I have a datacontract as part of my WCF Interface that inherits from IIdentity:
[DataContract]
public class AuthenticationIdentity : IIdentity
{
//implements IIdentity...
}
The service returns my AuthenticationIdentity objects just fine. However, when I try and do the obvious cast on the client:
AuthenticationIdentity aId = client.GetID();
IIdentity id = aId;
I get a complaint that AuthenticationIdentity cannot be cast to IIdentity. I've tried adding the ServiceKnownTypes to the interface:
[ServiceKnownType(typeof(AuthenticationIdentity))]
[ServiceKnownType(typeof(IIdentity))]
but still no luck. Any ideas?
If you control both sides of the wire (which it looks like you do since you want to cast to IIdentity), you can reference your DataContract from a shared assembly. Then you can use svcutil to share the DataContracts between the service and the consumer. Or, if you wanted to cut out svcutil altogether, you could write your own proxy to use the shared assembly.
Related
I have given reference to a dll in my WCF service application. My WCF operation requires input of type class (let's say XYZ) which is present in that dll.
Now, is it possible to expose that class to the clients so that they can call the exposed wcf method?
If yes then can you please explain the idea or with some pesudo code/references ?
Thanks in advance !
Contract:
[OperationContract]
void Add(XYZ item);
Server:
public void Add(XYZ item){}
[DataContract]
class XYZ{}
Client:
var item = new XYZ();
client.Add(item);
Dll containing 'XYZ' should be referenced by both Server and Client.
Class 'XYZ' should have 'DataContract' attribute.
Implementation is more or less similar to FaultContracts in WCF.
I am converting asmx web service to wcf while attempting to maintain backwards compatibility in the WSDL. One of the DataContract classes is generic. When the generic parameter is a built-in type, such as bool, the first letter is lowercased in WCF, whereas it was uppercased in asmx. E.g.
[Serializable]
public class MethodResult<T>
{
}
would generate
MethodResultOfBoolean
in asmx.
[DataContract(Name="MethodResultOf{0}")]
public class MethodResult<T>
{
}
generates
MethodResultOfboolean
in WCF.
Is there a way to make it use an uppercase letter in WCF?
I found that adding [XmlSerializerFormatAttribute] to the ServiceContract interface fixed this.
1) Does Binding use while creating ChannelFactory makes any difference to how serialization/deserialization works? (I know that binding used should match the server side binding of the service.)
I am using KnownType attribute in one of my DataContract but it does not work. But if I use XmlIncludeAttribute, it works! (I am migrating my ASMX services to WCF.. But I am not using any MessageContracts since I have freedom to update client side proxies too.)
[XmlInclude(typeof(Males))]
[DataContract]
public abstract class Person
{
[DataMember]
public int Name { get; set; }
}
2) If I use any Attribute ( to be specific - XmlInclude)) that uses XmlSerializer for the WCF DataContract, does WCF use XmlSerializer instead of DataContractSerializer?
DataContractSerializer supports everything that XmlSerializer supports, but the reverse is not true. But if a type is decorated with [DataContract], it switches over completely to the new DataContract programming model, completely throwing away support for [Serializable], IXmlSerializable, etc. types that it otherwise would have had.
So your [XmlInclude] magic works only if you're using ASMX and the traditional XmlSerializer. If you're using DataContractSerializer, you have to do known types, and XML-isms like [XmlInclude] and XML attributes are simply not supported. You can still use XmlSerializer instead of DataContractSerializer if you want to, though; all you need to do is decorate the service or operation you want to switch over to XmlSerializer with [XmlSerializerFormatAttribute.]
Hope this helps!
I have defined the following type in a class library project.
[CollectionDataContract()]
public class OperationException:System.Collections.Generic.Dictionary<string,ExceptionData>
{
[DataMember()]
public bool ExceptionExists { get; set; }
}
[DataContract()]
public class ExceptionData {[DataMember()] public string Msg;}
On my WCF service end, I am returning an object which contains the above class as a child member variable like this.
[DataContract()]
public class SaveClient
{
[DataMember()]
public string Id;
[DataMember()]
public OperationException ExceptionCollection;
}
I have the OperationException class library referenced on the client side. The problem is when I generate the proxy using Add Service Reference, a new definition of OperationException of type dictionary is generated. I do have the Reuse Types option set to true. I like to have Actual 'OperationException' type being used since I have to pass this object to other methods.
Thanks in Advance..!
Iftikhar.
I had the same issue and like you I had applied the CollectionDataContract attribute and told the proxy generator to reuse types from my shared assembly.
The fix was not obvious, you need to supply a hook in the Reference.svcmap file on your client to tell the generator to use your custom collection type.
In Reference.svcmap edit the CollectionMappings element as follows and then update the service reference:
<CollectionMappings>
<CollectionMapping TypeName="YourSharedAssemblyNamespace.OperationException" Category="List" />
</CollectionMappings>
I think the same objective can be achieved if you are using svcutil from the command line by supplying the collection type argument.
/collectionType:YourSharedAssemblyNamespace.OperationException
See these posts for more info:
http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/09eefbbc-bf63-4aa3-a0cb-01a9dbd7f496/
http://www.codeproject.com/KB/WCF/WCFCollectionTypeSharing.aspx
I am not sure why the WCF proxy generator doesn't just use it's common sense to find the shared collection types but there you go, chalk it up as another funny from the WCF tool design.
Does your client proxy assembly have a project reference to the class library where the type is added?
If the proxies generated by svcutil are not what you want, it's also very easy to write them by hand. Just create your own ClientBase-derived class and implement your service interface on it. Then you have control over which assembly types you want to reuse.
I have an application where client and server share types, and interoperability is not one of our concerns. I am planning to have a single repository for all web enabled objects, and i was thinking of a generic interface for my exposed service.
something like T GetObject(int id)
but wcf doesnt like it since its trying to expose its schema (which i dont really care about)
is it possible to do such a thing with WCF ?, i can use any type of binding doesnt have to be httpbinding or wsbinding...
No, you can't. Whether or not you want or need interoperability, the most basic foundation of WCF is message exchange.
The client send the server a message and gets back a response. That message is all that passes between client and server, and needs to be serializable into a XML or binary format. That's why any data being passed around must be atomic (like int, string) or a DataContract - a description for the WCF service stack about how to serialize and deserialize such objects.
You cannot pass any interfaces, or other "trickery" - all that goes between client and server must be expressable in XML schema, basically.
So I'm afraid what you're trying to achieve is quite contrary to what WCF offers. The world and paradigms of SOA (Service-Oriented Apps) are quite different and not always 100% in sync with the idea and mechanisms of OOP.
Marc
I suppose this is possible, though I'm not sure you'd want this. I'd take the following approach (untested, not sure if it works). First create the following project structure in your solution:
ServiceInterfaces
ServiceImplementations (references ServiceInterfaces and ModelClasses)
ModelClasses
Host (references ServiceInterfaces and ServiceImplementations)
Client (references ServiceInterfaces and ModelClasses)
In ServiceInterfaces you have an interface like this (I skipped the namespaces, etc to make the example shorter):
[ServiceContract]
public interface IMyService<T>
{
T GetObject(int id);
}
In ServiceImplementations you have a class that implements IMyService<T>:
public class MyService<T> : IMyService<T>
{
T GetObject(int id)
{
// Create something of type T and return it. Rather difficult
// since you only know the type at runtime.
}
}
In Host you have the correct configuration for your service in an App.config (or Web.config) file and the following code to host your service (given that it is a stand-alone app):
ServiceHost host = new ServiceHost(typeof(MessageManager.MessageManagerService))
host.Open();
And finally in Client you use a ChannelFactory<TChannel> class to define a proxy:
Binding binding = new BasicHttpBinding(); // For the example, could be another binding.
EndpointAddress address = new EndpointAddress("http://localhost:8000/......");
IMyService<string> myService =
ChannelFactory<IMyService<string>>.CreateChannel(binding, address);
string myObject = myService.GetObject(42);
Again, I'm not sure if this works. The trick is to share your service interfaces (in ServiceInterfaces) and domain model objects (in ModelClasses) between the host and the client. In my example I use a string to return from the service method but it could be any data contract type from the ModelClasses project.
You CAN DO that if you use ServiceKnownTypesDiscovery.
For example:
[ServiceKnownType("GetKnownTypes", typeof(ServiceKnownTypesDiscovery))]
public interface ISomeService
{
[OperationContract]
object Request(IRequestBase parameters);
}
where GetKnownTypes could be declared like so:
public static class ServiceKnownTypesDiscovery
{
public static IEnumerable<Type> GetKnownTypes(ICustomAttributeProvider provider)
{
var types = new List<Type>();
foreach (var asmFile in Directory.GetFiles(AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory, "*.dll"))
{
Assembly asm = Assembly.LoadFrom(asmFile);
types.AddRange(asm.GetTypes().Where(p=> Attribute.IsDefined(p,typeof(DataContractAttribute))));
}
return types;
}
}
In this case everything declared with [DataContract] (as long as they are discoverable on the server AND the client side) can be serialized.
I hope this helped!
Following the previous example, you could declare a DataContract with an object as DataMember. Then you could add an extension method to get and set a generic type on the object data member. You could also make this internal, this way you would be obliged to use the extension methods to get and set the value.
Of course, it only works if you generate the client using svcutil (or Visual Studio) and you reference the assembly containing the data contract and the class with the extensions methods.
Hope this helps...