Introduction of Web Services
                      
iFoWure Cbo Snesruvilcteasncy
 
https://www.ifourtechnolab.com/
INDEX
Introduction to Web Service
SOAP (Simple Object Access Protocol)
WSDL (Web Service Description Language)
WSDL Components
WCF (Windows Communication Foundation)
Advantages of WCF
Difference between WCF and Web service
WCF Service Components
Address
Binding
Contract
REST
WEB API
https://www.ifourtechnolab.com/
Introduction to Web Service
 An application that is designed to interact directly with other applications over the 
internet
 In simple sense, Web Services are means for interacting with objects over the Internet
 The Web service consumers are able to invoke method calls on remote objects by using 
SOAP and HTTP over the Web
 It is language independent and Web Services communicate by using standard web 
protocols and data formats, such as
HTTP
XML
SOAP
https://www.ifourtechnolab.com/
Introduction to Web Service (Cont.)
Flow
https://www.ifourtechnolab.com/
Introduction to Web Service (Cont.)
 Advantage:
Web Service messages are formatted as XML, a standard way for communication 
between two incompatible system. And this message is sent via HTTP, so that they can 
reach to any machine on the internet without being blocked by firewall
https://www.ifourtechnolab.com/
Types of Web service
 SOAP - Simple Object Access Protocol 
 REST  - Representation State Transfer
Three ways we can develop web service
 ASMX Web Service (SOAP)
 WCF (SOAP /REST)
 ASP.NET Web API ( REST) 
https://www.ifourtechnolab.com/
Web service request and response flow 
SOAP-REST Web service Communication Flow
https://www.ifourtechnolab.com/
Web service request and response flow Cont.
Web service Communication Flow
https://www.ifourtechnolab.com/
SOAP (Simple Object Access Protocol)
 Remote function calls that invokes method and executes them on Remote machine and 
translate the object communication into XML format
 In short, SOAP are way by which method calls are translate into XML format and sent via 
HTTP
https://www.ifourtechnolab.com/
SOAP (Cont.)
 SOAP and XML created the solution for the problem that developers were facing before
 Standard XML based protocol that communicated over HTTP
 SOAP is message format for sending messaged between applications using XML. It is 
independent of technology, platform and is extensible too
 SOAP and XML to give us connectivity between applications
https://www.ifourtechnolab.com/
WSDL (Web Service Description Language)
 A Standard by which a web service can tell clients what messages it accepts and which 
results it will return
 Contains every detail regarding using web service and Method and Properties provided by 
web service and URLs from which those methods can be accessed and Data Types used
 The operations and messages are described abstractly, and then bound to a concrete 
network protocol and message format to define an endpoint
 Related concrete endpoints are combined into abstract endpoints (services) 
 It is extensible to allow description of endpoints and their messages regardless of what 
message formats or network protocols are used to communicate, however, the only 
bindings described in this document describe how to use WSDL in conjunction with SOAP
https://www.ifourtechnolab.com/
WSDL Components
https://www.ifourtechnolab.com/
WSDL Components (Cont.)
WSDL 1.1 Term WSDL 2.0 Term Description
Contains a set of system functions 
Service Service that have been exposed to the 
Web-based protocols
Defines the address or connection 
Port Endpoint point to a Web service. It is 
typically represented by a simple 
HTTP URL string
Specifies the interface and defines 
the SOAP binding style (RPC
Binding Binding /Document) and transport (SOAP
 Protocol). The binding section also 
defines the operations
https://www.ifourtechnolab.com/
WSDL Components (Cont.)
PortType Interfa Defines a Web service, the operations that can be performed, and the messages that are 
ce used to perform the operation
Operation Opera Defines the SOAP actions and the way the message is encoded, for example, "literal." An 
tion operation is like a method or function call in a traditional programming language
Typically, a message corresponds to an operation. The message contains the information 
needed to perform the operation. Each message is made up of one or more logical parts. 
Each part is associated with a message-typing attribute
Message n/a The message name attribute provides a unique name among all messages. The part name attribute provides a unique name among all the parts of the enclosing message. 
Parts are a description of the logical content of a message. In RPC binding, a binding may 
reference the name of a part in order to specify binding-specific information about the 
part
Types Types Describes the data. The XML Schema language (also known as XSD) is used (inline or 
referenced) for this purpose
https://www.ifourtechnolab.com/
WCF (Windows Communication Foundation)
 Programming platform and runtime system for building, configuring and deploying 
network-distributed services
 Latest service oriented technology, Interoperability is the fundamental characteristics of 
WCF
 Unified programming model provided in .NET Framework 3.0
 Combined feature of Web Service, Remoting, MSMQ and COM+
 Provides a common platform for all .NET communication
https://www.ifourtechnolab.com/
Advantages of WCF
 Interoperable with other services when compared to .NET Remoting where the client and 
service have to be .NET
 Provide better reliability and security in compared to ASMX web services.
 No need to make much change in code for implementing the security model and changing 
the binding. Small changes in the configuration will make our requirements
 Integrated logging mechanism, changing the configuration file settings will provide this 
functionality
https://www.ifourtechnolab.com/
Difference between WCF and Web service
Features Web Service WCF
It can be hosted in IIS, windows activation service, Self-hosting, Windows 
Hosting It can be hosted in IIS service
Programming [WebService] attribute has to be added to [ServiceContract] attribute has to be added to the class
the class
Model [WebMethod] attribute represents the [OperationContract] attribute represents the method exposed to client
method exposed to client
One-way, Request- Response are the One-Way, Request-Response, Duplex are different type of operations 
Operation different operations supported in web 
service supported in WCF
XML System.Xml.serialization name space is System.Runtime.Serialization namespace is used for serialization
used for serialization
XML 1.0, MTOM(Message Transmission 
Encoding XML 1.0, MTOM, Binary, Custom
Optimization Mechanism), DIME, Custom
Transports Can be accessed through HTTP, TCP, Can be accessed through HTTP, TCP, Named pipes, MSMQ,P2P, Custom
Custom
Protocols Security Security, Reliable messaging, Transactions
https://www.ifourtechnolab.com/
WCF Service Components
 A WCF Service is composed of three components :
 Service Class - It implements some service as a set of methods
 Host Environment - It can be a Console application or a Windows Service or a Windows Forms 
application or IIS as in case of the normal .asmx web service in .NET
 Endpoints - All communications with the WCF service will happen via the endpoints. The endpoint 
is composed of 3 parts (collectively called as ABC's of endpoint) as defines below: 
 Address
 Binding
 Contract
https://www.ifourtechnolab.com/
Address
 The endpoints specify an Address that defines where the endpoint is hosted
 It’s basically url
 Example:
http://localhost/WCFServiceSample/Service.svc
https://www.ifourtechnolab.com/
Binding
 The endpoints also define a binding that specifies how a client will communicate with the 
service and the address where the endpoint is hosted
 Different Bindings supported by WCF:
Binding Description
Basic Web service communication. No security by 
BasicHttpBinding
default
Web services with WS-* support. Supports 
WSHttpBinding transactions
WSDualHttpBinding Web services with duplex contract and transaction support
https://www.ifourtechnolab.com/
Binding (Cont.)
WSFederationHttpBinding Web services with federated security. Supports transactions
MsmqIntegrationBinding Communication directly with MSMQ applications. Supports transactions
NetMsmqBinding Communication between WCF applications by using queuing. Supports transactions
NetNamedPipeBinding Communication between WCF applications on same computer. Supports duplex contracts and transactions
Communication between computers across peer-to-peer services. 
NetPeerTcpBinding Supports duplex contracts
NetTcpBinding Communication between WCF applications across computers. Supports duplex contracts and transactions
BasicHttpBinding Basic Web service communication. No security by default
WSHttpBinding Web services with WS-* support. Supports transactions
https://www.ifourtechnolab.com/
Contract
 The endpoints specify a Contract that defines which methods of the Service class will be 
accessible via the endpoint; each endpoint may expose a different set of methods
 Different contracts in WCF:
Service Contract
 It describe the operation that service can provide. For E.g., A Service provide to know the temperature of 
the city based on the zip code, this service is called as Service contract
 It will be created using Service and Operational Contract attribute
Message Contract
 Default SOAP message format is provided by the WCF runtime for communication between Client and 
service
 If it is not meeting requirements then we can create our own message format. This can be achieved by 
using Message Contract attribute
https://www.ifourtechnolab.com/
Contract (Cont.)
Data Contract
 It describes the custom data type which is exposed to the client. This defines the data types, 
which are passed to and from service
Data types like int, string are identified by the client because it is already mention in XML 
schema definition language document, but custom created class or data types cannot be 
identified by the client e.g. Employee data type
  By using Data Contract we can make client to be aware of Employee data type that are returning 
or passing parameter to the method
Fault Contract
Suppose the service we consumed is not working in the client application. we want to know the 
real cause of the problem. How we can know the error? For this we are having Fault Contract
  Fault Contract provides documented view for error occurred in the service to client. This helps 
us to easy identity, what error has occurred
https://www.ifourtechnolab.com/
REST
 REST stands for ‘Representational State Transfer’ and it is an architectural pattern for 
creating an API that uses HTTP as its underlying communication method 
 Almost every device that is connected to the internet already uses HTTP, it is the base protocol that 
the internet is built on which is why it makes such a great platform for an API
 HTTP is a request and response system, a calling client sends a request to an endpoint and the 
endpoint responds
 The client and endpoint can be anything but a typical example is a browser accessing a web server 
or an app accessing and API
https://www.ifourtechnolab.com/
REST (Cont.)
 There are several key implementation details with HTTP that you should be aware of:
Resources - REST uses addressable resources to define the structure of the API. These are the URLs you use to get 
to pages on the web
  Example: ‘http://www.microsoft.com/Surface-Pro-3’ is a resource
Request Verbs - A browser typically issues a GET verb to instruct the endpoint it wants to get data, however there 
are many other verbs available including things like POST, PUT and DELETE
Request Headers - Additional instructions that are sent with the request. These might define what type of response 
is required or authorization details
Request Body - Data that is sent with the request
 Example: A POST (creation of a new item) will required some data which is typically sent as the request body in the format 
of JSON or XML
Response Body - Main body of the response. If the request was to a web server, this might be a full HTML page, if it 
was to an API, this might be a JSON or XML document
Response Status codes - These codes are issues with the response and give the client details on the status of the 
request
https://www.ifourtechnolab.com/
WEB API
 The term API stands for ‘Application Programming Interface’
 In the world of web development the term ‘API’ is synonymous with online web services 
which client apps can use to retrieve and update data
 These online services have had several names/formats over the years such as SOAP, 
however the current popular choice is to create a REST (or RESTful) API
https://www.ifourtechnolab.com/
References
 http://www.tutorialspoint.com/webservices/
 http://www.w3schools.com/xml/xml_services.asp
 http://www.c-sharpcorner.com/uploadfile/00a8b7/web-service/
 https://www.tutorialspoint.com/asp.net/asp.net_web_services.htm
https://www.ifourtechnolab.com/
Thank You..
https://www.ifourtechnolab.com/