ESP8266 连接 MQTT

主控芯片：MM32F2377 (MB-039)

WiFi 适配器：ESP8266

开发环境：IAR 7.80.4

MQTT 模拟服务器：MQTT.fx

MQTT

MQTT is an OASIS standard messaging protocol for the Internet of Things (IoT). It is designed as an extremely lightweight publish/subscribe messaging transport that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth. MQTT today is used in a wide variety of industries, such as automotive, manufacturing, telecommunications, oil and gas, etc.

—— mqtt.org

MQTT(Message Queuing Telemetry Transport) 消息队列遥测传输协议，是一个基于客户端-服务器的消息发布/订阅传输协议。主要的概念有5个：

Broker 代理：MQTT 服务器
Publish 发布者：客户端
Subscribe 订阅者：客户端，可订阅多个 topic
Topic 主题：消息的类型，订阅主题之后就可以收到该 topic 的消息内容即 payload
Payload 消息内容：具体的内容

MQTT 模拟服务器：

MQTT 模拟服务器客户端使用

我在这里使用的是第二个 MQTT.fx，用这个客户端模拟一下 MQTT 的 Publish/Subscribe。

首先在 EMQ 官网上找到 MQTT 接入信息，主要是 Broker 和 TCP 端口号

在接下来的模拟服务器使用中，Broker Address 可以直接用 broker-cn.emqx.io，也可以到查询网上查找对应的 IP 地址：47.111.117.220

EMQ 分为在国内有专门的服务器，连接更方便一些，国外的 Broker Address 是 broker.emqx.io
打开 MQTT.fx，点击齿轮状的设置按钮，填写 Broker Address，Port 等，再到 User Credentials 里填写用户名和密码，OK，Connect
连接成功后，发布消息：填 topic，我这里 topic 叫 esp8266，以 json 格式进行发送，点击 Publish
去订阅消息，切换到 Subscribe，订阅 esp8266 这个 topic，然后再发布消息，就可以在这里看到了

ESP8266 + MQTT

ESP8266 的介绍以及基本使用可查看上一篇 CSDN 「Rose Island」MM32F3277 + ESP8266 使用指南（1. 实现 TCP Client 透传）。

首先需要确认 AT 指令集具有 MQTT 指令：

乐鑫官方 AT 下载地址
Ai-thinker AT 下载地址 (选择 ESP8266 MQTT 默认透传 AT 固件)

具体的 MQTT AT 指令集可查阅：

ESP MQTT AT Commands

ESP8266 MQTT 配置指令

配置 STA 模式：AT+CWMODE=1
连接路由器：AT+CWJAP="wifiName","wifiPsd"
配置 MQTT 属性：AT+MQTTUSERCFG=0,1,"clientID","username","password",0,0,""
连接制定的 MQTT broker：AT+MQTTCONN=0,"47.111.117.220",1883,0
查询 MQTT 连接状态：AT+MQTTCONN?
订阅 topic 数据：AT+MQTTSUB=0,"topicName",1
发布 topic 数据：AT+MQTTPUB=0,"topicName","payload",1,0

MM32F3277 + ESP8266 + MQTT

这里放的是与 MQTT 相关的函数，ESP8266 连网和 TCP 连接等函数可见「Rose Island」MM32F3277 + ESP8266 使用指南（1. 实现 TCP Client 透传）。

esp8266.c


/// @brief  Configure ESP8266 MQTT parameters.
/// @param  clientId: Client ID num.
/// @param  username: MQTT server username to log in MQTT broker.
/// @param  psd: MQTT server password to log in MQTT broker.
/// @param  scheme: Verification methods.
/// @retval None.

void ESP8266_MQTT_Init(char* clientId, char* username, char* psd, ESP8266_MQTT_Scheme_Typedef scheme)
{
    ESP8266_MQTT_InitStruct.ipAddr.mqttIPAddr0 = ESP8266_MQTT_HOST_IPADDR_0;
    ESP8266_MQTT_InitStruct.ipAddr.mqttIPAddr1 = ESP8266_MQTT_HOST_IPADDR_1;
    ESP8266_MQTT_InitStruct.ipAddr.mqttIPAddr2 = ESP8266_MQTT_HOST_IPADDR_2;
    ESP8266_MQTT_InitStruct.ipAddr.mqttIPAddr3 = ESP8266_MQTT_HOST_IPADDR_3;
    ESP8266_MQTT_InitStruct.port = (uint32_t)ESP8266_MQTT_PORT;
    ESP8266_MQTT_InitStruct.clientID = clientId;
    ESP8266_MQTT_InitStruct.username = username;
    ESP8266_MQTT_InitStruct.password = psd;
    ESP8266_MQTT_InitStruct.scheme = scheme;
    ESP8266_MQTT_InitStruct.mqttStatus = NO_INIT;
}


/// @brief  Connect with MQTT server.
/// @param  clientId: Client ID num.
/// @param  username: MQTT server username to log in MQTT broker.
/// @param  psd: MQTT server password to log in MQTT broker.
/// @param  scheme: Verification methods.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_Connect_MQTT(char* clientId, char* username, char* psd, ESP8266_MQTT_Scheme_Typedef scheme)
{
    ESP8266_MQTT_Init(clientId, username, psd, scheme);

    char *cmd = (char*)malloc(256);
    sprintf(cmd, "AT+MQTTUSERCFG=0,1,\"%s\",\"%s\",\"%s\",0,0,\"\"", clientId, username, psd);

    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        printf("Error: Fail to Configure MQTT \n");
        return ESP8266_ERROR;
    }else{
        ESP8266_MQTT_InitStruct.mqttStatus = USERCFG_SET;
        printf("OK: Configure MQTT successfully \n");
    }

    sprintf(cmd, "AT+MQTTCONN=0,\"%d.%d.%d.%d\",%d,0", ESP8266_MQTT_HOST_IPADDR_0, ESP8266_MQTT_HOST_IPADDR_1, ESP8266_MQTT_HOST_IPADDR_2, ESP8266_MQTT_HOST_IPADDR_3, ESP8266_MQTT_PORT);
    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        ESP8266_MQTT_InitStruct.mqttStatus = DISCONNECTED;
        printf("Error: Fail to Connect MQTT \n");
        return ESP8266_ERROR;
    }else{
        ESP8266_MQTT_InitStruct.mqttStatus = CONNECTED;
        printf("OK: Connect MQTT successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Check MQTT client state.
/// @param  None.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_Check_MQTT()
{
    char *cmd = "AT+MQTTCONN?";

    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        // printf("Error: Fail to Connect MQTT \n");
        return ESP8266_ERROR;
    }else{
        // printf("OK: Connect MQTT successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Subscribe topic from MQTT server.
/// @param  subTopic: Subscribed topic name.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_MQTT_SUB(char* subTopic)
{
    char *cmd = (char*)malloc(strlen("AT+MQTTSUB=0,\"%s\",1") + strlen(subTopic));
    sprintf(cmd, "AT+MQTTSUB=0,\"%s\",1", subTopic);

    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        ESP8266_MQTT_InitStruct.mqttStatus = CONNECTED_NO_SUB;
        printf("Error: Fail to Subscribe topic \n");
        return ESP8266_ERROR;
    }else{
        ESP8266_MQTT_InitStruct.mqttStatus = CONNECTED_AND_SUB;
        printf("OK: Subscribe topic successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Unsubscribe topic from MQTT server.
/// @param  subTopic: Unsubscribed topic name.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_MQTT_UNSUB(char* subTopic)
{
    char *cmd = (char*)malloc(strlen("AT+MQTTUNSUB=0,\"\"") + strlen(subTopic));
    sprintf(cmd, "AT+MQTTUNSUB=0,\"%s\"", subTopic);

    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        ESP8266_MQTT_InitStruct.mqttStatus = CONNECTED_NO_SUB;
        printf("Error: Fail to Subscribe topic \n");
        return ESP8266_ERROR;
    }else{
        ESP8266_MQTT_InitStruct.mqttStatus = CONNECTED_AND_SUB;
        printf("OK: Subscribe topic successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Publish topic to MQTT server.
/// @param  subTopic: Publish topic name.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_MQTT_PUB(char* pubTopic, char* data)
{
    char *cmd = (char*)malloc(strlen("AT+MQTTPUB=0,\"\",\"\",1,0") + strlen(pubTopic) + strlen(data));
    sprintf(cmd, "AT+MQTTPUB=0,\"%s\",\"%s\",1,0", pubTopic, data);

    if(ESP8266_Send_AT_Command_Times(cmd, "OK", 0xffff, 2)){
        printf("Error: Fail to Publish topic \n");
        return ESP8266_ERROR;
    }else{
        printf("OK: Publish topic successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Disconnect with MQTT server.
/// @param  None.
/// @retval ESP8266 OK or ERROR.

ESP8266_Error_Typedef ESP8266_MQTT_CLEAN()
{
    char *cmd = "AT+MQTTCLEAN=0";

    if(ESP8266_Send_AT_Command_Times(cmd, "OK\r\n", 0xffff, 2)){
        printf("Error: Fail to Disconnect MQTT \n");
        return ESP8266_ERROR;
    }else{
        ESP8266_MQTT_InitStruct.mqttStatus = NO_INIT;
        printf("OK: Disconnect MQTT successfully \n");
    }

    return ESP8266_OK;
}


/// @brief  Send key-value to MQTT.
/// @param  dataSend: The whole key-value.
/// @param  deviceId: Device id.
/// @param  deviceType: Device type.
/// @param  dataType: Data type.
/// @param  dataValue: Data value.
/// @retval None.

void ESP8266_Data_Send(char *dataSend, char *deviceId, char *deviceType, char *dataType, float dataValue)
{
    sprintf(dataSend,"{\r\n\"device_id\":\"%s\",\r\n\"device_type\":\"%s\",\r\n\"data_type\":\"%s\",\r\n\"data_value\":\"%.2f\"\r\n}",
                        deviceId, deviceType, dataType, dataValue);
    printf("data sent is %s \n", dataSend);
}

esp8266.h

typedef enum{
    NO_INIT                             = (uint8_t)0,
    USERCFG_SET                         = (uint8_t)1,
    CONNCFG_SET                         = (uint8_t)2,
    DISCONNECTED                        = (uint8_t)3,
    CONNECTED                           = (uint8_t)4,
    CONNECTED_NO_SUB                    = (uint8_t)5,
    CONNECTED_AND_SUB                   = (uint8_t)6
} ESP8266_MQTT_Status_Typedef;

typedef enum{
    NO_TLS                              = (uint8_t)1,
    TLS_NO_CA                           = (uint8_t)2,
    TLS_SERVICE_CA                      = (uint8_t)3,
    TLS_CLIENT_CA                       = (uint8_t)4,
    TLS_SERVICE_CLIENT_CA               = (uint8_t)5,
    WS_TCP                              = (uint8_t)6,
    WSS_NO_CA                           = (uint8_t)7,
    WSS_SERVICE_CA                      = (uint8_t)8,
    WSS_CLIENT_CA                       = (uint8_t)9,
    WSS_SERVICE_CLIENT_CA               = (uint8_t)10
} ESP8266_MQTT_Scheme_Typedef;

#define ESP8266_MQTT_CLIENTIP           "mm32f3270"
#define ESP8266_MQTT_USERNAME           "mm32"
#define ESP8266_MQTT_PSD                "mm32psd"
#define ESP8266_MQTT_HOST               "broker-cn.emqx.io"
#define ESP8266_MQTT_HOST_IPADDR_0      47
#define ESP8266_MQTT_HOST_IPADDR_1      111
#define ESP8266_MQTT_HOST_IPADDR_2      117
#define ESP8266_MQTT_HOST_IPADDR_3      220
#define ESP8266_MQTT_PORT               1883
#define ESP8266_MQTT_TOPIC              "esp8266"

typedef struct
{
    uint8_t                             mqttIPAddr0;
    uint8_t                             mqttIPAddr1;
    uint8_t                             mqttIPAddr2;
    uint8_t                             mqttIPAddr3;
}ESP8266_MQTT_IPADDR_Typedef;

typedef struct
{
    ESP8266_MQTT_IPADDR_Typedef         ipAddr;
    uint32_t                            port;
    char*                               clientID;
    char*                               username;
    char*                               password;
    ESP8266_MQTT_Scheme_Typedef         scheme;
    ESP8266_MQTT_Status_Typedef         mqttStatus;
} ESP8266_MQTT_Typedef;
ESP8266_MQTT_Typedef ESP8266_MQTT_InitStruct;