Dart

Check if a MIME Part is an Attachment

Demonstrates the Chilkat Mime.IsAttachment method, which returns whether the current part's Content-Disposition is attachment (matched case-insensitively). It takes no arguments.

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

Background: Whether a part is an attachment is about disposition, not content type — an image can be inline (Content-Disposition: inline) or an attachment. This predicate keys off that header, which is the right basis for deciding what to list as a downloadable attachment versus what to render within the message body.

Chilkat Dart Downloads

Download Chilkat for Dart

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Mime.IsAttachment method, which returns whether the part's Content-Disposition is attachment.  It takes no arguments and applies to the current
  // part.  This example iterates the parts of a multipart message and reports which ones match.

  final mime = CkMime();
  try {
    mime.loadMimeFile('qa_data/multipart_message.eml');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final n = mime.numParts;
  final partVar = CkMime();
  for (var i = 0; i < n; i++) {
    try {
      mime.partAt(i, partVar);
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    if (partVar.isAttachment()) {
      print('Part $i (${partVar.contentType}) is an attachment.');
    }
  }
}