Zoltan Hudak / Mbed OS MQTT_Hello_ENC28J60

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

Dependencies:   UIPEthernet MQTTClient

main.cpp@12:3af0ae09bd01, 2019-09-03 (annotated)

Committer:
hudakz
Date:
Tue Sep 03 13:45:22 2019 +0000
Revision:
12:3af0ae09bd01
Parent:
11:a049ad4b63c0
Child:
13:6b2f125cc9b8
Mbed OS 5 enabled.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 8:7b4e0d15249f 1 // In this example we create an MQTT client.
hudakz 8:7b4e0d15249f 2 // It's publishing messages with topic 'example/hello' and 'Hello World!' payload.
hudakz 8:7b4e0d15249f 3 // The MQTT client also subscribes to some topics which are in its interest to receive.
hudakz 8:7b4e0d15249f 4 // Ethernet connection is assured by an affordable ENC28J60 Ethernet module.
hudakz 12:3af0ae09bd01 5 //
hudakz 9:18b414a8c5f7 6 // MQTT broker is like a post office.
hudakz 9:18b414a8c5f7 7 // Its task is to distribute messages published by clients to all subscribers (other clients).
hudakz 9:18b414a8c5f7 8 // So the 'example/hello' messages published by this client will be sent to the broker.
hudakz 9:18b414a8c5f7 9 // Then the broker will send them to all clients which subscribed to such topic (example/hello).
hudakz 9:18b414a8c5f7 10 // Also this client will receive all messages with topics it subscribed to (if published such by other clients).
hudakz 9:18b414a8c5f7 11 // 'Mosquitto' is a free implementation of MQTT broker for Linux (e.g. Raspberry Pi, Ubuntu etc.)
hudakz 12:3af0ae09bd01 12 //
hudakz 12:3af0ae09bd01 13 #include "mbed.h"
hudakz 12:3af0ae09bd01 14 #include "UipEthernet.h"
hudakz 12:3af0ae09bd01 15 #include "MQTTClient.h"
hudakz 12:3af0ae09bd01 16 #include <string>
hudakz 12:3af0ae09bd01 17
hudakz 12:3af0ae09bd01 18 #define IP "192.168.1.35"
hudakz 12:3af0ae09bd01 19 #define GATEWAY "192.168.1.1"
hudakz 12:3af0ae09bd01 20 #define NETMASK "255.255.255.0"
hudakz 12:3af0ae09bd01 21 #define SERVER_IP "192.168.1.31" // IP address of your MQTT broker. Change to match your case.
hudakz 12:3af0ae09bd01 22
hudakz 12:3af0ae09bd01 23 // MAC address must unique within the connected network! Change it as needed.
hudakz 12:3af0ae09bd01 24 const uint8_t MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x06 };
hudakz 12:3af0ae09bd01 25 UipEthernet net(MAC, D11, D12, D13, D10); // mac, mosi, miso, sck, cs
hudakz 12:3af0ae09bd01 26 void onMqttMessage(char* topic, uint8_t* payload, unsigned int length); // ISR (callback) to handle arrived MQTT messages.
hudakz 12:3af0ae09bd01 27 TcpClient client;
hudakz 12:3af0ae09bd01 28 MQTTClient mqttClient(SERVER_IP, 1883, onMqttMessage, client);
hudakz 12:3af0ae09bd01 29 char message_buff[MQTT_MAX_PACKET_SIZE]; // buffer to store received messages
hudakz 9:18b414a8c5f7 30
hudakz 2:6cd2390302ac 31 /**
hudakz 2:6cd2390302ac 32 * @brief
hudakz 2:6cd2390302ac 33 * @note
hudakz 2:6cd2390302ac 34 * @param
hudakz 2:6cd2390302ac 35 * @retval
hudakz 2:6cd2390302ac 36 */
hudakz 12:3af0ae09bd01 37 int main(void)
hudakz 12:3af0ae09bd01 38 {
hudakz 12:3af0ae09bd01 39 const int MAX_TRIES = 5;
hudakz 12:3af0ae09bd01 40 const time_t INTERVAL = 5;
hudakz 12:3af0ae09bd01 41 int i = 0;
hudakz 12:3af0ae09bd01 42 bool connected = false;
hudakz 12:3af0ae09bd01 43 char payload[] = "Hello World!";
hudakz 12:3af0ae09bd01 44 time_t t = 0;
hudakz 12:3af0ae09bd01 45 time_t lastTime = t;
hudakz 8:7b4e0d15249f 46
hudakz 12:3af0ae09bd01 47 // Bring up the ethernet interface
hudakz 12:3af0ae09bd01 48 //net.set_network(IP, NETMASK, GATEWAY); // include this to use static IP address
hudakz 12:3af0ae09bd01 49 printf("MQTT client example\n");
hudakz 12:3af0ae09bd01 50 if (net.connect() != 0) {
hudakz 12:3af0ae09bd01 51 printf("Error connecting\n");
hudakz 12:3af0ae09bd01 52 return -1;
hudakz 3:3e5f4d503a66 53 }
hudakz 12:3af0ae09bd01 54
hudakz 12:3af0ae09bd01 55 // Show the network address
hudakz 12:3af0ae09bd01 56 const char* ip = net.get_ip_address();
hudakz 12:3af0ae09bd01 57 const char* netmask = net.get_netmask();
hudakz 12:3af0ae09bd01 58 const char* gateway = net.get_gateway();
hudakz 12:3af0ae09bd01 59 printf("IP address: %s\n", ip ? ip : "None");
hudakz 12:3af0ae09bd01 60 printf("Netmask: %s\n", netmask ? netmask : "None");
hudakz 12:3af0ae09bd01 61 printf("Gateway: %s\n", gateway ? gateway : "None");
hudakz 12:3af0ae09bd01 62
hudakz 12:3af0ae09bd01 63 printf("Connecting to the MQTT broker ... ");
hudakz 11:a049ad4b63c0 64 do {
hudakz 0:158b106f3cfc 65 wait(1.0);
hudakz 0:158b106f3cfc 66 connected = mqttClient.connect("myMQTTHelloClient");
hudakz 12:3af0ae09bd01 67 } while (!connected && (i++ < MAX_TRIES));
hudakz 0:158b106f3cfc 68
hudakz 12:3af0ae09bd01 69 if (connected) {
hudakz 12:3af0ae09bd01 70 printf("Connected.\r\n\r\n");
hudakz 9:18b414a8c5f7 71 // We can subscribe to various topics published by other clients.
hudakz 12:3af0ae09bd01 72 printf("Subscribing to topics:\r\n");
hudakz 12:3af0ae09bd01 73 printf("outdoor/temperature\r\n");
hudakz 12:3af0ae09bd01 74 printf("boiler/outlet/temperature\r\n");
hudakz 12:3af0ae09bd01 75 printf("\r\n");
hudakz 8:7b4e0d15249f 76 mqttClient.subscribe("outdoor/temperature");
hudakz 8:7b4e0d15249f 77 mqttClient.subscribe("boiler/outlet/temperature");
hudakz 2:6cd2390302ac 78 }
hudakz 2:6cd2390302ac 79 else {
hudakz 12:3af0ae09bd01 80 printf("Failed to connect to the MQTT broker.\r\n");
hudakz 12:3af0ae09bd01 81 return -1;
hudakz 0:158b106f3cfc 82 }
hudakz 0:158b106f3cfc 83
hudakz 12:3af0ae09bd01 84 while (1) {
hudakz 0:158b106f3cfc 85 t = time(NULL);
hudakz 12:3af0ae09bd01 86 if (t > (lastTime + INTERVAL)) {
hudakz 0:158b106f3cfc 87 lastTime = t;
hudakz 12:3af0ae09bd01 88 if (connected) {
hudakz 12:3af0ae09bd01 89 printf("Publishing: example/hello\r\n");
hudakz 0:158b106f3cfc 90 mqttClient.publish("example/hello", payload);
hudakz 0:158b106f3cfc 91 }
hudakz 2:6cd2390302ac 92 }
hudakz 12:3af0ae09bd01 93
hudakz 3:3e5f4d503a66 94 mqttClient.loop(); // MQTT client loop processing (receiving messages)
hudakz 0:158b106f3cfc 95 }
hudakz 0:158b106f3cfc 96 }
hudakz 0:158b106f3cfc 97
hudakz 2:6cd2390302ac 98 /**
hudakz 2:6cd2390302ac 99 * @brief Called on new MQTT message arrival
hudakz 8:7b4e0d15249f 100 * @note
hudakz 2:6cd2390302ac 101 * @param topic: The topic of the new message
hudakz 2:6cd2390302ac 102 * payload: The payload of the new message
hudakz 2:6cd2390302ac 103 * length: Payload's length
hudakz 2:6cd2390302ac 104 * @retval
hudakz 2:6cd2390302ac 105 */
hudakz 12:3af0ae09bd01 106 void onMqttMessage(char* topic, uint8_t* payload, unsigned int length)
hudakz 12:3af0ae09bd01 107 {
hudakz 0:158b106f3cfc 108 int i = 0;
hudakz 0:158b106f3cfc 109
hudakz 12:3af0ae09bd01 110 printf("Message arrived:\r\n");
hudakz 12:3af0ae09bd01 111 printf(" Topic: %s\r\n", topic);
hudakz 12:3af0ae09bd01 112 printf(" Length: %d\r\n", length);
hudakz 0:158b106f3cfc 113
hudakz 0:158b106f3cfc 114 // create character buffer with ending null terminator (string)
hudakz 12:3af0ae09bd01 115 for (i = 0; i < length; i++) {
hudakz 0:158b106f3cfc 116 message_buff[i] = payload[i];
hudakz 0:158b106f3cfc 117 }
hudakz 0:158b106f3cfc 118
hudakz 0:158b106f3cfc 119 message_buff[i] = '\0';
hudakz 12:3af0ae09bd01 120 printf(" Payload: %s\r\n\r\n", message_buff);
hudakz 0:158b106f3cfc 121 }