Google sheets MailApp

Introduction#

This service allows users to send emails with complete control over the content of the email. Unlike GmailApp, MailApp’s sole purpose is sending email. MailApp cannot access a user’s Gmail inbox.

Changes to scripts written using GmailApp are more likely to trigger a re-authorization request from a user than MailApp scripts.

A basic MailApp Example

MailApp is the api from Google App Script that can be used to send mail

function sendEmails() {

  var subject = "A subject for your new app!";
  var message = "And this is the very first message"
  var recipientEmail = "abc@example.com";

  MailApp.sendEmail(recipientEmail, subject, message);
}

The MailApp Class is limited to quotas based on your Google Account:

Consumer user (ie, personal Gmail account): 100 recipients/day
Google Apps (legacy) customer: 100 recipients/day
GSuite (basic/Gov/Edu/Business): 1500 recipients/day

You can check your email quota within MailApp

function checkQuota() {
  Logger.log(MailApp.getRemainingDailyQuota());
}

Access data from sheet

function getSheetData() {

  var sheet = SpreadsheetApp.getActiveSheet();

  var startRow = 2;  // First row of data to process
  var numRows = 100;   // Number of rows to process
  var startCol = 1;  //First column of data to process
  var numCols = 15;    // Number of columns to process 
  
  var dataRange = sheet.getRange(startRow, startCol, numRows, numCols);

  // Fetch values for each row in the Range.
  var data = dataRange.getValues();  

  return data;  
}

You can also modify the above function as follows to get data range dynamic from the content present in sheet:

function getDataSheet() {

  sheet = SpreadsheetApp.getActiveSheet();
   
   //Get data range based on content
  var dataRange = sheet.getDataRange();

  // Fetch values for each row in the Range.
  var data = dataRange.getValues();  

  return data;  
}

Use Sheet data to send email

Given - A have sheet of employees who have requested for reimbursement.

Requirement - We should sent out an email to the employee when their reimbursement is processed

So, the sheet is as follows:

The function for sending out an email is as follows:

function getDataSheet() {

  sheet = SpreadsheetApp.getActiveSheet();

  startRow = 2;  // First row of data to process
  numRows = 100;   // Number of rows to process
  startCol = 1;  //First column of data to process
  numCols = 15;    // Number of columns to process 
  
  var dataRange = sheet.getRange(startRow, startCol, numRows, numCols);

  // Fetch values for each row in the Range.
  var data = dataRange.getValues();  

  return data;  
}    

function getMessage(name, amount) {
  return "Hello " + name + ", Your reimbursement for amount " + amount + " is processed successfully";
}

function sendEmail() {
  
  var emailSent = "Yes";
  var reimbursed = "Yes";
  var emailCol = 5;
      
  var data = getDataSheet();
  
  for (var i = 0; i < data.length; i++) {
    
    var row = data[i];
    
    var isReimbursed = row[3];
    var isEmailSent = row[4];
    var name = row[0];
    var amount = row[2];
    
    if(isReimbursed == reimbursed && isEmailSent != emailSent) {
      
      var subject = "Reimbursement details";
      var message = getMessage(name, amount);
      
      var recipientEmail = row[1];
      
      MailApp.sendEmail(recipientEmail, subject, message);
      
      //Sheet range starts from index 1 and data range starts from index 0
      sheet.getRange(1 + i, emailCol).setValue(emailSent);
    }
  }
}

Sending HTML content in mail

In the above example, if we want to send out HTML content as message in the email, then create a HTML file by going to File -> New -> HTML file

Now you can see a HTML file besides your gs file as follows :

Now, update the getMessage() method from above example as follows :

function getMessage(name, amount) {
  var htmlOutput = HtmlService.createHtmlOutputFromFile('Message'); // Message is the name of the HTML file
  
  var message = htmlOutput.getContent()
  message = message.replace("%name", name);
  message = message.replace("%amount", amount);
  
  return message;
}

The call to MailApp api needs to be changed as well

MailApp.sendEmail(recipientEmail, subject, message, {htmlBody : message});

So the whole code will be as follows :

function getDataSheet() {

  sheet = SpreadsheetApp.getActiveSheet();

  startRow = 2;  // First row of data to process
  numRows = 100;   // Number of rows to process
  startCol = 1;  //First column of data to process
  numCols = 15;    // Number of columns to process 
  
  var dataRange = sheet.getRange(startRow, startCol, numRows, numCols);

  // Fetch values for each row in the Range.
  var data = dataRange.getValues();  

  return data;  
}

function getMessage(name, amount) {
  var htmlOutput = HtmlService.createHtmlOutputFromFile('Message');
  
  var message = htmlOutput.getContent()
  message = message.replace("%name", name);
  message = message.replace("%amount", amount);
  
  return message;
}

function sendEmail() {
  
  var emailSent = "Yes";
  var reimbursed = "Yes";
  var emailCol = 5;
      
  var data = getDataSheet();
  
  for (var i = 0; i < data.length; i++) {
    
    var row = data[i];
    
    var isReimbursed = row[3];
    var isEmailSent = row[4];
    var name = row[0];
    var amount = row[2];
    
    if(isReimbursed == reimbursed && isEmailSent != emailSent) {
      
      var subject = "Reimbursement details";
      var message = getMessage(name, amount);
      
      var recipientEmail = row[1];
      
      MailApp.sendEmail(recipientEmail, subject, message, {htmlBody : message});
      
      sheet.getRange(startRow + i, emailCol).setValue(emailSent);
    }
  }
}