What is WCF RIA service?
WCF RIA service is a framework to develop n-tier application for Rich Internet
Application (RIA). It is mainly used in RIA applications like Silverlight, AJAX
client, etc. It solves the major problem while developing business application
like decoupling the resource access, application logic and presentation layer.
WCF RIA service was introduced in Silverlight 4 with .net framework 4, and it
can be developed using visual studio2010.
Main problem developer are facing while developing the n-tier RIA application will be coordinating the application logic between middle tier and presentation tier. This problem will be solved by using WCF RIA service, it will synchronize the code between middle and presentation tier.
WCF RIA service will allow developer to write the set of service code and this server code will be available to the client side without manually duplicate that programming logic. RIA service client will be updated with business rule and entity present at the server side, when your recompile your project solution.
WCF RIA service will generate the code at the client side related to the service and domain entities declared at the server side.
RIA service exposes the data from server side to client side using Domain service, RIA service framework implements the each domain service as WCF service to access the data as business entity.
Main problem developer are facing while developing the n-tier RIA application will be coordinating the application logic between middle tier and presentation tier. This problem will be solved by using WCF RIA service, it will synchronize the code between middle and presentation tier.
WCF RIA service will allow developer to write the set of service code and this server code will be available to the client side without manually duplicate that programming logic. RIA service client will be updated with business rule and entity present at the server side, when your recompile your project solution.
WCF RIA service will generate the code at the client side related to the service and domain entities declared at the server side.
RIA service exposes the data from server side to client side using Domain service, RIA service framework implements the each domain service as WCF service to access the data as business entity.
fig: WCF RIA Serive architecture
Domain Service
Domain services are WCF services that expose the business logic of a WCF RIA
Services application. Domain service contains set of business related data
operation and it is exposed as WCF service.
Below diagram explains integration of the RIA service with WCF
The DomainService class is the base class for all classes that serve as domain services.
Below diagram explains integration of the RIA service with WCF
The DomainService class is the base class for all classes that serve as domain services.
- DomainServiceHost is the hosting class for domain service; internally
- DomainServiceHost uses the WCF ServiceHost class to host the application.
Example:
[EnableClientAccess()]
public class EmployeeDomainService : DomainService
{
private EmployeeData data = EmployeeData.Instance;
public IEnumerable < Employee> GetEmployees()
{
return data.EmployeeList;
}
}
fig: WCF RIA Domain Serive architecture
Problem solved in RIA
- To have best performance of the RIA application, app logic need to be available in client and server side. This problem is solved by auto generating the code at the client side while recompiling the project.
- Asynchronous call – Asynch service call are supported in Domain service by using WCF infrastructure
- Handling large data and data across different tier – Large amount of data can be access and filter using IQueryable object. Since entity objects used in domain service are serializable and so it can be access across different layer
- Security/Access control – ASP.Net membership frameworks are integrated with RIA service to provide security systems to RIA service
- Validation – Entity can be validated based using adding attribute to the class members
Example:
public class Member
{
[Key]
public int MemberId { get; set; }
public string Fname { get; set; }
[Required]
public string Lname { get; set; }
public DateTime JoinDate { get; set; }
[Range(30,90, ErrorMessage="sorry, you are either too young or too old for our club!")]
public int Age { get; set; }
}
Querying/Updating data in RIA Service
The below diagram are self explanatory to discuss about the querying or updating the data using RIA service
fig: WCF RIA to Query data
fig: WCF RIA to update data
How to Create WCF RIA Service
Download:
Silverlight_WCF_RIA_Service.zip
Step 1:Start the Visual Studio 2010 and click File -> New-> Project. Enter the project name and click “Create”
Step 2:Select “Enable WCF RIA Services”. This will make your Silverlight application to user WCF RIA service
Step 3:Create “Data” folder and add DataModel” class as
shown below. This is the data class which will return list of Employee
and update the employee list
Data Model class:
public class Employee
{
[Key]
public int EmpId { get; set; }
public string Fname { get; set; }
public string Lname { get; set; }
public DateTime JoinDate { get; set; }
public int Age { get; set; }
}
public partial class EmployeeData
{
private static readonly EmployeeData _instance = new EmployeeData();
private EmployeeData() { }
public static EmployeeData Instance
{
get
{
return _instance;
}
}
private List < Employee > empList = new List < Employee>()
{
new Employee() { EmpId = 1, Fname = "Sam", Lname = "kumar",
JoinDate=new DateTime(2010,7, 21), Age=30},
new Employee() { EmpId = 2, Fname = "Ram", Lname = "kumar",
JoinDate=new DateTime(2009,6,8), Age=35},
new Employee() { EmpId = 3, Fname = "Sasi", Lname = "M",
JoinDate=new DateTime(2008,3,5), Age=39},
new Employee() { EmpId = 4, Fname = "Praveen", Lname = "KR",
JoinDate=new DateTime(2010, 5,1), Age=56},
new Employee() { EmpId = 5, Fname = "Sathish", Lname = "V",
JoinDate = new DateTime(2006,12,15), Age=72},
new Employee() { EmpId = 6, Fname = "Rosh", Lname = "A",
JoinDate=new DateTime(2009,2,2), Age=25}
};
public IEnumerable< Employee > EmployeeList
{
get
{
return empList;
}
}
public void Update(Employee updEmployee)
{
Employee existing = empList.Find(p => p.EmpId == updEmployee.EmpId);
if (existing == null)
throw new KeyNotFoundException("Specified Employee cannot be found");
existing.Fname = updEmployee.Fname;
existing.Lname = updEmployee.Lname;
existing.JoinDate = updEmployee.JoinDate;
existing.Age = updEmployee.Age;
}
}
Step 4:To expose the Employee related operation to the
client side, Create domain service class. By right click project file
and select Add new item.
Step 5:Add code to return the Employee list
Domain Service class:
// TODO: Create methods containing your application logic.
[EnableClientAccess()]
public class EmployeeDomainService : DomainService
{
//Create instance of the Data access layer
private EmployeeData data = EmployeeData.Instance;
public IEnumerable< Employee> GetEmployee()
{
return data.EmployeeList ;
}
public void UpdateEmployee(Employee emp)
{
data.Update(emp);
}
}
Step 6:Compile the solution – After compilation RIA
service will generate the application logic at the client side using
DomainContext object. Enable show all files option for the solution and
view the auto generated code.
Step 7:View the DomainContext class are created at the client side.
Domain Context class at client:
///
/// The DomainContext corresponding to the 'EmployeeDomainService' DomainService.
///
public sealed partial class EmployeeDomainContext : DomainContext
{
#region Extensibility Method Definitions
///
/// This method is invoked from the constructor once initialization is complete and
/// can be used for further object setup.
///
partial void OnCreated();
#endregion
///
/// Initializes a new instance of the < see cref="EmployeeDomainContext"/> class.
///
public EmployeeDomainContext() :
this(new WebDomainClient< IEmployeeDomainServiceContract>(new
Uri("MyFirstRIAApplication-Web-EmployeeDomainService.svc",
UriKind.Relative)))
{
}
........
........
Step 8:Add DataGrid to Main.xaml file to display the
employee details query from DataModel and add two buttons to update and
reject the data changed from client side.
Main.xaml
< Grid x:Name="LayoutRoot" Background="White">
< StackPanel Orientation="Vertical" HorizontalAlignment="Left" >
< sdk:DataGrid x:Name="EmployeeGrid" AutoGenerateColumns="True"
RowEditEnded="EmployeeGrid_RowEditEnded" />
< Button Content="Accept" Height="23" Name="btnAccept"
Width="75" Margin="5" Click="btnAccept_Click" />
< Button Content="Reject" Height="23" Name="btnReject"
Width="75" Margin="5" Click="btnReject_Click"/>
</StackPanel>
</Grid>
Main.xaml.vb
public partial class MainPage : UserControl
{
//create instance of Doman context class
EmployeeDomainContext ctx = new EmployeeDomainContext();
public MainPage()
{
InitializeComponent();
//Load query data , Read data from DAL layer to UI
EntityQuery< Employee> query = ctx.GetEmployeeQuery();
LoadOperation< Employee> lo = ctx.Load< Employee>(query);
EmployeeGrid.ItemsSource = lo.Entities;
}
private void EmployeeGrid_RowEditEnded(object sender,
DataGridRowEditEndedEventArgs e)
{
}
private void btnAccept_Click(object sender, RoutedEventArgs e)
{
//Update the DAL with user changes
ctx.SubmitChanges();
}
private void btnReject_Click(object sender, RoutedEventArgs e)
{
//Roll back the user changes
ctx.RejectChanges();
}
}
Step 9:Run the application and see the output as shown below
Introduction to RESTful service
"REST, an architectural style for building distributed hypermedia driven applications, involves building Resource-Oriented Architecture (ROA) by defining resources that implement uniform interfaces using standard HTTP verbs (GET, POST, PUT, and DELETE), and that can be located/identified by a Uniform Resource Identifier (URI)."
Any Service which follows this REST architecture style is called as RESTful service. It became very popular because of it behavior, it is similar to the website i.e we can load the server information using web url in the browser. similarly we can also access/modify the server resource using Url in RESTful service
- RESTful service will allow the client (written in different language)to access or modify the resource in the server using URL.
- RESTful service uses the http protocol for its communication and it is stateless
- RESTful service can transfer the data in XML,JSON,RSS,ATOM
| SOAP | POX(plain-old XML) | REST |
|---|---|---|
|
|
|
- To create a resource on the server, use POST.
- To retrieve a resource, use GET.
- To change the state of a resource or to update it, use PUT.
- To remove or delete a resource, use DELETE.
How to create RESTful service
Download Souce:
MyFirstRESTfulService.zipStep 1: For our example we are suing “EmployeeData” class as Data Access Layer for storing and reading the employee information.
Data Model class:
namespace MyFirstRESTfulService
{
[DataContract]
public class Employee
{
[DataMember]
public int EmpId { get; set; }
[DataMember]
public string Fname { get; set; }
[DataMember]
public string Lname { get; set; }
[DataMember ]
public DateTime JoinDate { get; set; }
[DataMember]
public int Age { get; set; }
[DataMember]
public int Salary { get; set; }
[DataMember]
public string Designation { get; set; }
}
public partial class EmployeeData
{
private static readonly EmployeeData _instance = new EmployeeData();
private EmployeeData() { }
public static EmployeeData Instance
{
get
{
return _instance;
}
}
private List< Employee> empList = new List < Employee>()
{
new Employee() { EmpId = 1, Fname = "Sam", Lname = "kumar", JoinDate=new DateTime(2010,7, 21), Age=30,Salary=10000,Designation="Software Engineer"},
new Employee() { EmpId = 2, Fname = "Ram", Lname = "kumar", JoinDate=new DateTime(2009,6,8), Age=35,Salary=10000,Designation="Senior Software Engineer"},
new Employee() { EmpId = 3, Fname = "Sasi", Lname = "M", JoinDate=new DateTime(2008,3,5), Age=39,Salary=10000,Designation="Projet Manager"},
new Employee() { EmpId = 4, Fname = "Praveen", Lname = "KR", JoinDate=new DateTime(2010, 5,1), Age=56,Salary=10000,Designation="Projet Manager"},
new Employee() { EmpId = 5, Fname = "Sathish", Lname = "V", JoinDate = new DateTime(2006,12,15), Age=72,Salary=10000,Designation="Senior Software Engineer"},
new Employee() { EmpId = 6, Fname = "Rosh", Lname = "A", JoinDate=new DateTime(2009,2,2), Age=25,Salary=10000,Designation="Software Engineer"}
};
public List< Employee> EmployeeList
{
get
{
return empList;
}
}
public void Update(Employee updEmployee)
{
Employee existing = empList.Find(p => p.EmpId == updEmployee.EmpId);
if (existing == null)
throw new KeyNotFoundException("Specified Employee cannot be found");
existing.Fname = updEmployee.Fname;
existing.Lname = updEmployee.Lname;
existing.Age = updEmployee.Age;
}
public void Delete(int empid)
{
Employee existing = empList.Find(p => p.EmpId == empid);
empList.Remove(existing);
}
public void Add(Employee newEmployee)
{
empList.Add(new Employee
{
EmpId = newEmployee.EmpId,
Fname = newEmployee.Fname,
Lname = newEmployee.Lname,
Age = newEmployee.Age,
JoinDate = DateTime.Now,
Designation = newEmployee.Designation,
Salary = newEmployee.Salary
});
}
}
}
Interface and Implementation:
[ServiceContract()]
public interface IEmployeeService
{
[OperationContract]
List< Employee > GetAllEmployeeDetails();
[OperationContract]
Employee GetEmployee(int Id);
[OperationContract]
void AddEmployee(Employee newEmp);
[OperationContract]
void UpdateEmployee(Employee newEmp);
[OperationContract]
void DeleteEmployee(string empId);
}
[AspNetCompatibilityRequirements(RequirementsMode= AspNetCompatibilityRequirementsMode.Allowed )]
public class EmployeeService: IEmployeeService
{
public List < Employee > GetAllEmployeeDetails()
{
return EmployeeData.Instance.EmployeeList;
}
public Employee GetEmployee(int id)
{
IEnumerable< Employee > empList = EmployeeData.Instance.EmployeeList.Where(x => x.EmpId == id);
if (empList != null)
return empList.First< Employee >();
else
return null;
}
public void AddEmployee(Employee newEmp)
{
EmployeeData.Instance.Add(newEmp);
}
public void UpdateEmployee( Employee newEmp)
{
EmployeeData.Instance.Update(newEmp);
}
public void DeleteEmployee(string empId)
{
EmployeeData.Instance.Delete(System.Convert .ToInt32 (empId));
}
}
As it is mention in introduction section of RESTful service, all the resource located in server side can be accessed using url. Method exposed at the server side can be call using url, to do that we need to decorate the service method with “WebGet” or “WebInvoke” attribute as mention below
[ServiceContract()]
public interface IEmployeeService
{
[WebGet(UriTemplate = "Employee")]
[OperationContract]
List< Employee > GetAllEmployeeDetails();
[WebGet(UriTemplate = "Employee?id={id}")]
[OperationContract]
Employee GetEmployee(int Id);
[WebInvoke(Method = "POST", UriTemplate = "EmployeePOST")]
[OperationContract]
void AddEmployee(Employee newEmp);
[WebInvoke(Method = "PUT", UriTemplate = "EmployeePUT")]
[OperationContract]
void UpdateEmployee(Employee newEmp);
[WebInvoke(Method = "DELETE", UriTemplate = "Employee/{empId}")]
[OperationContract]
void DeleteEmployee(string empId);
}
Step 5: “Method” is another option we can add to the WebInvoke attribute to specify the mode of transfer like “PUT”, “POST”, or “DELETE”
Step 6: Now we have completed with service implementation project. Let’s start with Hosting the RESTful service. For this example we are using console application for hosting service. WCF framework has provided new class to host the RESTful service i.e WebServiceHost. By hosting the restful service with WebServiceHost host class will automatically set the binding and other configuration setting. In the below code you can see that I have only mention url for the hosting.
Uri httpUrl = new Uri("http://localhost:8090/MyService/EmployeeService");
WebServiceHost host = new WebServiceHost(typeof(MyFirstRESTfulService.EmployeeService), httpUrl);
host.Open();
foreach (ServiceEndpoint se in host.Description.Endpoints)
Console.WriteLine("Service is host with endpoint " + se.Address);
//Console.WriteLine("ASP.Net : " + ServiceHostingEnvironment.AspNetCompatibilityEnabled);
Console.WriteLine("Host is running... Press < Enter > key to stop");
Console.ReadLine();
WebChannelFactory < IEmployeeService > cf =
new WebChannelFactory< IEmployeeService >(
new Uri("http://localhost:8090/MyService/EmployeeService"));
IEmployeeService client = cf.CreateChannel();
var d = client.GetEmployee(1);
//Load all the Employee from the server and display
foreach (Employee e in client.GetAllEmployeeDetails() )
{
Console.WriteLine(string.Format("EmpID:{0}, Name:{1} {2}",e.EmpId ,e.Fname ,e.Lname ));
}
//Add new user
client.AddEmployee(new Employee() { EmpId = 11, Fname = "John", Lname = "J", JoinDate = new DateTime(2010, 7, 24), Age = 34, Salary = 10000, Designation = "Software Engineer" });
Console.WriteLine("******************After adding new user ****************");
//Load all the Employee from the server and display
foreach (Employee e in client.GetAllEmployeeDetails() )
{
Console.WriteLine(string.Format("EmpID:{0}, Name:{1} {2}",e.EmpId ,e.Fname ,e.Lname ));
}
Console.ReadLine();
}
JSON using WCF service
Download Souce:
MyFirstRESTfulService.zipJSON –JavaScript Object Notation.
“The JSON text format is syntactically identical to the code for creating JavaScript objects “.
In most of the browser based application, WCF can be consumed using javascript or jquery. When client makes the call to the WCF, JSON or XML is used for mode of communication. WCF has option to send the response in JSON object. This can be configured with WebGet or WebInvoke attribute.
In this sample we can create the sample RESTful service to expose the method to read/add/update/delete the employee information. Read the “How to create REST ful Service” articles for more information.
On top of the Restful service we need to update the ResponseMode attribute to send the business entity as JSON object. Below code shows how to configure the JSON response format.
[ServiceContract()]
public interface IEmployeeService
{
[WebGet(UriTemplate = "Employee", ResponseFormat=WebMessageFormat.Json )]
[OperationContract]
List < Employee > GetAllEmployeeDetails();
[WebGet(UriTemplate = "Employee?id={id}", ResponseFormat = WebMessageFormat.Json)]
[OperationContract]
Employee GetEmployee(int Id);
[WebInvoke(Method = "POST", UriTemplate = "EmployeePOST", ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
[OperationContract]
void AddEmployee(Employee newEmp);
[WebInvoke(Method = "PUT", UriTemplate = "EmployeePUT", ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
[OperationContract]
void UpdateEmployee(Employee newEmp);
[WebInvoke(Method = "DELETE", UriTemplate = "Employee/{empId}", ResponseFormat = WebMessageFormat.Json)]
[OperationContract]
void DeleteEmployee(string empId);
}
Below sample is the ASP.Net web application is used to explains about the CRUD from WCF service with response as JSON object.GET Method
function RefreshPage() {
var serviceUrl = "http://saravana:8090/MyService/EmployeeService/Employee";
$.ajax({
type: "GET",
url: serviceUrl,
dataType: 'json',
contentType: "application/json; charset=utf-8",
success: function (data) {
var itemRow = "< table >";
$.each(data, function (index, item) {
itemRow += "<tr><td>" + item.EmpId + "</td><td>" + item.Fname + "</td></tr>";
});
itemRow += "</table>";
$("#divItems").html(itemRow);
},
error: ServiceFailed
});
}
function POSTMethodCall() {
var EmpUser = [{ "EmpId": "13", "Fname": "WebClientUser", "Lname": "Raju", "JoinDate": Date(1224043200000), "Age": "23", "Salary": "12000", "Designation": "Software Engineer"}];
var st = JSON.stringify(EmpUser);
debugger;
$.ajax({
type: "POST",
url: "http://saravana:8090/MyService/EmployeeService/EmployeePOST",
data: JSON.stringify(EmpUser),
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
// Play with response returned in JSON format
},
error:ServiceFailed
});
}
<
function PUTMethodCall() {
var EmpUser = [{ "EmpId": "3", "Fname": "WebClientUser", "Lname": "Raju", "JoinDate": Date(1224043200000), "Age": "23", "Salary": "12000", "Designation": "Software Engineer"}];
$.ajax({
type: "PUT",
url: "http://saravana:8090/MyService/EmployeeService/EmployeePUT",
data: EmpUser,
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
// Play with response returned in JSON format
},
error: ServiceFailed
});
}
<
function DELETEMethodCall() {
$.ajax({
type: "DELETE",
url: "http://saravana:8090/MyService/EmployeeService/Employee/2",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
// Play with response returned in JSON format
},
error: function (msg) {
alert(msg);
}
});
}
Handling Exception in Silverlight application from WCF
Attachment:
Silverlight_WCF_Exception.zip
This article explains about handling the exception in
Silverlight application from WCF. I have created the sample Silverlight
application, which uses the WCF service for process the data. While
testing the application I came to know that exception message thrown
from WCF cannot be received at the client side(Silverlight application)
even after using the FaultException. I was always getting System.ServiceModel.CommunicationException: The remote server returned an error: NotFound.
Later I came to know that WCF throws the HTTP 500 series Fault
message but Silverlight can handle only 200 series. So we need to
convert the 500 series to 200 error message for Silverlight. Here is the
sample application for exception handling between WCF and Silverlight.
Step 1: We can customize the Endpoint behavior of the WCF service by inheriting the Beha and implementing the IEndpointBehavior. Actual code for converting the 500 error serice to 200 serivce in BeforeSendReply method.
Create a ClassLibrary project and name it as “Silverlight_WCF_FaultBehavior” and name the class as “SilverlightFaultBehavior”. Copy and paste the follwing code inside the SilverlightFaultBehavior class.
Step 1: We can customize the Endpoint behavior of the WCF service by inheriting the Beha and implementing the IEndpointBehavior. Actual code for converting the 500 error serice to 200 serivce in BeforeSendReply method.
Create a ClassLibrary project and name it as “Silverlight_WCF_FaultBehavior” and name the class as “SilverlightFaultBehavior”. Copy and paste the follwing code inside the SilverlightFaultBehavior class.
Imports System.ServiceModel.ConfigurationrviceModel.Configuration
Imports System.ServiceModel.Description
Imports System.ServiceModel.Dispatcher
Imports System.ServiceModel.Channels
Imports System.ServiceModel
Public Class SilverlightFaultBehavior
Inherits BehaviorExtensionElement
Implements IEndpointBehavior
Public Overrides ReadOnly Property BehaviorType() As System.Type
Get
Return GetType(SilverlightFaultBehavior)
End Get
End Property
Protected Overrides Function CreateBehavior() As Object
Return New SilverlightFaultBehavior
End Function
Public Sub AddBindingParameters(ByVal endpoint As ServiceEndpoint,
ByVal bindingParameters As BindingParameterCollection)
Implements IEndpointBehavior.AddBindingParameters
End Sub
Public Sub ApplyClientBehavior(ByVal endpoint As ServiceEndpoint,
ByVal clientRuntime As ClientRuntime)
Implements IEndpointBehavior.ApplyClientBehavior
End Sub
Public Sub ApplyDispatchBehavior(ByVal endpoint As ServiceEndpoint,
ByVal endpointDispatcher As EndpointDispatcher)
Implements IEndpointBehavior.ApplyDispatchBehavior
Dim inspector As New SilverlightFaultMessageInspector()
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(inspector)
End Sub
Public Sub Validate(ByVal endpoint As ServiceEndpoint)
Implements IEndpointBehavior.Validate
End Sub
Public Class SilverlightFaultMessageInspector
Implements IDispatchMessageInspector
Public Function AfterReceiveRequest(ByRef request As Message,
ByVal channel As IClientChannel,
ByVal instanceContext As InstanceContext) As Object
Implements IDispatchMessageInspector.AfterReceiveRequest
' Do nothing to the incoming message.
Return Nothing
End Function
Public Sub BeforeSendReply(ByRef reply As System.ServiceModel.Channels.Message,
ByVal correlationState As Object)
Implements IDispatchMessageInspector.BeforeSendReply
If reply.IsFault Then
Dim [property] As New HttpResponseMessageProperty()
' Here the response code is changed to 200.
[property].StatusCode = System.Net.HttpStatusCode.OK
reply.Properties(HttpResponseMessageProperty.Name) = [property]
End If
End Sub
End Class
End Class
Step 2: Build the project
Step 3: Create a new WCF service with Interface and implementation class as follows
Interface
<ServiceContract()> _ Public Interface IService <OperationContract()> _ Function Add(ByVal num1 As Integer, ByVal num2 As Integer) As Integer <OperationContract()> _ Function Subtract(ByVal num1 As Integer, ByVal num2 As Integer) As Integer End Interface
Public Class Service
Implements IService
Public Sub New()
End Sub
Public Function Add(ByVal num1 As Integer, ByVal num2 As Integer)
As Integer Implements IService.Add
Throw New FaultException("Error thrown by user for Add operation")
'Return num1 + num2
End Function
Public Function Subtract(ByVal num1 As Integer,
ByVal num2 As Integer) As Integer Implements IService.Subtract
Return num1 - num2
End Function
End Class
< Add the Silverlight_WCF_FaultBehavior project dll as reference to WCF Service
Step 5:
Step 5: In WCF we can extend the binding and behavior by using <extention> tag. In our case also we are extending the custom endpoint behavior as shown below. In the <behaviorExtensions> tag we need specify the fully qualified name of the cutom behaviour assembly.
Modify the Web.config file as shown bellow
Modify the Web.config file as shown bellow
<system.serviceModel> <services> <service name="Service" behaviorConfiguration="ServiceBehavior"> <!-- Service Endpoints --> <endpoint address="" binding="basicHttpBinding" contract="IService" behaviorConfiguration="SilverlightFaultBehavior"> <!-- Upon deployment, the following identity element should be removed or replaced to reflect the identity under which the deployed service runs. If removed, WCF will infer an appropriate identity automatically.--> <identity> <dns value="localhost"/> </identity> </endpoint> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/> </service> </services> <behaviors> <serviceBehaviors> <behavior name="ServiceBehavior"> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> <endpointBehaviors> <behavior name="SilverlightFaultBehavior"> <silverlightFaults/> </behavior> </endpointBehaviors> </behaviorss=“BlueCode”>> <extensions> <behaviorExtensions> <add name="silverlightFaults" type="Silverlight_WCF_FaultBehavior.SilverlightFaultBehavior, Silverlight_WCF_FaultBehavior, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"/> </behaviorExtensions> </extensionss=“BlueCode”>> </system.serviceModel>
Step 6: Create the any sample silverlight application as “Silverlight_WCF_Exception” and add this WCF service as Service Reference.
url: http://localhost/MathService/Service.svc
url: http://localhost/MathService/Service.svc
Step 7: Add a button to the MainPage.xaml and call the WCF method as shown below
Private Sub Button_Click(ByVal sender As System.Object,
ByVal e As System.Windows.RoutedEventArgs)
Dim proxy As New ServiceProxy.ServiceClient
AddHandler proxy.AddCompleted, AddressOf AddOperationCompleted
proxy.AddAsync(5, 6)
End Sub
Private Sub AddOperationCompleted(ByVal sender As Object,
ByVal e As ServiceProxy.AddCompletedEventArgs)
If e.Error IsNot Nothing Then
MessageBox.Show(e.Error.Message)
Else
MessageBox.Show(e.Result)
End If
End Sub
Step 8: Output will look like this
Conclution: This article explains about handling the exception in Silverlight application from WCF
Custom message header
Attachment:
CustomMessageHeader.zip
This article explains about customizing the wcf message flowing between service and client.
There are certain scenario in which you to pass some information from client to service, but not as parameter in operation contracts. Example, logging system at the service we need to log user or machine information, which made request to the service. In this kind of scenario we should not pass user or machine information as parameter in operation contract. Instead we can pass the information through message flowing between client and service vice versa. The information we need to send can be appended with message header and it can be received at the server side.
Let as create sample service and client application, in which client will send “User name” information through request message and service will respond with confirmation message.
I have created Math service with Add and Subtract functionality. Client consuming this service will send his user name information as string with requested message. Once request reached the service, it will read the information from the message header and display using console window. When service responding to the client, along with operation result, it will also send confirmation message to client through message header.
Step 1: Create IMathService interface decorated with Service and Operational contract attribute
IMathService.vbThere are certain scenario in which you to pass some information from client to service, but not as parameter in operation contracts. Example, logging system at the service we need to log user or machine information, which made request to the service. In this kind of scenario we should not pass user or machine information as parameter in operation contract. Instead we can pass the information through message flowing between client and service vice versa. The information we need to send can be appended with message header and it can be received at the server side.
Let as create sample service and client application, in which client will send “User name” information through request message and service will respond with confirmation message.
I have created Math service with Add and Subtract functionality. Client consuming this service will send his user name information as string with requested message. Once request reached the service, it will read the information from the message header and display using console window. When service responding to the client, along with operation result, it will also send confirmation message to client through message header.
Step 1: Create IMathService interface decorated with Service and Operational contract attribute
<ServiceContract()> _
Public Interface IMathService
<OperationContract()> _
Function Add(ByVal a As Integer, ByVal b As Integer) As Integer
<OperationContract()> _
Function Subtract(ByVal a As Integer, ByVal b As Integer) As Integer
End Interface
PrintRequestedUserID() method will read the “UserID” message header from incoming message using OperationContext. This User information is displayed in console window.
SendResponseWithMessage() method will send a confirmation message to the client as Message header through Operation context.
MathService.vb
Public Class MathService
Implements IMathService
Public Function Add(ByVal a As Integer, ByVal b As Integer) As Integer
Implements IMathService.Add
'This method call will retrive message send from client using MessageHeader
PrintRequestedUserID()
'This method call will send message to client using MessageHeader
SendResponseWithMessage()
Return a + b
End Function
Public Function Subtract(ByVal a As Integer, ByVal b As Integer) As Integer
Implements IMathService.Subtract
'This method call will retrive message send from client using MessageHeader
PrintRequestedUserID()
'This method call will send message to client using MessageHeader
SendResponseWithMessage()
Return a - b
End Function
Private Sub PrintRequestedUserID()
Dim userID As String = String.Empty
'Read the message header using "Name" and "NameSpace"
userID = OperationContext.Current.IncomingMessageHeaders
.GetHeader(Of String)("UserID", "ns")
Console.WriteLine("Requested user: " + userID)
End Sub
Private Sub SendResponseWithMessage()
'Creating new message header with "Content" value assigned in constructor
Dim mess As New MessageHeader(Of String)("This is sample message from service")
'Assigning Name and NameSpace to the message header value at server side
Dim header As System.ServiceModel.
Channels.MessageHeader = mess.GetUntypedHeader("ServiceMessage", "ns")
'Adding message header with OperationContext
'which will be received at the client side
OperationContext.Current.OutgoingMessageHeaders.Add(header)
End Sub
End Class
MyServiceHost.vb
Module MyServiceHost
Sub Main()
'Hosting the Math service using console application
Dim host As New ServiceHost(GetType(MyService.MathService))
host.Open()
Console.WriteLine("Service is running... Press to exit.")
Console.ReadLine()
End Sub
End Module
<system.serviceModel> <services><service name="MyService.MathService" behaviorConfiguration="MyServiceBehavior"> <endpoint address ="MathService" binding="basicHttpBinding" contract="MyService.IMathService"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/> <host> <baseAddresses> <add baseAddress="http://localhost:8090/MyService"/> </baseAddresses> </host> </service> </services> <behaviors> <serviceBehaviors > <behavior name ="MyServiceBehavior"> <serviceMetadata httpGetEnabled ="true"/> <serviceDebug includeExceptionDetailInFaults ="True"/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel>
Sub Main()
'Creating proxy class for service
Dim proxy As IMathService = Nothing
proxy = ChannelFactory(Of IMathService).CreateChannel(New BasicHttpBinding(),
New EndpointAddress("http://localhost:8090/MyService/MathService"))
'Lifetime of OperationContextScope defines the scope for OperationContext.
Dim scope As OperationContextScope = Nothing
scope = New OperationContextScope(proxy)
'Creating new message header with "Content" value assigned in constructor
Dim mess As New MessageHeader(Of String)
(System.Security.Principal.WindowsIdentity.GetCurrent().Name)
'Assigning Name and NameSpace to the message header value at client side
Dim header As System.ServiceModel.Channels.MessageHeader
= mess.GetUntypedHeader("UserID", "ns")
'Adding message header with OperationContext
'which will be received at the server side
OperationContext.Current.OutgoingMessageHeaders.Add(header)
'Making service call
Console.WriteLine("Sum of {0},{1}={2}", 1, 2, proxy.Add(1, 2))
'Displaying confrimation message from service
Console.WriteLine("Response Message: " + OperationContext.Current.
IncomingMessageHeaders.GetHeader(Of String)("ServiceMessage", "ns"))
Console.ReadLine()
End Sub
End Module
<ServiceContract()> _
Public Interface IMathService
Inherits IClientChannel
<OperationContract()> _
Function Add(ByVal a As Integer, ByVal b As Integer) As Integer
<OperationContract()> _
Function Subtract(ByVal a As Integer, ByVal b As Integer) As Integer
End Interface
Below figure shows the message flowing between service and client
Client application output
This article explain about customizing the wcf message header
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