简述
一款实现了消息推送协议 MQTT v3.1 的开源消息代理软件，提供轻量级的，支持可发布/可订阅的的消息推送模式，使设备对设备之间的短消息通信变得简单，比如现在应用广泛的低功耗传感器，手机、嵌入式计算机、微型控制器等移动设备。一个典型的应用案例就是 Andy Stanford-ClarkMosquitto（MQTT协议创始人之一）在家中实现的远程监控和自动化
mosquitto官网 http://mosquitto.org/
关于mqtt协议可参考 http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
yum安装
加源 centos6 [home_oojah_mqtt] name=mqtt (CentOS_CentOS-6) type=rpm-md baseurl=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-6/ gpgcheck=1 gpgkey=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-6/repodata/repomd.xml.key enabled=1 centos7 [home_oojah_mqtt] name=mqtt (CentOS_CentOS-7) type=rpm-md baseurl=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-7/ gpgcheck=1 gpgkey=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-7/repodata/repomd.xml.key enabled=1 yum list mosquit* yum 安装需要的包
编译安装
安装依赖
yum install gcc gcc-c++ libstdc++-devel openssl-devel c-ares-devel c-ares-devel uuid-devel libuuid-devel cmake
下载安装libwebsockets
libwebsockets是一款轻量级用来开发服务器和客户端的C库。按照官方（https://libwebsockets.org/）给出的介绍来看，它不仅支持ws，wss还同时支持http与https，可以轻轻松松结合openssl等库来实现ssl加密
[root@server6 mosquitto]# git clone https://github.com/warmcat/libwebsockets.git [root@server6 mosquitto]# cd libwebsockets/ [root@server6 libwebsockets]# mkdir build [root@server6 libwebsockets]# cd build [root@server6 build]# cmake .. [root@server6 build]# make install
cd /opt/mqtt
wget https://github.com/warmcat/libwebsockets/archive/v1.3-chrome37-firefox30.tar.gz
tar xf v1.3-chrome37-firefox30.tar.gz
cd libwebsockets-1.3-chrome37-firefox30/
mkdir build
cd build
cmake .. -DLIB_SUFFIX=64
make install
ldconfig
什么是Websockets及其工作原理？
WebSocket是一种计算机通信协议，通过单个TCP / IP连接提供全双工通信通道。维基
它与http密切相关，因为它使用http进行初始连接建立。
客户端和服务器使用http进行连接，然后协商连接升级到websockets，然后连接从http 切换到websockets。
客户端和服务器现在可以通过连接交换全双工二进制数据。
下载安装 mosquitto
cd /opt/mqtt/
wget http://mosquitto.org/files/source/mosquitto-1.4.2.tar.gz
tar xf mosquitto-1.4.2.tar.gz
cd mosquitto-1.4.2
sed -i 's#WITH_WEBSOCKETS:=no#WITH_WEBSOCKETS:=yes#g' config.mk
make
make install
cp mosquitto.conf /etc/mosquitto/
sed -i '/#port 1883/a port 1883 listener 9001 protocol websockets' /etc/mosquitto/mosquitto.conf
启动 -d
创建用户 useradd mosquitto
[root@ecs-2018-0002 mosquitto-1.4.14]# mosquitto -c /etc/mosquitto/mosquitto.conf Error: Unable to open include_dir '/etc/mosquitto/conf.d'. Error found at /etc/mosquitto/mosquitto.conf:10. Error: Unable to open configuration file. [root@ecs-2018-0002 mosquitto-1.4.14]# ll /etc/mosquitto/conf.d ls: cannot access /etc/mosquitto/conf.d: No such file or directory [root@ecs-2018-0002 mosquitto-1.4.14]# mkdir -p /etc/mosquitto/conf.d [root@ecs-2018-0002 mosquitto-1.4.14]# mosquitto -c /etc/mosquitto/mosquitto.conf 1539235869: mosquitto version 1.4.14 (build date 2018-10-11 13:25:17+0800) starting 1539235869: Config loaded from /etc/mosquitto/mosquitto.conf. 1539235869: Opening ipv4 listen socket on port 1883. 1539235869: Opening ipv6 listen socket on port 1883. ^C1539235887: mosquitto version 1.4.14 terminating 1539235887: Saving in-memory database to /var/lib/mosquitto/mosquitto.db. 1539235887: Error saving in-memory database, unable to open /var/lib/mosquitto/mosquitto.db.new for writing. 1539235887: Error: No such file or directory. [root@ecs-2018-0002 mosquitto-1.4.14]# mosquitto -c /etc/mosquitto/mosquitto.conf -d
[root@ecs-2018-0002 mosquitto-1.4.14]# netstat -lntp|grep 1883
tcp 0 0 0.0.0.0:1883 0.0.0.0:* LISTEN 974/mosquitto
tcp 0 0 :::1883 :::* LISTEN 974/mosquitto
问题报错
[root@admin mosquitto-1.4.2]# mosquitto -c /etc/mosquitto/mosquitto.conf
mosquitto: error while loading shared libraries: libwebsockets.so.4.0.0: cannot open shared object file: No such file or directory
添加库目录
vim /etc/ld.so.conf.d/liblocal.conf
/usr/local/lib64
/usr/local/lib
刷新链接库
ldconfig
[root@local wutest]# cat install_mqtt.sh yum install gcc gcc-c++ libstdc++-devel openssl-devel c-ares-devel c-ares-devel uuid-devel libuuid-devel cmake -y mkdir -p /opt/mqtt cd /opt/mqtt wget https://github.com/warmcat/libwebsockets/archive/v1.3-chrome37-firefox30.tar.gz tar xf v1.3-chrome37-firefox30.tar.gz cd libwebsockets-1.3-chrome37-firefox30/ mkdir build cd build cmake .. -DLIB_SUFFIX=64 make install cat >>/etc/ld.so.conf.d/liblocal.conf<<eop /usr/local/lib64 /usr/local/lib eop ldconfig cd /opt/mqtt/ wget http://mosquitto.org/files/source/mosquitto-1.4.2.tar.gz tar xf mosquitto-1.4.2.tar.gz cd mosquitto-1.4.2 sed -i 's#WITH_WEBSOCKETS:=no#WITH_WEBSOCKETS:=yes#g' config.mk make make install cp mosquitto.conf /etc/mosquitto/ sed -i '/#port 1883/a port 1883 listener 9001 protocol websockets' /etc/mosquitto/mosquitto.conf useradd mosquitto ldconfig
测试
1 启动代理服务
mosquitto -v
【-v】打印更多的调试信息
2 订阅主题
mosquitto_sub -v -t sensor
【-t】指定主题，此处为sensor
【-v】打印更多的调试信息
3 发布内容
mosquitto_pub -t sensor -m 666
【-t】指定主题
【-m】指定消息内容
4 运行结果
当发布者推送消息之后，订阅者获得以下内容
sensor 666
而代理服务器控制台中会出现——连接、消息发布和心跳等调试信息。通过代理服务器的调试输出可以了解MQTT协议的相关过程
http://goochgooch.co.uk/2014/08/01/building-mosquitto-1-4/
http://www.steves-internet-guide.com/mqtt-websockets/
https://blog.csdn.net/u013332124/article/details/79480639