eventListenerBohongan.go

package main
import (
    "fmt"
    "net/http"
)

type EventMessage struct {
    Event string
    Message interface{}
}

type Listener func(message interface{})

func screamListener1(message interface{}) {
    fmt.Println("[scream listener 1]", message)
}

func screamListener2(message interface{}) {
    fmt.Println("[scream listener 2]", message)
}

func main() {
    channel := make(chan EventMessage)
    eventListeners := make(map[string][]Listener)

    // register event listeners
    eventListeners["scream"] = []Listener{
        screamListener1, screamListener2,
    }

    // catch event and trigger corresponding listener
    go func() {
        for {
            fmt.Println("Receive messages")
            eventMessage := <-channel
            fmt.Println("Message received")
            event, message := eventMessage.Event, eventMessage.Message
            listeners := eventListeners[event]
            for _, listener := range listeners {
                listener(message)
            }
        }
    }()

    // emit event `scream Argh`
    fmt.Println("Send messages Argh")
    channel <- EventMessage{"scream", "Argh"}

    // emit event `scream Hi`
    fmt.Println("Send messages Hi")
    channel <- EventMessage{"scream", "Hi"}

    // create HTTP handler (i.e: our API Gateway)
    handler := http.HandlerFunc(func (writer http.ResponseWriter, request *http.Request) {
        fmt.Fprintf(writer, "hello, you've hit %s\n", request.URL.Path)
        // emit event `scream whatever the url path is`
        fmt.Println("Send messages", request.URL.Path)
        channel <- EventMessage{"scream", request.URL.Path}
    })

    // serve HTTP server
    http.ListenAndServe(":9999", handler)

}