Dart

Get a MIME Header Field Attribute

Demonstrates the Chilkat Mime.GetHeaderFieldAttribute method, which returns an attribute value parsed from a header field. The first argument is the header field name and the second is the attribute name. Surrounding quotes are removed.

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: Many MIME headers pack extra parameters after the main value — Content-Type: multipart/mixed; boundary="xyz" or Content-Disposition: attachment; filename="report.pdf". This method extracts one of those named attributes directly, saving you from parsing the header string yourself and correctly stripping quotes and handling encoded values.

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Dart

import 'package:chilkat/chilkat.dart';

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

  // Return an attribute value parsed from a header field.  The 1st argument is the header field
  // name and the 2nd is the attribute name.  For example, the "boundary" attribute of the
  // Content-Type header, or the "filename" attribute of Content-Disposition.
  final String boundary;
  try {
    boundary = mime.getHeaderFieldAttribute('Content-Type', 'boundary');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Content-Type boundary: $boundary');
}