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Handling XML Documents in a Web Service

For these documents, the complete infoset of the original document should be 

preserved, including comments and external entity references (as well as the 

referred entities).

  Some application processing requires the complete document infoset, includ 

ing comments and external entity references. As with the legally binding doc 

uments, it is necessary to preserve the complete infoset, including comments 

and external entity references, of the original document.

  When sent as attachments, it is possible to handle documents that may conform 

to schemas expressed in languages not supported by the Web service endpoint 

or that are prohibited from being present within a SOAP message infoset (such 

as the Document Type Declaration 

 for a DTD based schema).

For example, consider the travel agency Web service, which typically receives

a client request as an XML document containing all information needed to arrange

a particular trip. The information in the document includes details about the cus 

tomer's account, credit card status, desired travel destinations, preferred airlines,

class of travel, dates, and so forth. The Web service uses the documents contents

to perform such steps as verifying the customer's account, obtaining authorization

for the credit card, checking accommodations and transportation availability,

building an itinerary, and purchasing tickets. 

In essence, the service, which receives the request with the XML document,

starts a business process to perform a series of steps to complete the request. The

contents of the XML document are used throughout the business process. Han 

dling this type of scenario effectively requires some considerations in addition to

the general ones for all Web services. 

E

Good design expects XML documents to be received as 

javax.xml.transform.Source

 objects. See  Exchanging XML Documents  

on page 107, which discusses exchanging XML documents as parameters. 

Keep in mind the effect on interoperability (see  Interoperability  on page 86).

E

It is good design to do the validation and any required transformation of the 

XML documents as close to the endpoint as possible. Validation and transfor 

mation should be done before applying any processing logic to the document 

content. See Figure 3.4 and the discussion on receiving requests in  Receiving 

Requests  on page 89.