Add Basic Asynchronous Publish example. (#8)

* Add Basic Asynchronous Publish example.

* Add comment to setAlias method.

* Remove unused logic.

Author: nazt

examples/BasicAsyncPublish/BasicAsyncPublish.ino

@@ -0,0 +1,120 @@
+/*  NETPIE ESP8266 basic asynchronous publish sample                            */
+/*  More information visit : https://netpie.io             */
+
+#include <ESP8266WiFi.h>
+#include <MicroGear.h>
+#include "CMMC_Interval.hpp"
+
+const char* ssid     = <WIFI_SSID>;
+const char* password = <WIFI_KEY>;
+
+#define APPID   <APPID>
+#define KEY     <APPKEY>
+#define SECRET  <APPSECRET>
+#define ALIAS   "esp8266"
+
+
+WiFiClient client;
+CMMC_Interval timer001;
+
+int timer = 0;
+MicroGear microgear(client);
+
+/* If a new message arrives, do this */
+void onMsghandler(char *topic, uint8_t* msg, unsigned int msglen) {
+  msg[msglen] = '\0';
+  String _msg = String((char*)msg);
+
+  /* print message */
+  Serial.print("Incoming message --> ");
+  Serial.print(_msg);
+  Serial.printf(" at [%lu] \r\n", millis());
+
+}
+
+void onFoundgear(char *attribute, uint8_t* msg, unsigned int msglen) {
+  Serial.print("Found new member --> ");
+  for (int i = 0; i < msglen; i++) {
+    Serial.print((char)msg[i]);
+  }
+  Serial.println();
+}
+
+void onLostgear(char *attribute, uint8_t* msg, unsigned int msglen) {
+  Serial.print("Lost member --> ");
+  for (int i = 0; i < msglen; i++) {
+    Serial.print((char)msg[i]);
+  }
+  Serial.println();
+}
+
+/* When a microgear is connected, do this */
+void onConnected(char *attribute, uint8_t* msg, unsigned int msglen) {
+  Serial.println("Connected to NETPIE...");
+  /*
+    microgear can set its own alias, which to be used for others make a function call chat(). 
+    The alias will appear on the key management portal of netpie.io
+  */
+  
+  /* Set the alias of this microgear ALIAS */  
+  microgear.setAlias(ALIAS);
+}
+
+
+void setup() {
+  /* Add Event listeners */
+
+  /* Call onMsghandler() when new message arraives */
+  microgear.on(MESSAGE, onMsghandler);
+
+  /* Call onFoundgear() when new gear appear */
+  microgear.on(PRESENT, onFoundgear);
+
+  /* Call onLostgear() when some gear goes offline */
+  microgear.on(ABSENT, onLostgear);
+
+  /* Call onConnected() when NETPIE connection is established */
+  microgear.on(CONNECTED, onConnected);
+
+  Serial.begin(115200);
+  Serial.println("Starting...");
+
+  /* Initial WIFI, this is just a basic method to configure WIFI on ESP8266.                       */
+  /* You may want to use other method that is more complicated, but provide better user experience */
+  if (WiFi.begin(ssid, password)) {
+    while (WiFi.status() != WL_CONNECTED) {
+      delay(500);
+      Serial.print(".");
+    }
+  }
+
+  Serial.println("WiFi connected");
+  Serial.println("IP address: ");
+  Serial.println(WiFi.localIP());
+
+  Serial.println("Connecting to NETPIE.io");
+  /* Initial with KEY, SECRET and also set the ALIAS here */
+  microgear.init(KEY, SECRET, ALIAS);
+
+  /* connect to NETPIE to a specific APPID */
+  microgear.connect(APPID);
+}
+
+void loop() {
+  /* Call this method regularly otherwise the connection may be lost */
+  microgear.loop();
+  /* To check if the microgear is still connected */
+  if (microgear.connected()) {
+    // call microgear.chat every 2 seconds
+    timer001.every_ms(2000, []() {
+      Serial.printf("Publish at [%lu]\r\n", millis());
+      microgear.chat(ALIAS, "HELLO");
+    });
+
+  }
+  else {
+    Serial.println("connection lost, reconnect...");
+    microgear.connect(APPID);
+    delay(2000);
+  }
+}

examples/BasicAsyncPublish/CMMC_Interval.hpp

@@ -0,0 +1,37 @@
+#ifndef CMMC_NETPIE_INTERVAL_H
+#define CMMC_NETPIE_INTERVAL_H
+#include <Arduino.h>
+#include <functional>
+
+class CMMC_Interval
+{
+  private:
+    unsigned long _prev;
+    unsigned long _now;
+    unsigned long _threshold_ms;
+
+  public:
+    typedef std::function<void(void)> void_callback_t;
+
+    CMMC_Interval() {
+      _prev = millis();
+      _now  = millis();
+    };
+
+    ~CMMC_Interval() {
+    };
+
+    void every_ms(unsigned long ms, void_callback_t cb) {
+      _threshold_ms = ms;
+      _now  = millis();
+      unsigned long diff = _now - _prev;
+      if (diff >= _threshold_ms) {
+        _prev = millis();
+        cb();
+      }
+    }
+};
+
+
+#endif
+