Add Adafruit_MQTT_Client class that implements MQTT code for generic Arduino client. Add ESP8266 example using new MQTT client class. Fix bugs with using library on ESP8266 (move CC3000 to header-only class).

Adafruit_MQTT_Client.cpp

@@ -0,0 +1,72 @@
+#include "Adafruit_MQTT_Client.h"
+
+
+bool Adafruit_MQTT_Client::connectServer() {
+  // Grab server name from flash and copy to buffer for name resolution.
+  memset(buffer, 0, sizeof(buffer));
+  strcpy_P((char *)buffer, servername);
+  DEBUG_PRINT(F("Connecting to: ")); DEBUG_PRINTLN((char *)buffer);
+  // Connect and check for success (0 result).
+  int r = client->connect((char *)buffer, portnum);
+  DEBUG_PRINT(F("Connect result: ")); DEBUG_PRINTLN(r);
+  return r != 0;
+}
+
+bool Adafruit_MQTT_Client::disconnect() {
+  // Stop connection and return success (stop has no indication of failure).
+  client->stop();
+  return true;  
+}
+
+uint16_t Adafruit_MQTT_Client::readPacket(uint8_t *buffer, uint8_t maxlen,
+                                          int16_t timeout, 
+                                          bool checkForValidPubPacket) {
+  /* Read data until either the connection is closed, or the idle timeout is reached. */
+  uint16_t len = 0;
+  int16_t t = timeout;
+
+  while (client->connected() && (timeout >= 0)) {
+    //DEBUG_PRINT('.');
+    while (client->available()) {
+      //DEBUG_PRINT('!');
+      char c = client->read();
+      timeout = t;  // reset the timeout
+      buffer[len] = c;
+      //DEBUG_PRINTLN((uint8_t)c, HEX);
+      len++;
+      if (len == maxlen) {  // we read all we want, bail
+        DEBUG_PRINT(F("Read packet:\t"));
+        DEBUG_PRINTBUFFER(buffer, len);
+        return len;
+      }
+
+      // special case where we just one one publication packet at a time
+      if (checkForValidPubPacket) {
+        if ((buffer[0] == (MQTT_CTRL_PUBLISH << 4)) && (buffer[1] == len-2)) {
+          // oooh a valid publish packet!
+          DEBUG_PRINT(F("Read PUBLISH packet:\t"));
+          DEBUG_PRINTBUFFER(buffer, len);
+          return len;
+        }
+      }
+    }
+    timeout -= MQTT_CLIENT_READINTERVAL_MS;
+    delay(MQTT_CLIENT_READINTERVAL_MS);
+  }
+  return len;
+}
+
+bool Adafruit_MQTT_Client::sendPacket(uint8_t *buffer, uint8_t len) {
+  if (client->connected()) {
+    uint16_t ret = client->write(buffer, len);
+    DEBUG_PRINT(F("sendPacket returned: ")); DEBUG_PRINTLN(ret);
+    if (ret != len) {
+      DEBUG_PRINTLN("Failed to send complete packet.")
+      return false;
+    }
+  } else {
+    DEBUG_PRINTLN(F("Connection failed!"));
+    return false;
+  }
+  return true;
+}