5.7.1 Execution

/** PubNub settings. */
#define MAIN_PUBNUB_PUBLISH_KEY                         "demo" // "pub-c-e71e5bed-0fee-4263-a843-c9de85c8825e" 
#define MAIN_PUBNUB_SUBSCRIBE_KEY                       "demo" // "sub-c-746522be-7e35-11e5-98ab-0619f8985a4f"
#define MAIN_PUBNUB_CHANNEL				 "WINC1500_00:00" /**< Do not change - last digits will be updated with MAC address. */

The user can create their publish key and subscribe key in the PubNub web page.

/** Wi-Fi Settings */
#define MAIN_WLAN_SSID        "DEMO_AP" /* < Destination SSID */
#define MAIN_WLAN_AUTH        M2M_WIFI_SEC_WPA_PSK /* < Security manner */
#define MAIN_WLAN_PSK         "12345678" /* < Password for Destination SSID */

/* Initialize Socket API. */
socketInit();
registerSocketCallback(m2m_tcp_socket_handler, socket_resolve_cb);
...
/* Connect to AP using Wi-Fi settings from main.h. */
printf("main: Wi-Fi connecting to AP using hardcoded credentials...\r\n");
m2m_wifi_connect((char *)MAIN_WLAN_SSID, sizeof(MAIN_WLAN_SSID),
			MAIN_WLAN_AUTH, (char *)MAIN_WLAN_PSK, M2M_WIFI_CH_ALL);

while (1) {
	m2m_wifi_handle_events(NULL)

	/* Device is connected to AP. */
	....
	printf("main: subscribe event, PNR_OK\r\n");
	pubnub_subscribe(pPubNubCfg, PubNubChannel);				
	}

	/* Process any received messages from the channel we subscribed. */
	while (1) {
		char const *msg = pubnub_get(pPubNubCfg);
	....
		/* Any other type of JSON message. */
		printf("main: received message: %s\r\n", msg);
		...
		pubnub_subscribe(pPubNubCfg, PubNubChannel);

The first step is to initialize the PubNub client module by calling the function pubnub_init(). This function receives three parameters which are publishkey, subscribe key and a pointer to the context retrieved from the pubnub_get_ctx function.

/* Initialize PubNub API. */
printf("main: PubNub configured with following settings:\r\n");
printf("main:  - Publish key: \"%s\", Subscribe key: \"%s\", Channel: \"%s\".\r\n\r\n",
PubNubPublishKey, PubNubSubscribeKey, PubNubChannel);
pPubNubCfg = pubnub_get_ctx(0);
pubnub_init(pPubNubCfg, PubNubPublishKey, PubNubSubscribeKey);

/* Publish the temperature measurements periodically. */
if (gu32MsTicks - gu32publishDelay > MAIN_PUBNUB_PUBLISH_INTERVAL) {
    gu32publishDelay = gu32MsTicks;
    adc_start_conversion(&adc_instance);
    temperature = at30tse_read_temperature();
    adc_read(&adc_instance, &light);
    ...
    pubnub_publish(pPubNubCfg, PubNubChannel, buf);

In order to subscribe to a Pubnub channel, we need to use pubnub_subscribe() and pubnub_get() functions as shown below:

char const *msg = pubnub_get(pPubNubCfg);
...
pubnub_subscribe(pPubNubCfg, PubNubChannel);