mosquito的版本要大于1.4.2；
1.修改配置：
打开configure.mk中的WITH_WEBSOCKETS配置项，如下：
WITH_WEBSOCKETS:=yes
2.编译
make
3.安装websocket：
（1）下载源码：
（2）拷贝到编译mosquitto的主机上：
1）进入到下载的源码中：/home/jason/tools/libwebsockets-master
2）创建一个build文件夹
3）进入到build目录中；
4）执行cmke，使用命令：cmake ..
5）make && make install
mkdir buildcd
buildcmake ..
makemake install
4.常见问题：
（1）如果遇到：
[root@iZbp1i90l0ap2clvybw1gdZ src]# ./mosquitto
./mosquitto: error while loading shared libraries: libwebsockets.so.12: cannot open shared object file: No such file or directory
1）先在目录/usr/local/lib看下libwebsockets.so的位置，这里的后缀数字名可能会不一致，如下所示：
[root@iZbp1i90l0ap2clvybw1gdZ lib]# pwd
/usr/local/lib
[root@iZbp1i90l0ap2clvybw1gdZ lib]# ls
cmake libwebsockets.a libwebsockets.so libwebsockets.so.12 pkgconfig
2）建立ibwebsockets.so.12的软连接；
sudo ln -s /usr/local/lib/libwebsockets.so.12 /usr/lib/libwebsockets.so.12
3)执行：
ldconfig
（2）如果遇到问题
websockets.c:205:10: error: ‘struct mosquitto’ has no member named ‘ssl’
mosq->ssl = (SSL *)in;
解决办法，说明没有安装SSL，可以选择
安装ssl：
yum install openssl
yum install openssl-devel
（3）问题：Error: Websockets support not available.
[root@iZm5e92vqf4urefs01djnxZ mosquitto-1.4.15]# ./src/mosquitto -c mosquitto.conf
Error: Websockets support not available.
Error found at mosquitto.conf:297.
Error: Unable to open configuration file.
原因：编译mosquitto的时候没有打开websocket功能，但是配置文件中却把websocket打开了；
编译mosquitto的时候打开websocket功能需要将config.mk中的配置项WITH_WEBSOCKETS设置为yes；
5.配置mosquitto.conf
特别注意，mosquitto支持多端口监听，而且不同的端口支持不同的协议，这样部署一个mosquitto程序就可以同时支持mqtt协议和websocket协议，mosquitto默认的监听端口号是1883，在Default listener配置段中配置，配置项是：port；在不使用扩展配置项的时候也不启用任何自定义端口配置的时候，mosquitto默认使用1883端口，但是一旦用户启用了扩展监听端口就必须显示指出默认端口号，即：Default listener配置段的port参数：
# =================================================================
# Default listener
# =================================================================
# Port to use for the default listener.
#port 1883
mosquitto使用扩展监听端口来支持websocket，即它本身通过默认监听端口号（port参数指定）来接收mqtt协议的连接请求，同时启用另外一个监听端口号（listener参数指定）来接收websocket协议的连接请求，其配置如下（扩展监听端口的相关信息都是在Extra listeners配置段之后），启用扩展端口号需要在Extra listeners配置段之下，显示指出扩展监听端口的端口号listener以及所支持的应用层协议类型：
# =================================================================
# Extra listeners
# =================================================================
# Listen on a port/ip address combination. By using this variable
# multiple times, mosquitto can listen on more than one port. If
# this variable is used and neither bind_address nor port given,
# then the default listener will not be started.
#
The port number to listen on must be given. Optionally, an ip
# address or host name may be supplied as a second argument. In
# this case, mosquitto will attempt to bind the listener to that
# address and so restrict access to the associated network and
# interface. By default, mosquitto will listen on all interfaces.
# Note that for a websockets listener it is not possible to bind to a host
# name.
# listener port-number [ip address/host name]
listener 9001
# Choose the protocol to use when listening.
# This can be either mqtt or websockets.
# Certificate based TLS may be used with websockets, except that only the
# cafile, certfile, keyfile and ciphers options are supported.
protocol websocket