The World Wide Web Consortium (W3C) has published three specifications to help facilitate the inclusion of binary data such as graphics or photos into Web services applications. Improved processing of bulky XML files is part of the W3C's solution.

It's aiming to address the technical and performance issues arising with use of binary data in Web services. The specifications, for example, would reduce the number of bytes sent in transmitting a binary file to a mobile phone, according to Yves Lafon, the W3C team contact for the organization's XML protocol working group. The group worked on the three specifications.

Larging it

"The main issue is that when you want to transfer a large binary object in XML, you have to encode it in a way that makes the message far bigger than the binary data you want to send, and the (specifications) address (the problem) by reducing the size of the message you want to send," Lafon said.

In response, the W3C published the following Web Services Recommendations:

XML-binary Optimized Packaging

XML-binary Optimized Packaging (XOP), providing a standard method for applications to include binary data as-is, along with an XML document in a package. As a result, the applications need less space to store data and less bandwidth to transmit it. Working at the XML Information Set (Infoset) level, an abstract representation of an XML document can be serialized in different ways.

SOAP Message Transmission Optimization Mechanism

SOAP Message Transmission Optimization Mechanism (MTOM), which uses features of XOP to address SOAP messages and make SOAP 1.2 function faster. MTOM defines a "Transmission Optimization" feature to enable SOAP bindings to optimize the transmission and/or the wire format used to transfer a SOAP message. MTOM uses HTTP and XOP to send binary parts as well as the SOAP message in a MIME envelope to reduce bandwidth and time needed to encode and decode the data.

Resource Representation SOAP Header Block

Resource Representation SOAP Header Block (RRSHB), allowing SOAP message recipients to access cached representations of external resources. Recipients of a message can use either the original file identified by a URI or a cache copy accompanying the actual SOAP message. Used with MTOM, it can enhance speed and processing, since the external data is present when the recipient started processing the message.

IBM, Microsoft and BEA Systems have all endorsed the proposals.