React Native

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.

Chilkat React Native Downloads

Download Chilkat for React Native

React Native

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

function chilkatExample() {
  const mime = new Mime();
  try {
    mime.loadMimeFile('qa_data/message.eml');
  } catch {
    console.log(mime.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.
  let boundary: string;
  try {
    boundary = mime.getHeaderFieldAttribute('Content-Type', 'boundary');
  } catch {
    console.log(mime.lastErrorText);
    return;
  }

  console.log(`Content-Type boundary: ${boundary}`);
}