LPG Leakage Detector and Email Sender

#ifndef G_SENDER
#define G_SENDER
#define GS_SERIAL_LOG_1         // Print to Serial only server responce
//#define GS_SERIAL_LOG_2       //  Print to Serial client commands and server responce
#include <WiFiClientSecure.h>

class Gsender
{
    protected:
        Gsender();
    private:
        const int SMTP_PORT = 465;// STMP port change it if you use other smtp
        const char* SMTP_SERVER = "smtp.gmail.com";// gmail smtp server change if you use other smtp
        const char* EMAILBASE64_LOGIN = "YOUR EMAIL ID ENCODED WITH BASE64";// your email must me encoded with base64
        const char* EMAILBASE64_PASSWORD = "YOUR PASSWORD ENCODED WITH BASE64";// your password must be encoded with base64
        const char* FROM = "youremail@gmail.com";//yoyr email address with encoding
        const char* _error = nullptr;
        char* _subject = nullptr;
        String _serverResponce;
        static Gsender* _instance;
        bool AwaitSMTPResponse(WiFiClientSecure &client, const String &resp = "", uint16_t timeOut = 10000);

    public:
        static Gsender* Instance();
        Gsender* Subject(const char* subject);
        Gsender* Subject(const String &subject);
        bool Send(const String &to, const String &message);
        String getLastResponce();
        const char* getError();
};
#endif // G_SENDER

#include "Gsender.h"
Gsender* Gsender::_instance = 0;
Gsender::Gsender(){}
Gsender* Gsender::Instance()
{
    if (_instance == 0) 
        _instance = new Gsender;
    return _instance;
}

Gsender* Gsender::Subject(const char* subject)
{
  delete [] _subject;
  _subject = new char[strlen(subject)+1];
  strcpy(_subject, subject);
  return _instance;
}
Gsender* Gsender::Subject(const String &subject)
{
  return Subject(subject.c_str());
}

bool Gsender::AwaitSMTPResponse(WiFiClientSecure &client, const String &resp, uint16_t timeOut)
{
  uint32_t ts = millis();
  while (!client.available())
  {
    if(millis() > (ts + timeOut)) {
      _error = "SMTP Response TIMEOUT!";
      return false;
    }
  }
  _serverResponce = client.readStringUntil('\n');
#if defined(GS_SERIAL_LOG_1) || defined(GS_SERIAL_LOG_2) 
  Serial.println(_serverResponce);
#endif
  if (resp && _serverResponce.indexOf(resp) == -1) return false;
  return true;
}

String Gsender::getLastResponce()
{
  return _serverResponce;
}

const char* Gsender::getError()
{
  return _error;
}

bool Gsender::Send(const String &to, const String &message)
{
  WiFiClientSecure client;
#if defined(GS_SERIAL_LOG_2)
  Serial.print("Connecting to :");
  Serial.println(SMTP_SERVER);  
#endif
  if(!client.connect(SMTP_SERVER, SMTP_PORT)) {
    _error = "Could not connect to mail server";
    return false;
  }
  if(!AwaitSMTPResponse(client, "220")) {
    _error = "Connection Error";
    return false;
  }

#if defined(GS_SERIAL_LOG_2)
  Serial.println("HELO friend:");
#endif
  client.println("HELO friend");
  if(!AwaitSMTPResponse(client, "250")){
    _error = "identification error";
    return false;
  }

#if defined(GS_SERIAL_LOG_2)
  Serial.println("AUTH LOGIN:");
#endif
  client.println("AUTH LOGIN");
  AwaitSMTPResponse(client);

#if defined(GS_SERIAL_LOG_2)
  Serial.println("EMAILBASE64_LOGIN:");
#endif
  client.println(EMAILBASE64_LOGIN);
  AwaitSMTPResponse(client);

#if defined(GS_SERIAL_LOG_2)
  Serial.println("EMAILBASE64_PASSWORD:");
#endif
  client.println(EMAILBASE64_PASSWORD);
  if (!AwaitSMTPResponse(client, "235")) {
    _error = "SMTP AUTH error";
    return false;
  }
  
  String mailFrom = "MAIL FROM: <" + String(FROM) + '>';
#if defined(GS_SERIAL_LOG_2)
  Serial.println(mailFrom);
#endif
  client.println(mailFrom);
  AwaitSMTPResponse(client);

  String rcpt = "RCPT TO: <" + to + '>';
#if defined(GS_SERIAL_LOG_2)
  Serial.println(rcpt);
#endif
  client.println(rcpt);
  AwaitSMTPResponse(client);

#if defined(GS_SERIAL_LOG_2)
  Serial.println("DATA:");
#endif
  client.println("DATA");
  if(!AwaitSMTPResponse(client, "354")) {
    _error = "SMTP DATA error";
    return false;
  }
  
  client.println("From: <" + String(FROM) + '>');
  client.println("To: <" + to + '>');
  
  client.print("Subject: ");
  client.println(_subject);
  
  client.println("Mime-Version: 1.0");
  client.println("Content-Type: text/html; charset=\"UTF-8\"");
  client.println("Content-Transfer-Encoding: 7bit");
  client.println();
  String body = "<!DOCTYPE html><html lang=\"en\">" + message + "</html>";
  client.println(body);
  client.println(".");
  if (!AwaitSMTPResponse(client, "250")) {
    _error = "Sending message error";
    return false;
  }
  client.println("QUIT");
  if (!AwaitSMTPResponse(client, "221")) {
    _error = "SMTP QUIT error";
    return false;
  }
  return true;
}

># ESP8266 LPG Leakage Email Sender
>**Monitors the LPG sensor output 500 times and takes the average of the sampling to reduce reading noise,and if the value is greater than the threshold value, it sends email to the recipient.**  

>**Before uploading the code make to sure to change in the Gsender header file:**  
-     const int SMTP_PORT = 465;// STMP port change it if you use other smtp  
-     const char* SMTP_SERVER = "smtp.gmail.com";// gmail smtp server change if you use other smtp  
-     const char* EMAILBASE64_LOGIN = "YOUR EMAIL ID ENCODED WITH BASE64";// your email must me encoded with base64  
-     const char* EMAILBASE64_PASSWORD = "YOUR PASSWORD ENCODED WITH BASE64";// your password must be encoded with base64  
-     const char* FROM = "youremail@gmail.com";//your email address with encoding  
  
>**Change these lines as per your need:**  
-     const int sensorPin = A0; //connect sensor A0 output to this pin  
-     const char *ssid = "xxxxxxxxx";    // WIFI network name  
-     const char *password = "xxxxxxxx"; // WIFI network password  
-     uint8_t connection_state = 0;       // Connected to WIFI or not  
-     uint8_t nSampling = 500;            //change as per your need  
-     uint16_t threshold = 200;           // change as per your need  


>**Parts list:**  
-     NodeMCU :  https://www.amazon.in/Generic-Nodemcu-Esp8266-Internet-Development/dp/B07262H53W/ref=sr_1_1?keywords=nodemcu&qid=1583588225&sr=8-1  
-     Gas Sensor:   https://www.amazon.in/REES52-Arduino-Compatible-Sensor-Methane/dp/B018GW70G0/ref=sr_1_2?crid=2O01SJT84RKL&keywords=mq4+gas+detector+sensor&qid=1583588254&sprefix=mq4+%2Caps%2C390&sr=8-2  
-     Jumper Wires: https://www.amazon.in/Electrobot-Jumper-Wires-120-Pieces/dp/B071VQLQQQ/ref=sr_1_5?keywords=jumper+wire&qid=1583588298&sr=8-5  
  

>Project made and maintained by ***Kumar Aditya***   

>Base64 Encode: https://www.base64encode.org/



>The source code along with libraries can be found at:
https://github.com/rahuladitya303/programs/tree/master/ESP8266_LPG_Leakage_Email_Sender