When discuss about web services it is important to deal with
client and service.
Service à
Functionalities exposed to the world
Client à
Party consuming the service
Web Services provide facility to communicate between
applications in an efficient way. But we have to face some limitations when
work with the web services.
Communication
can happen over Http protocols only
Only
support for the Simplex communication (one way communication ex: radio, TV)
WCF (Windows Communication Foundation) comes with reducing
the limitations of the normal
web services and provide more user friendly facilities.
Let’s compare the web services with WCF
Web Services
|
WCF
|
Communication can happen over Http protocols only
|
Can be communicate via Http, TCP, IPC or MSMQ
|
Only support for simplex communication
|
Support for simplex, half duplex and full duplex communication
|
Hosted inside web servers like IIS
|
Can host in many ways( inside the IIS, windows services and even self-hosting
is possible)
|
Use
XmlSerializer |
Use
DataContractSerializer which
is better in Performance as compared to XmlSerializer.
(in
XmlSerializer
some of the fields can’t serialize ex:-hash tables, classes which not
implement the IEnumerable and IDictionary interface, non-public methods and
properties) |
Unhandled exceptions are returned to the client as SOAP faults
|
Unhandled exceptions are not returned to clients as SOAP faults.
(A
configuration setting is provided to have the unhandled exceptions returned
to clients for the purpose of debugging.)
|
Support for XML and Http binding
|
Support for different type of binding (WSHttpBinding,BasicHttpBinding,WSDualHttpBinding)
|
When establishing a service using WCF end point is one of
the mostly important thing that we need to know
End point provides the answers to many questions arise
during the WCF service. Following are the main points we can identify by using
the end point of a WCF service.
Address describe the location where the
service locate from a client perspective
Binding describe how can
client access to the service (protocol, message format)
Contract what
are the operations can perform using the particular service(functionality
provide to the client)
Possible ways of
hosting the WCF services
·
Self- Hosting (Console application, Windows
applications or any type of manage applications can use to self- hosting)
·
Web servers (IIS)
·
Windows services
Data-Contract
serialization Vs. XML serialization
(stay with me for more details soon...................................)
WCF instance modes
Per-Call –instance create for each call.
Most efficient in term of memory but need to maintain the session
Per-Session –instance create for a complete
session of a user so no need to maintain the sessions manually sessions are
maintained.
Single –only one instance
created for all client/user and shared among all and least efficient in terms
of memory
Security modes use in WCF
Transport level
security
Providing security
at the transport layer itself and Concerned about integrity, privacy, and
authentication of message.
Guarantees the
point-to-point communication and order of packets going through the
communication way
But
communication problems like dropping network connection can leak the security
Message level
security
Secure the message by encrypting it before sending
Guarantees the number of packets delivering and order of packets too
Binding use in WCF
- BasicHTTP à When converting the already created ASMX web service to WCF service BasicHttpBinding can be used.
- NetTCP
- MSMQ
Contract use in WCF
- ServiceContract
- OperationContract
- DataContract
- DataMember
- FaultContract
- MessageContract
(stay with me for more details soon...................................)
References:
- http://www.codeproject.com/Articles/406096/A-beginners-tutorial-for-understanding-Windows
- http://www.codeproject.com/Articles/139787/What-s-the-Difference-between-WCF-and-Web-Services
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