This print for content only-size & color not accurate 7" X 9-1/4" / casebound / malloy

■

I N T R O D U C I N G  W I N D O W S   C O M M U N I C AT I O N   F O U N D AT I O N

881

8849CH25.qxd  10/16/07  10:51 AM  Page 881

---

In Table 25-3, note that a WCF binding can be represented in code (via class types within the

System.ServiceModel namespace) or as XML attributes defined within *.config files.

Table 25-3.

The HTTP-Centric WCF Bindings

Binding Class

Binding Element

Meaning in Life

BasicHttpBinding

Used to build a WS-Basic Profile (WS-I

Basic Profile 1.1)–conformant WCF

service. This binding uses HTTP as the

transport and Text/XML as the default

message encoding.

WSHttpBinding

Similar to BasicHttpBinding, but

provides more web service features.

This binding adds support for

transactions, reliable messaging,

and WS-Addressing.

WSDualHttpBinding

Similar to WSHttpBinding, but for use

with duplex contracts (e.g., the service

and client can send messages back

and forth). This binding supports only

SOAP security and requires reliable

messaging.

WSFederationHttpBinding

A secure and interoperable binding

that supports the WS-Federation

protocol, enabling organizations that

are in a federation to efficiently

authenticate and authorize users.

As the name suggests, BasicHttpBinding is the simplest of all web service–centric protocols.

Specifically, this binding will ensure that your WCF service conforms to a specification named WS-I

Basic Profile 1.1 defined by WS-I. The main reason to use this binding is to maintain backward com-

patibility with applications that were previously built to communicate with ASP.NET web services

(which have been part of the .NET libraries since version 1.0). 

The WSHttpBinding protocol not only incorporates support for a subset of the WS-* specifica-

tion (transactions, security, and reliable sessions), but also supports the ability to handle binary

data encoding using Message Transmission Optimization Mechanism (MTOM).

The main benefit of WSDualHttpBinding is that it adds the ability to allow the caller and sender

to communicate using 

duplex messaging, which is just a fancy way of saying they can engage in a

two-way conversation. When selecting WSDualHttpBinding, you can hook into the WCF publish/

subscribe event model.

Finally, WSFederationHttpBinding is the web service–based protocol you may wish to consider

when security is of the utmost importance. This binding supports the WS-Trust, WS-Security, and

WS-SecureConversation specifications, which are represented by the WCF CardSpace APIs. 

TCP-Based Bindings

If you are building a distributed application involving machines that are configured with the .NET

3.0/3.5 libraries (in other words, all machines are running Windows XP, Windows Server 2003, or

Windows Vista), you can gain performance benefits bypassing web service bindings and opting for a

TCP binding, which ensures all data is encoded in a compact binary format rather than XML. Again,

when using the bindings shown in Table 25-4, the client and host must be .NET applications. 

C H A P T E R   2 5