flutter web和移动设备中基于MQTT证书的身份验证

Question

我正试图在Flutter项目中使用MQTT来测试原型。我正在使用自定义的基于证书的身份验证。

我使用的是mqtt_client包。连接之前SecurityContext在web中给出此错误不支持的操作：默认SecurityContext getter

下面是我的样本代码

try {
SecurityContext securityContext =
SecurityContext(withTrustedRoots: false);
securityContext.setTrustedCertificatesBytes(caCertificate);
securityContext.useCertificateChainBytes(caCertificate);
securityContext.setClientAuthoritiesBytes(clientCertificate,
password: String.fromCharCodes(privateKey));
} catch (e) {
print(e);
}
_client = MqttClient('m.test.com', _identifier);
_client.port = 8883;
_client.keepAlivePeriod = 20;
_client.onDisconnected = onDisconnected;
_client.secure = true;
//_client.securityContext = securityContext;
_client.onBadCertificate = ((X509Certificate cert) => false);
_client.logging(on: true);```

Answer 1

这对我很有效，但我不明白(动态a(在做什么。。。也许有人可以更详细地解释一下？

void initializeMQTTClient() async {
_client = MqttServerClient(_host, _identifier);
_client.port = 8883; //1883
_client.keepAlivePeriod = 20;
_client.onDisconnected = onDisconnected;
_client.secure = true; // false
_client.logging(on: true);
_client.securityContext = SecurityContext.defaultContext;
// _client.useWebSocket = false;
/// Add the successful connection callback
_client.onConnected = onConnected;
_client.onSubscribed = onSubscribed;
_client.onBadCertificate = (dynamic a) => true;