Zoltan Hudak / Mbed OS MQTT_Hello_ENC28J60

MQTT Client example program. Ethernet connection is via an ENC28J60 module.

Dependencies:   UIPEthernet MQTTClient

main.cpp@2:6cd2390302ac, 2015-03-21 (annotated)

Committer:
hudakz
Date:
Sat Mar 21 23:45:41 2015 +0000
Revision:
2:6cd2390302ac
Parent:
1:49fb5754df16
Child:
3:3e5f4d503a66
Comments updated.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 2:6cd2390302ac 1 // In this example an MQTT client is created.
hudakz 2:6cd2390302ac 2 // It is publishing a simple 'example/hello' message with payload 'Hello World.'
hudakz 2:6cd2390302ac 3 // and subscribes to 'outdoor/temperature' messages assumably published by other client(s).
hudakz 2:6cd2390302ac 4 // Ethernet connection is assured via an ENC28J60 module.
hudakz 0:158b106f3cfc 5 #include "mbed.h"
hudakz 0:158b106f3cfc 6 #include <UIPEthernet.h>
hudakz 0:158b106f3cfc 7 #include <UIPClient.h>
hudakz 0:158b106f3cfc 8 #include <MQTTClient.h>
hudakz 0:158b106f3cfc 9 #include <string>
hudakz 0:158b106f3cfc 10
hudakz 2:6cd2390302ac 11 using namespace std;
hudakz 2:6cd2390302ac 12
hudakz 2:6cd2390302ac 13 Serial pc(USBTX, USBRX);
hudakz 0:158b106f3cfc 14
hudakz 0:158b106f3cfc 15 // UIPEthernet is the name of a global instance of UIPEthernetClass.
hudakz 0:158b106f3cfc 16 // Do not change the name! It is used within the UIPEthernet library.
hudakz 0:158b106f3cfc 17 // Adapt the SPI pin names to your mbed platform/board if not present yet.
hudakz 0:158b106f3cfc 18 #if defined(TARGET_LPC1768)
hudakz 2:6cd2390302ac 19 UIPEthernetClass UIPEthernet(p11, p12, p13, p8); // mosi, miso, sck, cs
hudakz 0:158b106f3cfc 20 #elif defined(TARGET_LPC1114)
hudakz 2:6cd2390302ac 21 UIPEthernetClass UIPEthernet(dp2, dp1, dp6, dp25); // mosi, miso, sck, cs
hudakz 0:158b106f3cfc 22 #elif defined(TARGET_LPC11U68)
hudakz 2:6cd2390302ac 23 UIPEthernetClass UIPEthernet(P0_9, P0_8, P1_29, P0_2); // mosi, miso, sck, cs
hudakz 2:6cd2390302ac 24 #elif defined(TARGET_NUCLEO_F103RB)
hudakz 2:6cd2390302ac 25 UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6); // mosi, miso, sck, cs
hudakz 0:158b106f3cfc 26 #endif
hudakz 0:158b106f3cfc 27
hudakz 0:158b106f3cfc 28 // Make sure that the MAC number is unique within the connected network.
hudakz 2:6cd2390302ac 29 const uint8_t MY_MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 };
hudakz 0:158b106f3cfc 30 // IP address must be unique and compatible with your network too. Change as appropriate.
hudakz 2:6cd2390302ac 31 const IPAddress MY_IP(192, 168, 1, 181);
hudakz 2:6cd2390302ac 32 char message_buff[100];
hudakz 2:6cd2390302ac 33 IPAddress serverIP(192, 168, 1, 30); // MQTT broker (e.g. 'Mosquitto' running on a Raspberry Pi or Linux machine)
hudakz 2:6cd2390302ac 34 EthernetClient ethernetClient;
hudakz 2:6cd2390302ac 35 void onMqttMessage(char* topic, uint8_t* payload, unsigned int length);
hudakz 2:6cd2390302ac 36 MQTTClient mqttClient(serverIP, 1883, onMqttMessage, ethernetClient);
hudakz 0:158b106f3cfc 37
hudakz 2:6cd2390302ac 38 /**
hudakz 2:6cd2390302ac 39 * @brief
hudakz 2:6cd2390302ac 40 * @note
hudakz 2:6cd2390302ac 41 * @param
hudakz 2:6cd2390302ac 42 * @retval
hudakz 2:6cd2390302ac 43 */
hudakz 2:6cd2390302ac 44
hudakz 2:6cd2390302ac 45 int main(void) {
hudakz 0:158b106f3cfc 46 const int MAX_COUNT = 5;
hudakz 0:158b106f3cfc 47 int i = 0;
hudakz 0:158b106f3cfc 48 bool connected = false;
hudakz 0:158b106f3cfc 49 char* payload = "Hello World.";
hudakz 0:158b106f3cfc 50 time_t t = 0;
hudakz 0:158b106f3cfc 51 time_t lastTime = t;
hudakz 0:158b106f3cfc 52
hudakz 0:158b106f3cfc 53 // initialize the ethernet device
hudakz 2:6cd2390302ac 54
hudakz 1:49fb5754df16 55 UIPEthernet.begin(MY_MAC, MY_IP);
hudakz 2:6cd2390302ac 56
hudakz 2:6cd2390302ac 57 // The MQTT broker is like a post office distributing messages published by clients to all subscribers (clients).
hudakz 2:6cd2390302ac 58 // So the 'example/hello' messages published by this client will be sent via the broker to all clients which subscribed to such messages.
hudakz 2:6cd2390302ac 59 // This way also this client will receive all subscribed messages (in this case 'outdoor/temperature' messages)
hudakz 2:6cd2390302ac 60 // published by other clients (however not directly but via the broker).
hudakz 2:6cd2390302ac 61 pc.printf("Connecting to MQTT broker ..\r\n");
hudakz 2:6cd2390302ac 62 do
hudakz 2:6cd2390302ac 63 {
hudakz 0:158b106f3cfc 64 wait(1.0);
hudakz 0:158b106f3cfc 65 connected = mqttClient.connect("myMQTTHelloClient");
hudakz 0:158b106f3cfc 66 } while(!connected && (i < MAX_COUNT));
hudakz 0:158b106f3cfc 67
hudakz 0:158b106f3cfc 68 if(connected) {
hudakz 2:6cd2390302ac 69 pc.printf("MQTT broker connected.\r\n");
hudakz 0:158b106f3cfc 70 mqttClient.subscribe("outdoor/temperature");
hudakz 0:158b106f3cfc 71 pc.printf("Subscribed to: outdoor/temperature\r\n");
hudakz 2:6cd2390302ac 72 }
hudakz 2:6cd2390302ac 73 else {
hudakz 2:6cd2390302ac 74 pc.printf("Failed to connect to MQTT broker.\r\n");
hudakz 0:158b106f3cfc 75 }
hudakz 0:158b106f3cfc 76
hudakz 0:158b106f3cfc 77 while(1) {
hudakz 0:158b106f3cfc 78 t = time(NULL);
hudakz 0:158b106f3cfc 79 if(t > (lastTime + 5)) {
hudakz 0:158b106f3cfc 80 lastTime = t;
hudakz 0:158b106f3cfc 81 if(connected) {
hudakz 0:158b106f3cfc 82 mqttClient.publish("example/hello", payload);
hudakz 0:158b106f3cfc 83 pc.printf("Published: example/hello\r\n");
hudakz 0:158b106f3cfc 84 }
hudakz 2:6cd2390302ac 85 }
hudakz 0:158b106f3cfc 86
hudakz 0:158b106f3cfc 87 mqttClient.loop(); // MQTT client loop processing
hudakz 0:158b106f3cfc 88 }
hudakz 0:158b106f3cfc 89 }
hudakz 0:158b106f3cfc 90
hudakz 2:6cd2390302ac 91 /**
hudakz 2:6cd2390302ac 92 * @brief Called on new MQTT message arrival
hudakz 2:6cd2390302ac 93 * @note
hudakz 2:6cd2390302ac 94 * @param topic: The topic of the new message
hudakz 2:6cd2390302ac 95 * payload: The payload of the new message
hudakz 2:6cd2390302ac 96 * length: Payload's length
hudakz 2:6cd2390302ac 97 * @retval
hudakz 2:6cd2390302ac 98 */
hudakz 2:6cd2390302ac 99 void onMqttMessage(char* topic, uint8_t* payload, unsigned int length) {
hudakz 0:158b106f3cfc 100 int i = 0;
hudakz 0:158b106f3cfc 101
hudakz 0:158b106f3cfc 102 pc.printf("Message arrived:\r\n");
hudakz 0:158b106f3cfc 103 pc.printf(" Topic: %s\r\n", topic);
hudakz 0:158b106f3cfc 104 pc.printf(" Length: %d\r\n", length);
hudakz 0:158b106f3cfc 105
hudakz 0:158b106f3cfc 106 // create character buffer with ending null terminator (string)
hudakz 0:158b106f3cfc 107 for(i = 0; i < length; i++) {
hudakz 0:158b106f3cfc 108 message_buff[i] = payload[i];
hudakz 0:158b106f3cfc 109 }
hudakz 0:158b106f3cfc 110
hudakz 0:158b106f3cfc 111 message_buff[i] = '\0';
hudakz 0:158b106f3cfc 112 pc.printf(" Payload: %s\r\n", message_buff);
hudakz 0:158b106f3cfc 113 }