/// <inheritdoc cref="IMqttClientConfigBuilder.WithAuthentication" />
public IMqttClientConfigBuilder WithAuthentication(string?method, byte[]?data)
{
_builder.WithAuthentication(method, data);
return(this);
}
public async Task ConnectAsync(Options options, TaskCompletionSource <int> closedPromise)
{
if (options.Verbose)
{
MqttNetGlobalLogger.LogMessagePublished += (s, e) =>
{
var trace = $">> [{e.LogMessage.Timestamp:O}] [{e.LogMessage.ThreadId}] [{e.LogMessage.Source}] [{e.LogMessage.Level}]: {e.LogMessage.Message}";
if (e.LogMessage.Exception != null)
{
trace += Environment.NewLine + e.LogMessage.Exception.ToString();
}
Console.WriteLine(trace);
};
}
var factory = new MqttFactory();
var client = factory.CreateMqttClient();
client.UseApplicationMessageReceivedHandler(msg => this.HandleMessageAsync(msg));
var tlsOptions = new MqttClientOptionsBuilderTlsParameters();
tlsOptions.UseTls = true;
var clientOptions = new MqttClientOptionsBuilder()
.WithTcpServer(opt => opt.NoDelay = true)
.WithClientId(options.ClientId)
.WithTcpServer(options.Hostname, 8883)
.WithTls(tlsOptions)
.WithProtocolVersion(MQTTnet.Formatter.MqttProtocolVersion.V500)
// .WithUserProperty("host", hostName) // normally it is not needed as SNI is added by most TLS implementations.
.WithUserProperty("api-version", "2020-10-01-preview")
.WithCommunicationTimeout(TimeSpan.FromSeconds(30))
.WithKeepAlivePeriod(TimeSpan.FromSeconds(300))
.WithCleanSession(false); // keep existing subscriptions
if (string.IsNullOrEmpty(options.SasKey))
{
tlsOptions.Certificates = new[] { new X509Certificate(options.ClientCertificatePath, options.ClientCertificatePassword) };
clientOptions.WithAuthentication("X509", null);
}
else
{
var at = DateTimeOffset.UtcNow;
var atString = at.ToUnixTimeMilliseconds().ToString();
var expiry = at.AddMinutes(40);
var expiryString = expiry.ToUnixTimeMilliseconds().ToString();
string toSign = $"{options.Hostname}\n{options.ClientId}\n{options.SasPolicy}\n{atString}\n{expiryString}\n";
var hmac = new HMACSHA256(Convert.FromBase64String(options.SasKey));
var sas = hmac.ComputeHash(Encoding.UTF8.GetBytes(toSign));
clientOptions
.WithAuthentication("SAS", sas)
.WithUserProperty("sas-at", atString)
.WithUserProperty("sas-expiry", expiryString);
if (!string.IsNullOrEmpty(options.SasPolicy))
{
// include only if using SAS policy
clientOptions.WithUserProperty("sas-policy", options.SasPolicy);
}
}
// Set up disconnection handling: print out details and allow process to close
client.UseDisconnectedHandler(disconnectArgs =>
{
Console.WriteLine($"Disconnected: {disconnectArgs.ReasonCode}");
if (disconnectArgs.AuthenticateResult?.UserProperties != null)
{
foreach (var prop in disconnectArgs.AuthenticateResult.UserProperties)
{
Console.WriteLine($"{prop.Name}: {prop.Value}");
}
}
closedPromise.SetResult(1);
});
try
{
// once connection is established, we may start receiving messages based on subscriptions
// from previous connections - better set client before connection.
this.client = client;
var connectResult = await client.ConnectAsync(clientOptions.Build(), CancellationToken.None);
if (connectResult.ResultCode != MqttClientConnectResultCode.Success)
{
var status = GetStatus(connectResult.UserProperties)?.ToString("x4");
throw new Exception($"Connect failed. Status: {connectResult.ResultCode}; status: {status}");
}
if (!connectResult.IsSessionPresent)
{
// only subscribe if haven't subscribed already.
// This optimization only works of a single SUBSCRIBE is used to subscribe to everything at once or
// if app keeps track of what has been successfully acknowledged by server.
var subscribeResult = await client.SubscribeAsync(
new MqttTopicFilter
{
Topic = "$iothub/methods/+",
QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce
},
new MqttTopicFilter
{
Topic = "$iothub/commands",
QualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce
},
new MqttTopicFilter
{
Topic = "$iothub/twin/patch/desired",
QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce
});
// make sure subscriptions were successful
if (subscribeResult.Items.Count != 3 ||
subscribeResult.Items[0].ResultCode != MqttClientSubscribeResultCode.GrantedQoS0 ||
subscribeResult.Items[1].ResultCode != MqttClientSubscribeResultCode.GrantedQoS1 ||
subscribeResult.Items[2].ResultCode != MqttClientSubscribeResultCode.GrantedQoS0)
{
throw new ApplicationException("Failed to subscribe");
}
}
}
catch (MqttConnectingFailedException ex)
{
Console.WriteLine($"Failed to connect, reason code: {ex.ResultCode}");
if (ex.Result?.UserProperties != null)
{
foreach (var prop in ex.Result.UserProperties)
{
Console.WriteLine($"{prop.Name}: {prop.Value}");
}
}
throw;
}
}
