Dart

Set a MIME Body, Preserving Content Headers

Demonstrates the Chilkat Mime.SetBody method, which sets the current part's body while preserving the existing content headers (Content-Type, charset, Content-Transfer-Encoding). The only argument is the body text; it is a void method.

Background: Unlike the SetBodyFrom... methods, which set both the content and the headers that describe it, SetBody replaces only the body text and leaves the existing Content-Type and encoding in place. That is what you want when the media type is already correct and you simply need to swap in new content — updating a templated part, for instance — without re-declaring its type.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Mime.SetBody method, which sets the current part's body while preserving the
  // existing content headers (Content-Type, charset, Content-Transfer-Encoding).  The only argument
  // is the body text.  It is a void method.

  final mime = CkMime();

  // Establish the content headers first.
  try {
    mime.setBodyFromPlainText('initial');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Replace just the body text, keeping the existing Content-Type and encoding.
  mime.setBody('This is the replacement body text.');

  final String mimeText;
  try {
    mimeText = mime.getMime();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(mimeText);
}