(Node.js) Process Large POP3 Mailbox

Demonstrates how to read email from a mailbox that may contain a large number of emails.

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.

    var mailman = new chilkat.MailMan();

    mailman.MailHost = "pop.example.com";

    mailman.PopUsername = "myLogin";
    mailman.PopPassword = "myPassword";

    mailman.MailPort = 995;
    mailman.PopSsl = true;

    // Get the list of UIDLs for all emails in the mailbox.
    // sa: StringArray
    var sa = mailman.GetUidls();
    if (mailman.LastMethodSuccess == false) {
        console.log(mailman.LastErrorText);
        return;
    }

    var i;
    var numEmails = sa.Count;
    if (numEmails == 0) {
        console.log("Mailbox is empty");
        return;
    }

    var chunkSize = 6;

    // Download the emails in chunks of 6 emails each.
    var chunkBeginIdx = 0;
    var chunkEndIdx = chunkSize - 1;
    if (chunkEndIdx >= numEmails) {
        chunkEndIdx = numEmails - 1;
    }

    var saChunk = new chilkat.StringArray();
    while ((chunkBeginIdx < numEmails)) {

        console.log(chunkBeginIdx + " to " + chunkEndIdx);

        // Build a chunk of UIDLs.
        saChunk.Clear();
        for (i = chunkBeginIdx; i <= chunkEndIdx; i++) {
            saChunk.Append(sa.GetString(i));
        }

        // Log the UIDLs in this chunk...
        var chunkStr = saChunk.SaveToText();
        console.log(chunkStr);

        // Download this chunk of email from the POP3 server.
        // bundle: EmailBundle
        var bundle = mailman.FetchMultiple(saChunk);
        if (mailman.LastMethodSuccess == false) {
            console.log(mailman.LastErrorText);
            return;
        }

        console.log("Downloaded " + bundle.MessageCount + " emails.");
        console.log("----");

        // Process the bundle...
        // (your application's processing code goes here...)

        // Get the next chunk...
        chunkBeginIdx = chunkBeginIdx+chunkSize;
        chunkEndIdx = chunkEndIdx+chunkSize;
        if (chunkEndIdx >= numEmails) {
            chunkEndIdx = numEmails - 1;
        }

    }


}

chilkatExample();