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Chapter 12: Advanced Web Services Topics
The last thing to mention in this section is that XML parsing isn’t the only option
available to parse and process XML messages. Because Perl is so good at dealing with
the text, and XML messages are all text, it’s possible to implement regexp-based
parsing to extract the parameters and other information required to execute the
method call. Although the logic that generates that regular expression can be quite
complex, it’s possible to generate the pattern once, store it, and match the incoming
requests against stored patterns. While this solution has limited scope, it can be used
for simple requests (having regular processing for all other requests), and prelimi-
nary tests show that this approach can reduce the response time in a factor of 10.
There’s no doubt that web services are still in a nascent stage. However, looking
around, it’s easy to find many live working systems that use web services to solve real
problems for people and businesses. Most of the implemented systems work either
inside the enterprise, or across multiple enterprises, and mostly operate with simple
concepts and already available vocabularies.
In development are more than 20 specifications in the web-services field that address
aspects such as routing, security, packaging, service description, advertising and dis-
covery, transactions, and business process workflow. However, it’s important to real-
ize that most describe how to do things, rather than what to do. In most cases “what”
is overlooked and as the result, there is no shared understanding of concepts, meta-
data, and semantics. The huge amounts of work that have been done by many stan-
dards bodies to somehow address this problem and define common vocabularies
wasn’t as fruitful as many people hoped. This is due to a couple of reasons. First,
defining vocabularies is a difficult and time-consuming task. Second, even when stan-
dards are defined, people don’t always follow them and if they do, standards don’t
adapt well to the constantly changing business requirements and environment.
Most problems companies experience in this field are social rather than technical.
Different cultures, points of view, historic roots, and business processes create differ-
ent semantics and disjoint vocabularies. A complete solution that would be a func-
tional, adaptable, flexible, and maintainable system will include not only a
sophisticated loosely coupled physical infrastructure (web services) but also an infor-
mation infrastructure with similar properties (shared understanding of semantics and
concepts) and perhaps even a human infrastructure (right people do the right things
in terms of process, planning, and architecture).
Web services are only the first step in the right direction.