kemal baykal rasim ismayilov. web services(1) a software system which connects the machines over a...
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Kemal BaykalRasim Ismayilov
Web Services(1)A software system which connects the
machines over a network in an interoperable manner
The main idea is to make the communication between business systems and clients and also within each other.
The main advantage of Web services is to allow organizations to communicate data without knowing each other's IT systems behind the firewall.
Web Services(2)Does not provide GUI unlike the server/client
systems.Share business logic, data and processes
through a programmatic interfaceNormally the applications interact with each
other, not with usersBut you can add a GUI to gain extra
functionalities over the users.
Applications in Web ServicesXML is used to tag
the dataSOAP is used to
transfer the dataWSDL is used for
describing the services available
UDDI is used for listing which services are available
XML (Extensible Markup Language)It is classified as an extensible language
because it allows its users to define their own tags
Main purpose is to facilitate the sharing of structured data across different information systems
It is the language both machines and human beings can understand easily
It is used both to encode documents and serialize data
SOAP (Service Oriented Architecture Protocol)is a protocol for exchanging XML-based
messages over computer networksused to encode the information in Web
service request and response messages before sending them over a network
SOAP messages are independent of any operating system or protocol
may be transported using a variety of Internet protocols, including SMTP, MIME, and HTTP
SOAP elementsEnvelope element, identifies the XML
document as a SOAP message (required) Header element, contains header
information (optional)Body element, contains call and response
information (required)Fault element, provides information about
errors that occurred while processing the message (optional)
SOAP’s ProtocolsSOAP uses SMTP and
HTTP as an application layer protocol for transport.
HTTP is used more because it works well with today's Internet infrastructure.
SOAP works well with network firewalls.
SOAPAdvantages DisadvantagesSOAP allows the use of
different transport protocols.
Using SOAP allows easier communication behind proxies and firewalls
Because of the verbose XML format, SOAP can be considerably slower than technologies such as CORBA. This is not the case when only small messages are sent
Many SOAP implementations limit the amount of data that can be sent.
WSDL (Web Services Description Language)an XML-based language that provides a
model for describing Web servicesdescribe Web service's capabilities as
collections of communication endpoints capable of exchanging messages
an integral part of UDDI and the language that UDDI uses
is used to describe what a web service can do, where it resides, and how to call it
WSDL’s elements (1)Types : a container for data type definitions
using some type system Message: an abstract, typed definition of the
data being communicatedOperation: an abstract description of an
action supported by the servicePort Type: an abstract set of operations
supported by one or more endpoints
WSDL’s elements (2)Binding: a concrete protocol specification
for a particular port typePort: a single endpoint defined as a
combination of a binding and a network address
Service: a collection of related endpoints
WSDL’s Propertiesis a template for how services should be
described and bound by clientsis often used in with SOAP and XML Schema
to provide web services over the InternetA client program connecting to a web service
can read the WSDL to determine what functions are available on the server
was developed by Microsoft and IBM
UDDI (Universal Description, Discovery and Integration)
a Web-based distributed directory that enables businesses to list themselves on the Internet and discover each other
is platform independentis XML baseddesigned to be interrogated by SOAP
messagesto provide access to WSDL documents
describing the protocol bindings and message formats
UDDI ComponentsWhite Pages:
address, contact, and known identifiers
Yellow Pages: industrial categorizations based on standard taxonomies
Green Pages: technical information about services exposed by the business
UDDI Data TypesbusinessEntity: The top level structure,
describing a business or other entity for which information is being registered
bindingTemplate: Information necessary to use specific services which may have bindings to one or more protocols..
businessService: Description of a set of services which may contain one or more bindingTemplates.
tModel: Technical “finger print” for a given service which may also function as namespace to identify other entities
Additional Specifications for WS (1)WS SecurityWS ReliabilityWS Reliable
MessagingWS AddressingWS Transaction
Additional Specifications for WS (2)They are all specified by OASIS community
(Microsoft, IBM, VeriSign and Forum Systems)They use different technology (xml) not like
traditional httpSo the technology for security, reliable
messaging, reliability, addressing and transactions differ. They are XML based.
For example, as an alternative to use HTTPS to secure the channel, it uses XML based technologies such as XML Signature, XML Encyription,...
Web Services vs Java RMIWeb Services Java RMIinteroperabletransfer by xml files
(knowing what goes in wire)
easy access of enterprise business operations
platform-independent, easy interaction through different applications
needs large bandwidths
better performancetransfer by bytes integrated with Javaless CPU&memory usagedoesn’t need large
bandwidths
Alternative Solution!dual technology can
be usedWeb Service
implementation for external users
an alternative higher performance variant of internal use by Java RMI
Referenceshttp://www.ribomation.com/riboutils/
webservices-performance/article.htmlhttp://mercury.it.swin.edu.au/ctg/AWSA04/
Papers/gray.pdfhttp://en.wikipedia.org/wiki/Web_servicehttp://www.webopedia.com/TERM/W/
Web_services.html