React Native Requires Chilkat v11.0.0+

Load .eml and Examine the Structure, Attachments, and Related Items

See more Email Object Examples

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. React Native

import { Email, JsonObject, Mime } from '@chilkat/react-native'

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

  const emlPath = 'C:/AAWorkarea/beatrix/roesner.eml';

  const mime = new Mime();

  try {
    mime.loadMimeFile(emlPath);
  } catch {
    console.log(mime.lastErrorText);
    return;
  }

  console.log('---- MIME structure ----');
  console.log(mime.getStructure('text'));
  console.log('------------------------');

  const email = new Email();
  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) {
    console.log(`Signature(s) valid = ${email.signaturesValid}`);
  }

  if (email.receivedEncrypted) {
    console.log(`Decrypted successfully = ${email.decrypted}`);
  }

  let i = 0;
  const 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++;
  }

  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.

  const 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++;
  }

  // The email could also have attached messages.
  // An attached message is another email that was attached to this email.
  const em = new Email();
  const numAttachedMessages = email.numAttachedMessages;
  console.log(`Number of attached messages = ${numAttachedMessages}`);
  i = 0;
  while (i < numAttachedMessages) {
    console.log(`---- Attached message ${i}`);

    // Examine the attached email
    email.getAttachedEmail(i, em);
    console.log(`from: ${em.from}`);
    console.log(`subject: ${em.subject}`);
    i++;
  }

  // An email could also be a multipart/report email. 
  // This is a DSN (Delivery Status Notification)
  // The NumReports property indicates how many "reports" exist.
  const 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++;
  }

  // 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()) {

    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')}`);

    const jsonDsnInfo = new JsonObject();
    email.getDsnInfo(jsonDsnInfo);
    jsonDsnInfo.emitCompact = false;
    console.log(jsonDsnInfo.emit());
  }
}