Modifying a Header's Content

To change a Header's content you should know what type of header it is and then call it's appropriate setter method. All headers also have a setFieldBodyModel() method that accepts a mixed parameter and delegates to the correct setter.

1. Get the HeaderSet from the entity by via its getHeaders() method.
2. Get the Header by using the HeaderSet's get() as described in Retrieving Headers.
3. Call the Header's appropriate setter method as described in Header Types or call the header's setFieldBodyModel() method.

$headers = $message->getHeaders();

//Change the Subject: header
$subj = $headers->get('Subject');
$subj->setValue('new subject here');

//Change the To: header
$to = $headers->get('To');
$to->setNameAddresses(array(
  'person@example.org' => 'Person',
  'thing@example.org'
));

//Using the setFieldBodyModel() just delegates to the correct method
// So here to calls setNameAddresses()
$to->setFieldBodyModel(array(
  'person@example.org' => 'Person',
  'thing@example.org'
));