Mosquitto-1.5在Linux上的安装以及Android客户端的实现

一、关于MQTT

　　MQTT（Message Queuing Telemetry Transport，消息队列遥测传输协议），是一种基于发布/订阅（publish/subscribe）模式的"轻量级"通讯协议，该协议构建于TCP/IP协议上，由IBM在1999年发布。MQTT最大优点在于，可以以极少的代码和有限的带宽，为连接远程设备提供实时可靠的消息服务。作为一种低开销、低带宽占用的即时通讯协议，使其在物联网、小型设备、移动应用等方面有较广泛的应用。

　　MQTT是一个基于客户端-服务器的消息发布/订阅传输协议。MQTT协议是轻量、简单、开放和易于实现的，这些特点使它适用范围非常广泛。在很多情况下，包括受限的环境中，如：机器与机器（M2M）通信和物联网（IoT）。其在，通过卫星链路通信传感器、偶尔拨号的医疗设备、智能家居、及一些小型化设备中已广泛使用。

　　而Mosquitto是一个实现了MQTT3.1协议的代理服务器，由MQTT协议创始人之一的Andy Stanford-Clark开发，它为我们提供了非常棒的轻量级数据交换的解决方案，本文将基于mosquitto实现Android手机和阿里云服务器的mqtt通讯。

二、Mosquitto在Ubuntu上安装

1）下载源码压缩包 ：https://mosquitto.org/download/

2）解压源代码包:

tar -zxvf mosquitto-1.5.tar.gz

3）安装编译环境:

sudo apt-get install gcc

sudo apt-get install libssl-dev

sudo apt-get install g++

sudo apt-get install uuid-dev

sudo apt-get install libc-ares-dev

sudo apt-get install libc-ares2

4）进入第2步中解压开的源代码目录，对源代码进行编译:

cd mosquito-1.5

sudo make　　　　// 编译生成可执行文件

sudo make install    // 安装到系统目录，可省略

　注：其中config.mk包括了多个选项, 可按需关闭或开启，但一旦开启则需要先安装对应的模块：

    # 是否支持tcpd/libwrap功能.
    #WITH_WRAP:=yes

    # 是否开启SSL/TLS支持
    #WITH_TLS:=yes

    # 是否开启TLS/PSK支持
    #WITH_TLS_PSK:=yes

    # Comment out to disable client client threading support.
    #WITH_THREADING:=yes

    # 是否使用严格的协议版本（老版本兼容会有点问题）
    #WITH_STRICT_PROTOCOL:=yes

    # 是否开启桥接模式
    #WITH_BRIDGE:=yes

    # 是否开启持久化功能
    #WITH_PERSISTENCE:=yes

    # 是否监控运行状态
    #WITH_MEMORY_TRACKING:=yes

5）启动服务

cd src

mosquito -c mosquitto.conf.example      //通过示例配置文件启动

　　通过 mosquito --help 查看详细选项说明：

 -c : specify the broker config file.
 -d : put the broker into the background after starting.
 -h : display this help.
 -p : start the broker listening on the specified port.
      Not recommended in conjunction with the -c option.
 -v : verbose mode - enable all logging types. This overrides
      any logging options given in the config file.

　另外 主题订阅 和 消息发布 的客户端文件生成在 client 目录，同样通过如下指令查看详细参数说明：

　mosquitto_sub --help

mosquitto_sub is a simple mqtt client that will subscribe to a set of topics and print all messages it receives.
mosquitto_sub version 1.5 running on libmosquitto 1.5.0.

Usage: mosquitto_sub {[-h host] [-p port] [-u username [-P password]] -t topic | -L URL [-t topic]}
                     [-c] [-k keepalive] [-q qos]
                     [-C msg_count] [-R] [--retained-only] [-T filter_out] [-U topic ...]
                     [-F format]
                     [-W timeout_secs]
                     [-A bind_address]
                     [-i id] [-I id_prefix]
                     [-d] [-N] [--quiet] [-v]
                     [--will-topic [--will-payload payload] [--will-qos qos] [--will-retain]]
                     [--proxy socks-url]
       mosquitto_sub --help

 -A : bind the outgoing socket to this host/ip address. Use to control which interface
      the client communicates over.
 -c : disable 'clean session' (store subscription and pending messages when client disconnects).
 -C : disconnect and exit after receiving the 'msg_count' messages.
 -d : enable debug messages.
 -F : output format.
 -h : mqtt host to connect to. Defaults to localhost.
 -i : id to use for this client. Defaults to mosquitto_sub_ appended with the process id.
 -I : define the client id as id_prefix appended with the process id. Useful for when the
      broker is using the clientid_prefixes option.
 -k : keep alive in seconds for this client. Defaults to 60.
 -L : specify user, password, hostname, port and topic as a URL in the form:
      mqtt(s)://[username[:password]@]host[:port]/topic
 -N : do not add an end of line character when printing the payload.
 -p : network port to connect to. Defaults to 1883 for plain MQTT and 8883 for MQTT over TLS.
 -P : provide a password
 -q : quality of service level to use for the subscription. Defaults to 0.
 -R : do not print stale messages (those with retain set).
 -t : mqtt topic to subscribe to. May be repeated multiple times.
 -T : topic string to filter out of results. May be repeated.
 -u : provide a username
 -U : unsubscribe from a topic. May be repeated.
 -v : print published messages verbosely.
 -V : specify the version of the MQTT protocol to use when connecting.
      Can be mqttv31 or mqttv311. Defaults to mqttv311.
 -W : Specifies a timeout in seconds how long to process incoming MQTT messages.
 --help : display this message.
 --quiet : don't print error messages.
 --retained-only : only handle messages with the retained flag set, and exit when the
                   first non-retained message is received.
 --will-payload : payload for the client Will, which is sent by the broker in case of
                  unexpected disconnection. If not given and will-topic is set, a zero
                  length message will be sent.
 --will-qos : QoS level for the client Will.
 --will-retain : if given, make the client Will retained.
 --will-topic : the topic on which to publish the client Will.
 --proxy : SOCKS5 proxy URL of the form:
           socks5h://[username[:password]@]hostname[:port]
           Only "none" and "username" authentication is supported.

See http://mosquitto.org/ for more information.

　mosquitto_pub --help

mosquitto_pub is a simple mqtt client that will publish a message on a single topic and exit.
mosquitto_pub version 1.5 running on libmosquitto 1.5.0.

Usage: mosquitto_pub {[-h host] [-p port] [-u username [-P password]] -t topic | -L URL}
                     {-f file | -l | -n | -m message}
                     [-c] [-k keepalive] [-q qos] [-r]
                     [-A bind_address]
                     [-i id] [-I id_prefix]
                     [-d] [--quiet]
                     [-M max_inflight]
                     [-u username [-P password]]
                     [--will-topic [--will-payload payload] [--will-qos qos] [--will-retain]]
                     [--proxy socks-url]
       mosquitto_pub --help

 -A : bind the outgoing socket to this host/ip address. Use to control which interface
      the client communicates over.
 -d : enable debug messages.
 -f : send the contents of a file as the message.
 -h : mqtt host to connect to. Defaults to localhost.
 -i : id to use for this client. Defaults to mosquitto_pub_ appended with the process id.
 -I : define the client id as id_prefix appended with the process id. Useful for when the
      broker is using the clientid_prefixes option.
 -k : keep alive in seconds for this client. Defaults to 60.
 -L : specify user, password, hostname, port and topic as a URL in the form:
      mqtt(s)://[username[:password]@]host[:port]/topic
 -l : read messages from stdin, sending a separate message for each line.
 -m : message payload to send.
 -M : the maximum inflight messages for QoS 1/2..
 -n : send a null (zero length) message.
 -p : network port to connect to. Defaults to 1883 for plain MQTT and 8883 for MQTT over TLS.
 -P : provide a password
 -q : quality of service level to use for all messages. Defaults to 0.
 -r : message should be retained.
 -s : read message from stdin, sending the entire input as a message.
 -t : mqtt topic to publish to.
 -u : provide a username
 -V : specify the version of the MQTT protocol to use when connecting.
      Can be mqttv31 or mqttv311. Defaults to mqttv311.
 --help : display this message.
 --quiet : don't print error messages.
 --will-payload : payload for the client Will, which is sent by the broker in case of
                  unexpected disconnection. If not given and will-topic is set, a zero
                  length message will be sent.
 --will-qos : QoS level for the client Will.
 --will-retain : if given, make the client Will retained.
 --will-topic : the topic on which to publish the client Will.
 --proxy : SOCKS5 proxy URL of the form:
           socks5h://[username[:password]@]hostname[:port]
           Only "none" and "username" authentication is supported.

See http://mosquitto.org/ for more information.

使用示例（通过三个终端分别输入以下指令）：

mosquitto -c mosquitto.conf -p 1884  //启动服务，如果不指定端口则默认使用1883
mosquitto_sub -h 192.168.153.130 -p  -u root -P  -t topic01  //订阅主题"topic01"
mosquitto_pub -h 192.168.153.130 -p  -t topic01 -m "message01"　　　//发布消息给订阅"topic01"的订阅客户端

　通过以上步骤大致了解mosquitto在Linux系统上的安装和使用方法，同样在阿里云服务器上运行mosquitto后，即可通过手机MQTT客户端与云服务器端进行消息交互。

　PS：阿里云服务器1883端口默认被屏蔽，需要自己另外配置一个端口！

三、Mqtt Android客户端开发

　基于Android的Mqtt客户端组件进行接口封装，使用更加简易：

（1）构建MqttService对象

　　/**
     * 构建EasyMqttService对象
     */
    private void buildEasyMqttService() {
        mqttService = new EasyMqttService.Builder()
                //设置自动重连
                .autoReconnect(true)
                //设置不清除回话session 可收到服务器之前发出的推送消息
                .cleanSession(false)
                //唯一标示 保证每个设备都唯一就可以 建议 imei
                .clientId("your clientId")
                //mqtt服务器地址 格式例如：tcp://10.0.261.159:1883
                .serverUrl("your mqtt servier url")
                //心跳包默认的发送间隔
                .keepAliveInterval()
                //构建出EasyMqttService 建议用application的context
                .bulid(this.getApplicationContext());
    }

（2）连接Mqtt服务器

　　/**
     * 连接Mqtt服务器
     */
    private void connect() {
        mqttService.connect(new IEasyMqttCallBack() {
            @Override
            public void messageArrived(String topic, String message, int qos) {
                //推送消息到达
            }

            @Override
            public void connectionLost(Throwable arg0) {
                //连接断开
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken arg0) {

            }

            @Override
            public void connectSuccess(IMqttToken arg0) {
                //连接成功
            }

            @Override
            public void connectFailed(IMqttToken arg0, Throwable arg1) {
                //连接失败
            }
        });
    }

（3）订阅主题

 　　/**
     * 订阅主题 这里订阅三个主题分别是"a", "b", "c"
     */
    private void subscribe() {
        String[] topics = new String[]{"a", "b", "c"};
        //主题对应的推送策略 分别是0, 1, 2 建议服务端和客户端配置的主题一致
        // 0 表示只会发送一次推送消息 收到不收到都不关心
        // 1 保证能收到消息，但不一定只收到一条
        // 2 保证收到切只能收到一条消息
        int[] qoss = new int[]{, , };
        mqttService.subscribe(topics, qoss);
    }

（4）关闭连接

     /**
     * 关闭连接
     */
    private void close() {
        mqttService.close();
    }

（5）断开连接

　　 /**
     * 断开连接
     */
    private void disconnect() {
        mqttService.disconnect();
    }

（6）判断连接状态

    /**
     * 判断服务是否连接
     */
    private boolean isConnected() {
        return mqttService.isConnected();
    }

（7）发布消息

/**
  * 发布消息
  */
public void publish(String msg, String topic, int qos, boolean retained) {
    try {
        client.publish(topic, msg.getBytes(), qos, retained);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

完整的Demo实现了UI动态输入及消息显示，可用于对mqtt服务器进行测试，已上传至GitHub：https://github.com/dragonforgithub/SmartControl

编译生成的Linux及Android客户端软件已传至百度云：链接：https://pan.baidu.com/s/1M_fCCITsW2cXGQLo3MWW0Q  提取码：9r6p

另外可以参考eclipse出品的Android Demo进一步学习： https://github.com/eclipse/paho.mqtt.android

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