esl

Description

esl is a go library to connect to freeSWITCH via esl.

Installation

Installation can be done as usual:

$ go get github.com/vma/esl

How it works

esl.NewConnection create a new esl connection and take a ConnectionHandler interface which defines the callbacks to handle the esl events.

Example of use

This simple example originate a call, park it and start music on hold when it is answered. When the call is hanged up, we close the connection, which ends the con.HandleEvents() loop.

package main

import (
        "fmt"
        "log"

        "github.com/vma/esl"
)

type Handler struct {
        CallId  string
        BgJobId string
}

const (
        Caller = "+33184850000"
        Callee = "+33184850001"
)

func main() {
        handler := &Handler{}
        con, err := esl.NewConnection("127.0.0.1:8021", handler)
        if err != nil {
                log.Fatal("ERR connecting to freeswitch:", err)
        }
        con.HandleEvents()
}

func (h *Handler) OnConnect(con *esl.Connection) {
        con.SendRecv("event", "plain", "ALL")
        h.CallId, _ = con.Api("create_uuid")
        log.Println("call id:", h.CallId)
        h.BgJobId, _ = con.BgApi("originate", "{origination_uuid="+h.CallId+
                ",origination_caller_id_number="+Caller+"}sofia/gateway/provider/"+Callee, "&park()")
        log.Println("originate bg job id:", h.BgJobId)
}

func (h *Handler) OnDisconnect(con *esl.Connection, ev *esl.Event) {
        log.Println("esl disconnected:", ev)
}

func (h *Handler) OnClose(con *esl.Connection) {
        log.Println("esl connection closed")
}

func (h *Handler) OnEvent(con *esl.Connection, ev *esl.Event) {
        log.Printf("%s - event %s %s %s\n", ev.UId, ev.Name, ev.App, ev.AppData)
        fmt.Println(ev) // send to stderr as it is very verbose
        switch ev.Name {
        case esl.BACKGROUND_JOB:
                log.Printf("bg job result:%s\n", ev.GetTextBody())
        case esl.CHANNEL_ANSWER:
                log.Println("call answered, starting moh")
                con.Execute("playback", h.CallId, "local_stream://moh")
        case esl.CHANNEL_HANGUP:
                hupcause := ev.Get("Hangup-Cause")
                log.Printf("call terminated with cause %s", hupcause)
                con.Close()
        }
}

TODO

• add documentation
• add tests
• more usage examples