Gmail Labeling Script: "Contact Exists"

This Google Apps Script automatically labels Gmail threads with the "Contact Exists" label if the sender's email address exists in your Google Contacts. If the sender is not in your contacts or is in a group labeled "Ignore," the email will be labeled as "Not in Contacts." This helps you efficiently organize and manage your inbox by processing only unlabeled emails and excluding those from ignored contacts.

Features

• Searches recent, unlabeled emails in your Gmail inbox.
• Checks if the sender's email address exists in your Google Contacts.
• Labels the email thread with "Contact Exists" if a match is found and the contact is not in the "Ignore" group.
• Labels the email thread with "Not in Contacts" if the sender is not in your contacts or is in the "Ignore" group.
• Ensures that emails are processed only once, avoiding reprocessing.

Installation

Follow the steps below to install and configure this script:

1. Create a New Google Apps Script Project

1. Go to Google Apps Script.
2. Click on New Project.
3. Name your project (e.g., "Gmail Contact Labeler").

2. Copy the Script

Copy the following code into the Apps Script editor:

function addLabelIfContactExists() {
  var lock = LockService.getScriptLock();
  
  if (lock.tryLock(30000)) {
    try {
      processEmails();
    } finally {
      lock.releaseLock();
    }
  } else {
    Logger.log("Script is already running. Exiting to prevent overlap.");
  }
}

function processEmails() {
  // Search for emails from the last day that have no user labels
  var threads = GmailApp.search('newer_than:1d has:nouserlabels'); 
  var contactLabel = GmailApp.getUserLabelByName('Contact Exists');
  var notInContactsLabel = GmailApp.getUserLabelByName('Not in Contacts');
  
  if (!contactLabel) {
    contactLabel = GmailApp.createLabel('Contact Exists');
  }
  
  if (!notInContactsLabel) {
    notInContactsLabel = GmailApp.createLabel('Not in Contacts');
  }

  for (var i = 0; i < threads.length; i++) {
    var messages = threads[i].getMessages();
    for (var j = 0; j < messages.length; j++) {
      var from = messages[j].getFrom();
      var email = extractEmail(from);
      if (isContactExistsAndNotIgnored(email)) {
        threads[i].addLabel(contactLabel);
      } else {
        threads[i].addLabel(notInContactsLabel);
      }
    }
  }
}

function isContactExistsAndNotIgnored(email) {
  var contacts = ContactsApp.getContactsByEmailAddress(email);
  if (contacts.length > 0) {
    for (var i = 0; i < contacts.length; i++) {
      var contact = contacts[i];
      var groups = contact.getContactGroups();
      for (var j = 0; j < groups.length; j++) {
        if (groups[j].getName().toLowerCase() === 'ignore') {
          return false; // Ignore this contact
        }
      }
    }
    return true; // Contact exists and is not ignored
  }
  return false; // Contact does not exist
}

function extractEmail(fromField) {
  var emailPattern = /<(.+)>/;
  var match = fromField.match(emailPattern);
  return match ? match[1] : fromField;
}

3. Authorize the Script

1. Click the Run button (►) in the Apps Script editor.
2. A dialog will appear asking for permission to access your Gmail and Contacts. Review and authorize the permissions.

4. Set Up a Trigger

To have the script run automatically:

1. Click on the clock icon (Triggers) in the Apps Script editor.
2. Click + Add Trigger.
3. Select addLabelIfContactExists for the function to run.
4. Set the time-based trigger to run every minute, hourly, daily, etc., based on your preference.

5. Customize the Script (Optional)

• Search Query: The script searches for emails from the last day that have no user-applied labels using newer_than:1d has:nouserlabels. You can adjust the search query to fit your needs.
• Label Names: Change the label names from "Contact Exists" and "Not in Contacts" to something else if you prefer different labels.
• Ignore Group: The script checks for contacts in the "Ignore" group. Make sure this group exists in your Google Contacts if you want to use this feature.

6. Save and Test

• After setting everything up, save your project.
• Run the script manually or wait for the trigger to execute.
• Check your Gmail to see if the appropriate emails have been labeled with "Contact Exists" or "Not in Contacts."

Disclaimer

This script is provided as-is, without any warranties or guarantees. Use it at your own risk. The author is not responsible for any issues or damages that may arise from using this script, including but not limited to unintended email labeling or any other unexpected behavior.

By using this script, you agree to take full responsibility for any actions it performs on your Gmail account. Always test the script in a controlled environment before deploying it widely.

Troubleshooting

• If the script doesn't seem to be working, check the execution logs by going to View > Logs in the Apps Script editor.
• Ensure that the script has the necessary permissions to access your Gmail and Contacts.
• If emails are not being labeled as expected, double-check the search query and ensure the labels and contact groups are set up correctly.

License

This script is provided under the MIT License. Feel free to use and modify it to suit your needs.