What is .NET 3.0?
In one simple equation .NET 3.0 = .NET 2.0 + Windows Communication Foundation + Windows
Presentation Foundation + Windows Workflow Foundation + Windows Card Space.
What is WCF?
Windows Communication Foundation (WCF) is an SDK for developing and deploying services on Windows. WCF provides a runtime environment for services, enabling you to expose CLR types as services, and to consume other services as CLR types.
First let us give a short answer to this: - “WCF (Indigo was the code name for WCF) is a
unification of .NET framework communication technologies
“.WCF is a unification technology,
which unites the following technologies:-
• NET remoting
• MSMQ
• Web services
• COM+.
What was the code name for WCF?
The code name of WCF was Indigo .
WCF is a unification of .NET framework communication technologies which unites the following technologies:-
1.Web services
2.MSMQ
3.NET remoting
4.COM+
What are the main components of WCF?
The main components of WCF are
1. Service class
2. Hosting environment
3. End point
Where we can host WCF services?
Every WCF services must be hosted somewhere. There are three ways of hosting WCF services.
They are
1. IIS
2. Self Hosting
3. WAS (Windows Activation Service)
What is service and client in perspective of data communication?
A service is a unit of functionality exposed to the world.
The client of a service is merely the party consuming the service.
What are different elements of WCF Srevices Client configuration file?
WCF Services client configuration file contains endpoint, address, binding and contract.
A sample client config file looks like
What is endpoint in WCF?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service. In WCF the relationship between Address, Contract and Binding is called Endpoint.
What are ends, contract, address, and bindings?
The above terminologies are the core on which SOA stands. Every service must expose one or
more ends by which the service can be available to the client. End consists of three important
things where, what and how:-
• Contract (What)
Contract is an agreement between two or more parties. It defines the protocol how client should
communicate with your service. Technically, it describes parameters and return values for a
method.
• Address (Where)
An Address indicates where we can find this service. Address is a URL, which points to the
location of the service.
• Binding (How)
Bindings determine how this end can be accessed. It determines how communications is done.
For instance, you expose your service, which can be accessed using SOAP over HTTP or
BINARY over TCP. So for each of these communications medium two bindings will be created.
Below figure, show the three main components of end. You can see the stock ticker
is the service
class, which has an end hosted on www.soa.com with HTTP and TCP binding support and using
Stock Ticker interface type.
What is binding and how many types of bindings are there in WCF?
A binding defines how an endpoint communicates to the world. A binding defines the transport (such as HTTP or TCP) and the encoding being used (such as text or binary). A binding can contain binding elements that specify details like the security mechanisms used to secure messages, or the message pattern used by an endpoint.
WCF supports nine types of bindings.
Basic binding
Offered by the BasicHttpBinding class, this is designed to expose a WCF service as a legacy ASMX web service, so that old clients can work with new services. When used by the client, this binding enables new WCF clients to work with old ASMX services.
This binding is used when we need to use SOAP over HTTP. This binding
can also be configured to be used as HTTPS. It can be also configured to send data in plain text or
in optimized form like MTOM.
TCP binding
Offered by the NetTcpBinding class, this uses TCP for cross-machine communication on the intranet. It supports a variety of features, including reliability, transactions, and security, and is optimized for WCF-to-WCF communication. As a result, it requires both the client and the service to use WCF.
This binding sends binary-encoded SOAP, including support for reliable
message transfer, security, and transactions, directly over TCP. The biggest disadvantage of
NetTcpBinding is that both server and client should be also made in .NET language.
Peer network binding
Offered by the NetPeerTcpBinding class, this uses peer networking as a transport. The peer network-enabled client and services all subscribe to the same grid and broadcast messages to it.
IPC binding
Offered by the NetNamedPipeBinding class, this uses named pipes as a transport for same-machine communication. It is the most secure binding since it cannot accept calls from outside the machine and it supports a variety of features similar to the TCP binding.
Web Service (WS) binding
Offered by the WSHttpBinding class, this uses HTTP or HTTPS for transport, and is designed to offer a variety of features such as reliability, transactions, and security over the Internet.
It is same like BasicHttpBinding. In short, it uses SOAP over HTTP. But with
it also supports reliable message transfer, security and transaction. WS-Reliable Messaging,
security with WS-Security, and transactions with WS-Atomic Transaction supports reliable
message.
Federated WS binding
Offered by the WSFederationHttpBinding class, this is a specialization of the WS binding, offering support for federated security.
Duplex WS binding
Offered by the WSDualHttpBinding class, this is similar to the WS binding except it also supports bidirectional communication from the service to the client.
MSMQ binding
Offered by the NetMsmqBinding class, this uses MSMQ for transport and is designed to offer support for disconnected queued calls.
MSMQ integration binding
Offered by the MsmqIntegrationBinding class, this converts WCF messages to and from MSMQ messages, and is designed to interoperate with legacy MSMQ clients.
This binding sends binary-encoded SOAP over MSMQ. This binding can
only be used for WCF-to-WCF communication.
Which specifications does WCF follow?
WCF supports specifications defined by WS-* specifications. WS-* specifications are defined
together by Microsoft, IBM, SUN and many other big companies so that they can expose there
service through a common protocol. WCF supports all specifications defined we will understand
them one by one.
• Messaging (WS-Addressing):- SOAP is the fundamental protocol for web services. WS
Addressing defines some extra additions to SOAP headers, which makes SOAP free from
underlying transport protocol. One of the good things about Message transmission is MTOM,
also termed as Message Transmission Optimization Mechanism. They optimize transmission
format for SOAP messages in XML-Binary formant using XML optimized packaging (XOP).
Because the data will sent in binary and optimized format, it will give us huge performance
gain.
• Security (WS-Security, WS-Trust, and WS-Secure Conversation): All the three WSdefine
authentication, security, data integrity and privacy features for a service.
• Reliability (WS-Reliable Messaging): This specification ensures end-to-end
communication when we want SOAP messages to be traversed back and forth many times.
• Transactions (WS-Coordination and WS-Atomic Transaction): These two specifications
enable transaction with SOAP messages.
• Metadata (WS-Policy and WS-Metadata exchange): WSDL is a implementation of WSMetadata
Exchange protocol. WS-Policy defines more dynamic features of a service, which
cannot be expressed by WSDL.
WCF follows WS-* specifications other
languages like JAVA , C++ can also exploit features like Messaging , Security , Reliability and
transactions written in C# or VB.NET. This is the biggest achievement of WCF to integrate the
above features with other languages.
What is the difference WCF and Web services?
Web services can only be invoked by HTTP. While Service or a WCF component can be invoked
by any protocol and any transport type. Second web services are not flexible. However, Services
are flexible. If you make a new version of the service then you need to just expose a new end.
Therefore, services are agile and which is a very practical approach looking at the current
business trends.
what are the advantages of hosting WCF Services in IIS as
compared to self-hosting?
There are two main advantages of using IIS over self-hosting:-
Automatic activation
IIS provides automatic activation that means the service is not necessary to be running in
advance. When any message is received by the service it then launches and fulfills the request.
But in case of self hosting the service should always be running.
Process recycling
If IIS finds that a service is not healthy that means if it has memory leaks etc, IIS recycles the
process. For every browser instance, a
worker process is spawned and the request is serviced. When the browser disconnects the worker,
process stops and you loose all information. IIS also restarts the worker process. By default, the
worker process is recycled at around 120 minutes. So why does IIS recycle. By restarting the
worker process it ensures any bad code or memory leak do not cause issue to the whole system.
In case of self-hosting both the above features, you will need to code yourself. Lot of work
right!!.
what are the various ways of hosting a WCF service?
There are three major ways to host a WCF service:-
• Self-hosting the service in his own application domain. This we have already covered in
the first section. The service comes in to existence when you create the object of Service
Host class and the service closes when you call the Close of the Service Host class.
• Host in application domain or process provided by IIS Server.
• Host in Application domain and process provided by WAS (Windows Activation
Service) Server.
Which are the various programming approaches for WCF?/ What is one-way operation?
IsOneWay equal to true ensures that the client does not have to wait for the response. So methods
marked by IsOneWay to true should always return void. In this, the caller does not get anything
in return so it is called as one-way communication.
In one simple equation .NET 3.0 = .NET 2.0 + Windows Communication Foundation + Windows
Presentation Foundation + Windows Workflow Foundation + Windows Card Space.
What is WCF?
Windows Communication Foundation (WCF) is an SDK for developing and deploying services on Windows. WCF provides a runtime environment for services, enabling you to expose CLR types as services, and to consume other services as CLR types.
First let us give a short answer to this: - “WCF (Indigo was the code name for WCF) is a
unification of .NET framework communication technologies
“.WCF is a unification technology,
which unites the following technologies:-
• NET remoting
• MSMQ
• Web services
• COM+.
What was the code name for WCF?
The code name of WCF was Indigo .
WCF is a unification of .NET framework communication technologies which unites the following technologies:-
1.Web services
2.MSMQ
3.NET remoting
4.COM+
What are the main components of WCF?
The main components of WCF are
1. Service class
2. Hosting environment
3. End point
Where we can host WCF services?
Every WCF services must be hosted somewhere. There are three ways of hosting WCF services.
They are
1. IIS
2. Self Hosting
3. WAS (Windows Activation Service)
What is service and client in perspective of data communication?
A service is a unit of functionality exposed to the world.
The client of a service is merely the party consuming the service.
What are different elements of WCF Srevices Client configuration file?
WCF Services client configuration file contains endpoint, address, binding and contract.
A sample client config file looks like
What is endpoint in WCF?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service. In WCF the relationship between Address, Contract and Binding is called Endpoint.
What are ends, contract, address, and bindings?
The above terminologies are the core on which SOA stands. Every service must expose one or
more ends by which the service can be available to the client. End consists of three important
things where, what and how:-
• Contract (What)
Contract is an agreement between two or more parties. It defines the protocol how client should
communicate with your service. Technically, it describes parameters and return values for a
method.
• Address (Where)
An Address indicates where we can find this service. Address is a URL, which points to the
location of the service.
• Binding (How)
Bindings determine how this end can be accessed. It determines how communications is done.
For instance, you expose your service, which can be accessed using SOAP over HTTP or
BINARY over TCP. So for each of these communications medium two bindings will be created.
Below figure, show the three main components of end. You can see the stock ticker
is the service
class, which has an end hosted on www.soa.com with HTTP and TCP binding support and using
Stock Ticker interface type.
What is binding and how many types of bindings are there in WCF?
A binding defines how an endpoint communicates to the world. A binding defines the transport (such as HTTP or TCP) and the encoding being used (such as text or binary). A binding can contain binding elements that specify details like the security mechanisms used to secure messages, or the message pattern used by an endpoint.
WCF supports nine types of bindings.
Basic binding
Offered by the BasicHttpBinding class, this is designed to expose a WCF service as a legacy ASMX web service, so that old clients can work with new services. When used by the client, this binding enables new WCF clients to work with old ASMX services.
This binding is used when we need to use SOAP over HTTP. This binding
can also be configured to be used as HTTPS. It can be also configured to send data in plain text or
in optimized form like MTOM.
TCP binding
Offered by the NetTcpBinding class, this uses TCP for cross-machine communication on the intranet. It supports a variety of features, including reliability, transactions, and security, and is optimized for WCF-to-WCF communication. As a result, it requires both the client and the service to use WCF.
This binding sends binary-encoded SOAP, including support for reliable
message transfer, security, and transactions, directly over TCP. The biggest disadvantage of
NetTcpBinding is that both server and client should be also made in .NET language.
Peer network binding
Offered by the NetPeerTcpBinding class, this uses peer networking as a transport. The peer network-enabled client and services all subscribe to the same grid and broadcast messages to it.
IPC binding
Offered by the NetNamedPipeBinding class, this uses named pipes as a transport for same-machine communication. It is the most secure binding since it cannot accept calls from outside the machine and it supports a variety of features similar to the TCP binding.
Web Service (WS) binding
Offered by the WSHttpBinding class, this uses HTTP or HTTPS for transport, and is designed to offer a variety of features such as reliability, transactions, and security over the Internet.
It is same like BasicHttpBinding. In short, it uses SOAP over HTTP. But with
it also supports reliable message transfer, security and transaction. WS-Reliable Messaging,
security with WS-Security, and transactions with WS-Atomic Transaction supports reliable
message.
Federated WS binding
Offered by the WSFederationHttpBinding class, this is a specialization of the WS binding, offering support for federated security.
Duplex WS binding
Offered by the WSDualHttpBinding class, this is similar to the WS binding except it also supports bidirectional communication from the service to the client.
MSMQ binding
Offered by the NetMsmqBinding class, this uses MSMQ for transport and is designed to offer support for disconnected queued calls.
MSMQ integration binding
Offered by the MsmqIntegrationBinding class, this converts WCF messages to and from MSMQ messages, and is designed to interoperate with legacy MSMQ clients.
This binding sends binary-encoded SOAP over MSMQ. This binding can
only be used for WCF-to-WCF communication.
Which specifications does WCF follow?
WCF supports specifications defined by WS-* specifications. WS-* specifications are defined
together by Microsoft, IBM, SUN and many other big companies so that they can expose there
service through a common protocol. WCF supports all specifications defined we will understand
them one by one.
• Messaging (WS-Addressing):- SOAP is the fundamental protocol for web services. WS
Addressing defines some extra additions to SOAP headers, which makes SOAP free from
underlying transport protocol. One of the good things about Message transmission is MTOM,
also termed as Message Transmission Optimization Mechanism. They optimize transmission
format for SOAP messages in XML-Binary formant using XML optimized packaging (XOP).
Because the data will sent in binary and optimized format, it will give us huge performance
gain.
• Security (WS-Security, WS-Trust, and WS-Secure Conversation): All the three WSdefine
authentication, security, data integrity and privacy features for a service.
• Reliability (WS-Reliable Messaging): This specification ensures end-to-end
communication when we want SOAP messages to be traversed back and forth many times.
• Transactions (WS-Coordination and WS-Atomic Transaction): These two specifications
enable transaction with SOAP messages.
• Metadata (WS-Policy and WS-Metadata exchange): WSDL is a implementation of WSMetadata
Exchange protocol. WS-Policy defines more dynamic features of a service, which
cannot be expressed by WSDL.
WCF follows WS-* specifications other
languages like JAVA , C++ can also exploit features like Messaging , Security , Reliability and
transactions written in C# or VB.NET. This is the biggest achievement of WCF to integrate the
above features with other languages.
What is the difference WCF and Web services?
Web services can only be invoked by HTTP. While Service or a WCF component can be invoked
by any protocol and any transport type. Second web services are not flexible. However, Services
are flexible. If you make a new version of the service then you need to just expose a new end.
Therefore, services are agile and which is a very practical approach looking at the current
business trends.
what are the advantages of hosting WCF Services in IIS as
compared to self-hosting?
There are two main advantages of using IIS over self-hosting:-
Automatic activation
IIS provides automatic activation that means the service is not necessary to be running in
advance. When any message is received by the service it then launches and fulfills the request.
But in case of self hosting the service should always be running.
Process recycling
If IIS finds that a service is not healthy that means if it has memory leaks etc, IIS recycles the
process. For every browser instance, a
worker process is spawned and the request is serviced. When the browser disconnects the worker,
process stops and you loose all information. IIS also restarts the worker process. By default, the
worker process is recycled at around 120 minutes. So why does IIS recycle. By restarting the
worker process it ensures any bad code or memory leak do not cause issue to the whole system.
In case of self-hosting both the above features, you will need to code yourself. Lot of work
right!!.
what are the various ways of hosting a WCF service?
There are three major ways to host a WCF service:-
• Self-hosting the service in his own application domain. This we have already covered in
the first section. The service comes in to existence when you create the object of Service
Host class and the service closes when you call the Close of the Service Host class.
• Host in application domain or process provided by IIS Server.
• Host in Application domain and process provided by WAS (Windows Activation
Service) Server.
Which are the various programming approaches for WCF?/ What is one-way operation?
IsOneWay equal to true ensures that the client does not have to wait for the response. So methods
marked by IsOneWay to true should always return void. In this, the caller does not get anything
in return so it is called as one-way communication.
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