OpcLabs.MqttNet communication package
This communication package is based on MQTTnet and MQTTnet.Extensions.ManagedClient libraries by Christian Kratky. See MQTT communication packages for a summary of the communication package and the library. The library support Client and Server roles; the communication package only supports the Client role.
See Using communication packages for instructions on how to select the communication package, and configure it. The type name of the message channel object is: OpcLabs.MqttNet.ManagedMqttClientMessageChannel,OpcLabs.MqttNet .
URL string
If the URL scheme has "mqtt", "mqtts", "ssl" or "tcp" scheme, TCP protocol (possibly with SSL/TLS) will be used. In this case, the URL is parsed by the communication package and various pieces of information are extracted from it. The syntax is:
scheme:[//[username[:password]@]host[:port]][/clientId=clientId]
If the client credentials has not been specified in the configuration (see below), which is the default, the username and password from the URL are used. The port defaults to 1883 for "mqtt", "tcp" schemes, and to 8883 for "mqtts", "ssl" schemes.
The "mqtt" and "tcp" schemes are equivalent, and denote a use of TCP protocol without SSL/TLS. The "mqtts" and "ssl" schemes are equivalent, and denote a use of TCP protocol with SSL/TLS.
Using the clientId query parameter you can override the default clientId supplied by host software.
Examples:
mqtt://test.mosquitto.org mqtts://test.mosquitto.org
If the URL scheme has "ws" or "wss" scheme, WebSocket protocol (possibly with TLS, for "wss") will be used. In this case, the URL is passed onto the underlying library without further parsing.
Examples:
ws://test.mosquitto.org:8080/mqtt wss://test.mosquitto.org:8081/mqtt
If the scheme in the URL is not one of the schemes listed here, the message channel will still open, using the clientId and cleanSession flag provided by the host software, and all other parameters given by the configuration properties.
Configuration
The table below lists the available properties, their types, and descriptions. Most properties come from configurable options of the underlying library, so please refer to the its documentation for details (we could not find a comprehensive reference documentation for this library, that's why most descriptions are missing). Do not get scared by the number of configurable properties; the relevant ones can usually stay at their defaults, or usually overridden from the host software (as noted). We will emphasize specific properties if they are important.
| Property | Type | Description |
|---|---|---|
| ClientWaitTimeout | System.Int32 | Determines the maximum wait time for the client to open before publishing a message. In milliseconds. |
| ManagedMqttClientOptions | MQTTnet.Extensions.ManagedClient.ManagedMqttClientOptions | |
| ManagedMqttClientOptions.AutoReconnectDelay | System.TimeSpan | Default is 5 seconds. |
| ManagedMqttClientOptions.ClientOptions | MQTTnet.Client.Options.IMqttClientOptions | |
| ManagedMqttClientOptions.ConnectionCheckInterval | System.TimeSpan | Default is 1 second. |
| ManagedMqttClientOptions.MaxPendingMessages | System.Int32 | Default is 2^31-1. |
| ManagedMqttClientOptions.PendingMessagesOverflowStrategy | MQTTnet.Server.MqttPendingMessagesOverflowStrategy | Default is DropNewMessage. |
| ManagedMqttClientOptions.Storage | MQTTnet.Extensions.ManagedClient.IManagedMqttClientStorage | |
| MqttClientOptions | MQTTnet.Client.Options.MqttClientOptions | |
| MqttClientOptions.AuthenticationData | System.Byte[] | |
| MqttClientOptions.AuthenticationMethod | System.String | |
| MqttClientOptions.ChannelOptions | MQTTnet.Client.Options.IMqttClientChannelOptions | Default value is null. For known URL schemes, it gets overridden by a value determined during URL resolution. For "mqtt", "mqtts", "ssl", "tcp" schemes, value from the MqttClientTcpOptions property is used. For "ws", "wss" schemes, value from the MqttClientWebSocketOptions is used. |
| MqttClientOptions.CleanSession | System.Boolean | Always gets set to the value specified by the host software (do not use). |
| MqttClientOptions.ClientId | System.String | Default value is null. When null, gets overridden by the ClientId specified by the host software. For "mqtt", "mqtts", "ssl", "tcp" URL schemes, it can further be overridden by a "clientId" query parameter in the URL. |
| MqttClientOptions.Credentials | MQTTnet.Client.Options.IMqttClientCredentials | Default value is null. When null, for "mqtt", "mqtts", "ssl", "tcp" URL schemes, if the URL contains user-specific information, gets overridden by the credentials with user name and password from the URL. |
| MqttClientOptions.CommunicationTimeout | System.Timespan | Default is 10 seconds. |
| MqttClientOptions.ExtendedAuthenticationExchangeHandler | MQTTnet.Client.ExtendedAuthenticationExchange. |
|
| MqttClientOptions.KeepAlivePeriod | System.Timespan | Default is 15 seconds. |
| MqttClientOptions.KeepAliveSendInterval | System.Nullable<System.TimeSpan> | |
| MqttClientOptions.MaximumPacketSize | System.Nullable<System.UInt32> | |
| MqttClientOptions.ProtocolVersion | MQTTnet.Formatter.MqttProtocolVersion | Default is V311. |
| MqttClientOptions.ReceiveMaximum | System.Nullable<UInt16> | |
| MqttClientOptions.RequestProblemInformation | System.Nullable<System.Boolean> | |
| MqttClientOptions.RequestResponseInformation | System.Nullable<System.Boolean> | |
| MqttClientOptions.SessionExpiryInterval | System.Nullable<System.UInt32> | |
| MqttClientOptions.TopicAliasMaximum | System.Nullable<System.UInt16> | |
| MqttClientOptions.WillDelayInterval | System.Nullable<System.UInt16> | |
| MqttClientTcpOptions | MQTTnet.Client.Options.MqttClientTcpOptions | |
| MqttClientTcpOptions.AddressFamily | System.Net.Sockets.AddressFamily | Default is Unspecified. |
| MqttClientTcpOptions.BufferSize | System.Int32 | Default is 65536. |
| MqttClientTcpOptions.DualMode | System.Nullable<System.Boolean> | |
| MqttClientTcpOptions.NoDelay | System.Boolean | |
| MqttClientTcpOptions.Port | System.Nullable<System.Int32> | For "mqtt", "tcp" URL schemes, gets overridden by the value specified in the URL, or 1883 if not specified. For "mqtts", "ssl" URL schemes, gets overridden by the value specified in the URL, or 8883 if not specified. |
| MqttClientTcpOptions.Server | System.String | |
| MqttClientTcpOptions.TlsOptions | MQTTnet.Client.Options.MqttClientTlsOptions | For "mqtt", "tcp", "mqtts", "ssl" URL schemes, some sub-properties (described here) get overridden. |
| MqttClientTcpOptions.TlsOptions.AllowUntrustedCertificates | System.Boolean | |
| MqttClientTcpOptions.TlsOptions.Certificates | System.List<System.Security.Cryptography.X509Certificates. System.List<System.Byte[]> (.NET Standard) |
For "mqtts", "ssl" URL schemes, may get overridden by hosting software. |
| MqttClientTcpOptions.TlsOptions.CertificateValidationCallback | System.Func<System.Security.Cryptography.X509Certificates. |
For "mqtts", "ssl" URL schemes, may get overridden by hosting software. |
| MqttClientTcpOptions.TlsOptions.IgnoreCertificateChainErrors | System.Boolean | |
| MqttClientTcpOptions.TlsOptions.IgnoreCertificateRevocationErrors | System.Boolean | |
| MqttClientTcpOptions.TlsOptions.SslProtocol | System.Security.Authentication.SslProtocols | Default is Tls12. |
| MqttClientTcpOptions.TlsOptions.UseTls | System.Boolean | Gets set to false for "mqtt", "tcp" URL schemes, gets set to true for "mqtts", "ssl" URL scheme. |
| MqttClientWebSocketOptions | MQTTnet.Client.Options.MqttClientWebSocketOptions | |
| MqttClientWebSocketOptions.CookieContainer | System.Net.CookieContainer | |
| MqttClientWebSocketOptions.ProxyOptions | MQTTnet.Client.Options.MqttClientWebSocketProxyOptions | |
| MqttClientWebSocketOptions.RequestHeaders | System.Collections.Generic.IDictionary<System.String, System.String> | |
| MqttClientWebSocketOptions.SubProtocols | System.Collections.Generic.ICollection<System.String> | Default is { "mqtt" }. |
| MqttClientWebSocketOptions.TlsOptions | MQTTnet.Client.Options.MqttClientTlsOptions | For "ws", "wss" URL schemes, some sub-properties (described here) get overridden. |
| MqttClientWebSocketOptions.TlsOptions.AllowUntrustedCertificates | System.Boolean | |
| MqttClientWebSocketOptions.TlsOptions.Certificates | System.List<System.Security.Cryptography.X509Certificates. System.List<System.Byte[]> (.NET Standard) |
For "wss" URL scheme, may get overridden by hosting software. |
| MqttClientWebSocketOptions.TlsOptions.CertificateValidationCallback | System.Func<System.Security.Cryptography.X509Certificates. |
For "wss" URL scheme, may get overridden by hosting software. |
| MqttClientWebSocketOptions.TlsOptions.IgnoreCertificateChainErrors | System.Boolean | |
| MqttClientWebSocketOptions.TlsOptions.IgnoreCertificateRevocationErrors | System.Boolean | |
| MqttClientWebSocketOptions.TlsOptions.SslProtocol | System.Security.Authentication.SslProtocols | Default is Tls12. |
| MqttClientWebSocketOptions.TlsOptions.UseTls | System.Boolean | Gets set to false for "ws" URL scheme, gets set to true for "wss" URL scheme. |
| MqttClientWebSocketOptions.Uri | System.String | For "ws", "wss" URL schemes, gets overridden by the input URL string. |
