Transcript Web Services in the Justice Arena

Web Services: An
Introduction
Al Kassam
Briyante Software Corp
[email protected]
What is a web service?
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Many Definitions
At a minimum, a Web Service is a piece of selfcontained software that works over the Internet
and uses a standardized XML-based messaging
system
In simpler terms, it’s a program (which exists on
an unrelated computer on the Internet) which can
be run there on demand by a program on your
computer
How does it work?
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In its most basic form, it is a Web-based Remote
Procedure Call (RPC) mechanism.
XML is used to encode all communications
XML-RPC and Simple Object Access Protocol
(SOAP) are currently the most common protocols
in use for conducting the RPC
Application Server
Internet
Client Application
Web Service
Web Services interaction
Client Application
GetTemperature( “92010” )
Return( “65” )
Process returned Value
Application Server
GetTemperature( “90210” )
Return( “65” )
What’s good about WS ?
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Shares many similarities with existing web
based interaction (http/s, firewalls, etc)
Clients and servers can be created using
unrelated technologies
Supports all web site security models
(http/s, certificates, LDAP etc.)
Offers additional security features beyond
that of web sites (WS Security).
Pitfalls
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Massively distributed, therefore no
standards for error management
Far greater need for security
Response time cannot be guaranteed
Two aspects to Web Services
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Use Web Services that others have
created (consumption)
Create your own Web Services for others
to use (publishing)
Consuming Web Services
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Universal Description, Discovery and Integration
(UDDI) registries are used to catalogue available
Web Services
Use an XML-RPC or SOAP toolkit for your
platform and your preferred programming
language
Build your application logic around data
retrieved from many different organizations
through their published Web Services
Publishing Web Services
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Create your Web Service using your
preferred programming language and
either the XML-RPC or SOAP toolkit for
your platform
Use the Web Service Description
Language (WSDL) to describe your Web
Service to other software systems
Allow others to discover your Web Service
by publishing to a UDDI server
How do they help me?
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Provide access to a wider range of
information and services than a web site.
No need to copy data locally as it is
always available across the internet.
Software systems can reap the same
benefits as web client users.
Facilitates electronic collaboration
between (disparate) systems.
How does this help Justice?
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Existing agencies
already form the hubs
for justice related
information.
Large amounts of
useful information
already exist, but in
disparate systems.
Where can an officer look for
information?
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Existing systems
provide access to
information stored
locally within an
agency.
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Some agencies offer
information services
via a web portal of
some kind.
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Web Services can
help create a new
“face” for an agency
Web Services in Justice
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An ideal platform for data sharing without the
need to gather data in one place
Information obtained from multiple agencies can
be presented in a unified view
Elegantly solves integration of disparate island
of data throughout Justice
Can be real time
Available 24 hours a day
Dig Deeper
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MS Web Services Enhancements 1.0/2.0
provides for much broader use of Web
Services (WS-Security, WS-Addressing,
etc)
www.oreillynet.com
www.w3c.org
“Web Services Essentials”, Ethan Cerami