Merge pull request #24 from adafruit/get-mqtt-method

Use /get MQTT topic to trigger resend of feed data.

Author: abachman

examples/adafruitio_00_publish/adafruitio_00_publish.ino

@@ -66,7 +66,9 @@ void loop() {
   // increment the count by 1
   count++;
 
-  // wait one second (1000 milliseconds == 1 second)
-  delay(1000);
+  // Adafruit IO is rate limited for publishing, so a delay is required in
+  // between feed->save events. In this example, we will wait three seconds
+  // (1000 milliseconds == 1 second) during each loop.
+  delay(3000);
 
 }

examples/adafruitio_01_subscribe/adafruitio_01_subscribe.ino

@@ -32,14 +32,6 @@ void setup() {
 
   Serial.print("Connecting to Adafruit IO");
 
-  // because Adafruit IO doesn't support the MQTT
-  // retain flag right now, we need to load the
-  // last value for the "counter" feed manually and
-  // send it our handleMessage function
-  if (counter->exists()) {
-    handleMessage(counter->lastValue());
-  }
-
   // start MQTT connection to io.adafruit.com
   io.connect();
 
@@ -52,12 +44,16 @@ void setup() {
   // wait for an MQTT connection
   // NOTE: when blending the HTTP and MQTT API, always use the mqttStatus
   // method to check on MQTT connection status specifically
-
   while(io.mqttStatus() < AIO_CONNECTED) {
     Serial.print(".");
     delay(500);
   }
 
+  // Because Adafruit IO doesn't support the MQTT retain flag, we can use the
+  // get() function to ask IO to resend the last value for this feed to just
+  // this MQTT client after the io client is connected.
+  counter->get();
+
   // we are connected
   Serial.println();
   Serial.println(io.statusText());
@@ -72,6 +68,9 @@ void loop() {
   // io.adafruit.com, and processes any incoming data.
   io.run();
 
+  // Because this sketch isn't publishing, we don't need
+  // a delay() in the main program loop.
+
 }
 
 // this function is called whenever a 'counter' message

examples/adafruitio_02_pubsub/adafruitio_02_pubsub.ino

@@ -22,6 +22,19 @@
 // this int will hold the current count for our sketch
 int count = 0;
 
+// Track time of last published messages and limit feed->save events to once
+// every IO_LOOP_DELAY milliseconds.
+//
+// Because this sketch is publishing AND subscribing, we can't use a long
+// delay() function call in the main loop since that would prevent io.run()
+// from being called often enough to receive all incoming messages.
+//
+// Instead, we can use the millis() function to get the current time in
+// milliseconds and avoid publishing until IO_LOOP_DELAY milliseconds have
+// passed.
+#define IO_LOOP_DELAY 5000
+unsigned long lastUpdate = 0;
+
 // set up the 'counter' feed
 AdafruitIO_Feed *counter = io.feed("counter");
 
@@ -53,6 +66,7 @@ void setup() {
   // we are connected
   Serial.println();
   Serial.println(io.statusText());
+  counter->get();
 
 }
 
@@ -64,16 +78,18 @@ void loop() {
   // io.adafruit.com, and processes any incoming data.
   io.run();
 
-  // save count to the 'counter' feed on Adafruit IO
-  Serial.print("sending -> ");
-  Serial.println(count);
-  counter->save(count);
+  if (millis() > (lastUpdate + IO_LOOP_DELAY)) {
+    // save count to the 'counter' feed on Adafruit IO
+    Serial.print("sending -> ");
+    Serial.println(count);
+    counter->save(count);
 
-  // increment the count by 1
-  count++;
+    // increment the count by 1
+    count++;
 
-  // wait one second (1000 milliseconds == 1 second)
-  delay(1000);
+    // after publishing, store the current time
+    lastUpdate = millis();
+  }
 
 }
 

examples/adafruitio_03_multiple_feeds/adafruitio_03_multiple_feeds.ino

@@ -24,6 +24,11 @@ int count = 0;
 // holds the boolean (true/false) state of the light
 bool is_on = false;
 
+// track time of last published messages and limit feed->save events to once
+// every IO_LOOP_DELAY milliseconds
+#define IO_LOOP_DELAY 15000
+unsigned long lastUpdate;
+
 // set up the 'counter' feed
 AdafruitIO_Feed *counter = io.feed("counter");
 
@@ -65,47 +70,54 @@ void setup() {
   Serial.println();
   Serial.println(io.statusText());
 
+  // make sure all feeds get their current values right away
+  counter->get();
+  counter_two->get();
+  light->get();
+
 }
 
 void loop() {
 
   // process messages and keep connection alive
   io.run();
 
-  Serial.println();
-
-  // save current count to 'counter'
-  Serial.print("sending -> counter ");
-  Serial.println(count);
-  counter->save(count);
-
-  // increment the count by 1 and save the value to 'counter-two'
-  Serial.print("sending -> counter-two ");
-  Serial.println(count + 1);
-  counter_two->save(count + 1);
-
-  // print out the light value we are sending to Adafruit IO
-  Serial.print("sending -> light ");
-  if(is_on)
-    Serial.println("is on.\n");
-  else
-    Serial.println("is off.\n");
-
-  // save state of light to 'light' feed
-  light->save(is_on);
-
-  // increment count value
-  count++;
-
-  // for the purpose of this demo, toggle the
-  // light state based on the count value
-  if((count % 2) == 0)
-    is_on = true;
-  else
-    is_on = false;
-
-  // wait two seconds (2000 milliseconds == 2 seconds)
-  delay(2000);
+  if (millis() > (lastUpdate + IO_LOOP_DELAY)) {
+    Serial.println();
+
+    // save current count to 'counter'
+    Serial.print("sending -> counter ");
+    Serial.println(count);
+    counter->save(count);
+
+    // increment the count by 1 and save the value to 'counter-two'
+    Serial.print("sending -> counter-two ");
+    Serial.println(count + 1);
+    counter_two->save(count + 1);
+
+    // print out the light value we are sending to Adafruit IO
+    Serial.print("sending -> light ");
+    if(is_on)
+      Serial.println("is on.\n");
+    else
+      Serial.println("is off.\n");
+
+    // save state of light to 'light' feed
+    light->save(is_on);
+
+    // increment count value
+    count++;
+
+    // for the purpose of this demo, toggle the
+    // light state based on the count value
+    if((count % 2) == 0)
+      is_on = true;
+    else
+      is_on = false;
+
+    // update timer
+    lastUpdate = millis();
+  }
 
 }
 

examples/adafruitio_04_location/adafruitio_04_location.ino

@@ -27,6 +27,11 @@ double lat = 42.331427;
 double lon = -83.045754;
 double ele = 0;
 
+// track time of last published messages and limit feed->save events to once
+// every IO_LOOP_DELAY milliseconds
+#define IO_LOOP_DELAY 5000
+unsigned long lastUpdate;
+
 // set up the 'location' feed
 AdafruitIO_Feed *location = io.feed("location");
 
@@ -55,6 +60,7 @@ void setup() {
   // we are connected
   Serial.println();
   Serial.println(io.statusText());
+  location->get();
 
 }
 
@@ -63,28 +69,30 @@ void loop() {
   // process messages and keep connection alive
   io.run();
 
-  Serial.println("----- sending -----");
-  Serial.print("value: ");
-  Serial.println(value);
-  Serial.print("lat: ");
-  Serial.println(lat, 6);
-  Serial.print("lon: ");
-  Serial.println(lon, 6);
-  Serial.print("ele: ");
-  Serial.println(ele, 2);
-
-  // save value and location data to the
-  // 'location' feed on Adafruit IO
-  location->save(value, lat, lon, ele);
-
- // shift all values (for demo purposes)
-  value += 1;
-  lat -= 0.01;
-  lon += 0.02;
-  ele += 1;
-
-  // wait one second (1000 milliseconds == 1 second)
-  delay(1000);
+  if (millis() > (lastUpdate + IO_LOOP_DELAY)) {
+    Serial.println("----- sending -----");
+    Serial.print("value: ");
+    Serial.println(value);
+    Serial.print("lat: ");
+    Serial.println(lat, 6);
+    Serial.print("lon: ");
+    Serial.println(lon, 6);
+    Serial.print("ele: ");
+    Serial.println(ele, 2);
+
+    // save value and location data to the
+    // 'location' feed on Adafruit IO
+    location->save(value, lat, lon, ele);
+
+    // shift all values (for demo purposes)
+    value += 1;
+    lat -= 0.01;
+    lon += 0.02;
+    ele += 1;
+
+    // wait one second (1000 milliseconds == 1 second)
+    lastUpdate = millis();
+  }
 
 }