I'm trying to add ad-hoc discovery to a simple WCF service-client setup (currently implemented by self hosting in a console app). Debugging using VS2010 on windows 7, and doing whatever I can find in online tutorial, but still - the discovery client simply finds nothing. Needless to say if I open a client to the correct service endpoint I can access the service from the client.
service code:
using (var selfHost = new ServiceHost(typeof(Renderer)))
{
try
{
selfHost.Open();
...
selfHost.Close();
service app.config:
<?xml version="1.0"?>
<configuration>
<system.serviceModel>
<services>
<service name="TestApp.Renderer">
<host>
<baseAddresses>
<add baseAddress="http://localhost:9000" />
</baseAddresses>
</host>
<endpoint address="ws" binding="wsHttpBinding" contract="TestApp.IRenderer"/>
<endpoint kind="udpDiscoveryEndpoint"/>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior>
<serviceDiscovery/>
<serviceMetadata httpGetEnabled="True"/>
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
client discovery code:
DiscoveryClient discoveryClient = new DiscoveryClient(new UdpDiscoveryEndpoint());
var criteria = new FindCriteria(typeof(IRenderer)) { Duration = TimeSpan.FromSeconds(5) };
var endpoints = discoveryClient.Find(criteria).Endpoints;
The 'endpoints' collection always comes out empty. I've tried running the service and client from the debugger, from a command line, from an admin command line - everything, but to no avail (all on the local machine, of course, not to mantion I'll need it running on my entire subnet eventually)
Any help would be appreciated :-)
Here is a super simple discovery example. It does not use a config file, it is all c# code, but you can probably port the concepts to a config file.
share this interface between host and client program (copy to each program for now)
[ServiceContract]
public interface IWcfPingTest
{
[OperationContract]
string Ping();
}
put this code in the host program
public class WcfPingTest : IWcfPingTest
{
public const string magicString = "djeut73bch58sb4"; // this is random, just to see if you get the right result
public string Ping() {return magicString;}
}
public void WcfTestHost_Open()
{
string hostname = System.Environment.MachineName;
var baseAddress = new UriBuilder("http", hostname, 7400, "WcfPing");
var h = new ServiceHost(typeof(WcfPingTest), baseAddress.Uri);
// enable processing of discovery messages. use UdpDiscoveryEndpoint to enable listening. use EndpointDiscoveryBehavior for fine control.
h.Description.Behaviors.Add(new ServiceDiscoveryBehavior());
h.AddServiceEndpoint(new UdpDiscoveryEndpoint());
// enable wsdl, so you can use the service from WcfStorm, or other tools.
var smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
h.Description.Behaviors.Add(smb);
// create endpoint
var binding = new BasicHttpBinding(BasicHttpSecurityMode.None);
h.AddServiceEndpoint(typeof(IWcfPingTest) , binding, "");
h.Open();
Console.WriteLine("host open");
}
put this code in the client program
private IWcfPingTest channel;
public Uri WcfTestClient_DiscoverChannel()
{
var dc = new DiscoveryClient(new UdpDiscoveryEndpoint());
FindCriteria fc = new FindCriteria(typeof(IWcfPingTest));
fc.Duration = TimeSpan.FromSeconds(5);
FindResponse fr = dc.Find(fc);
foreach(EndpointDiscoveryMetadata edm in fr.Endpoints)
{
Console.WriteLine("uri found = " + edm.Address.Uri.ToString());
}
// here is the really nasty part
// i am just returning the first channel, but it may not work.
// you have to do some logic to decide which uri to use from the discovered uris
// for example, you may discover "127.0.0.1", but that one is obviously useless.
// also, catch exceptions when no endpoints are found and try again.
return fr.Endpoints[0].Address.Uri;
}
public void WcfTestClient_SetupChannel()
{
var binding = new BasicHttpBinding(BasicHttpSecurityMode.None);
var factory = new ChannelFactory<IWcfPingTest>(binding);
var uri = WcfTestClient_DiscoverChannel();
Console.WriteLine("creating channel to " + uri.ToString());
EndpointAddress ea = new EndpointAddress(uri);
channel = factory.CreateChannel(ea);
Console.WriteLine("channel created");
//Console.WriteLine("pinging host");
//string result = channel.Ping();
//Console.WriteLine("ping result = " + result);
}
public void WcfTestClient_Ping()
{
Console.WriteLine("pinging host");
string result = channel.Ping();
Console.WriteLine("ping result = " + result);
}
on the host, simply call the WcfTestHost_Open() function, then sleep forever or something.
on the client, run these functions. It takes a little while for a host to open, so there are several delays here.
System.Threading.Thread.Sleep(8000);
this.server.WcfTestClient_SetupChannel();
System.Threading.Thread.Sleep(2000);
this.server.WcfTestClient_Ping();
host output should look like
host open
client output should look like
uri found = http://wilkesvmdev:7400/WcfPing
creating channel to http://wilkesvmdev:7400/WcfPing
channel created
pinging host
ping result = djeut73bch58sb4
this is seriously the minimum I could come up with for a discovery example. This stuff gets pretty complex fast.
Damn! it was the firewall... for some reason all UDP communication was blocked - disabling the firewall solved the problem. Now I only need to figure out the correct firewall configuration...
Related
I'm experiencing a problem with WCF client connections using a self-created certificate.
Certificate created as follows:
Makecert -r -pe -n "CN=MySslSocketCertificate" -b 01/01/2015 -e 01/01/2025 -sk exchange -ss my
Server code:
Public Sub StartWcfServer()
Dim binding As New NetTcpBinding()
binding.Security.Mode = SecurityMode.Transport
binding.Security.Transport.ProtectionLevel = Net.Security.ProtectionLevel.EncryptAndSign
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Certificate
binding.TransferMode = TransferMode.Streamed
Dim baseAddress As New Uri($"net.tcp://192.168.1.1:1234/WcfServer")
_serviceHost = New ServiceHost(GetType(WcfServer), baseAddress)
_serviceHost.Credentials.ServiceCertificate.SetCertificate(StoreLocation.CurrentUser, StoreName.My, X509FindType.FindByIssuerName, "MySslSocketCertificate")
_serviceHost.Credentials.ClientCertificate.Authentication.RevocationMode = X509RevocationMode.NoCheck
_serviceHost.Credentials.ClientCertificate.Authentication.CertificateValidationMode = ServiceModel.Security.X509CertificateValidationMode.None
_serviceHost.Credentials.ClientCertificate.Authentication.TrustedStoreLocation = StoreLocation.CurrentUser
ServicePointManager.ServerCertificateValidationCallback = New RemoteCertificateValidationCallback(AddressOf ValidateServerCertificate)
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 Or SecurityProtocolType.Tls12
_serviceHost.AddServiceEndpoint(GetType(IWcfServer), binding, baseAddress)
_serviceHost.Open()
End Sub
Private Function ValidateServerCertificate(sender As Object, certificate As X509Certificate, chain As X509Chain, sslPolicyErrors As SslPolicyErrors) As Boolean
Return True
End Function
Client code:
private void InitialiseWcfClient()
{
var binding = new NetTcpBinding();
binding.Security.Mode = SecurityMode.Transport;
binding.Security.Transport.ProtectionLevel = System.Net.Security.ProtectionLevel.EncryptAndSign;
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.None;
binding.TransferMode = TransferMode.Streamed;
var url = $"net.tcp://192.168.1.1:1234/WcfServer";
var address = new EndpointAddress(url);
var channelFactory = new ChannelFactory<IWcfServer>(binding, address);
WcfServer = channelFactory.CreateChannel();
}
// call to server which causes the error
WcfServer.CallMethod();
Client-side error:
System.IdentityModel.Tokens.SecurityTokenValidationException: 'The X.509 certificate CN=MySslSocketCertificate chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.
Server-side error:
System.Security.Authentication.AuthenticationException: 'The remote certificate is invalid according to the validation procedure.'
Bro,regardless of whether we specify the Authencation mode on the server-side, we should establish the trust relationship between the server and the client when authenticating the client with a certificate.
Namely, we should install the server certificate on the client-side and install the client certificate on the server side. Based on the authentication mode value, the certificate installation place is difference, commonly we should install it in the Local CA. Besides, considering some access permission issues, we had better install the certificate in Local machine store location other than Current User.
Also, when we explicitly specify the security mode to Transport, we should provide a certificate on the server side.
sh.Credentials.ServiceCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.My, X509FindType.FindByThumbprint, "cbc81f77ed01a9784a12483030ccd497f01be71c");
At the same time, the client is supposed to provide a certificate to represent identity.
factory.Credentials.ClientCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.My, X509FindType.FindByThumbprint, "9ee8be61d875bd6e1108c98b590386d0a489a9ca");
I have made a demo, ,wish it is helpful to you.
Server.
class Program
{
static void Main(string[] args)
{
using (ServiceHost sh = new ServiceHost(typeof(MyService)))
{
sh.Credentials.ServiceCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.My, X509FindType.FindByThumbprint, "cbc81f77ed01a9784a12483030ccd497f01be71c");
sh.Open();
Console.WriteLine("serivce is ready....");
Console.ReadLine();
sh.Close();
}
}
}
[ServiceContract]
public interface IService
{
[OperationContract]
string Test();
}
public class MyService : IService
{
public string Test()
{
return DateTime.Now.ToString();
}
}
App.config(Server side)
<system.serviceModel>
<services>
<service name="VM1.MyService">
<endpoint address="" binding="netTcpBinding" contract="VM1.IService" bindingConfiguration="mybinding">
</endpoint>
<endpoint address="mex" binding="mexTcpBinding" contract="IMetadataExchange" ></endpoint>
<host>
<baseAddresses>
<add baseAddress="net.tcp://localhost:5566"/>
</baseAddresses>
</host>
</service>
</services>
<bindings>
<netTcpBinding>
<binding name="mybinding">
<security mode="Transport">
<transport clientCredentialType="Certificate"></transport>
</security>
</binding>
</netTcpBinding>
</bindings>
<behaviors>
<serviceBehaviors>
<behavior>
<serviceMetadata />
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
Client.
class Program
{
static void Main(string[] args)
{
Uri uri = new Uri("net.tcp://vabqia969vm:5566");
NetTcpBinding binding = new NetTcpBinding();
binding.Security.Mode = SecurityMode.Transport;
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Certificate;
ChannelFactory<IService> factory = new ChannelFactory<IService>(binding, new EndpointAddress(uri));
factory.Credentials.ClientCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.My, X509FindType.FindByThumbprint, "9ee8be61d875bd6e1108c98b590386d0a489a9ca");
IService service = factory.CreateChannel();
try
{
var result = service.Test();
Console.WriteLine(result);
}
catch (Exception)
{
throw;
}
}
}
[ServiceContract]
public interface IService
{
[OperationContract]
string Test();
}
Result.
One more thing must be noted that we should ensure the client certificate have the client authentication Intended purposes.
Feel free to let me know if there is anything I can help with.
I have a persistent problem, which I have been researching for a couple days now. I am working on transitioning a WCF service to use a dynamic port, a need has finally come into scope for this. I am most of the way there; however, I am getting the error:
System.ArgumentException: This collection already contains an address with scheme net.tcp.
I have searched online for an answer, and have only found solutions to if the scheme was http. I will provide some code, to aid those who desire to help me and others with this problem.
I have a services.development.config file. We have the app.config file separated for specific reasons within the organization.
<service name="MLITS.Pulse.Pulse" behaviorConfiguration="PulseCSBehavior">
<host>
<baseAddresses>
<add baseAddress="net.tcp://localhost:14613/PulseService"/>
</baseAddresses>
</host>
<endpoint name="NetTcpEndPoint"
address=""
binding="netTcpBinding"
contract="MLITS.Pulse.IPulse" />
<endpoint name="NetTcpMetadataPoint"
address="mex"
binding="mexTcpBinding"
contract="IMetadataExchange" />
We also have the endpoint address in a client.development.config file.
<endpoint address="net.tcp://localhost:14613/PulseService" binding="netTcpBinding"
bindingConfiguration="NetTcpEndPoint" contract="PulseService.IPulse" name="NetTcpEndPoint" />
Now it is my understanding with the method I'm using, I am able to keep the specific port number specified here, and later change it. Now the way I'm changing the port number is adding the session id to the base port number (which would be the 14613). The following code is the method that does just that.
public static void DynamicAddress()
{
int sessionIdentification = 0;
int portNumber = 0;
int newPort = 0;
string uriString = string.Empty;
sessionIdentification = Process.GetCurrentProcess().SessionId;
portNumber = 14613;
newPort = portNumber + sessionIdentification;
uriString = "net.tcp://localhost:" + newPort + "/PulseService";
//seperate the port from the rest of the service
//add the session id to the port
//put the address back together and return it
Uri uri = new Uri(uriString);
ServiceHost objServiceHost = new ServiceHost(typeof(Pulse), uri);
}
The error appears when we try and process the ServiceHost line. My question is: How do I resolve this, for it to function correctly?
Keep in mind, I have tried commenting out the base addresses in the services.development.config file, as well as the endpoint address in the client.development.config file. When doing this I have ran into other issues that were because I've commented the address out.
I have resolved the issue I was having in regards to this question. Instead of trying to assign the service host with another URI, I had to first clear the Endpoints and then add my new service endpoint. The only changes I made were to the DynamicPort method. Code Follows:
public static void DynamicAddress(
{
int sessionIdentification = 0;
int portNumber = 0;
int newPort = 0;
string uriString = string.Empty;
sessionIdentification = Process.GetCurrentProcess().SessionId;
portNumber = 14613;
newPort = portNumber + sessionIdentification;
uriString = "net.tcp://localhost:" + newPort + "/PulseService";
Uri uri = new Uri(uriString);
ServiceHost objServiceHost = new ServiceHost(typeof(Pulse));
objServiceHost.Description.Endpoints.Clear();
objServiceHost.AddServiceEndpoint(typeof(Pulse), new NetTcpBinding(), uri);
}
I'm busy writing a file server/client tool that basically uses a hosted Service to send and receive data to and from the server. Since this solution will be used by many different people, its not really advisable to have them go and edit the App.Config file for their setup. What I would like to do is change this at runtime so that the user(s) have full control over the settings to use. So, this is my App.Config file:
<system.serviceModel>
<services>
<service name="FI.ProBooks.FileSystem.FileRepositoryService">
<endpoint name="" binding="netTcpBinding"
address="net.tcp://localhost:5000"
contract="FI.ProBooks.FileSystem.IFileRepositoryService"
bindingConfiguration="customTcpBinding" />
</service>
</services>
<bindings>
<netTcpBinding>
<binding name="customTcpBinding" transferMode="Streamed" maxReceivedMessageSize="20480000" />
</netTcpBinding>
</bindings>
</system.serviceModel>
What I would like to do is to change only the address (in this example, net.tcp://localhost:5000) when the application is executed. So I must be able to read the current value and display that to the user, and then take their input and save it back into that field.
The test below may help you. Essentially the steps are
Instantiate an instance of the host that reads the configuration from the .config file;
Create a new instance of EndpointAddress using the same configuration as the old one, but changing the uri and assign it to the Address property of your ServiceEndpoint.
[TestMethod]
public void ChangeEndpointAddressAtRuntime()
{
var host = new ServiceHost(typeof(FileRepositoryService));
var serviceEndpoint = host.Description.Endpoints.First(e => e.Contract.ContractType == typeof (IFileRepositoryService));
var oldAddress = serviceEndpoint.Address;
Console.WriteLine("Curent Address: {0}", oldAddress.Uri);
var newAddress = "net.tcp://localhost:5001";
Console.WriteLine("New Address: {0}", newAddress);
serviceEndpoint.Address = new EndpointAddress(new Uri(newAddress), oldAddress.Identity, oldAddress.Headers);
Task.Factory.StartNew(() => host.Open());
var channelFactory = new ChannelFactory<IFileRepositoryService>(new NetTcpBinding("customTcpBinding"), new EndpointAddress(newAddress));
var channel = channelFactory.CreateChannel();
channel.Method();
(channel as ICommunicationObject).Close();
channelFactory = new ChannelFactory<IFileRepositoryService>(new NetTcpBinding("customTcpBinding"), oldAddress);
channel = channelFactory.CreateChannel();
bool failedWithOldAddress = false;
try
{
channel.Method();
}
catch (Exception e)
{
failedWithOldAddress = true;
}
(channel as ICommunicationObject).Close();
Assert.IsTrue(failedWithOldAddress);
}
you can create the service instance providing a configuration name and endpoint. So you can use;
EndpointAddress endpoint = new EndpointAddress(serviceUri);
var client= new MyServiceClient(endpointConfigurationName,endpoint )
look at msdn article.
I have a basic WCF library project which I am trying to host in console application. The Program.cs file's Main method is as given below:
static void Main(string[] args)
{
// Create a binding and set the security mode to Message.
BasicHttpBinding b = new BasicHttpBinding();//WSHttpBinding(SecurityMode.Message);
Type contractType = typeof(SecureWCFLib.IService1);
Type implementedContract = typeof(SecureWCFLib.Service1);
Uri baseAddress = new Uri("http://localhost:8733/Design_Time_Addresses/SecureWCFLib/Service1/");
ServiceHost sh = new ServiceHost(implementedContract, baseAddress);
sh.AddServiceEndpoint(contractType, b, "Service1");
ServiceMetadataBehavior sm = new ServiceMetadataBehavior();
sm.HttpGetEnabled = true;
sh.Description.Behaviors.Add(sm);
sh.Open();
Console.WriteLine("Listening");
Console.ReadLine();
sh.Close();
}
I have another console application which acts as a client. I am trying to consume the service in Program.cs as given below:
static void Main(string[] args)
{
IService1 productChannel = null;
EndpointAddress productAddress = new EndpointAddress("http://localhost:8733/Design_Time_Addresses/SecureWCFLib/Service1/");
productChannel = ChannelFactory<IService1>.CreateChannel(new BasicHttpBinding(), productAddress);
string result = productChannel.GetData(123);
Console.WriteLine(result);
Console.Read();
}
But I get exception as
{"The remote server returned an error: (404) Not Found."}
Please let me know what I am doing wrong over here.
EndpointAddress productAddress = new EndpointAddress("http://localhost:8733/Design_Time_Addresses/SecureWCFLib/Service1/Service1");
add Services1 to the end of constructor parameter.
client endpointaddress = serviceshost_baseAddress + relative address.
Your code is equale to configuration:
<service name="SecureWCFLib.Service1">
<host>
<baseAddresses>
<add baseAddress="http://localhost:8733/Design_Time_Addresses/SecureWCFLib/Service1/" />
</baseAddresses>
</host>
<endpoint address="Service1" binding="basicHttpBinding" contract="SecureWCFLib.IService1">
</endpoint>
<behaviors>
<!--......-->
<behaviors>
</service>
If you want have access to your web service on IIS express by other clients , you must grant remote access to IIS express's port.
Please see below link .
http://johan.driessen.se/posts/Accessing-an-IIS-Express-site-from-a-remote-computer
http://www.iis.net/learn/extensions/using-iis-express/handling-url-binding-failures-in-iis-express
I am creating a server in .NET and a client application for Android. I would like to implement an authentication method which sends username and password to server and a server sends back a session string.
I'm not familiar with WCF so I would really appreciate your help.
In java I've written the following method:
private void Login()
{
HttpClient httpClient = new DefaultHttpClient();
try
{
String url = "http://192.168.1.5:8000/Login?username=test&password=test";
HttpGet method = new HttpGet( new URI(url) );
HttpResponse response = httpClient.execute(method);
if ( response != null )
{
Log.i( "login", "received " + getResponse(response.getEntity()) );
}
else
{
Log.i( "login", "got a null response" );
}
} catch (IOException e) {
Log.e( "error", e.getMessage() );
} catch (URISyntaxException e) {
Log.e( "error", e.getMessage() );
}
}
private String getResponse( HttpEntity entity )
{
String response = "";
try
{
int length = ( int ) entity.getContentLength();
StringBuffer sb = new StringBuffer( length );
InputStreamReader isr = new InputStreamReader( entity.getContent(), "UTF-8" );
char buff[] = new char[length];
int cnt;
while ( ( cnt = isr.read( buff, 0, length - 1 ) ) > 0 )
{
sb.append( buff, 0, cnt );
}
response = sb.toString();
isr.close();
} catch ( IOException ioe ) {
ioe.printStackTrace();
}
return response;
}
But on the server side so far I haven't figured out anything.
I would be really thankful if anyone could explain how to create an appropriate method string Login(string username, string password) with appropriate App.config settings and Interface with appropriate [OperationContract] signature in order to read these two parameters from client and reply with session string.
Thanks!
To get started with WCF, it might be easiest to just use the default SOAP format and HTTP POST (rather than GET) for the web-service bindings. The easiest HTTP binding to get working is "basicHttpBinding". Here is an example of what the ServiceContract/OperationContract might look like for your login service:
[ServiceContract(Namespace="http://mycompany.com/LoginService")]
public interface ILoginService
{
[OperationContract]
string Login(string username, string password);
}
The implementation of the service could look like this:
public class LoginService : ILoginService
{
public string Login(string username, string password)
{
// Do something with username, password to get/create sessionId
// string sessionId = "12345678";
string sessionId = OperationContext.Current.SessionId;
return sessionId;
}
}
You can host this as a windows service using a ServiceHost, or you can host it in IIS like a normal ASP.NET web (service) application. There are a lot of tutorials out there for both of these.
The WCF service config might look like this:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.serviceModel>
<behaviors>
<serviceBehaviors>
<behavior name="LoginServiceBehavior">
<serviceMetadata />
</behavior>
</serviceBehaviors>
</behaviors>
<services>
<service name="WcfTest.LoginService"
behaviorConfiguration="LoginServiceBehavior" >
<host>
<baseAddresses>
<add baseAddress="http://somesite.com:55555/LoginService/" />
</baseAddresses>
</host>
<endpoint name="LoginService"
address=""
binding="basicHttpBinding"
contract="WcfTest.ILoginService" />
<endpoint name="LoginServiceMex"
address="mex"
binding="mexHttpBinding"
contract="IMetadataExchange" />
</service>
</services>
</system.serviceModel>
</configuration>
(The MEX stuff is optional for production, but is needed for testing with WcfTestClient.exe, and for exposing the service meta-data).
You'll have to modify your Java code to POST a SOAP message to the service. WCF can be a little picky when inter-operating with non-WCF clients, so you'll have to mess with the POST headers a little to get it to work. Once you get this running, you can then start to investigate security for the login (might need to use a different binding to get better security), or possibly using WCF REST to allow for logins with a GET rather than SOAP/POST.
Here is an example of what the HTTP POST should look like from the Java code. There is a tool called "Fiddler" that can be really useful for debugging web-services.
POST /LoginService HTTP/1.1
Content-Type: text/xml; charset=utf-8
SOAPAction: "http://mycompany.com/LoginService/ILoginService/Login"
Host: somesite.com:55555
Content-Length: 216
Expect: 100-continue
Connection: Keep-Alive
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Body>
<Login xmlns="http://mycompany.com/LoginService">
<username>Blah</username>
<password>Blah2</password>
</Login>
</s:Body>
</s:Envelope>
Another option might be to avoid WCF all-together and just use a .NET HttpHandler. The HttpHandler can grab the query-string variables from your GET and just write back a response to the Java code.
You will need something more that a http request to interact with a WCF service UNLESS your WCF service has a REST interface. Either look for a SOAP web service API that runs on android or make your service RESTful. You will need .NET 3.5 SP1 to do WCF REST services:
http://msdn.microsoft.com/en-us/netframework/dd547388.aspx
From my recent experience i would recommend ksoap library to consume a Soap WCF Service, its actually really easy, this anddev thread migh help you out too.
If I were doing this I would probably use WCF REST on the server and a REST library on the Java/Android client.