i'm having some problems implementing my WCF message interceptor. Basically i'm accessing the body contents and performing an xslt tranform over the nodeset to sort it alphabethicaly.
I've tested the XSLT stylesheet and it's working no problems. I write the result of the transform to a MemoryStream object and then attempt to recreate the message from the stream contents.
I examine the resulting stream using either a StreamReader or by loading it into an XmlDocument and i can see the the xml it contains it my expected result from the XSLT transform.
My problem occures when i try to recreate the message! I create an XmlReader based on the stream and use this as my body source for Message.CreateMessage(.....);
I cannot understand why i'm suddenly losing the "correct" contents in the stream when i could examine it and see a couple of statements earlier.
Help very much appreciated!
Full code of the method below:
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, IClientChannel channel, InstanceContext instanceContext)
{
MessageBuffer msgbuf = request.CreateBufferedCopy(int.MaxValue);
Message tmpMessage = msgbuf.CreateMessage();
XmlDictionaryReader xdr = tmpMessage.GetReaderAtBodyContents();
MemoryStream ms = new MemoryStream();
_compiledTransform.Transform(xdr,null,ms);
ms.Position = 0;
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(ms);
MemoryStream newStream = new MemoryStream();
xmlDoc.Save(newStream);
newStream.Position = 0;
//To debug contents of the stream
StreamReader sr = new StreamReader(newStream);
var temp = sr.ReadToEnd();
//At this point the XSLT tranforms has resulted in the fragment we want so all good!
XmlReaderSettings settings = new XmlReaderSettings();
settings.ConformanceLevel = ConformanceLevel.Fragment;
newStream.Position = 0;
XmlReader reader = XmlReader.Create(newStream,settings);
reader.MoveToContent();
//Reader seems to have lost the correct fragment!!! At least returned message does not contain correct fragment.
Message newMessage = Message.CreateMessage(request.Version, null, reader);
newMessage.Properties.CopyProperties(request.Properties);
request = newMessage;
return request;
}
I think your code works Griff. I've just plugged it into an existing an existing IDispatchMessageInspector implementation and it generated a good (transformed) message. I therefore suspect your problem lies elsewhere.
How are you establishing that the 'losing' the correct contents? Could whatever is inspecting the transformed message be reading the message prior to transformation by mistake?
Unless you are trying to correlate state with the BeforeSendReply method then you should be returning null instead of the request reference.
Related
I have a WCF connected service in a .net core application. I'm using the code that is autogenerated taken the wsdl definition.
Currently at the top of the request xml is including this line:
<?xml version="1.0" encoding="utf-16"?>
I can't find a simple way to change this encoding to UTF-8 when sending the request.
Since I could find a configuration option a the request/client objects, I've tried to change the message with following code at IClientMessageInspector.BeforeSendRequest
public object BeforeSendRequest(ref Message request, IClientChannel channel)
{
// Load a new xml document from current request
var xmlDocument = new XmlDocument();
xmlDocument.LoadXml(request.ToString());
((XmlDeclaration)xmlDocument.FirstChild).Encoding = Encoding.UTF8.HeaderName;
// Create streams to copy
var memoryStream = new MemoryStream();
var xmlWriter = XmlWriter.Create(memoryStream);
xmlDocument.Save(xmlWriter);
xmlWriter.Flush();
xmlWriter.Close();
memoryStream.Position = 0;
var xmlReader = XmlReader.Create(memoryStream);
// Create a new message
var newMessage = Message.CreateMessage(request.Version, null, xmlReader);
newMessage.Headers.CopyHeadersFrom(request);
newMessage.Properties.CopyProperties(request.Properties);
return null;
}
But the newMessage object still writes the xml declaration using utf-16. I can see it while debugging at the watch window since.
Any idea on how to accomplish this (should be) simple change will be very apreciated.
Which binding do you use to create the communication channel? The textmessageencoding element which has been contained in the CustomBinding generally contains TextEncoding property.
https://learn.microsoft.com/en-us/dotnet/framework/configure-apps/file-schema/wcf/textmessageencoding
WriteEncoding property specifies the character set encoding to be used for emitting messages on the binding. Valid values are
UnicodeFffeTextEncoding: Unicode BigEndian encoding
Utf16TextEncoding: Unicode encoding
Utf8TextEncoding: 8-bit encoding
The default is Utf8TextEncoding. This attribute is of type Encoding.
As for the specific binding, it contains the textEncoding property too.
https://learn.microsoft.com/en-us/dotnet/api/system.servicemodel.basichttpbinding.textencoding?view=netframework-4.0
Feel free to let me know if there is anything I can help with.
I'm using the REST API of OneDrive in my WCF Web Service. Everything works well but the Download of a file. I need to get the Stream object of the file downloaded but MemoryStream class gives me an Exception about ReadTimeout and WriteTimeout.
This is the code:
.... some code ....
var rClient = new RestClient("https://apis.live.net/v5.0/");
var rRequest = new RestRequest(rootFile.id + "/content", Method.GET);
rRequest.AddParameter("access_token", data.accessToken);
var rResponse = rClient.Execute(rRequest); // THE RESPONSE IS OK
byte[] array = rResponse.RawBytes;
Stream stream = new MemoryStream(array); // PROBLEM HERE!
return stream;
So when I create the Stream Object the MemoryStream throw 2 Exception on the fields ReadTimeout and WriteTimeout saying that they are not supported for this stream.
I don't know how to solve it
As suggested by Will in the comment, I discovered that the Exception on ReadTimeout and WriteTimeout was not the real problem. The Exception was thrown by a null object in the caller method, after the code posted above.
Below there is the point where the Exception was thrown: the Current object was null.
stream = client.DownloadFile(token);
if (stream != null)
{
**WebOperationContext.Current.OutgoingResponse.ContentType = "text/octet-stream";** //HERE
return stream;
}
I removed the line and everything was fixed
I've implemented a WCF Routing service; I would also like the service (or a similar WCF service) to transform the payload in a prescribed and uniform (content-agnostic) fashion. For example, the payload will always take the form Foo<T> and I would like to pass it on as Bar<T> in all cases. I'm happy for the transformation to be XSLT or programmatic. I don't care what happens to messages received that aren't of the type Foo<T>.
I wish to use WCF as it provides a lot of OOTB functionality (e.g. its support for numerous bindings). It's not practical to implement a WCF service with numerous boilerplate methods to transform each closed generic (Foo<Class1> -> Bar<Class1>; Foo<Class2> -> Bar<Class2>; etc), as this would require recompilation/redeployment every time a new message type was to be routed.
To the best of my knowledge, WCF doesn't handle open generics and WCF Routing doesn't facilitate content transformation OOTB. That said, System.ServiceModel.Routing.RoutingService obviously intercepts WCF calls in some non-specific form, so I was hoping to leverage the same pattern to achieve my goal. Can anyone please provide direction on how to do this (or indicate why it's not possible)?
As I suggested in my comments on the question, there is a solution to this using the IDispatchMessageInspector. Please find below an extremely dumbed-down version of what I ended up writing (easier than me posting the code for 20 classes). If anyone wants a full solution implementing this code in a significantly cleaner and more advanced manner, let me know and I'll put my demo up on CodeProject. For now, I'll presume you're happy with a snippet of the guts.
The Console commands can obvious be removed (they're just so you can debug if you're self-hosting).
public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
if (request == null || request.IsEmpty)
return null;
Console.WriteLine();
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine(request);
Console.ResetColor();
// Load the request into a document.
XPathDocument document;
MemoryStream stream;
using (stream = new MemoryStream())
{
using (XmlDictionaryWriter writer = XmlDictionaryWriter.CreateTextWriter(stream))
{
request.WriteMessage(writer);
writer.Flush();
stream.Position = 0L;
document = new XPathDocument(stream);
}
}
// Load the XSLT.
XslCompiledTransform transformer = new XslCompiledTransform();
transformer.Load("RequestTransformation.xslt");
// Transform the document.
byte[] transformedDocument;
using (stream = new MemoryStream())
{
transformer.Transform(document, null, stream);
transformedDocument = stream.ToArray();
}
// Construct new request from tranformed document.
stream = new MemoryStream(transformedDocument);
XmlReader reader = XmlReader.Create(stream);
Message modifiedMessage = Message.CreateMessage(reader, int.MaxValue, request.Version);
modifiedMessage.Properties.CopyProperties(request.Properties);
request = modifiedMessage;
Console.WriteLine();
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine(new System.Text.UTF8Encoding(false).GetString(transformedDocument));
Console.ResetColor();
return null;
}
I am using the Spring.Rest framework.
If we receive a 402, the body will contain a proto which in turn will contain various error information.
The Exception raised on a 402 is an instance of Spring.Rest.Client.HttpClientErrorException.
The response within the exception is an instance of Spring.HttpResponseMessage.
The Body within the response is of type byte[].
This means I have a byte[] while the Deserialiser is expecting a Stream.
In order to deserialise the proto contained in the body I have done the following:
MemoryStream mStream = new MemoryStream();
mStream.Write(exception.Response.Body,0,exception.Response.Body.Length);
var proto = Serializer.Deserialize<XXXRestProtoException>(mStream);
when I inspect the proto returned, its properties are all null.
Is my approach correct, or do I need to do more before presenting the Stream to the Deserialize method?
We have confirmed that the proto definitions used on Client and Server are in sync and the body is well formed on the server.
The Stream produced by this code has the same length and contents as the given byte[], which in turn matches the content-length header.
If you Write to a stream, then the Position is left at the end of the stream; 2 simple options:
rewind the stream; between the Write and the Deserialize, put:
ms.Position = 0;
initialize the stream from the blob:
MemoryStream mStream = new MemoryStream(exception.Response.Body);
I'd usually use the latter.
Greetings, all. Here is my situation. I am attempting to make an HttpWebRequest to a local handler file and I keep getting the following exception:
Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
Now, I'm using a local handler file because I am writing some integration code for a third party that the site will be using. Until I have a test environment available for me to make requests to, I'm basically mocking the process with a local handler file. Here is the relevant code. Thanks.
WebRequest code (subRequest variable is object passed to the method executing this code):
XmlSerializer serializer;
XmlDocument xmlDoc = null;
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(requestUrl);
webRequest.Method = "POST";
webRequest.ContentType = "text/xml";
webRequest.KeepAlive = true;
webRequest.Accept = "*/*";
serializer = new XmlSerializer(subRequest.GetType());
XmlWriter writer = new XmlTextWriter(webRequest.GetRequestStream(), Encoding.UTF8);
serializer.Serialize(writer, subRequest);
writer.Close();
xmlDoc = new XmlDocument();
xmlDoc.Load(XmlReader.Create(webRequest.GetResponse().GetResponseStream()));
The "requestUrl" is defined as "http://localhost:2718/Handlers/MyHandler.ashx". I can hit the handler file just fine and have stepped through the code. All it does is assemble an XML response as a string and writes it out to the Response object:
context.Response.ContentType = "text/xml";
string newSubscriptionId = Utils.GetUniqueKey();
StringBuilder sb = new StringBuilder();
sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
// Assemble XML string here
context.Response.Write(sb.ToString());
As far as I can tell, this is all working just fine. But when my code hits the last line of the WebRequest chunk:
xmlDoc.Load(XmlReader.Create(webRequest.GetResponse().GetResponseStream()));
Is when the exception is thrown. Any ideas? Thanks in advance.
James
First, if you don't intend to reuse the connection or there's not going to be another request to the same schema/server/port, I would set KeepAlive to false.
The problem is that XmlDocument.Load() does not read the entire stream before the server closes the connection or that it keeps reading beyond the end and when the server keep-alive timeout is over, the connection is closed by the server. Also, you never close the response stream. To verify that this theory is correct, do something like:
// Optional -> webRequest.KeepAlive = false;
string xml = null;
using (StreamReader reader = new StreamReader (webRequest.GetResponse().GetResponseStream())) {
xml = reader.ReadToEnd ();
}
xmlDoc.LoadXml (xml);
and see if that fixes your problem.