The document discusses web services, including their definition, key elements, and how they are developed and deployed. Specifically, it defines web services as software systems designed to support interoperable machine-to-machine interactions over a network. It describes the core standards and protocols involved - SOAP for messaging, WSDL for interface description, and UDDI as a registry. The document also outlines the architecture of web services, including how clients communicate with services via SOAP, and how services are described and registered using WSDL and UDDI. Finally, it briefly discusses tools for deploying web services on servers like IIS and WebSphere.
2. What is Web service ?
• Method of communication between two electronic
devices over the web
• A service that is "always on”
• W3C definition
– a software system designed to support interoperable
machine-to-machine interaction over a network.
3. 3
• It has an interface described in a machine-processable
format (WSDL)
• Other systems interact with the Web service using
SOAP messages
• Features of Web Services
– Language Independent
– Operating System Independent
More about Web service
4. Web service Platform elements
• SOAP is a simple protocol for exchange of information.
• UDDI is a specification designed to allow businesses of all
sizes to benefit in the new digital economy.
• WSDL defines the XML grammar for describing services as
collections of communication endpoints capable of
exchanging messages.
7. WSDL
• WSDL is written in XML
• used to describe & locate Web services
WSDL Ports
• The <portType> element is the most
important WSDL element.
• It defines a web service,
the operations that can be performed, and
the messages that are involved.
8. Type Definition
One-way The operation can receive a message but
will not return a response
Request-response The operation can receive a request and will
return a response
Solicit-response The operation can send a request and will
wait for a response
Notification The operation can send a message but will
not wait for a response
Operation Types
The request-response type is the most common operation type, but
WSDL defines four types:
10. UDDI
• Universal Description, Discovery and
Integration (UDDI)
• UDDI is a directory for storing information
about web services
• UDDI is a directory of web service interfaces
described by WSDL
• UDDI communicates via SOAP
• UDDI uses WSDL to describe interfaces to web
services
11. SOAP-based communication
SOAP:
• Data in a well-defined XML format
• Transport over various protocols
• HTTP, SMTP are the most used
• Server side: either an RPC call or a message
delivered
12. SOAP Elements
• Envelope (mandatory)
– Top element of the XML document representing the
message.
• Header (optional)
– Determines how a recipient of a SOAP message should
process the message
– Adds features to the SOAP message such as
authentication, transaction management, payment,
message routes, etc…
• Body (mandatory)
– Exchanges information intended for the recipient of the
message.
– Typical use is for RPC calls and error reporting.
15. SOAP Fault
• Used to carry error and/or status information
within a SOAP message
• Appears within the SOAP body
• Defines the following:
– faultcode (mandatory)
• algorithmic mechanism for identifying the fault
• defined in the SOAP spec
– Faultstring (mandatory)
• human readable explanation of the fault
16. SOAP Fault
– faultactor (optional)
• information about who caused the fault to happen
• URI value identifying the source
– Detail
• error information related only to the Body element.
• if not present then indicates that the fault is not
related to the Body element.
19. JSON
• Java Script Object Notation
• A new ”fat“ free alternative to XML
• Much smaller grammar
• Maps more directly onto the data
structures used in modern programming
languages
• JSON has the same interoperability
potential as XML
20. JSON Objects and JSON
Arrays
• JSON values can be
• Number, string, Boolean or null value
• JSON Objects
• Contains multiple name value pairs
• JSON Array
• Contains multiple JSON objects