('assets/ca.crt').readAsBytesSync() or await rootBundle.load("assets/ca.crt") in the Widget neither of these methods work properly FileSystemException: Cannot open file. But it works fine until the main function calls runApp(const App()), I don't know why!

3. In the main () function configuration HttpOverrides. The method of HttpOverrides.global = _HttpOverrides _HttpOverrides. createHttpClient will be multiple calls even if I just call the HTTP request at a time, Setting the certificate is also invalid, and this method is only suitable for ignoring the certificate globally.

The solution:
Adds a global variable, initialized before runApp(const App()).Use this global variable where http requests are required

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  var chainBytes = await rootBundle.load("assets/ca.crt");

  Global.dio.httpClientAdapter = IOHttpClientAdapter(
    createHttpClient: () {
      SecurityContext securityContext = SecurityContext(withTrustedRoots: true);
      securityContext.setTrustedCertificatesBytes(chainBytes.buffer.asUint8List());
      // securityContext.useCertificateChainBytes(chainBytes.buffer.asUint8List());
      final client = HttpClient(
        context: securityContext,
      );
      // client.badCertificateCallback = (cert, host, port) => true;

      return client;
    },
  );

  runApp(const BiliApp());
}

This may not be the best way but it's the one I can think of right now.