We have already seen the overall structure of a SOAP message, as defined by the SOAP Envelope, in Figure 3-4. All SOAP messages, no matter how lengthy or complex, ultimately conform to this structure. The only caveat is there must be at least one body block within the SOAP body element in a message and there does not necessarily have to be a SOAP header or any SOAP header blocks. There is no upper limit on the number of header or body blocks, however. A sample SOAP message is presented here in Figure 3-5:
<?xml version="1.0" encoding="UTF-8"?> <env:Envelope xmlns:env="http://www.w3.org/2002/06/soap-envelope" > <env:Header> <tx:transaction-id xmlns:tx="http://transaction.example.org" env:encodingStyle="http://transaction.example.org/enc" ...