mqtt

package
v0.8.0 Latest Latest
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 Go to latest Published: May 3, 2024 License: MIT Imports: 9 Imported by: 0

Documentation

Overview

Package mqtt provides a simple MQTT client wrapper around the paho.mqtt lib.

Index

Constants

View Source 
const (
	MqttTcp  = "mqtt://"
	MqttsTcp = "mqtts://"
	Ws       = "ws://"
	Wss      = "wss://"
)

Variables

This section is empty.

Functions

This section is empty.

Types

type Broker 

type Broker struct {
	// contains filtered or unexported fields
}

Broker defines the properties ,which are needed to build the broker host and the TLS connection

func NewBrokerBuilder 

func NewBrokerBuilder() *Broker

NewBrokerBuilder configures the connection parameters like:

  • Host, port, protocol
  • TLS connection

func (*Broker) Build 

func (b *Broker) Build() Option

Build should be called, when all configuration is done. It creates an Option type, which is used in NewClient function.

func (*Broker) WithHost 

func (b *Broker) WithHost(host string) *Broker

WithHost defines the host of the broker. Can be either a DNS or an IP.

func (*Broker) WithPort 

func (b *Broker) WithPort(port int) *Broker

WithPort defines the port of the broker to connect to.

func (*Broker) WithProtocol 

func (b *Broker) WithProtocol(protocol protocol) *Broker

WithProtocol defines the protocol to use. There are these two options:

  • tcp (normal - mqtt:// or secured - mqtts://)
  • websocket (normal - ws:// or secured - wss://)

Provides an autocorrection, when WithTlsCertificates is set.

func (*Broker) WithSkipVerification 

func (b *Broker) WithSkipVerification() *Broker

WithSkipVerification the client will skip validating the cert chain and the hostname 

see: [crypto/tls.Config.skipVerification]

func (*Broker) WithTlsCertificates 

func (b *Broker) WithTlsCertificates(caPemPath, clientCrtPath, clientKeyPath string) *Broker

WithTlsCertificates uses TLS and certificate auth for the connection.

  • caPemPath points to the MQTT servers root CA
  • clientCrtPath points to the public cert of the client
  • clientKeyPath points to the private key of the client

If either clientCrtPath or clientKeyPath is an empty string, nothing will be changed.

func (*Broker) WithUsernameAndPassword 

func (b *Broker) WithUsernameAndPassword(username, password string) *Broker

WithUsernameAndPassword defines the username and password, if the broker requires authentication.

type Client 

type Client struct {
	// contains filtered or unexported fields
}

Client struct, which holds the client itself and the options for it.

func CreateClient deprecated 

func CreateClient(ip string, port int, clientId string) *Client

Deprecated: Use "NewClient" instead of this. Will be removed in future version.

func NewClient 

func NewClient(options ...Option) *Client

NewClient Creates a new MQTT client with default configuration. To override the configuration, use the predefined options ("withBroker", "withClientId" and "withOrderMatters") or customize them by providing the Option type as parameter.

func (*Client) Connect 

func (c *Client) Connect() error

Connect connects to the mqtt broker. Return an error, if something went wrong.

func (*Client) Disconnect 

func (c *Client) Disconnect() error

Disconnect does a clean disconnect from the mqtt broker.

func (*Client) LoopForever 

func (c *Client) LoopForever()

LoopForever Halts the current thread.

func (*Client) Publish 

func (c *Client) Publish(message *Message)

Publish sends the give message to the mqtt broker. It uses QOS 2 and waits until arrival confirmation.

func (*Client) Subscribe 

func (c *Client) Subscribe(topic string, fn func(message Message))

Subscribe subscribes to a topic and execute a function on message arrival. Returns an error, if the client is not connected to a mqtt broker.

type Message 

type Message struct {
	Topic string
	Value any
}

Message defines the default message which is received and sent by the mqtt client. Here are two fields:

  • Topic: The topic to which the message should be sent
  • Value: Any struct or type (simple string or a complex type)

func (Message) FromJson 

func (m Message) FromJson() string

FromJson converts a JSON struct to a string.

func (Message) ToRawString 

func (m Message) ToRawString() string

ToRawString converts the received JSON string to an ordinary string

func (Message) ToStruct 

func (m Message) ToStruct(target any)

ToStruct converts the received JSON message to the given target struct

type Option 

type Option func(options *pahoMqtt.ClientOptions)

Option defines the function which overrides the default options of the mqtt client.

func WithBroker 

func WithBroker(ip string, port int) Option

WithBroker defines the host and port of the mqtt broker. (default port usually is 1883)

func WithClientId 

func WithClientId(clientId string) Option

WithClientId defines the client name which will be registered on the broker.

func WithOrderMatters 

func WithOrderMatters(orderMatters bool) Option

WithOrderMatters defines if the order of publish and subscribed message is respected. -> it indicates that messages can be delivered asynchronously from the client to the application and possibly arrive out of order. See pahoMqtt.ClientOptions.Order and the "SetOrderMatters" function.

type StatusPublishMessage 

type StatusPublishMessage struct {
	Type      StatusType `json:"type" binding:"required"`
	Status    string     `json:"status"`
	Timestamp time.Time  `json:"timestamp"`
}

StatusPublishMessage defines a possible message to represent a "health message"

type StatusType 

type StatusType string

StatusType can be used for a basic status message (like a "health message") with 

const (
	Info  StatusType = "info"
	Error StatusType = "error"
	Warn  StatusType = "warn"
)

Default StatusType constants.

Source Files

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