• 【FreeSwitch开发实践】C语言中使用ESL连接FreeSwitch

    🏠 作     者：小小马车夫
    🍅 所属专栏：【FreeSwitch开发实践】
    🥝 专栏介绍：主要介绍博主在实际项目中使用FreeSwitch开发外呼类项目的一些经验心得，主要涉及FreeSwitch的基本安装编译、基本配置、ESL、WSS、录音、自定义模块、media bug、语音播放、MRCP及对接AI机器人等内容。内容在持续更新中，如果感兴趣可以对专栏进行订阅~
    🍒 个人警醒与诸君共勉：间歇性的努力和蒙混过日子，都是对之前努力的清零。

    系列文章目录

    【FreeSwitch开发实践】centos7下编译安装freeswitch及常见编译问题的解决
    【FreeSwitch开发实践】freeswitch配置wss
    【FreeSwitch开发实践】freeswitch配置wss证书问题 Encrypted Alert/Certification Unknown
    【FreeSwitch开发实践】ESL简介
    【FreeSwitch开发实践】ESL配置
    【FreeSwitch开发实践】在nodejs中用ESL连接FreeSwitch
    【FreeSwitch开发实践】死锁问题解决Over Session Limit 1000/Locked, Waiting on external entities

    文章目录

    前言

    之前在【FreeSwitch开发实践】在nodejs中用ESL连接FreeSwitch一文介绍了在NodeJS下使用ESL连接FreeSwitch, 本文则对在C语言下使用ESL连接FreeSwitch作了一个系统介绍。和NodeJS下使用ESL需要安装modesl模块一样，C语言下使用ESL也需要libesl库.

    1、libesl库编译安装

    libesl库在FreeSwitch中是自带的，所以编译FreeSwitch的时候，实际已经安装了libesl，这里单独对FreeSwitch下编译libesl简要说明下：

    #进入FreeSwitch下libesl源码目录
/data/freeswitch/libs/esl
make
make install

    • 1
    • 2
    • 3
    • 4

    运行完编译命令后，libesl实际已经安装到了FreeSwitch的安装目录下：
    /usr/local/freeswitch/lib/

    在这里插入图片描述

    2、在Makefile中引入libesl

    上一节说明了，libesl的编译安装过程以及编译后库的生成目录，这里对在Makefile中引入libesl,介绍下。
    Makefile如下：

    TOP_PATH  := $(shell pwd)
INCLUDE   := -I/data/freeswitch/libs/esl/src/include
LIBS_PATH := -L/usr/local/freeswitch/lib
LIBS      := -lesl -lpthread
CC	:= gcc
TARGET    :=  esl_test
 
SRCDIRS		:= ./ 
CFILES		:= $(foreach dir, $(SRCDIRS), $(wildcard $(dir)/*.c))
CFILENDIR	:= $(CFILES)
COBJS		:= $(patsubst %, %, $(CFILENDIR:.c=.o))
 
.PHONY: clean
 
$(TARGET):$(COBJS)
	$(CC) $^ $(INCLUDE) $(LIBS_PATH) $(LIBS) -o $(TOP_PATH)/$@
 
$(COBJS) : %.o : %.c
	$(CC) -c $<  $(INCLUDE)  $(LIBS_PATH) $(LIBS) -o $@
 
clean:
	@rm *.o
	@rm $(TOP_PATH)/$(TARGET)

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23

    其中， INCLUDE 是FreeSwitch中esl头文件的目录， LIBS_PATH 是libesl的最终生成目录，LIBS 为引入的库，-lesl则为libesl.a库的引入。

    3、ESL连接FreeSwitch

    先看一下用C语言版本的ESL连接FreeSwitch

     esl_handle_t handle = {{0}};
 esl_global_set_default_logger(ESL_LOG_LEVEL_DEBUG);

 memset(&handle, 0, sizeof(handle));
 if (esl_connect_timeout(&handle, "10.0.8.10", 8021, "", "ClueCon", 3000)) {
         esl_global_set_default_logger(7);
         esl_log(ESL_LOG_ERROR, "Error Connecting [%s]\n", handle.err);
         return -1;
 }


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10

    连接FreeSwitch用的接口是esl_connect_timeout, 需要的参数分别是·ip、端口、密码和超时时间，基本和NodeJS中类似。

    4、ESL事件订阅

    esl_events(&handle, ESL_EVENT_TYPE_PLAIN, "CHANNEL_ANSWER");
esl_events(&handle, ESL_EVENT_TYPE_PLAIN, "CHANNEL_HANGUP_COMPLETE");

    • 1
    • 2

    事件订阅用到的esl_events接口， 第3个参数是事件名称, 第2个参数是事件体的类型，包括plain/xml/json，定义如下：

    typedef enum {
	ESL_EVENT_TYPE_PLAIN,
	ESL_EVENT_TYPE_XML,
	ESL_EVENT_TYPE_JSON
} esl_event_type_t;

    • 1
    • 2
    • 3
    • 4
    • 5

    5、事件监听

    esl_recv_event_timed(handle, 10, 1, NULL);

    • 1

    完整的定义如下：

    /*!
    \brief Poll the handle's socket until an event is received, a connection error occurs or ms expires
    \param handle Handle to poll
    \param ms Maximum time to poll
    \param check_q If set to 1, will check the handle queue (handle->race_event) and return the last event from it
    \param[out] save_event If this is not NULL, will return the event received
*/
ESL_DECLARE(esl_status_t) esl_recv_event_timed(esl_handle_t *handle, uint32_t ms, int check_q, esl_event_t **save_event);

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8

    6、完整的例子

    下面是完整的例子，包括ESL连接，发送命令和事件订阅、事件监听。

    #include 
#include 
#include 
#include 
#include 

static void _sleep_ns(int secs, long nsecs) {
#ifndef WIN32
	if (nsecs > 999999999) {
		secs += nsecs/1000000000;
		nsecs = nsecs % 1000000000;
	}
	{
		struct timespec ts = { secs, nsecs };
		nanosleep(&ts, NULL);
	}
#else
	Sleep(secs*1000 + nsecs/1000000);
#endif
}

static void sleep_ns(long nsecs) { _sleep_ns(0, nsecs); }
static void sleep_ms(int msecs) { sleep_ns(msecs*1000000); }
static void sleep_s(int secs) { _sleep_ns(secs, 0); }
static void *msg_thread_run(esl_thread_t *me, void *obj);
static esl_mutex_t *MUTEX = NULL;
static int thread_running = 0, thread_up = 0, check_up = 0;


int main()
{
    char cmd_str[2048] = "";
    esl_handle_t handle = {{0}};
    esl_global_set_default_logger(ESL_LOG_LEVEL_DEBUG);

    memset(&handle, 0, sizeof(handle));
    //ESL连接FreeSwitch
    if (esl_connect_timeout(&handle, "10.0.8.10", 8021, "", "ClueCon", 3000)) {
            esl_global_set_default_logger(7);
            esl_log(ESL_LOG_ERROR, "Error Connecting [%s]\n", handle.err);
            return -1;
    }

	esl_mutex_create(&MUTEX);

	//启动ESL事件临听线程
    if (esl_thread_create_detached(msg_thread_run, &handle) != ESL_SUCCESS) {
        esl_log(ESL_LOG_ERROR, "Error starting thread!\n");
		esl_disconnect(&handle);
		return 0;
	}

	//ESL事件订阅
	esl_events(&handle, ESL_EVENT_TYPE_PLAIN, "CHANNEL_ANSWER");
	esl_events(&handle, ESL_EVENT_TYPE_PLAIN, "CHANNEL_HANGUP_COMPLETE");

	//发送api version命令
	snprintf(cmd_str, sizeof(cmd_str), "api version\n\n");
	esl_send_recv(&handle, cmd_str);
	//接收api version返回
	if (handle.last_sr_event && handle.last_sr_event->body) {
		esl_log(ESL_LOG_INFO, "%s\n", handle.last_sr_event->body);
	}

	//拨打软电话命令api originate user/1000 &echo
	snprintf(cmd_str, sizeof(cmd_str), "api originate user/1000 &echo\n\n");
	esl_send_recv(&handle, cmd_str);
	if (handle.last_sr_event && handle.last_sr_event->body) {
		esl_log(ESL_LOG_INFO, "%s\n", handle.last_sr_event->body);
	}

	//等待，防止主线程退出
    while(handle.connected)
    {
    	sleep_ms(10);
    }
	//断开ESL连接
    esl_disconnect(&handle);
	
	//等待ESL事件监听线程退出
	do {
		esl_mutex_lock(MUTEX);
		check_up = thread_up;
		esl_mutex_unlock(MUTEX);
		sleep_ms(10);
	} while (check_up > 0);

    esl_mutex_destroy(&MUTEX);
}
//事件监听线程
static void *msg_thread_run(esl_thread_t *me, void *obj)
{
	esl_handle_t *handle = (esl_handle_t *) obj;
	thread_running = 1;
	esl_mutex_lock(MUTEX);
	thread_up = 1;
	esl_mutex_unlock(MUTEX);

    while(thread_running && handle->connected) {
		int aok = 1;
		esl_status_t status;
	
		esl_mutex_lock(MUTEX);
		//等待事件到来，只有esl_events注册的事件才能监听到
		status = esl_recv_event_timed(handle, 10, 1, NULL);
		esl_mutex_unlock(MUTEX);
		
		if (status == ESL_BREAK) {
			sleep_ms(1);
		} else if (status == ESL_FAIL) {
			esl_log(ESL_LOG_WARNING, "Disconnected.\n");
			thread_running = 0;
		} else if (status == ESL_SUCCESS) {	
		    //事件到来，打印事件体
            esl_log(ESL_LOG_INFO, "coming event_body:%xs\n", handle->last_event);
            if (handle->last_event->body) {
           		esl_log(ESL_LOG_INFO, "event_body:%s\n", handle->last_event->body);
            }
	    }
    }
    esl_mutex_lock(MUTEX);  
	thread_up = 0;
	esl_mutex_unlock(MUTEX);  
	thread_running = 0;
	esl_log(ESL_LOG_DEBUG, "Thread Done\n");
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61
    • 62
    • 63
    • 64
    • 65
    • 66
    • 67
    • 68
    • 69
    • 70
    • 71
    • 72
    • 73
    • 74
    • 75
    • 76
    • 77
    • 78
    • 79
    • 80
    • 81
    • 82
    • 83
    • 84
    • 85
    • 86
    • 87
    • 88
    • 89
    • 90
    • 91
    • 92
    • 93
    • 94
    • 95
    • 96
    • 97
    • 98
    • 99
    • 100
    • 101
    • 102
    • 103
    • 104
    • 105
    • 106
    • 107
    • 108
    • 109
    • 110
    • 111
    • 112
    • 113
    • 114
    • 115
    • 116
    • 117
    • 118
    • 119
    • 120
    • 121
    • 122
    • 123
    • 124
    • 125
    • 126

    本例子是博主亲自实验过的，基于fs_cli实现，如果读者有兴趣可以详细看一下fs_cli源码，应该会有更多收获。

    输出：

    [root@VM-8-10-centos esl_test]# ./esl_test 
[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Type] = [auth/request]
[DEBUG] esl.c:1467 esl_recv_event() RECV MESSAGE
Event-Name: SOCKET_DATA
Content-Type: auth/request


[DEBUG] esl.c:1495 esl_send() SEND
auth ClueCon


[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Type] = [command/reply]
[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Reply-Text] = [+OK accepted]
[DEBUG] esl.c:1467 esl_recv_event() RECV MESSAGE
Event-Name: SOCKET_DATA
Content-Type: command/reply
Reply-Text: +OK accepted


[DEBUG] esl.c:1495 esl_send() SEND
event plain CHANNEL_ANSWER


[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Type] = [command/reply]
[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Reply-Text] = [+OK event listener enabled plain]
[DEBUG] esl.c:1495 esl_send() SEND
event plain CHANNEL_HANGUP_COMPLETE


[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Type] = [command/reply]
[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Reply-Text] = [+OK event listener enabled plain]
[DEBUG] esl.c:1495 esl_send() SEND
api version


[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Type] = [api/response]
[DEBUG] esl.c:1303 esl_recv_event() RECV HEADER [Content-Length] = [113]
[INFO] test.c:59 main() FreeSWITCH Version 1.10.7-release+git~20211024T163933Z~883d2cb662~64bit (git 883d2cb 2021-10-24 16:39:33Z 64bit)

[DEBUG] esl.c:1495 esl_send() SEND
api originate user/1000 &echo

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41

    answer事件

    [INFO] test.c:108 msg_thread_run() coming event_body:a40008c0s
[INFO] test.c:110 msg_thread_run() event_body:Event-Name: CHANNEL_ANSWER
Core-UUID: 8f363510-c0cf-4aa4-bbfc-577cc6ff543b
FreeSWITCH-Hostname: VM-8-10-centos
FreeSWITCH-Switchname: VM-8-10-centos
FreeSWITCH-IPv4: 10.0.8.10
FreeSWITCH-IPv6: fe80%3A%3A5054%3Aff%3Afe58%3A28ea
Event-Date-Local: 2022-07-17%2022%3A34%3A37
Event-Date-GMT: Sun,%2017%20Jul%202022%2014%3A34%3A37%20GMT
Event-Date-Timestamp: 1658068477404961
Event-Calling-File: switch_channel.c
Event-Calling-Function: switch_channel_perform_mark_answered
Event-Calling-Line-Number: 3884
Event-Sequence: 646
Channel-State: CS_CONSUME_MEDIA
Channel-Call-State: RINGING
Channel-State-Number: 7
Channel-Name: sofia/internal/1000%4061.149.73.246%3A3387
Unique-ID: ba515d00-58f1-4433-af24-f0cafeac7e4e
Call-Direction: outbound
Presence-Call-Direction: outbound
Channel-HIT-Dialplan: false
Channel-Presence-ID: 1000%4010.0.8.10
Channel-Call-UUID: ba515d00-58f1-4433-af24-f0cafeac7e4e
Answer-State: answered
Channel-Read-Codec-Name: PCMU
Channel-Read-Codec-Rate: 8000
Channel-Read-Codec-Bit-Rate: 64000
Channel-Write-Codec-Name: PCMU
Channel-Write-Codec-Rate: 8000
Channel-Write-Codec-Bit-Rate: 64000
Caller-Direction: outbound
Caller-Logical-Direction: outbound
Caller-Caller-ID-Number: 0000000000
Caller-Orig-Caller-ID-Number: 0000000000
Caller-Callee-ID-Name: Outbound%20Call
Caller-Callee-ID-Number: 1000
Caller-Network-Addr: 61.149.73.246
Caller-ANI: 0000000000
Caller-Destination-Number: 1000
Caller-Unique-ID: ba515d00-58f1-4433-af24-f0cafeac7e4e
Caller-Source: src/switch_ivr_originate.c
Caller-Context: default
Caller-Channel-Name: sofia/internal/1000%4061.149.73.246%3A3387
Caller-Profile-Index: 1
Caller-Profile-Created-Time: 1658068471904968
Caller-Channel-Created-Time: 1658068471904968
Caller-Channel-Answered-Time: 1658068477404961
Caller-Channel-Progress-Time: 1658068471984961
Caller-Channel-Progress-Media-Time: 0
Caller-Channel-Hangup-Time: 0
Caller-Channel-Transfer-Time: 0
Caller-Channel-Resurrect-Time: 0
Caller-Channel-Bridged-Time: 0
Caller-Channel-Last-Hold: 0
Caller-Channel-Hold-Accum: 0
Caller-Screen-Bit: true
Caller-Privacy-Hide-Name: false
Caller-Privacy-Hide-Number: false
variable_direction: outbound
variable_is_outbound: true

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61

    hangup事件

    [INFO] test.c:108 msg_thread_run() coming event_body:8400df60s
[INFO] test.c:110 msg_thread_run() event_body:Event-Name: CHANNEL_HANGUP_COMPLETE
Core-UUID: f7005cb2-45e7-4643-ae7e-d10d45a7b4d1
FreeSWITCH-Hostname: VM-8-10-centos
FreeSWITCH-Switchname: VM-8-10-centos
FreeSWITCH-IPv4: 10.0.8.10
FreeSWITCH-IPv6: fe80%3A%3A5054%3Aff%3Afe58%3A28ea
Event-Date-Local: 2022-07-17%2022%3A32%3A42
Event-Date-GMT: Sun,%2017%20Jul%202022%2014%3A32%3A42%20GMT
Event-Date-Timestamp: 1658068362698622
Event-Calling-File: switch_core_state_machine.c
Event-Calling-Function: switch_core_session_reporting_state
Event-Calling-Line-Number: 943
Event-Sequence: 846950
Hangup-Cause: NORMAL_CLEARING
Channel-State: CS_REPORTING
Channel-Call-State: HANGUP
Channel-State-Number: 11
Channel-Name: sofia/external/1001%4010.0.8.10
Unique-ID: 44c3b4f0-7091-49ea-8f61-8a368648609a
Call-Direction: inbound
Presence-Call-Direction: inbound
Channel-HIT-Dialplan: true
Channel-Call-UUID: 44c3b4f0-7091-49ea-8f61-8a368648609a
Answer-State: hangup
Hangup-Cause: NORMAL_CLEARING
Caller-Direction: inbound
Caller-Logical-Direction: inbound
Caller-Username: 1001
Caller-Dialplan: XML
Caller-Caller-ID-Name: 1001
Caller-Caller-ID-Number: 1001
Caller-Orig-Caller-ID-Name: 1001
Caller-Orig-Caller-ID-Number: 1001
Caller-Network-Addr: 20.52.185.66
Caller-ANI: 1001
Caller-Destination-Number: 2985720103


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38

    总结

    以上就是今天的内容，详细的介绍了C语言使用ESL连接FreeSwitch。

    如果觉得有些帮助或觉得文章还不错，请关注一下博主，你的关注是我持续写作的动力。另外，如果有什么问题，可以在评论区留言，或者私信博主，博主看到后会第一时间回复。

  • 相关阅读:
    leetcode每天5题-Day31
    A-古代汉语知识点整理大全
    Unity调用C++ dll的那些坑
    java常见集合
    Python学习------Day05
    企业架构LNMP学习笔记46
    代码随想录算法训练营刷题复习4 ：单调栈
    阿里二面：SpringCloud 有几种服务调用方式？
    spark性能调优 | 内存优化
    SpringCloud-MQ消息队列
  • 原文地址：https://blog.csdn.net/xxm524/article/details/125840597