Connect_By_Hostname.ino

/*********************************************************************************************************************************
  Connect_By_Hostname.ino
      
  Library for communicating with a MySQL or MariaDB Server
  
  Based on and modified from Dr. Charles A. Bell's MySQL_Connector_Arduino Library https://github.com/ChuckBell/MySQL_Connector_Arduino
  to support nRF52, SAMD21/SAMD51, SAM DUE, STM32F/L/H/G/WB/MP1, ESP8266, ESP32, etc. boards using W5x00, ENC28J60, LAM8742A Ethernet,
  WiFiNINA, ESP-AT, built-in ESP8266/ESP32 WiFi.

  The library provides simple and easy Client interface to MySQL or MariaDB Server.
  
  Built by Khoi Hoang https://github.com/khoih-prog/MySQL_MariaDB_Generic
  Licensed under MIT license
 **********************************************************************************************************************************/
/*
  MySQL Connector/Arduino Example : connect by hostname

  This example demonstrates how to connect to a MySQL server resolving the
  hostname for cases when you do not know the IP address of the server or
  it changes because it is in the cloud.

  For more information and documentation, visit the wiki:
  https://github.com/ChuckBell/MySQL_Connector_Arduino/wiki.

  INSTRUCTIONS FOR USE

  1) Change the hostname variable to the hostname of the MySQL server
  2) Change the user and password to a valid MySQL user and password
  3) Connect a USB cable to your Arduino
  4) Select the correct board and port
  5) Compile and upload the sketch to your Arduino
  6) Once uploaded, open Serial Monitor (use 115200 speed) and observe

  If you do not see messages indicating you have a connection, refer to the
  manual for troubleshooting tips. The most common issues are the server is
  not accessible from the network or the user name and password is incorrect.

  Note: The MAC address can be anything so long as it is unique on your network.

  Created by: Dr. Charles A. Bell
*/
#include "defines.h"

#include <MySQL_Generic.h>

#if USE_NATIVE_ETHERNET
  #include <NativeDns.h>
  DNSClient dns_client;   // DNS instance
#elif USE_QN_ETHERNET

#endif

#define USING_HOST_NAME     true

#if USING_HOST_NAME
  // Optional using hostname, and Ethernet built-in DNS lookup
  char server[] = "your_account.ddns.net"; // change to your server's hostname/URL
#else
  IPAddress server(192, 168, 2, 112);
#endif

uint16_t server_port = 5698;    //3306;

char user[]             = "invited-guest";              // MySQL user login username
char password[]         = "the-invited-guest";          // MySQL user login password

IPAddress server_addr;

MySQL_Connection conn((Client *)&client);


void initEthernet()
{
#if USE_NATIVE_ETHERNET
  MYSQL_DISPLAY(F("======== USE_NATIVE_ETHERNET ========"));
#elif USE_QN_ETHERNET
  MYSQL_DISPLAY(F("=========== USE_QN_ETHERNET ==========="));
#endif

#if USE_NATIVE_ETHERNET

  // start the ethernet connection and the server:
  // Use DHCP dynamic IP and random mac
  uint16_t index = millis() % NUMBER_OF_MAC;
  // Use Static IP
  //Ethernet.begin(mac[index], ip);
  Ethernet.begin(mac[index]);

  MYSQL_DISPLAY(F("========================="));

  MYSQL_DISPLAY1("Using mac index =", index);
  MYSQL_DISPLAY1("Connected! IP address:", Ethernet.localIP());

  // give the Ethernet shield 2 seconds to initialize:
  delay(2000);

#else

  #if USING_DHCP
    // Start the Ethernet connection, using DHCP
    Serial.print("Initialize Ethernet using DHCP => ");
    Ethernet.begin();
  #else   
    // Start the Ethernet connection, using static IP
    Serial.print("Initialize Ethernet using static IP => ");
    Ethernet.begin(myIP, myNetmask, myGW);
    Ethernet.setDNSServerIP(mydnsServer);
  #endif

  if (!Ethernet.waitForLocalIP(5000))
  {
    Serial.println("Failed to configure Ethernet");

    if (!Ethernet.linkStatus())
    {
      Serial.println("Ethernet cable is not connected.");
    }

    // Stay here forever
    while (true)
    {
      delay(1);
    }
  }

  if (!Ethernet.waitForLink(5000))
  {
    Serial.println(F("Failed to wait for Link"));
  }
  else
  {
    Serial.print("IP Address = ");
    Serial.println(Ethernet.localIP());
  }

#endif  
}

void setup()
{
  Serial.begin(115200);
  while (!Serial && millis() < 5000); // wait for serial port to connect

  MYSQL_DISPLAY2("\nStarting Connect_By_Hostname on", BOARD_NAME, SHIELD_TYPE);
  MYSQL_DISPLAY(MYSQL_MARIADB_GENERIC_VERSION);

  initEthernet();

  MYSQL_DISPLAY3("Connecting to SQL Server @", server, ", Port =", server_port)  
  MYSQL_DISPLAY3("User =", user, ", PW =", password);
}

void loop()
{
  MYSQL_DISPLAY("Connecting...");
  
  //if (conn.connect(server, server_port, user, password))
  if (conn.connectNonBlocking(server, server_port, user, password) != RESULT_FAIL)
  {
    MYSQL_DISPLAY("Closing connection...");
    conn.close();                     // close the connection
  } 
  else 
  {
    MYSQL_DISPLAY("\nConnect failed. Trying again on next iteration.");
  }

  MYSQL_DISPLAY("\nSleeping...");
  MYSQL_DISPLAY("================================================");
 
  delay(60000);
}