Flutter https with self signed certificate

Question

I am using flutter to connect with java java server implementation over https. I first tested it to be working using just http.

I then switched to https on the server side and pointed it at my self signed certificate I created using keytool.

Then I tried to connect to it using the http dart package. The resulted in the following exception...

Unhandled Exception: HandshakeException: Handshake error in client (OS Error: E/flutter ( 7370): CERTIFICATE_VERIFY_FAILED: self signed certificate(handshake.cc:354))

I am assuming I need to set my client to trust my servers self signed certificate. I have looked at the APi reference and could not figure out how to get this to happen...

My dart code in my flutter app is as follows...

void testMessage() {
    var url = 'https://192.168.100.105:8443';
    var response = await http.post(url, body: "{\"message_name\": \"TestMessage\", \"contents\": { \"field1\":\"blah\", \"field2\":\"blah\" }}");
    print('Response status: ${response.statusCode}');
    print('Response body: ${response.body}');
}

Solution 1

While Pascal's answer works, it only applies to the dart:io HttpClient. To apply the badCertificateCallback to the http package's Client instances, do the following:

Create a class that overrides HttpOverrides in the following way:

class DevHttpOverrides extends HttpOverrides {
  @override
  HttpClient createHttpClient(SecurityContext context) {
    return super.createHttpClient(context)
      ..badCertificateCallback = (X509Certificate cert, String host, int port) => true;
  }
}

Then in your main, instantiate your class as the global HttpOverride:

HttpOverrides.global = new DevHttpOverrides();

This should make all Client ignore bad certificates and is therefore onl;y recommended in development. Credit goes to this issue: https://github.com/dart-lang/http/issues/458

Solution 2

While developing you can use the badCertificateCallback callback of HttpClient and just return true. This will accept all bad certificates.

  HttpClient client = HttpClient()
    ..badCertificateCallback = ((X509Certificate cert, String host, int port) => true);

To accept a specific bad certificate you may experiment with this code from here: https://github.com/dart-lang/http/issues/14#issuecomment-311184690

import 'dart:io';
import 'package:http/http.dart' as http;

bool _certificateCheck(X509Certificate cert, String host, int port) =>
    host == 'local.domain.ext'; // <- change

HttpClient client = new HttpClient()
    ..badCertificateCallback = (_certificateCheck);