Dart

Attach a File to a Multipart MIME Entity

Demonstrates the Chilkat Mime.AppendPartFromFile method, which reads a local file, creates an attachment part, and appends it. The only argument is the file path; the content headers are chosen from the filename extension.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the one-call way to add an attachment: Chilkat reads the file, infers its Content-Type from the extension, base64-encodes binary content, and appends it as a child part — typically inside a multipart/mixed. It is the building block behind adding attachments to an email, saving you from constructing the part and setting its headers by hand.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Mime.AppendPartFromFile method, which reads a local file, creates an attachment
  // part, and appends it.  The only argument is the file path; the content headers are chosen from
  // the filename extension.

  final mime = CkMime();
  try {
    mime.newMultipartMixed();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // A message body part.
  final bodyPart = CkMime();
  try {
    bodyPart.setBodyFromPlainText('Please see the attached files.');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  try {
    mime.appendPart(bodyPart);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Attach files directly.
  try {
    mime.appendPartFromFile('qa_data/report.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  try {
    mime.appendPartFromFile('qa_data/photo.jpg');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Number of parts: ${mime.numParts}');
}