Archive for the 'WCF' Category
Impersonation and Delegation in WCF
| Impersonation is a technique that WCF Services use to authorize the caller’s identity to access to service resources such as files and database tables. Service resources can be located either on local service machine or remotely hosted. The resources are being accessed by WCF Service’s process identity or specific windows identity. |  |
Difference between Impersonation and Delegation in WCF?
Impersonation is used to access the resources when the resources are on the same machine as the service. Delegation is used to access the resources that are remotely hosted.
There are two types of Impersonation in WCF
- Imperative Impersonation – Perform programmatically at run time
- Declarative Impersonation – Applied with a static attribute which associated with an operation.
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1 commentHow to choose right WCF binding?
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Binding in WCF defines how clients can connect with your service. The base class for all bindings in WCF is System.ServiceModel.Channels.Binding. A Binding includes definition for WS-* protocols used, the message encoding and the transport protocol. The available WCF Bindings are
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1 commentTransport and Message Security in WCF
This post discusses about transport and message security. In Transport Security user credentials and claims are passed using transport layer. The transport protocols are TCP, HTTP, MSMQ and IPC. Each of these protocols have their own mechanism for passing user credentials. The most common approach is using secure socket layer(SSL) for encrypting the details which sent over HTTPS.
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No commentsService Orientation vs Object Orientation
Services are good communication technique to use across application and platform boundaries. Service-oriented approach always preferred when you are building a distributed application. Object orientation approach provides a view of what a system should look and effective for producing logical models. Object based approach can fail to consider real-world factors like physical distribution and network communication. This post compares the two approaches.
| Object Orientation | Service Orientation |
| Suitable in a homogeneous platform and execution environment. |
Suitable in a heterogeneous platform and execution environment. |
| Shares types, not schemas. | Shares schemas, not types. |
| Runs in cheap and transparent communication. | The cost is variable and requires explicit communication. |
| Life-time of objects is maintained by the infrastructure. | Services are autonomous –Security and failure isolation are necessary. |
| It requires synchronized deployment of both client and server. | It allows continuous, separate deployment of client and server. |
| Provides no guide-lines for state management and ownership. | It maintains and uses the reference state. |
| You can predict the sequence of events, timeframe and outcome of invocations. | Message orientation approach and supports asynchronous and long-running communications. |
| Goal is to transparently use functions and types remotely. | Goal is to provide inter-service isolation and interoperability based on standards. |
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No commentsWCF 4.5 Features
This post discusses the new features in WCF 4.5. There have been significant improvements in WCF 4.5 on configuration.
Simplifying the generated configuration file in client
| A client configuration file is generated when you add a service reference in Visual Studio 2010. The configuration files in earlier version of WCF contained the value of every binding property even if it is a default value. In WCF 4.5 Configuration files contain binding properties that are set to non-default value. | |
Example of configuration file generated by WCF 3.0
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No commentsWebSockets in ASP.NET 4.5
This post discuss about using WebSockets in ASP.NET 4.5. You can read this post to get an understanding about WebSockets. This post shows piece of code which uses WebSockets in ASP.NET 4.5 and the code is related to simple chat application.
The HTML of Web Form chat application looks as below
It contains a text box where you can type your text message and button where it sends a message to the server. You can notice there is <ul> element which shows the list of other messages which are arriving from the server.
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No commentsWCF Services in Windows Azure
| What is Windows Azure? Windows Azure provides developers computation power storage and can scale web applications on internet through Microsoft Datacenters. Developers can use Azure platform to build WCF service application using their existing Visual Studio 2010 expertise. |  |
Windows Azure supports the protocols and formats including SOAP, REST and XML. This post discuss about creating a simple WCF Service and hosting it on Windows Azure and consuming in client application.
1. Create a WCF Service Contract in Windows Class Library project as shown below which in-turn you use in Web role, worker role and in client application. Read more about roles in windows Azure here
1: using System;
2: using System.ServiceModel;
3: namespace WCFContract
4: {
5: [ServiceContract]
6: public interface IContract
7: {
8: // This operating returns the server information, including
9: // the role's name and instance id
10: [OperationContract]
11: string GetRoleInfo();
12:
13: // This operation returns the information of the channel
14: // being used between the client & the server.
15: [OperationContract]
16: string GetCommunicationChannel();
17: }
18: }
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1 commentWCF AJAX Service Without Configuration
| This post discusses how to develop Windows Communication Foundation (WCF) service using AJAX and without any configuration settings for WCF. This service can be consumed from Javascript. The service uses a special setting in .svc file which automatically enables an AJAX endpoint. | |
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No commentsWCF Service using MTOM in .NET FW 4
Web services having a greater interoperability to communicate messages across heterogeneous systems, however challenge is serializing the data into XML. Users may want to send images,videos, drawings, xml documents etc. together with SOAP message.
What is MTOM?
Message Transmission Optimization Mechanism (MTOM) is a mechanism of transferring transferring large amounts binary data as an attachment to SOAP message.
Typical SOAP message transmission shown in the below image
Image Source crosscheknet.com
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1 commentWCF Discovery with UDP
Inorder to call the WindowsCommunicationFoundation service, a port or pipe which assigned to the service must be available and the client must know the address endpoints before calling the services.
If the service could use any available address then client can discover that address at runtime. There is a industry standard-based solution which helps in discovering the service addresses.
Address Discovery
Discovery relies on the User Datagram Protocol(UDP). Client uses UDP to broadcast discovery requests for any end-point which supports the contract type. These requests are received by dedicated end-points. The end-points responds back to the client with service-address that support specified contract.
WCF offers a standard discovery endpoint with the type UdpDiscoveryEndpoint
