Serverless email saving with Google Apps Script in Google Sheets

README.md

Setup steps

• Create a new Google Sheets document
• Rename the list 1 to collect (name can be changed to your own)
• Optionally describe the first column as email and the second column as subscription date
• Open Add-ons » Apps Script
• Paste the extension code into the editor
• Click deploy at the top
• Deploy as a web application
• Copy macro link
• Send a POST application/x-www-form-urlencoded request with an email field
• I'm proud of you

code.gs

function doPost(e) {
  try {
    Logger.log(e);

    const email = e.parameter.email.toLowerCase().trim();

    if (email.indexOf('@') === -1) {
      throw new Error('It\'s not email');
    }

    const doc = SpreadsheetApp.getActiveSpreadsheet();

    const sheet = doc.getSheetByName("collect");

    for (const values of sheet.getDataRange().getValues()) {
      if (values[0] !== email) {
        continue;
      }

      return ContentService.createTextOutput()
        .setMimeType(ContentService.MimeType.JSON)
        .setContent(JSON.stringify({
          success: true,
          code: 'DUPLICATE'
        }));
    }

    sheet.appendRow([email, (new Date()).toISOString()]);

    return ContentService.createTextOutput()
      .setMimeType(ContentService.MimeType.JSON)
      .setContent(JSON.stringify({
        success: true  
      }));
  } catch (error) {
    Logger.log('Failed hanle post');
    Logger.log(error);

    return ContentService.createTextOutput()
      .setMimeType(ContentService.MimeType.JSON)
      .setContent(JSON.stringify({
        success: false  
      }));
  }
}