MQTT Client example program. Ethernet connection is via an ENC28J60 module.
Dependencies: UIPEthernet MQTTClient
main.cpp
- Committer:
- hudakz
- Date:
- 2015-11-29
- Revision:
- 9:18b414a8c5f7
- Parent:
- 8:7b4e0d15249f
- Child:
- 10:27440d67d4f2
File content as of revision 9:18b414a8c5f7:
// In this example we create an MQTT client. // It's publishing messages with topic 'example/hello' and 'Hello World!' payload. // The MQTT client also subscribes to some topics which are in its interest to receive. // Ethernet connection is assured by an affordable ENC28J60 Ethernet module. #include "mbed.h" #include <UIPEthernet.h> #include <UIPClient.h> #include <MQTTClient.h> #include <string> Serial pc(USBTX, USBRX); // UIPEthernet is the name of a global instance of UIPEthernetClass. // Do not change the name! It is used within the UIPEthernet library. // Adapt the SPI pin names to your mbed platform/board if not present yet. #if defined(TARGET_LPC1768) UIPEthernetClass UIPEthernet(p11, p12, p13, p8); // mosi, miso, sck, cs #elif defined(TARGET_NUCLEO_F103RB) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_F030R8) || defined(TARGET_NUCLEO_F401RE) \ || defined(TARGET_NUCLEO_F302R8) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_F411RE) || defined(TARGET_NUCLEO_F334R8) \ || defined(TARGET_NUCLEO_F072RB) || defined(TARGET_NUCLEO_F091RC) || defined(TARGET_NUCLEO_F303RE) || defined(TARGET_NUCLEO_F070RB) \ || defined(TARGET_KL25Z ) || defined(TARGET_KL46Z) || defined(TARGET_K64F) || defined(TARGET_KL05Z) \ || defined(TARGET_K20D50M) || defined(TARGET_K22F) \ || defined(TARGET_NRF51822) \ || defined(TARGET_RZ_A1H) UIPEthernetClass UIPEthernet(D11, D12, D13, D10); // mosi, miso, sck, cs #endif // MAC number must be unique within the connected network. Modify as appropriate. const uint8_t MY_MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 }; // MQTT broker is like a post office. // Its task is to distribute messages published by clients to all subscribers (other clients). // So the 'example/hello' messages published by this client will be sent to the broker. // Then the broker will send them to all clients which subscribed to such topic (example/hello). // Also this client will receive all messages with topics it subscribed to (if published such by other clients). // 'Mosquitto' is a free implementation of MQTT broker for Linux (e.g. Raspberry Pi, Ubuntu etc.) IPAddress serverIP(192, 168, 1, 30); // IP address of your MQTT broker (change to match) EthernetClient ethernetClient; void onMqttMessage(char* topic, uint8_t* payload, unsigned int length); MQTTClient mqttClient(serverIP, 1883, onMqttMessage, ethernetClient); char message_buff[100]; // buffer to store received messages #define DHCP 1 // comment out this line if you'd like to use static IP address #if !defined(DHCP) // In case you'd like to use static IP address: // IP address must be unique and compatible with your network. // Change as appropriate. const IPAddress MY_IP(192, 168, 1, 181); #endif /** * @brief * @note * @param * @retval */ int main(void) { const int MAX_TRIES = 5; const unsigned long INTERVAL = 5; int i = 0; bool connected = false; char* payload = "Hello World!"; unsigned long t = 0; unsigned long lastTime = t; // initialize the ethernet device #if defined(DHCP) pc.printf("Searching for DHCP server..\r\n"); if(UIPEthernet.begin(MY_MAC) != 1) { pc.printf("No DHCP server found.\r\n"); pc.printf("Exiting application.\r\n"); return 0; } pc.printf("DHCP server found and configuration info received.\r\n"); IPAddress localIP = UIPEthernet.localIP(); pc.printf("Local IP = "); for(uint8_t i = 0; i < 3; i++) pc.printf("%d.", localIP[i]); pc.printf("%d\r\n", localIP[3]); #else UIPEthernet.begin(MY_MAC, MY_IP); #endif pc.printf("Connecting to MQTT broker ..\r\n"); do { wait(1.0); connected = mqttClient.connect("myMQTTHelloClient"); } while(!connected && (i++ < MAX_TRIES)); if(connected) { pc.printf("MQTT broker connected.\r\n"); // We can subscribe to various topics published by other clients. pc.printf("Subscribing to topics:\r\n"); pc.printf(" outdoor/temperature\r\n"); pc.printf(" boiler/outlet/temperature\r\n"); mqttClient.subscribe("outdoor/temperature"); mqttClient.subscribe("boiler/outlet/temperature"); } else { pc.printf("Failed to connect to MQTT broker.\r\n"); } while(1) { t = time(NULL); if(t > (lastTime + INTERVAL)) { lastTime = t; if(connected) { pc.printf("Publishing: example/hello\r\n"); mqttClient.publish("example/hello", payload); } } mqttClient.loop(); // MQTT client loop processing (receiving messages) } } /** * @brief Called on new MQTT message arrival * @note * @param topic: The topic of the new message * payload: The payload of the new message * length: Payload's length * @retval */ void onMqttMessage(char* topic, uint8_t* payload, unsigned int length) { int i = 0; pc.printf("Message arrived:\r\n"); pc.printf(" Topic: %s\r\n", topic); pc.printf(" Length: %d\r\n", length); // create character buffer with ending null terminator (string) for(i = 0; i < length; i++) { message_buff[i] = payload[i]; } message_buff[i] = '\0'; pc.printf(" Payload: %s\r\n", message_buff); }