Hello again, and welcome to the second module.
In the first module, we introduced systems based on services.
And discussed various web standards using web-based systems.
So what is a web service?
These are questions that you will be able to answer by the end of this module.
architectures, even based on different standards and technologies.
A service is some functionality that is exposed for use by other processes.
the needs they address, it may be helpful to discuss what came before.
different parts of your business.
Even with only six different nodes there are up to 15 pairwise interactions.
Most of these will need wrappers in order to interact.
difficult to maintain and extend.
The exact architecture varies, but it uses a form of middleware.
This approach helps to manage complexity in one organization.
interactions, where the interactions are between businesses instead of within them.
In particular which business implements the middleware?
Is it hosted by a third party?
How does the business protect its data from outside influence?
in practice EAI is not used for B2B interactions.
Instead interactions between businesses are better implemented as web services.
a specific set of standards and protocols for implementing services over the web.
interoperable machine-to-machine interaction over a network.
standards that make up web services.
learned about in the last module.
XML if you need a more in depth refresher.
On top of that it's HTTP, the Hypertext Transfer Protocol.
Web services can also be built on top of other transfer protocols.
But we will focus on HTTP.
a strong foundation for platform independence and interoperability.
That's why it is the basis for the web services we are discussing in this module.
As well as for RESTful web services, which are covered in the next module.
XML formatted documents, usually in a request response messaging design.
with structured information that is both machine readable and human readable.
XML is used for many facets of web services, as you will see.
Web services need to have certain functions and behaviors.
the standards that enable those activities.
In order for a service requester to use a particular service it must invoke it.
except that it must be done through a request in XML.
since a service may offer several along with the parameters in Data.
based on XML and allows services to send information to one another.
SOAP at one time stood for Simple Object Access Protocol.
Though this meaning has since been dropped.
service providers use these SOAP messages to send each other information.
systems coded in different language and on different platform can easily communicate.
In order for services to interact they must know how to interact.
WSDL is the standard protocol for describing the interface of a service.
Like SOAP, WSDL descriptions are written in XML.
that a service requester can bind itself to this interface.
so that a service requester can begin invoking it.
binding can be done by generating the necessary code automatically.
service providers need ways to come into contact.
universal description, discovery and integration.
UDDI is used to build public or private registries of web services.
other aspects of the service.
UDDI are the three foundational standards of web services.
themselves, and to be published registries where they can be discovered.
All of them rely on web infrastructure.
WS coordination to coordinate the activities of many surfaces.
simply BPEL, which stands for Business Process Execution Language.
BPEL allows developers to combine existing services into new composite services.
which can either be composites themselves, or basic.
A basic service does not rely on other services.
The act of combining services into new services is called service composition.
published in standardized ways, their internal implementation does not matter.
in different languages and still effectively interact.
parameters that are supported by the service provider.
because the standardised communication between services and service requester.
on any platform that supports standard web technology.
how interactions are mediated become simpler.
is instead covered by web service standards.
within businesses, between businesses, and in other contexts.
independence and a service-oriented architecture.