WCF Client reading JSONP responses - wcf

I'm writing a simple client for a web service using WCF. Unfortunately, the web service only answers with JSONP messages, not plain JSON.
Is that possible to use built-in features from .NET 4.0 to do this or do I need to extend something else to strip function name, { and } from the answer I get from the server? I know how to read JSON responses, but not JSONP yet.

What you need is a custom message encoder. On the server side, it's the encoder which adds the padding (function call) to the response, so you need something similar on the client side to remove that padding before handling the message (likely delegating it to another encoder). The other thing you'll need to worry about at the encoder is that often the content-type used for JSONP (application/x-javascript) is not recognized as a JSON content-type (because it's not, it's a function call), so the encoder should also "translate" that content-type into one which is understood by the encoder to which the call is delegated.
The code below shows an example of such an encoder. The service has been modified to always wrap the result, as you mentioned your service does.
public class StackOverflow_11255528
{
[ServiceContract]
public interface ICalculator
{
[WebGet(ResponseFormat = WebMessageFormat.Json)]
int Add(int x, int y);
[WebGet(ResponseFormat = WebMessageFormat.Json)]
int Subtract(int x, int y);
}
[ServiceContract]
public class CalculatorService
{
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public Stream Add(int x, int y)
{
return ReturnWrapped(x + y);
}
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public Stream Subtract(int x, int y)
{
return ReturnWrapped(x - y);
}
private Stream ReturnWrapped(int result)
{
string callback = "Something";
string response = string.Format("{0}({1});", callback, result);
WebOperationContext.Current.OutgoingResponse.ContentType = "application/x-javascript";
return new MemoryStream(Encoding.UTF8.GetBytes(response));
}
}
public class JsonpAwareClientMessageEncodingBindingElement : MessageEncodingBindingElement
{
WebMessageEncodingBindingElement webEncoding;
public JsonpAwareClientMessageEncodingBindingElement()
{
this.webEncoding = new WebMessageEncodingBindingElement();
}
public override MessageEncoderFactory CreateMessageEncoderFactory()
{
return new JsonpAwareClientMessageEncoderFactory(this.webEncoding.CreateMessageEncoderFactory());
}
public override MessageVersion MessageVersion
{
get { return this.webEncoding.MessageVersion; }
set { this.webEncoding.MessageVersion = value; }
}
public override BindingElement Clone()
{
return new JsonpAwareClientMessageEncodingBindingElement();
}
public override IChannelFactory<TChannel> BuildChannelFactory<TChannel>(BindingContext context)
{
context.BindingParameters.Add(this);
return context.BuildInnerChannelFactory<TChannel>();
}
class JsonpAwareClientMessageEncoderFactory : MessageEncoderFactory
{
private MessageEncoderFactory factory;
public JsonpAwareClientMessageEncoderFactory(MessageEncoderFactory factory)
{
this.factory = factory;
}
public override MessageEncoder Encoder
{
get { return new JsonpAwareClientMessageEncoder(this.factory.Encoder); }
}
public override MessageVersion MessageVersion
{
get { return this.factory.MessageVersion; }
}
}
class JsonpAwareClientMessageEncoder : MessageEncoder
{
private MessageEncoder encoder;
public JsonpAwareClientMessageEncoder(MessageEncoder encoder)
{
this.encoder = encoder;
}
public override string ContentType
{
get { return this.encoder.ContentType; }
}
public override string MediaType
{
get { return this.encoder.MediaType; }
}
public override MessageVersion MessageVersion
{
get { return this.encoder.MessageVersion; }
}
public override bool IsContentTypeSupported(string contentType)
{
if (contentType == "application/x-javascript")
{
contentType = "application/json";
}
return this.encoder.IsContentTypeSupported(contentType);
}
public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
{
if (contentType == "application/x-javascript")
{
contentType = "application/json";
}
byte openParenthesis = (byte)'(';
byte closeParenthesis = (byte)')';
int startOfParenthesis = buffer.Offset;
int count = buffer.Count;
while (buffer.Array[startOfParenthesis] != openParenthesis)
{
startOfParenthesis++;
count--;
}
// Skipped 'Func', now skipping '('
startOfParenthesis++;
count--;
// Now need to trim the closing parenthesis and semicolon, if any
int endOfParenthesis = buffer.Offset + buffer.Count - 1;
while (buffer.Array[endOfParenthesis] != closeParenthesis)
{
endOfParenthesis--;
count--;
}
// Skipped back to ')', now remove it
endOfParenthesis--;
count--;
return this.encoder.ReadMessage(new ArraySegment<byte>(buffer.Array, startOfParenthesis, count), bufferManager, contentType);
}
public override Message ReadMessage(Stream stream, int maxSizeOfHeaders, string contentType)
{
throw new NotSupportedException("Streamed mode not supported");
}
public override ArraySegment<byte> WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset)
{
return this.encoder.WriteMessage(message, maxMessageSize, bufferManager, messageOffset);
}
public override void WriteMessage(Message message, Stream stream)
{
throw new NotSupportedException("Streamed mode not supported");
}
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(CalculatorService), new Uri(baseAddress));
WebHttpBinding binding = new WebHttpBinding { CrossDomainScriptAccessEnabled = true };
host.AddServiceEndpoint(typeof(CalculatorService), binding, "").Behaviors.Add(new WebHttpBehavior());
host.Open();
Console.WriteLine("Host opened");
WebClient c = new WebClient();
Console.WriteLine(c.DownloadString(baseAddress + "/Add?x=5&y=8&callback=Func"));
CustomBinding clientBinding = new CustomBinding(
new JsonpAwareClientMessageEncodingBindingElement(),
new HttpTransportBindingElement { ManualAddressing = true });
ChannelFactory<ICalculator> factory = new ChannelFactory<ICalculator>(clientBinding, new EndpointAddress(baseAddress));
factory.Endpoint.Behaviors.Add(new WebHttpBehavior());
ICalculator proxy = factory.CreateChannel();
Console.WriteLine(proxy.Subtract(456, 432));
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}

There is no direct way which I know but lets first try to understand difference between a JSON and JSONP
//JSON
{"prop":"val"}
//JSONP
func({"prop":"val"});
To get the JSON string you could simply strip every thing in between the "(" and ")" braces and then use different JSON libraries to convert it in to objects.
string jsonString = Regex.Match(jsonpString, #"\(([^)]*)\)").Groups[1].Value

Related

WCF REST read URL-encoded response

I'm trying to use WCF to consume a 3rd-party REST service which responds with URL-encoded data:
a=1&b=2&c=3
I have this now:
[DataContract]
class Response {
[DataMember(Name="a")]
public int A { get;set;}
[DataMember(Name="b")]
public int B { get;set;}
[DataMember(Name="c")]
public int C { get;set;}
}
[ServiceContract]
interface IService
{
[OperationContract]
Response Foo();
}
But it comes back with:
There was an error checking start element of object of type Response. The data at the root level is invalid. Line 1, position 1.
WCF does not "understand" forms-data content type (application/x-www-forms-urlencoded), so it won't be able to read that response directly. You can either implement a message formatter which will be able to convert that format into your contract, or you can receive the response as a Stream (which will give you the full bytes of the response), which you can decode into your class.
The code below shows how you could implement a formatter for this operation. It's not generic, but you should get the picture of what needs to be done.
public class StackOverflow_16493746
{
[ServiceContract]
public class Service
{
[WebGet(UriTemplate = "*")]
public Stream GetData()
{
WebOperationContext.Current.OutgoingResponse.ContentType = "application/x-www-form-urlencoded";
return new MemoryStream(Encoding.UTF8.GetBytes("a=1&b=2&c=3"));
}
}
[ServiceContract]
interface IService
{
[WebGet]
Response Foo();
}
[DataContract]
class Response
{
[DataMember(Name = "a")]
public int A { get; set; }
[DataMember(Name = "b")]
public int B { get; set; }
[DataMember(Name = "c")]
public int C { get; set; }
}
public class MyResponseFormatter : IClientMessageFormatter
{
private IClientMessageFormatter originalFormatter;
public MyResponseFormatter(IClientMessageFormatter originalFormatter)
{
this.originalFormatter = originalFormatter;
}
public object DeserializeReply(Message message, object[] parameters)
{
HttpResponseMessageProperty httpResp = (HttpResponseMessageProperty)
message.Properties[HttpResponseMessageProperty.Name];
if (httpResp.Headers[HttpResponseHeader.ContentType] == "application/x-www-form-urlencoded")
{
if (parameters.Length > 0)
{
throw new InvalidOperationException("out/ref parameters not supported in this formatter");
}
byte[] bodyBytes = message.GetReaderAtBodyContents().ReadElementContentAsBase64();
NameValueCollection pairs = HttpUtility.ParseQueryString(Encoding.UTF8.GetString(bodyBytes));
Response result = new Response();
foreach (var key in pairs.AllKeys)
{
string value = pairs[key];
switch (key)
{
case "a":
result.A = int.Parse(value);
break;
case "b":
result.B = int.Parse(value);
break;
case "c":
result.C = int.Parse(value);
break;
}
}
return result;
}
else
{
return this.originalFormatter.DeserializeReply(message, parameters);
}
}
public Message SerializeRequest(MessageVersion messageVersion, object[] parameters)
{
throw new NotSupportedException("This is a reply-only formatter");
}
}
public class MyClientBehavior : WebHttpBehavior
{
protected override IClientMessageFormatter GetReplyClientFormatter(OperationDescription operationDescription, ServiceEndpoint endpoint)
{
return new MyResponseFormatter(base.GetReplyClientFormatter(operationDescription, endpoint));
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
WebServiceHost host = new WebServiceHost(typeof(Service), new Uri(baseAddress));
host.Open();
Console.WriteLine("Host opened");
ChannelFactory<IService> factory = new ChannelFactory<IService>(new WebHttpBinding(), new EndpointAddress(baseAddress));
factory.Endpoint.Behaviors.Add(new MyClientBehavior());
IService proxy = factory.CreateChannel();
Response resp = proxy.Foo();
Console.WriteLine("a={0},b={1},c={2}", resp.A, resp.B, resp.C);
((IClientChannel)proxy).Close();
factory.Close();
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}

Microsoft.Samples.GZipEncoder with [WebGet(ResponseFormat=WebMessageFormat.Json]?

With the help of this question and this post I've managed to get WebHttpBinding to work with compression (by means of copy-pasting the code). When pointing the browser to my service method, it downloads a file which I can rename to .zip and decompress, so the compression part works. But I'm not able to use Json instead of XML. When I add the webget attribute to the method I just get "[Fiddler] ReadResponse() failed: The server did not return a response for this request."
Also the GZipMessageEncoder.WriteMessage isn't even called. What do I need to change in order to get this working with Json ?
Thanks.
From the post on MSDN, you'd also need to override the MessageEncoder.IsContentTypeSupported to make sure that the gzip encoder also accepts JSON.
The code below has the modified version of that code. I also added a message inspector to add a Content-Encoding header, which will allow the browsers to understand the data as-is.
public class StackOverflow_14602036
{
[DataContract]
public class MyDC
{
[DataMember]
public string str;
[DataMember]
public int[] intArray;
public static MyDC CreateLargeInstance(int size)
{
Random rndGen = new Random(1);
StringBuilder sb = new StringBuilder();
MyDC result = new MyDC();
for (int i = 0; i < size; i++)
{
sb.Append((char)rndGen.Next('a', 'z'));
}
result.str = sb.ToString();
result.intArray = new int[size];
for (int i = 0; i < size; i++)
{
result.intArray[i] = rndGen.Next();
}
return result;
}
}
[ServiceContract]
public interface ITest
{
[WebGet(ResponseFormat = WebMessageFormat.Json)]
MyDC GetLargeData(int size);
}
public class Service : ITest
{
public MyDC GetLargeData(int size)
{
return MyDC.CreateLargeInstance(size);
}
}
#region Gzip Encoder Sample
//This class is used to create the custom encoder (GZipMessageEncoder)
internal class GZipMessageEncoderFactory : MessageEncoderFactory
{
MessageEncoder encoder;
//The GZip encoder wraps an inner encoder
//We require a factory to be passed in that will create this inner encoder
public GZipMessageEncoderFactory(MessageEncoderFactory messageEncoderFactory)
{
if (messageEncoderFactory == null)
throw new ArgumentNullException("messageEncoderFactory", "A valid message encoder factory must be passed to the GZipEncoder");
encoder = new GZipMessageEncoder(messageEncoderFactory.Encoder);
}
//The service framework uses this property to obtain an encoder from this encoder factory
public override MessageEncoder Encoder
{
get { return encoder; }
}
public override MessageVersion MessageVersion
{
get { return encoder.MessageVersion; }
}
//This is the actual GZip encoder
class GZipMessageEncoder : MessageEncoder
{
static string GZipContentType = "application/x-gzip";
//This implementation wraps an inner encoder that actually converts a WCF Message
//into textual XML, binary XML or some other format. This implementation then compresses the results.
//The opposite happens when reading messages.
//This member stores this inner encoder.
MessageEncoder innerEncoder;
//We require an inner encoder to be supplied (see comment above)
internal GZipMessageEncoder(MessageEncoder messageEncoder)
: base()
{
if (messageEncoder == null)
throw new ArgumentNullException("messageEncoder", "A valid message encoder must be passed to the GZipEncoder");
innerEncoder = messageEncoder;
}
//public override string CharSet
//{
// get { return ""; }
//}
public override string ContentType
{
get { return GZipContentType; }
}
public override string MediaType
{
get { return GZipContentType; }
}
//SOAP version to use - we delegate to the inner encoder for this
public override MessageVersion MessageVersion
{
get { return innerEncoder.MessageVersion; }
}
public override bool IsContentTypeSupported(string contentType)
{
return this.innerEncoder.IsContentTypeSupported(contentType);
}
//Helper method to compress an array of bytes
static ArraySegment<byte> CompressBuffer(ArraySegment<byte> buffer, BufferManager bufferManager, int messageOffset)
{
MemoryStream memoryStream = new MemoryStream();
memoryStream.Write(buffer.Array, 0, messageOffset);
using (GZipStream gzStream = new GZipStream(memoryStream, CompressionMode.Compress, true))
{
gzStream.Write(buffer.Array, messageOffset, buffer.Count);
}
byte[] compressedBytes = memoryStream.ToArray();
byte[] bufferedBytes = bufferManager.TakeBuffer(compressedBytes.Length);
Array.Copy(compressedBytes, 0, bufferedBytes, 0, compressedBytes.Length);
bufferManager.ReturnBuffer(buffer.Array);
ArraySegment<byte> byteArray = new ArraySegment<byte>(bufferedBytes, messageOffset, compressedBytes.Length - messageOffset);
return byteArray;
}
//Helper method to decompress an array of bytes
static ArraySegment<byte> DecompressBuffer(ArraySegment<byte> buffer, BufferManager bufferManager)
{
MemoryStream memoryStream = new MemoryStream(buffer.Array, buffer.Offset, buffer.Count - buffer.Offset);
MemoryStream decompressedStream = new MemoryStream();
int totalRead = 0;
int blockSize = 1024;
byte[] tempBuffer = bufferManager.TakeBuffer(blockSize);
using (GZipStream gzStream = new GZipStream(memoryStream, CompressionMode.Decompress))
{
while (true)
{
int bytesRead = gzStream.Read(tempBuffer, 0, blockSize);
if (bytesRead == 0)
break;
decompressedStream.Write(tempBuffer, 0, bytesRead);
totalRead += bytesRead;
}
}
bufferManager.ReturnBuffer(tempBuffer);
byte[] decompressedBytes = decompressedStream.ToArray();
byte[] bufferManagerBuffer = bufferManager.TakeBuffer(decompressedBytes.Length + buffer.Offset);
Array.Copy(buffer.Array, 0, bufferManagerBuffer, 0, buffer.Offset);
Array.Copy(decompressedBytes, 0, bufferManagerBuffer, buffer.Offset, decompressedBytes.Length);
ArraySegment<byte> byteArray = new ArraySegment<byte>(bufferManagerBuffer, buffer.Offset, decompressedBytes.Length);
bufferManager.ReturnBuffer(buffer.Array);
return byteArray;
}
//One of the two main entry points into the encoder. Called by WCF to decode a buffered byte array into a Message.
public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
{
//Decompress the buffer
ArraySegment<byte> decompressedBuffer = DecompressBuffer(buffer, bufferManager);
//Use the inner encoder to decode the decompressed buffer
Message returnMessage = innerEncoder.ReadMessage(decompressedBuffer, bufferManager);
returnMessage.Properties.Encoder = this;
return returnMessage;
}
//One of the two main entry points into the encoder. Called by WCF to encode a Message into a buffered byte array.
public override ArraySegment<byte> WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset)
{
//Use the inner encoder to encode a Message into a buffered byte array
ArraySegment<byte> buffer = innerEncoder.WriteMessage(message, maxMessageSize, bufferManager, messageOffset);
//Compress the resulting byte array
return CompressBuffer(buffer, bufferManager, messageOffset);
}
public override Message ReadMessage(System.IO.Stream stream, int maxSizeOfHeaders, string contentType)
{
GZipStream gzStream = new GZipStream(stream, CompressionMode.Decompress, true);
return innerEncoder.ReadMessage(gzStream, maxSizeOfHeaders);
}
public override void WriteMessage(Message message, System.IO.Stream stream)
{
using (GZipStream gzStream = new GZipStream(stream, CompressionMode.Compress, true))
{
innerEncoder.WriteMessage(message, gzStream);
}
// innerEncoder.WriteMessage(message, gzStream) depends on that it can flush data by flushing
// the stream passed in, but the implementation of GZipStream.Flush will not flush underlying
// stream, so we need to flush here.
stream.Flush();
}
}
}
// This is constants for GZip message encoding policy.
static class GZipMessageEncodingPolicyConstants
{
public const string GZipEncodingName = "GZipEncoding";
public const string GZipEncodingNamespace = "http://schemas.microsoft.com/ws/06/2004/mspolicy/netgzip1";
public const string GZipEncodingPrefix = "gzip";
}
//This is the binding element that, when plugged into a custom binding, will enable the GZip encoder
public sealed class GZipMessageEncodingBindingElement
: MessageEncodingBindingElement //BindingElement
, IPolicyExportExtension
{
//We will use an inner binding element to store information required for the inner encoder
MessageEncodingBindingElement innerBindingElement;
//By default, use the default text encoder as the inner encoder
public GZipMessageEncodingBindingElement()
: this(new TextMessageEncodingBindingElement()) { }
public GZipMessageEncodingBindingElement(MessageEncodingBindingElement messageEncoderBindingElement)
{
this.innerBindingElement = messageEncoderBindingElement;
}
public MessageEncodingBindingElement InnerMessageEncodingBindingElement
{
get { return innerBindingElement; }
set { innerBindingElement = value; }
}
//Main entry point into the encoder binding element. Called by WCF to get the factory that will create the
//message encoder
public override MessageEncoderFactory CreateMessageEncoderFactory()
{
return new GZipMessageEncoderFactory(innerBindingElement.CreateMessageEncoderFactory());
}
public override MessageVersion MessageVersion
{
get { return innerBindingElement.MessageVersion; }
set { innerBindingElement.MessageVersion = value; }
}
public override BindingElement Clone()
{
return new GZipMessageEncodingBindingElement(this.innerBindingElement);
}
public override T GetProperty<T>(BindingContext context)
{
if (typeof(T) == typeof(XmlDictionaryReaderQuotas))
{
return innerBindingElement.GetProperty<T>(context);
}
else
{
return base.GetProperty<T>(context);
}
}
public override IChannelFactory<TChannel> BuildChannelFactory<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.BuildInnerChannelFactory<TChannel>();
}
public override IChannelListener<TChannel> BuildChannelListener<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.BuildInnerChannelListener<TChannel>();
}
public override bool CanBuildChannelListener<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.CanBuildInnerChannelListener<TChannel>();
}
void IPolicyExportExtension.ExportPolicy(MetadataExporter exporter, PolicyConversionContext policyContext)
{
if (policyContext == null)
{
throw new ArgumentNullException("policyContext");
}
XmlDocument document = new XmlDocument();
policyContext.GetBindingAssertions().Add(document.CreateElement(
GZipMessageEncodingPolicyConstants.GZipEncodingPrefix,
GZipMessageEncodingPolicyConstants.GZipEncodingName,
GZipMessageEncodingPolicyConstants.GZipEncodingNamespace));
}
}
#endregion
static Binding GetBinding()
{
CustomBinding custom = new CustomBinding(new WebHttpBinding());
for (int i = 0; i < custom.Elements.Count; i++)
{
if (custom.Elements[i] is WebMessageEncodingBindingElement)
{
WebMessageEncodingBindingElement webBE = (WebMessageEncodingBindingElement)custom.Elements[i];
custom.Elements[i] = new GZipMessageEncodingBindingElement(webBE);
break;
}
}
return custom;
}
class MyContentEncodingBehavior : IEndpointBehavior, IDispatchMessageInspector
{
public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
}
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(this);
}
public void Validate(ServiceEndpoint endpoint)
{
}
public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
return null;
}
public void BeforeSendReply(ref Message reply, object correlationState)
{
HttpResponseMessageProperty resp = (HttpResponseMessageProperty)reply.Properties[HttpResponseMessageProperty.Name];
resp.Headers[HttpResponseHeader.ContentEncoding] = "gzip";
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
var endpoint = host.AddServiceEndpoint(typeof(ITest), GetBinding(), "");
endpoint.Behaviors.Add(new WebHttpBehavior());
endpoint.Behaviors.Add(new MyContentEncodingBehavior());
host.Open();
Console.WriteLine("Host opened");
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(baseAddress + "/GetLargeData?size=1000");
HttpWebResponse resp;
try
{
resp = (HttpWebResponse)req.GetResponse();
}
catch (WebException ex)
{
resp = (HttpWebResponse)ex.Response;
}
Console.WriteLine("HTTP/{0} {1} {2}", resp.ProtocolVersion, (int)resp.StatusCode, resp.StatusDescription);
foreach (var header in resp.Headers.AllKeys)
{
Console.WriteLine("{0}: {1}", header, resp.Headers[header]);
}
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}

Implementing RequestWrapper for RESTful WCF service

I've written a simple object called RequestWrapper that contains single method of type:
TResult WrapRequest<TResult>(Func<TResult> action)
It wraps any action with try..catch, error handling, logging, database connection, transaction (commit & rollback), etc.
Currently I use it like this: (example, not production code)
return RequestWrapper.WrapRequest(() =>
{
Topic entity = GetRepository<Topic>().Find(uid);
if (entity == null)
throw new EntityNotFoundException("Topic not found.");
return new Topic
{
Name = entity.Name,
Posts = entity.Posts.Select(x => new Post
{
Body = x.Body,
}).ToList()
};
});
I simply wrap around every method of my RESTful web service (using WCF and WebHttpBinding).
My question is: How should I implement behavior that would do the wrapping for me automatically? Is it possible?
You can use a custom IOperationInvoker which wraps the original one does what you need. The code below shows a sample implementation of one, and you can find more information about invokers at http://blogs.msdn.com/b/carlosfigueira/archive/2011/05/17/wcf-extensibility-ioperationinvoker.aspx.
public class StackOverflow_10156890
{
[ServiceContract]
public interface ITest
{
[WebGet]
[WrappedOperationBehavior]
string Echo(string text);
[WebInvoke(BodyStyle = WebMessageBodyStyle.WrappedRequest)]
[WrappedOperationBehavior]
int Divide(int x, int y);
}
public class Service : ITest
{
public string Echo(string text)
{
return text;
}
public int Divide(int x, int y)
{
return x / y;
}
}
class RequestWrapperOperationInvoker : IOperationInvoker
{
IOperationInvoker originalInvoker;
public RequestWrapperOperationInvoker(IOperationInvoker originalInvoker)
{
this.originalInvoker = originalInvoker;
}
public object[] AllocateInputs()
{
return this.originalInvoker.AllocateInputs();
}
public object Invoke(object instance, object[] inputs, out object[] outputs)
{
Console.WriteLine("Do initialization, etc. here");
object result = null;
try
{
result = this.originalInvoker.Invoke(instance, inputs, out outputs);
}
catch (Exception e)
{
Console.WriteLine("Log exception: {0}: {1}", e.GetType().FullName, e.Message);
result = null;
outputs = null;
}
finally
{
Console.WriteLine("Do finalization, etc. here");
}
return result;
}
public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state)
{
throw new NotSupportedException("Only synchronous operations supported");
}
public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result)
{
throw new NotSupportedException("Only synchronous operations supported");
}
public bool IsSynchronous
{
get { return true; }
}
}
class WrappedOperationBehaviorAttribute : Attribute, IOperationBehavior
{
public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation)
{
}
public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation)
{
dispatchOperation.Invoker = new RequestWrapperOperationInvoker(dispatchOperation.Invoker);
}
public void Validate(OperationDescription operationDescription)
{
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
var endpoint = host.AddServiceEndpoint(typeof(ITest), new WebHttpBinding(), "");
endpoint.Behaviors.Add(new WebHttpBehavior());
host.Open();
Console.WriteLine("Host opened");
WebClient c = new WebClient();
Console.WriteLine(c.DownloadString(baseAddress + "/Echo?text=Hello%20world"));
c = new WebClient();
c.Headers[HttpRequestHeader.ContentType] = "application/json";
Console.WriteLine(c.UploadString(baseAddress + "/Divide", "{\"x\":12,\"y\":0}"));
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}

Using ISO-8859-1 encoding between WCF and Oracle/Linux

I have a WCF service that send/receives data and work perfectly with all my utf-8 clients.
But, one of my customers is trying to access this service with a Oracle 9i/Linux call, that works with ISO-8859-1 encoding, and we are having problems with special characters.
I can't use this suggested solution, since the client is Linux and cannot install DLLs.
Based on this scenario, can anyone please suggest me another solution (wich can involve changes in the client, in the service or in both)?
Thanks in advance.
That solution (using the CustomTextEncoder) should work in your scenario as well? The linux client can continue sending the data as it pleases (i.e., in iso-8859-1), and the encoder, used on the server only, would be able to read it. The encoder then can decide how to encode the response back to the client (UTF-8 or iso-8859-1 again).
If you want the response to be in iso-8859-1 as well you may also need something like a message inspector to update the content-type header with the appropriate charset.
Update: example with the custom encoder using ISO-8859-1
public class StackOverflow_7033442
{
[ServiceContract]
public interface ITest
{
[OperationContract]
string Echo(string text);
}
public class Service : ITest
{
public string Echo(string text)
{
return text;
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
CustomBinding binding = new CustomBinding(
new CustomTextMessageBindingElement("iso-8859-1", "text/xml", MessageVersion.Soap11),
new HttpTransportBindingElement());
host.AddServiceEndpoint(typeof(ITest), binding, "");
host.Open();
Console.WriteLine("Host opened");
string request = #"<?xml version=""1.0"" encoding=""iso-8859-1""?>
<s:Envelope xmlns:s=""http://schemas.xmlsoap.org/soap/envelope/"">
<s:Body>
<Echo xmlns=""http://tempuri.org/"">
<text>Hello áéíóú</text>
</Echo>
</s:Body>
</s:Envelope>";
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(baseAddress);
req.Method = "POST";
req.ContentType = "text/xml; charset=iso-8859-1";
req.Headers["SOAPAction"] = "http://tempuri.org/ITest/Echo";
Stream reqStream = req.GetRequestStream();
Encoding encoding = Encoding.GetEncoding("iso-8859-1");
byte[] reqBytes = encoding.GetBytes(request);
reqStream.Write(reqBytes, 0, reqBytes.Length);
reqStream.Close();
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
Console.WriteLine("HTTP/{0} {1} {2}", resp.ProtocolVersion, (int)resp.StatusCode, resp.StatusDescription);
foreach (var header in resp.Headers.AllKeys)
{
Console.WriteLine("{0}: {1}", header, resp.Headers[header]);
}
if (resp.ContentLength > 0)
{
Console.WriteLine(new StreamReader(resp.GetResponseStream(), encoding).ReadToEnd());
}
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
#region Custom Text Message Encoder sample, verbatim
public class CustomTextMessageEncoder : MessageEncoder
{
private CustomTextMessageEncoderFactory factory;
private XmlWriterSettings writerSettings;
private string contentType;
public CustomTextMessageEncoder(CustomTextMessageEncoderFactory factory)
{
this.factory = factory;
this.writerSettings = new XmlWriterSettings();
this.writerSettings.Encoding = Encoding.GetEncoding(factory.CharSet);
this.contentType = string.Format("{0}; charset={1}",
this.factory.MediaType, this.writerSettings.Encoding.HeaderName);
}
public override string ContentType
{
get
{
return this.contentType;
}
}
public override string MediaType
{
get
{
return factory.MediaType;
}
}
public override MessageVersion MessageVersion
{
get
{
return this.factory.MessageVersion;
}
}
public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
{
byte[] msgContents = new byte[buffer.Count];
Array.Copy(buffer.Array, buffer.Offset, msgContents, 0, msgContents.Length);
bufferManager.ReturnBuffer(buffer.Array);
MemoryStream stream = new MemoryStream(msgContents);
return ReadMessage(stream, int.MaxValue);
}
public override Message ReadMessage(Stream stream, int maxSizeOfHeaders, string contentType)
{
XmlReader reader = XmlReader.Create(stream);
return Message.CreateMessage(reader, maxSizeOfHeaders, this.MessageVersion);
}
public override ArraySegment<byte> WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset)
{
MemoryStream stream = new MemoryStream();
XmlWriter writer = XmlWriter.Create(stream, this.writerSettings);
message.WriteMessage(writer);
writer.Close();
byte[] messageBytes = stream.GetBuffer();
int messageLength = (int)stream.Position;
stream.Close();
int totalLength = messageLength + messageOffset;
byte[] totalBytes = bufferManager.TakeBuffer(totalLength);
Array.Copy(messageBytes, 0, totalBytes, messageOffset, messageLength);
ArraySegment<byte> byteArray = new ArraySegment<byte>(totalBytes, messageOffset, messageLength);
return byteArray;
}
public override void WriteMessage(Message message, Stream stream)
{
XmlWriter writer = XmlWriter.Create(stream, this.writerSettings);
message.WriteMessage(writer);
writer.Close();
}
}
public class CustomTextMessageEncoderFactory : MessageEncoderFactory
{
private MessageEncoder encoder;
private MessageVersion version;
private string mediaType;
private string charSet;
internal CustomTextMessageEncoderFactory(string mediaType, string charSet,
MessageVersion version)
{
this.version = version;
this.mediaType = mediaType;
this.charSet = charSet;
this.encoder = new CustomTextMessageEncoder(this);
}
public override MessageEncoder Encoder
{
get
{
return this.encoder;
}
}
public override MessageVersion MessageVersion
{
get
{
return this.version;
}
}
internal string MediaType
{
get
{
return this.mediaType;
}
}
internal string CharSet
{
get
{
return this.charSet;
}
}
}
public class CustomTextMessageBindingElement : MessageEncodingBindingElement, IWsdlExportExtension
{
private MessageVersion msgVersion;
private string mediaType;
private string encoding;
private XmlDictionaryReaderQuotas readerQuotas;
CustomTextMessageBindingElement(CustomTextMessageBindingElement binding)
: this(binding.Encoding, binding.MediaType, binding.MessageVersion)
{
this.readerQuotas = new XmlDictionaryReaderQuotas();
binding.ReaderQuotas.CopyTo(this.readerQuotas);
}
public CustomTextMessageBindingElement(string encoding, string mediaType,
MessageVersion msgVersion)
{
if (encoding == null)
throw new ArgumentNullException("encoding");
if (mediaType == null)
throw new ArgumentNullException("mediaType");
if (msgVersion == null)
throw new ArgumentNullException("msgVersion");
this.msgVersion = msgVersion;
this.mediaType = mediaType;
this.encoding = encoding;
this.readerQuotas = new XmlDictionaryReaderQuotas();
}
public CustomTextMessageBindingElement(string encoding, string mediaType)
: this(encoding, mediaType, MessageVersion.Soap11WSAddressing10)
{
}
public CustomTextMessageBindingElement(string encoding)
: this(encoding, "text/xml")
{
}
public CustomTextMessageBindingElement()
: this("UTF-8")
{
}
public override MessageVersion MessageVersion
{
get
{
return this.msgVersion;
}
set
{
if (value == null)
throw new ArgumentNullException("value");
this.msgVersion = value;
}
}
public string MediaType
{
get
{
return this.mediaType;
}
set
{
if (value == null)
throw new ArgumentNullException("value");
this.mediaType = value;
}
}
public string Encoding
{
get
{
return this.encoding;
}
set
{
if (value == null)
throw new ArgumentNullException("value");
this.encoding = value;
}
}
// This encoder does not enforces any quotas for the unsecure messages. The
// quotas are enforced for the secure portions of messages when this encoder
// is used in a binding that is configured with security.
public XmlDictionaryReaderQuotas ReaderQuotas
{
get
{
return this.readerQuotas;
}
}
#region IMessageEncodingBindingElement Members
public override MessageEncoderFactory CreateMessageEncoderFactory()
{
return new CustomTextMessageEncoderFactory(this.MediaType,
this.Encoding, this.MessageVersion);
}
#endregion
public override BindingElement Clone()
{
return new CustomTextMessageBindingElement(this);
}
public override IChannelFactory<TChannel> BuildChannelFactory<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.BuildInnerChannelFactory<TChannel>();
}
public override bool CanBuildChannelFactory<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
return context.CanBuildInnerChannelFactory<TChannel>();
}
public override IChannelListener<TChannel> BuildChannelListener<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.BuildInnerChannelListener<TChannel>();
}
public override bool CanBuildChannelListener<TChannel>(BindingContext context)
{
if (context == null)
throw new ArgumentNullException("context");
context.BindingParameters.Add(this);
return context.CanBuildInnerChannelListener<TChannel>();
}
public override T GetProperty<T>(BindingContext context)
{
if (typeof(T) == typeof(XmlDictionaryReaderQuotas))
{
return (T)(object)this.readerQuotas;
}
else
{
return base.GetProperty<T>(context);
}
}
#region IWsdlExportExtension Members
void IWsdlExportExtension.ExportContract(WsdlExporter exporter, WsdlContractConversionContext context)
{
}
void IWsdlExportExtension.ExportEndpoint(WsdlExporter exporter, WsdlEndpointConversionContext context)
{
// The MessageEncodingBindingElement is responsible for ensuring that the WSDL has the correct
// SOAP version. We can delegate to the WCF implementation of TextMessageEncodingBindingElement for this.
TextMessageEncodingBindingElement mebe = new TextMessageEncodingBindingElement();
mebe.MessageVersion = this.msgVersion;
((IWsdlExportExtension)mebe).ExportEndpoint(exporter, context);
}
#endregion
}
#endregion
}

How do I implement Orchestration on WCF using MessageInspector

I have a WCF Service, And I inspect that using MessageInspector ( inherit IDispatchMessageInspector)
I want to do some thing before running service and result of that ı want not run service.
I want to prevent client call but client dont receive exception.
Can you help me
This scenario looks like the post in the MSDN WCF forum entitled "IDispatchMessageInspector.AfterReceiveRequest - skip operation and manually generate custom response instead". If this is what you need (when you receive a message in the inspector, you decide that you want to skip the service operation, but return a message to the client and the client should not see an exception), then this answer should work for you as well. Notice that you'll need to create the response message in the same format as the client expects, otherwise you'll have an exception.
This code uses three of the (many) WCF extensibility points to achieve that scenario, a message inspector (as you've mentioned you're using), a message formatter and an operation invoker. I've blogged about them in an ongoing series about WCF extensibility at http://blogs.msdn.com/b/carlosfigueira/archive/2011/03/14/wcf-extensibility.aspx.
public class Post_55ef7692_25dc_4ece_9dde_9981c417c94a
{
[ServiceContract(Name = "ITest", Namespace = "http://tempuri.org/")]
public interface ITest
{
[OperationContract]
string Echo(string text);
}
public class Service : ITest
{
public string Echo(string text)
{
return text;
}
}
static Binding GetBinding()
{
BasicHttpBinding result = new BasicHttpBinding();
return result;
}
public class MyOperationBypasser : IEndpointBehavior, IOperationBehavior
{
internal const string SkipServerMessageProperty = "SkipServer";
public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
}
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new MyInspector(endpoint));
}
public void Validate(ServiceEndpoint endpoint)
{
}
public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation)
{
}
public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation)
{
dispatchOperation.Formatter = new MyFormatter(dispatchOperation.Formatter);
dispatchOperation.Invoker = new MyInvoker(dispatchOperation.Invoker);
}
public void Validate(OperationDescription operationDescription)
{
}
class MyInspector : IDispatchMessageInspector
{
ServiceEndpoint endpoint;
public MyInspector(ServiceEndpoint endpoint)
{
this.endpoint = endpoint;
}
public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
Message result = null;
HttpRequestMessageProperty reqProp = null;
if (request.Properties.ContainsKey(HttpRequestMessageProperty.Name))
{
reqProp = request.Properties[HttpRequestMessageProperty.Name] as HttpRequestMessageProperty;
}
if (reqProp != null)
{
string bypassServer = reqProp.Headers["X-BypassServer"];
if (!string.IsNullOrEmpty(bypassServer))
{
result = Message.CreateMessage(request.Version, this.FindReplyAction(request.Headers.Action), new OverrideBodyWriter(bypassServer));
}
}
return result;
}
public void BeforeSendReply(ref Message reply, object correlationState)
{
Message newResult = correlationState as Message;
if (newResult != null)
{
reply = newResult;
}
}
private string FindReplyAction(string requestAction)
{
foreach (var operation in this.endpoint.Contract.Operations)
{
if (operation.Messages[0].Action == requestAction)
{
return operation.Messages[1].Action;
}
}
return null;
}
class OverrideBodyWriter : BodyWriter
{
string bypassServerHeader;
public OverrideBodyWriter(string bypassServerHeader)
: base(true)
{
this.bypassServerHeader = bypassServerHeader;
}
protected override void OnWriteBodyContents(XmlDictionaryWriter writer)
{
writer.WriteStartElement("EchoResponse", "http://tempuri.org/");
writer.WriteStartElement("EchoResult");
writer.WriteString(this.bypassServerHeader);
writer.WriteEndElement();
writer.WriteEndElement();
}
}
}
class MyFormatter : IDispatchMessageFormatter
{
IDispatchMessageFormatter originalFormatter;
public MyFormatter(IDispatchMessageFormatter originalFormatter)
{
this.originalFormatter = originalFormatter;
}
public void DeserializeRequest(Message message, object[] parameters)
{
if (message.Properties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
Message returnMessage = message.Properties[MyOperationBypasser.SkipServerMessageProperty] as Message;
OperationContext.Current.IncomingMessageProperties.Add(MyOperationBypasser.SkipServerMessageProperty, returnMessage);
OperationContext.Current.OutgoingMessageProperties.Add(MyOperationBypasser.SkipServerMessageProperty, returnMessage);
}
else
{
this.originalFormatter.DeserializeRequest(message, parameters);
}
}
public Message SerializeReply(MessageVersion messageVersion, object[] parameters, object result)
{
if (OperationContext.Current.OutgoingMessageProperties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
return null;
}
else
{
return this.originalFormatter.SerializeReply(messageVersion, parameters, result);
}
}
}
class MyInvoker : IOperationInvoker
{
IOperationInvoker originalInvoker;
public MyInvoker(IOperationInvoker originalInvoker)
{
if (!originalInvoker.IsSynchronous)
{
throw new NotSupportedException("This implementation only supports synchronous invokers");
}
this.originalInvoker = originalInvoker;
}
public object[] AllocateInputs()
{
return this.originalInvoker.AllocateInputs();
}
public object Invoke(object instance, object[] inputs, out object[] outputs)
{
if (OperationContext.Current.IncomingMessageProperties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
outputs = null;
return null; // message is stored in the context
}
else
{
return this.originalInvoker.Invoke(instance, inputs, out outputs);
}
}
public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state)
{
throw new NotSupportedException();
}
public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result)
{
throw new NotSupportedException();
}
public bool IsSynchronous
{
get { return true; }
}
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(ITest), GetBinding(), "");
endpoint.Behaviors.Add(new MyOperationBypasser());
foreach (var operation in endpoint.Contract.Operations)
{
operation.Behaviors.Add(new MyOperationBypasser());
}
host.Open();
Console.WriteLine("Host opened");
ChannelFactory<ITest> factory = new ChannelFactory<ITest>(GetBinding(), new EndpointAddress(baseAddress));
ITest proxy = factory.CreateChannel();
Console.WriteLine(proxy.Echo("Hello"));
Console.WriteLine("And now with the bypass header");
using (new OperationContextScope((IContextChannel)proxy))
{
HttpRequestMessageProperty httpRequestProp = new HttpRequestMessageProperty();
httpRequestProp.Headers.Add("X-BypassServer", "This message will not reach the service operation");
OperationContext.Current.OutgoingMessageProperties.Add(
HttpRequestMessageProperty.Name,
httpRequestProp);
Console.WriteLine(proxy.Echo("Hello"));
}
((IClientChannel)proxy).Close();
factory.Close();
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}