SOAP Header

• Each element contained by Header is called header block.
  • Usually contain information for the processing of the message.
  • Information might be meant for intermediaries.

<?xml version='1.0' ?>
<env:Envelope xmlns:env="http://www.w3.org/2001/12/soap-envelope"> 
  <env:Header>
    <m:reservation xmlns:m="http://example.org/reservation" 
      env:actor="http://www.w3.org/2001/12/soap-envelope/actor/next"
      env:mustUnderstand="true">
      <m:reference>uuid:093a2da1-q345-739r-ba5d-pqff98fe8j7d</reference>
        <m:dateAndTime>2001-11-29T13:20:00.000-05:00</m:dateAndTime>
      </m:reservation>
      <n:passenger xmlns:n="http://mycompany.example.com/employees"
        env:actor="http://www.w3.org/2001/12/soap-envelope/actor/next"
        env:mustUnderstand="true">
        <n:name>John Q. Public</n:name>
      </n:passenger>
  </env:Header>
....
</env:Envelope>

• The fact that the actor attribute has a value of next means that the header block should be processed by the next intermediary.
• Each receiver will check if he is an actor. If so then he will handle and remove element. He then passes on the message.
• The mustUnderstand attribute specifies that the receivers to what the block says, or fail.