(Node.js) Load .eml and Examine the Structure, Attachments, and Related Items

Demonstrates how to load examine the MIME structure of a .eml, and also examine the attachment and related item filenames, attached messages, and multipart/report and DSN information.

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 emlPath = "C:/AAWorkarea/beatrix/roesner.eml";

    var mime = new chilkat.Mime();

    var success = mime.LoadMimeFile(emlPath);
    if (success !== true) {
        console.log(mime.LastErrorText);
        return;
    }

    console.log("---- MIME structure ----");
    console.log(mime.GetStructure("text"));
    console.log("------------------------");

    var email = new chilkat.Email();
    success = email.LoadEml(emlPath);

    // Was this a signed and/or encrypted email?
    // If so, then loading the .eml automatically unwraps
    // (i.e. verifies signatures and decrypts) and the resultant
    // email is what existed prior to signing/encrypting.
    console.log("Email was Signed: " + email.ReceivedSigned);
    console.log("Email was Encrypted: " + email.ReceivedEncrypted);
    if (email.ReceivedSigned == true) {
        console.log("Signature(s) valid = " + email.SignaturesValid);
    }

    if (email.ReceivedEncrypted == true) {
        console.log("Decrypted successfully = " + email.Decrypted);
    }

    var i = 0;
    var numAttach = email.NumAttachments;
    console.log("Number of attachments = " + numAttach);

    while (i < numAttach) {
        console.log("---- Attachment " + i);

        // Examine the filename (if any)
        console.log("filename: " + email.GetAttachmentFilename(i));
        // Examine the content-ID (if any)
        console.log("Content-ID: " + email.GetAttachmentContentID(i));
        // Examine the content-type
        console.log("Content-Type: " + email.GetAttachmentContentType(i));
        // Examine the content-disposition
        console.log("Content-Disposition" + email.GetAttachmentHeader(i,"content-disposition"));
        // Examine the attachment size:
        console.log("Size (in bytes) of the attachment: " + email.GetAttachmentSize(i));

        i = i+1;
    }

    console.log("--");

    // Now for the related items.

    // Note: A MIME sub-part can potentially be both a related item AND an attachment.
    // The typical case is when the item is contained under the multipart/related enclosure and 
    // the item also has a "Content-Disposition" header indicating "attachment".
    // The location within multipart/related makes it a "related item", yet the Content-Disposition can also make it semantically an attachment.
    // Related items and attachments are not necessarily mutually exclusive.

    var numRelated = email.NumRelatedItems;
    console.log("Number of related items = " + numRelated);
    i = 0;
    while (i < numRelated) {
        console.log("---- Related Item " + i);

        // Examine the filename (if any)
        console.log("filename: " + email.GetRelatedFilename(i));
        // Examine the content-ID (if any)
        console.log("Content-ID: " + email.GetRelatedContentID(i));
        // Examine the content-type
        console.log("Content-Type: " + email.GetRelatedContentType(i));
        // Examine the content-location (if any)
        console.log("Content-Location" + email.GetRelatedContentLocation(i));

        i = i+1;
    }

    // The email could also have attached messages.
    // An attached message is another email that was attached to this email.
    var numAttachedMessages = email.NumAttachedMessages;
    console.log("Number of attached messages = " + numAttachedMessages);
    i = 0;
    while (i < numAttachedMessages) {
        console.log("---- Attached message " + i);

        // Examine the attached email
        // em: Email
        var em = email.GetAttachedMessage(i);
        console.log("from: " + em.From);
        console.log("subject: " + em.Subject);

        i = i+1;
    }

    // An email could also be a multipart/report email. 
    // This is a DSN (Delivery Status Notification)
    // The NumReports property indicates how many "reports" exist.
    var numReports = email.NumReports;
    console.log("Number of reports = " + numReports);
    i = 0;
    while (i < numReports) {
        console.log("---- Report " + i);
        // Get the raw report data...
        console.log(email.GetReport(i));
        i = i+1;
    }

    // If the email is a multipart/report, then the information
    // from the message/delivery-status part of the email can be retrieved:
    if (email.IsMultipartReport() == true) {

        console.log("--- Delivery Status Information:");
        console.log("Status: " + email.GetDeliveryStatusInfo("Status"));
        console.log("Action: " + email.GetDeliveryStatusInfo("Action"));
        console.log("Reporting-MTA: " + email.GetDeliveryStatusInfo("Reporting-MTA"));

        // sa: StringArray
        var sa = email.GetDsnFinalRecipients();
        var numFinalRecipients = sa.Count;
        i = 0;
        while (i < numFinalRecipients) {
            console.log("final recipient: " + sa.GetString(i));
            i = i+1;
        }

    }


}

chilkatExample();