WCF - Passing CurrentPrincipal in the Header - wcf

I have a WCF service that needs to know the Principal of the calling user.
In the constructor of the service I have:
Principal = OperationContext.Current.IncomingMessageHeaders.GetHeader<MyPrincipal>("myPrincipal", "ns");
and in the calling code I have something like:
using (var factory = new ChannelFactory<IMyService>(localBinding, endpoint))
{
var proxy = factory.CreateChannel();
using (var scope = new OperationContextScope((IContextChannel)proxy))
{
var customHeader = MessageHeader.CreateHeader("myPrincipal", "ns", Thread.CurrentPrincipal);
OperationContext.Current.OutgoingMessageHeaders.Add(customHeader);
newList = proxy.CreateList();
}
}
This all works fine.
My question is, how can I avoid having to wrap all proxy method calls in the using (var scope...{ [create header and add to OperationContext]?
Could I create a custom ChannelFactory that will handle adding the myPrincipal header to the operation context? Something like that would save a whole load of copy/paste which I'd rather not do but I'm not sure how to achieve it:)
Thanks

The correct time to set a WCF principal is via IAuthorizationPolicy, by specifying a custom policy in configuration. This covered in full here. If you try setting the principal at other points (an inspector, perhaps) it can get reset by the system.

Related

Not able to filter WCF methods for dynamically created proxy

Some months back I was working on a project to display the WCF methods and thier parameters in a dropdown. At that time I was creating a proxy using Add Service Reference and hardcoded the service interface in the code.
How can I show all the methods that are available in my WCF in a dropdown
But when I try to create the proxy dynamically to do the same, the below code doesn't work. Please help me to show only the methods that was defined by me.
// Using Dynamic Proxy Factory by Vipul Modi # Microsoft
DynamicProxyFactory factory = new DynamicProxyFactory(txtService.Text);
// endpoints.
string sContract = "";
foreach (ServiceEndpoint endpoint in factory.Endpoints)
{
sContract = endpoint.Contract.Name; //this is the service interface name, IAccountInfoService
}
DynamicProxy proxy = factory.CreateProxy(sContract);
Type proxyType = proxy.ProxyType;
MethodInfo[] methods = proxyType.GetMethods();
foreach (var method in methods)
{
//if (method.GetCustomAttributes(typeof(OperationContractAttribute), true).Length == 0)
// continue;
string methodName = method.Name;
ddlMethods.Items.Add(methodName);
}
The code commented method.GetCustomAttributes(typeof(OperationContractAttribute), true).Length doesn't work. It doesn't show any method. If I comment it out, then the result is all methods and variables. I want to restrict it to only user defined methods.
i dont know anything about DynamicProxyFactory but looking at http://blogs.msdn.com/b/vipulmodi/archive/2006/11/16/dynamic-programming-with-wcf.aspx it makes me think that
1) the proxy doesnt actually emit methods with the attribute. it doesn't seem to have a need to though i suppose you could tweak the code on your own to make that happen.
2) if you just want a list of method names, it seems you can get that from factory.Contracts

ChannelFactory Credentials + object is read only

Greetings, what is the problem that when I try to set credentials for my factory as follows:
ChannelFactory<IWCFSeekService> factory = Factory;
if (factory != null)
{
factory.Credentials.UserName.UserName = CServiceCredentials.Instance.Username;
_Channel = factory.CreateChannel();
}
I get an exception that object is read-only. It occurs when I want to set username.
Yes, the MSDN documentation is pretty clear:
C#
public ClientCredentials Credentials { get; }
The property only has a get accessor - no set accessor --> it's readonly.
Also in the MSDN docs:
Remarks
The ClientCredentials object is stored
as a type of endpoint behavior and can
be accessed through the Behaviors
property.
The OnOpened method initializes a
read-only copy of the
ClientCredentials object for the
factory.
So what is it you're doing to do here??
UPDATE: you cannot set the user credentials that your client proxy is supposed to use on the channel factory. See this excellent blog post on how to do it anyway - with a bit of a detour:
first, remove the default endpoint behavior from the factory
secondly, instantiate your own credentials
thirdly, set those new credentials as new endpoint behavior on factory
// step one - find and remove default endpoint behavior
var defaultCredentials = factory.Endpoint.Behaviors.Find<ClientCredentials>();
factory.Endpoint.Behaviors.Remove(defaultCredentials);
// step two - instantiate your credentials
ClientCredentials loginCredentials = new ClientCredentials();
loginCredentials.UserName.UserName = CServiceCredentials.Instance.Username;
loginCredentials.UserName.Password = “Password123″;
// step three - set that as new endpoint behavior on factory
factory.Endpoint.Behaviors.Add(loginCredentials); //add required ones
Seems a bit odd and complicated, but that seems to be the one and only way to achieve this!
To complete this answer, the actual way in which it worked for everyone as explained at
http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/4668e261-0fd0-4ca5-91d2-497aa479f2a9/
You need not to remove, but override found credentials:
var credentialBehaviour = factory.Endpoint.Behaviors.Find < ClientCredentials > ();
credentialBehaviour.UserName.UserName = "test";
credentialBehaviour.UserName.Password = "test";
This has solved my problem.
This will not happen if the service reference is added through -> Add service reference ->Advanced->Add Web Reference-> Url/wsdl (local disk file).
The reference.cs file generated is different and will allow you to set credentials.
The error is because you might have added the reference through first screen itself (Add service reference)

WCF: Why does passing in a remote endpoint fail?

The problem I am having connecting a wcf client application to a host running on a separate machine is documented in a question previously asked:
WCF: Why does passing in a remote endpoint fail?
However, the solution provided here says you need to use a SpnEndpointIdentity with an empty string. Since my code doesn't look anything like the case in the example I have referenced, I need to know what to do with the SpnEndpointIdentity object I have created.
I have a ChannelFactory upon which I call Create channel, passing in an EndpointAddress:
public override void InitialiseChannel()
{
SpnEndpointIdentity spnEndpointIdentity = new SpnEndpointIdentity("");
var address = new EndpointAddress(EndpointName);
Proxy = ChannelFactory.CreateChannel(address);
}
(NB: ChannelFactory is of type IChannelFactory, where T is the service contract interface)
So what do I do with spnEndpointIdentity? I can't pass it to CreateChannel.
Or perhaps I can use it somehow when I create the channel factory:
private ChannelFactory<T> CreateChannelFactory()
{
var binding = new NetTcpBinding
{
ReaderQuotas = { MaxArrayLength = 2147483647 },
MaxReceivedMessageSize = 2147483647
};
SpnEndpointIdentity spnEndpointIdentity = new SpnEndpointIdentity("");
var channelFactory = new ChannelFactory<T>(binding);
return channelFactory;
}
Again, I can't pass it into the constructor, so what do I do with it?
Thanks.
You almiost got it.
What you're missing is that you associate the EndpointIdentity with the EndpointAddress, and then provide that to CreateChannel():
SpnEndpointIdentity spnEndpointIdentity = new SpnEndpointIdentity("");
var address = new EndpointAddress(EndpointName, spnEndpointIdentity);

Dynamically Building ChannelFactory

I'm trying to dynamically creating the ChannelFactory :
var serviceType = GetServiceProxy();
var interfaceType = serviceType.GetServiceInterface(); //return IServiceInterface
var service = new ChannelFactory(binding, address);
the problem is, as you can see, on the second line, where I don't have the generic type, and unfortunately, ChannelFactory does not have an overload that accepts the Type.
Any way around it??
Found that I can only do this with reflection. Of course you also have to call the methods using reflection.
to create the "ChannelFactory" and call the "CreateChannel" method:
private ChannelFactory CreateChannelFactory()
{
var channelFactoryType = typeof (ChannelFactory);
channelFactoryType = channelFactoryType.MakeGenericType(serviceType);
return (ChannelFactory)Activator.CreateInstance(channelFactoryType, binding, address);
}
private object CreateChannel()
{
var createchannel = channelFactory.GetType().GetMethod("CreateChannel", new Type[0]);
return createchannel.Invoke(channelFactory, null);
}
Now the channel is created but since just the interface type is available, I only can get the methods to invoke:
var serviceType = service.GetType();
var remoteMethod = service.GetMethod(invocation.Method.Name);
remoteMethod.Invoke(service, invocation.Arguments);
Hadi: does this forum post here (check out the answer by Roman Kiss, presenting a custom ChannelFactory2 class) address what you're looking for??
If so, you can stop reading my reply :-)
Well, typically you would do this:
1) have your service interface (IMyServiceInterface)
2) create / retrieve your binding and endpoint information
3) Create a channel factory for that interface:
ChannelFactory<IMyServiceInterface> myChannelFactory =
new ChannelFactory<IMyServiceInterface>(myBinding, myEndpoint);
4) from that channel factory, create your client proxy:
IMyServiceInterface client = myChannelFactory.CreateChannel();
5) Call methods on that client:
client.DoStuff();
So which part is it that you want to make more generic / more dynamic, and why?? What's the motivation / driving force behind that idea??
Marc

WCF OutgoingMessageHeaders not saving values

I am trying to write a MessageHeader to the OutgoingMessageHeaders but the value isn't sticking.
BasicHttpBinding basicHttpBinding = new BasicHttpBinding();
EndpointAddress endpointAddress = new EndpointAddress("http://localhost:1003/Client.svc");
IClientService serviceClient = new ChannelFactory<IClientService>(basicHttpBinding, endpointAddress).CreateChannel();
// attempt 1
using (OperationContextScope scope = new OperationContextScope(serviceClient as IContextChannel))
{
OperationContext.Current.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader("SessionId","","ABC"));
}
// attempt 2
using (OperationContextScope scope = new OperationContextScope(serviceClient as IContextChannel))
{
OperationContext.Current.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader("SessionId","","ABC"));
}
OK, you can see that I am setting OutgoingMessageHeaders twice but that is simply to prove a point. In the second attempt, before I do the actual add, I inspect the OperationContext.Current.OutgoingMessageHeaders. I would expect this to have one entry. But it is zero. As soon as it gets out of the using scope the value is lost.
When this flows through to the server, it says it can't find the message header, indicating that as far as its concerned it hasn't been saved either.
Why isn't my MessageHeader sticking?
Jeff
The end of the using block calls the dispose and resets the previous OperationContext.
So you want something like this with the service call inside of the OperationContextScope.
using (OperationContextScope scope = new OperationContextScope(serviceClient as IContextChannel))
{
OperationContext.Current.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader("SessionId", "", "ABC"));
serviceClient.CallOperation();
}