using System;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Dispatcher;

///
/// This inspector adds a user agent to the outgoing web request. It is based on code at:
/// http://anoriginalidea.wordpress.com/2010/08/19/adding-the-user-agent-when-calling-a-web-service-with-wcf/
///
class HttpUserAgentMessageInspector : IClientMessageInspector
{
private const string UserAgentHTTPHeader = “user-agent”;
private readonly string _userAgent;

public HttpUserAgentMessageInspector(string userAgent)
{
_userAgent = userAgent;
}

public object BeforeSendRequest(ref Message request, IClientChannel channel)
{
HttpRequestMessageProperty httpRequestMessage;
Object httpRequestMessageObject;
if(request.Properties.TryGetValue(HttpRequestMessageProperty.Name, out httpRequestMessageObject))
{
httpRequestMessage = (HttpRequestMessageProperty) httpRequestMessageObject;
if(String.IsNullOrEmpty(httpRequestMessage.Headers[UserAgentHTTPHeader]))
{
httpRequestMessage.Headers[UserAgentHTTPHeader] = _userAgent;
}

} else
{
httpRequestMessage = new HttpRequestMessageProperty();
httpRequestMessage.Headers.Add(UserAgentHTTPHeader, _userAgent);
request.Properties.Add(HttpRequestMessageProperty.Name, httpRequestMessage);
}
return null;
}

public void AfterReceiveReply(ref Message reply, object correlationState)
{
return;
}
}

using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;

///
/// This behavior adds a user agent to the outgoing web request. It is based on code at:
/// http://anoriginalidea.wordpress.com/2010/08/19/adding-the-user-agent-when-calling-a-web-service-with-wcf/
///
class HttpUserAgentEndpointBehavior : IEndpointBehavior
{
private readonly string _userAgent;

public HttpUserAgentEndpointBehavior(string userAgent)
{
_userAgent = userAgent;
}

public void Validate(ServiceEndpoint endpoint)
{
return;
}

public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
{
return;
}

public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
return;
}

public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
var inspector = new HttpUserAgentMessageInspector(_userAgent);
clientRuntime.MessageInspectors.Add(inspector);
}
}