Intercept messages from published

[darlandieterich]

How intercept messages from published?

My init code:

package main

import (
	"context"
	"net"
	"os"
	"os/signal"
	"syscall"
	"log"
	"github.com/DrmagicE/gmqtt"
)
func main() {
	// listener
	ln, err := net.Listen("tcp", ":1883")
	if err != nil {
		log.Fatalln(err.Error())
		return
	}

	s := gmqtt.NewServer(
		gmqtt.WithTCPListener(ln),
	)

	s.Run()
	signalCh := make(chan os.Signal, 1)
	signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM)
	<-signalCh
	s.Stop(context.Background())
}

[DrmagicE]

You can either use the OnMsgArrived hook or implement a plugin.Here is some examples:

1. Using hook: https://github.com/DrmagicE/gmqtt/blob/v0.1.3/examples/hook/main.go#L76
2. Using plugin: Modify message before delivering to client #24 (comment)

[darlandieterich]

Hi!
Ok, then, how intercept the message in string?

OnMsgArrived: func(ctx context.Context, client gmqtt.Client, msg packets.Message) (valid bool) {
        fmt.Println(msg) ///&{false 0 false /test/hello 0 [116 101 115 116 97 110 100 111 111 111 32 111 117 116 114 111 32 118 97 108 111 114 32 49 52 58 48 57 58 52 57 40 53 57 57 41]}
	fmt.Println("Topic", msg.Topic)
	fmt.Println("Payload", msg.Payload)

	//Only qos1 & qos0 are acceptable(will be delivered)
	if msg.Qos() == packets.QOS_2 {
		return false
	}
	return true
},

tnks

[DrmagicE]

fmt.Println("Payload", string(msg.Payload))

[darlandieterich]

well, I tried this before, but show error on compile:
cannot convert msg.Payload (type func() []byte) to type string

[DrmagicE]

Oh, my fault.. Payload is a function .Try fmt.Println("Payload", string(msg.Payload())) @darlandieterich

[darlandieterich]

now this run so charm 👍