(Node.js) Reading Unread POP3 Email

The POP3 protocol does not provide the ability to ask the server which emails are "unread". Furthermore, a pure POP3 server does not even keep this information. Some servers, such as Exchange Server, expose both POP3 and IMAP interfaces. In these cases, information about read/unread status exists on the server, but it is only available via the IMAP protocol. Email clients such as Outlook and Thunderbird keep read/unread information on the client computer. This example demonstrates how UIDLs can be saved to track and read "unread" email.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The mailman object is used for receiving (POP3) 
    // and sending (SMTP) email.
    var mailman = new chilkat.MailMan();

    // Set the POP3 server's hostname
    mailman.MailHost = "pop.someMailServer.com";

    // Set the POP3 login/password.
    mailman.PopUsername = "***";
    mailman.PopPassword = "***";

    // You may keep a list of already-seen UIDLs in a text file:
    // If this is the first time you're running this example,
    // create an empty text file named "seenUidls.txt"
    var saSeenUidls = new chilkat.StringArray();
    var success = saSeenUidls.LoadFromFile("seenUidls.txt");
    if (success !== true) {
        console.log("failed to load seenUidls.txt");
        return;
    }

    // Get the complete list of UIDLs on the mail server.
    // saUidls: StringArray
    var saUidls = mailman.GetUidls();
    if (mailman.LastMethodSuccess == false) {
        console.log(mailman.LastErrorText);
        return;
    }

    // Create a new string array object (it's an object, not an actual array)
    // and add the UIDLs from saUidls that aren't already seen.
    var saUnseenUidls = new chilkat.StringArray();

    var i = 0;
    var n = saUidls.Count;
    while (i < n) {
        if (saSeenUidls.Contains(saUidls.GetString(i)) !== true) {
            success = saUnseenUidls.Append(saUidls.GetString(i));
        }

        i = i+1;
    }

    if (saUnseenUidls.Count == 0) {
        console.log("No unseen emails!");

        return;
    }

    // Download in full the unseen emails:
    // bundle: EmailBundle
    var bundle = mailman.FetchMultiple(saUnseenUidls);
    if (mailman.LastMethodSuccess == false) {
        console.log(mailman.LastErrorText);

        return;
    }

    // email: Email
    var email;
    i = 0;
    while (i < bundle.MessageCount) {
        email = bundle.GetEmail(i);
        console.log(email.From);
        console.log(email.Subject);
        console.log("----");

        i = i+1;
    }

    // Save saUidls to "seenUidls.txt"
    success = saUidls.SaveToFile("seenUidls.txt");


}

chilkatExample();