freeswitch笔记(3)-esl入门

题外话:昨天是2020年元宵节,正值"新型肺炎"第二阶段防治关键时期,返沪后按规定自觉在家隔离14天,不出去给社会添乱,真心希望这次疫情快点过去。

 

废话不多说,继续学习,上篇借助工具大致体验了voip client的使用,这篇学习如何用代码来实现类似的功能。esl全称Event Socket Library, 通过它可以与freeswitch进行交互,esl client支持多种语言,本文将以esl java client为例,演示一些基本用法:

 

一、两种模式:inbound、outbound

freeswitch(以下简单fs)启动后,内置了一个tcp server,默认会监听8021端口,通过esl,java 应用可以监听该端口,获取fs的各种事件通知,这种模式称为inbound模式。

如上图,inbound模式下:java应用引用esl java client的jar包后(注:esl java client底层是依赖netty实现的),连接到fs(fs内置了mod_event_socket模块,会在本地默认监听2081端口),连接成功后,如果有来电,fs会触发各种事件,透过已经连上的通道,通知java应用,java应用可以针对特定事件做些处理(有必要的话,还可以发送命令给fs),当然连接成功后,java应用也可以直接向fs发送命令,比如对外呼叫某个号码。

 

如果反过来,java应用起1个端口,自己充当tcp server,fs连接java应用,就称为outbound模式,如下图:

java应用利用esl java client在本机监听某个端口,相当于启动了一个tcp server(底层仍然是基于nettty实现),当fs收到来电时,会连接java应用的tcp server(注:需要修改fs的配置,否则fs不知道tcp server的ip\port这些连接信息),然后java应用可以根据自身业务做些处理,发送命令给fs(比如:给客人放段音乐或转接到特定目标),通话结束后(比如:主叫方挂断,或被叫方拒接),fs会断开连接,直到下次再有来电。

 

tips:inbound/outbound 是站在fs的角度来看的,外部应用连进来,就是inbound;fs连出去,就是outbound。 二种模式基本上都可以完成大多数业务功能,如何选取看各自特点,比如:如果要监控所有来电情况或实现客人自助语音服务,inbound相对更方便(可以很轻松获取所有事件)。对于来电后的人工客服分配,outbound则更简单(比如:客人来电拨打某个对外暴露公用客服号码比如400电话时,fs把客人来电通过tcp connect最终给到java app,java应用按一定分配规则 ,比如哪个客服最空闲,把来电bridge到该客服分机即可)

 

二、inbound 代码示例

2.1 pom依赖

<dependency>
    <groupId>org.freeswitch.esl.client</groupId>
    <artifactId>org.freeswitch.esl.client</artifactId>
    <version>0.9.2</version>
</dependency>

2.2 演示代码

下面的代码,演示了连接到fs后,利用client直接发起外呼。

package com.cnblogs.yjmyzz.freeswitch.esl;

import org.freeswitch.esl.client.IEslEventListener;
import org.freeswitch.esl.client.inbound.Client;
import org.freeswitch.esl.client.inbound.InboundConnectionFailure;
import org.freeswitch.esl.client.transport.event.EslEvent;

/**
 * @author 菩提树下的杨过
 */
public class InboundApp {


    public static void main(String[] args) throws InterruptedException {
        Client client = new Client();
        try {
            //连接freeswitch
            client.connect("localhost", 8021, "ClueCon", 10);

            client.addEventListener(new IEslEventListener() {

                @Override
                public void eventReceived(EslEvent event) {
                    String eventName = event.getEventName();
                    //这里仅演示了CHANNEL_开头的几个常用事件
                    if (eventName.startsWith("CHANNEL_")) {
                        String calleeNumber = event.getEventHeaders().get("Caller-Callee-ID-Number");
                        String callerNumber = event.getEventHeaders().get("Caller-Caller-ID-Number");
                        switch (eventName) {
                            case "CHANNEL_CREATE":
                                System.out.println("发起呼叫, 主叫:" + callerNumber + " , 被叫:" + calleeNumber);
                                break;
                            case "CHANNEL_BRIDGE":
                                System.out.println("用户转接, 主叫:" + callerNumber + " , 被叫:" + calleeNumber);
                                break;
                            case "CHANNEL_ANSWER":
                                System.out.println("用户应答, 主叫:" + callerNumber + " , 被叫:" + calleeNumber);
                                break;
                            case "CHANNEL_HANGUP":
                                String response = event.getEventHeaders().get("variable_current_application_response");
                                String hangupCause = event.getEventHeaders().get("Hangup-Cause");
                                System.out.println("用户挂断, 主叫:" + callerNumber + " , 被叫:" + calleeNumber + " , response:" + response + " ,hangup cause:" + hangupCause);
                                break;
                            default:
                                break;
                        }
                    }
                }

                @Override
                public void backgroundJobResultReceived(EslEvent event) {
                    String jobUuid = event.getEventHeaders().get("Job-UUID");
                    System.out.println("异步回调:" + jobUuid);
                }
            });

            client.setEventSubscriptions("plain", "all");

            //这里必须检查,防止网络抖动时,连接断开
            if (client.canSend()) {
                System.out.println("连接成功,准备发起呼叫...");
                //(异步)向1000用户发起呼叫,用户接通后,播放音乐/tmp/demo1.wav
                String callResult = client.sendAsyncApiCommand("originate", "user/1000 &playback(/tmp/demo.wav)");
                System.out.println("api uuid:" + callResult);
            }

        } catch (InboundConnectionFailure inboundConnectionFailure) {
            System.out.println("连接失败!");
            inboundConnectionFailure.printStackTrace();
        }
        
    }
}

参考输出结果类似如下:

连接成功,准备发起呼叫...
api uuid:54ae7272-62c1-4d1f-87a1-aab2080538dc
发起呼叫, 主叫:0000000000 , 被叫:1000
用户应答, 主叫:0000000000 , 被叫:1000
异步回调:54ae7272-62c1-4d1f-87a1-aab2080538dc
用户挂断, 主叫:1000 , 被叫:0000000000 , response:null ,hangup cause:NORMAL_CLEARING

代码稍微解释一下:

a) 18行,连接fs的用户名、密码、端口,可以在freeswitch安装目录下的conf/autoload_configs/event_socket.conf.xml 找到

 1 <configuration name="event_socket.conf" description="Socket Client">
 2   <settings>
 3     <param name="nat-map" value="false"/>
 4     <param name="listen-ip" value="0.0.0.0"/>
 5     <param name="listen-port" value="8021"/>
 6     <param name="password" value="ClueCon"/>
 7     <!--<param name="apply-inbound-acl" value="loopback.auto"/>-->
 8     <!--<param name="stop-on-bind-error" value="true"/>-->
 9   </settings>
10 </configuration>
View Code

强烈建议,把第4行listen-ip改成0.0.0.0(或具体的本机ip地址),默认的::是ipv6格式,很多情况会导致esl client连接失败,改成0.0.0.0相当于强制使用ipv4

b) 考虑到网络可能发生抖动,在发送命令前,建议参考60行的做法,先判断canSend()

c) 61行,client.sendAsyncApiCommand 这里以异步方式,发送了一个命令给fs(即:呼叫1000用户,接通后再放段声音)。异步方式下,命令是否发成功当时并不知道,但是这个方法会返回一个uuid的字符串,fs收到后,会在backgroundJobResultReceived回调中,把这个uuid再还回来,参见上面贴出的输出结果。(基于这个机制,可以做些重试处理,比如:先把uuid存下来,如果约定的时间内,uuid异步回调还没回来,可以视为发送失败,再发一次)

 

重要提示:esl java client 0.9.2这个版本,inbound模式下,长时间使用有内存泄露问题,网上有很多这个介绍及修复办法,建议生产环境使用前,先修改esl client的源码。

 

三、outbound示例

3.1 修改dialplan配置

出于演示目的,这里修改/usr/local/freeswitch/conf/dialplan/default.xml,在文件开头部分添加一段:

<extension name="socket_400_example">
      <condition field="destination_number" expression="^400\d+$">
            <action application="socket" data="localhost:8086 async full"/>
      </condition>
</extension>

即:当来电的被叫号码为400开头时,fs将利用socket,连接到localhost:8086

3.2 编写业务逻辑

a) SampleOutboundHandler
package com.cnblogs.yjmyzz.freeswitch.esl.outbound;

import org.freeswitch.esl.client.outbound.AbstractOutboundClientHandler;
import org.freeswitch.esl.client.transport.SendMsg;
import org.freeswitch.esl.client.transport.event.EslEvent;
import org.freeswitch.esl.client.transport.message.EslHeaders;
import org.freeswitch.esl.client.transport.message.EslMessage;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;

import java.util.ArrayList;
import java.util.List;

/**
 * @author 菩提树下的杨过
 */
public class SampleOutboundHandler extends AbstractOutboundClientHandler {

    @Override
    protected void handleConnectResponse(ChannelHandlerContext ctx, EslEvent event) {
        System.out.println("Received connect response :" + event);
        if (event.getEventName().equalsIgnoreCase("CHANNEL_DATA")) {
            // this is the response to the initial connect
            System.out.println("=======================  incoming channel data  =============================");
            System.out.println("Event-Date-Local: " + event.getEventDateLocal());
            System.out.println("Unique-ID: " + event.getEventHeaders().get("Unique-ID"));
            System.out.println("Channel-ANI: " + event.getEventHeaders().get("Channel-ANI"));
            System.out.println("Answer-State: " + event.getEventHeaders().get("Answer-State"));
            System.out.println("Caller-Destination-Number: " + event.getEventHeaders().get("Caller-Destination-Number"));
            System.out.println("=======================  = = = = = = = = = = =  =============================");

            // now bridge the call
            bridgeCall(ctx.getChannel(), event);


        } else {
            throw new IllegalStateException("Unexpected event after connect: [" + event.getEventName() + ']');
        }
    }

    private void bridgeCall(Channel channel, EslEvent event) {
        List<String> extNums = new ArrayList<>(2);
        extNums.add("1000");
        extNums.add("1010");
        //随机找1个目标(注:这里只是演示目的,真正分配时,应该考虑到客服的忙闲情况,通常应该分给最空闲的客服)
        String destNumber = extNums.get((int)Math.abs(System.currentTimeMillis() % 2));

        SendMsg bridgeMsg = new SendMsg();
        bridgeMsg.addCallCommand("execute");
        bridgeMsg.addExecuteAppName("bridge");
        bridgeMsg.addExecuteAppArg("user/" + destNumber);

        //同步发送bridge命令接通
        EslMessage response = sendSyncMultiLineCommand(channel, bridgeMsg.getMsgLines());
        if (response.getHeaderValue(EslHeaders.Name.REPLY_TEXT).startsWith("+OK")) {
            String originCall = event.getEventHeaders().get("Caller-Destination-Number");
            System.out.println(originCall + " bridge to " + destNumber + " successful");
        } else {
            System.out.println("Call bridge failed: " + response.getHeaderValue(EslHeaders.Name.REPLY_TEXT));
        }
    }

    @Override
    protected void handleEslEvent(ChannelHandlerContext ctx, EslEvent event) {
        System.out.println("received event:" + event);
    }

    @Override
    protected void handleDisconnectionNotice() {
        super.handleDisconnectionNotice();
        System.out.println("Received disconnection notice");
    }
}

重点看下bridgeCall这个方法,假设有2个客服号码1000、1010可用,随机挑1个,然后将来电接通到这个号码。

b) AbstractOutboundPipelineFactory
package com.cnblogs.yjmyzz.freeswitch.esl.outbound;

import org.freeswitch.esl.client.outbound.AbstractOutboundClientHandler;
import org.freeswitch.esl.client.outbound.AbstractOutboundPipelineFactory;

/**
 * @author 菩提树下的杨过
 */
public class SamplePipelineFactory extends AbstractOutboundPipelineFactory {

    @Override
    protected AbstractOutboundClientHandler makeHandler() {
        return new SampleOutboundHandler();
    }
}

还需要一个工厂类,包装一下。

c)OutboundApp 程序入口
package com.cnblogs.yjmyzz.freeswitch.esl.outbound;

import org.freeswitch.esl.client.outbound.SocketClient;

/**
 * @author 菩提树下的杨过
 */
public class OutboundApp {

    public static void main(String[] args) throws InterruptedException {

        new Thread(() -> {
            SocketClient socketClient = new SocketClient(8086, new SamplePipelineFactory());
            socketClient.start();
        }).start();

        while (true) {
            Thread.sleep(500);
        }
    }

}  

输出结果:

Received connect response :EslEvent: name=[CHANNEL_DATA] headers=5, eventHeaders=169, eventBody=0 lines.
=======================  incoming channel data  =============================
Event-Date-Local: 2020-02-09 12:02:35
Unique-ID: bd659733-d460-4f0f-8c73-4cd4f1e39f68
Channel-ANI: 1002
Answer-State: ringing
Caller-Destination-Number: 4008123123
=======================  = = = = = = = = = = =  =============================
4008123123 bridge to 1010 successful
Received disconnection notice

 

文中示例代码git地址: https://github.com/yjmyzz/freeswitch-esl-java-client-sample

  

参考文章:

https://freeswitch.org/confluence/display/FREESWITCH/mod_event_socket

https://freeswitch.org/confluence/display/FREESWITCH/Java+ESL+Client

posted @ 2020-02-09 12:04  菩提树下的杨过  阅读(3274)  评论(3编辑  收藏