I came across this situation.
Main Function:
Message msg = Message.CreateMessage(MessageVersion.Default, "Process");
String xmlData ="<Name>Navin</Name>";
Byte[] ba = Encoding.ASCII.GetBytes(xmlData);
MemoryStream ms = new MemoryStream(ba);
XmlWriter xw = XmlWriter.Create(ms);
msg.WriteBody(xw);
readMessage(msg);
In readMessage(Message msg):
XmlDictionaryReader xdr = msg.GetReaderAtBodyContents();
WHen i do this i am getting this error.
Unhandled Exception: System.InvalidOperationException: This message cannot suppo
rt the operation because it has been written.
How to overcome this.
Waiting for response.
Thanks in advance.
According to MSDN Message.GetReaderAtBodyContents Method, you can't access the message body once it's been read or written - it can only be accessed once. You need to use 'CreateBufferedCopy' to access a message multiple times.
I didn't find any examples in the MSDN documentation, but it looks like you'd need to create a MessageBuffer instance via Message.CreateBufferedCopy, and then you can use the MessageBuffer's CreateMessage method to gain access to the contents of the buffer.
See:
Message.CreateBufferedCopy Method
MessageBuffer Class
MessageBuffer.CreateMessage Method
Related
I am trying to add an event from my local database to the Davical server (in fact, this should apply to any CalDav server, as long as it is compliant with the CalDav protocol)...
From what I could read here, I can send a PUT request to add events contained in a VCALENDAR collection... So here is what I try to do:
try {
// Create the HttpWebRequest object
HttpWebRequest Request = (HttpWebRequest)HttpWebRequest.Create("http://my_caldav_srv/davical.php/user/mycalendar");
// Add the network credentials to the request
Request.Credentials = new NetworkCredential(usr, pwd);
// Specify the method
Request.Method = "PUT";
// some headers - I MAY BE MISSING THINGS HERE???
Request.Headers.Add("Overwrite", "T");
// set the body of the request...
Request.ContentLength = bodyStr.Length;
Stream reqStream = Request.GetRequestStream();
// Write the string to the destination as a text file.
reqStream.Write( Encoding.UTF8.GetBytes(body), 0, body.Length);
// Set the content type header.
Request.ContentType = contentType.Trim();
// Send the method request and get the response from the server.
Response = (HttpWebResponse)Request.GetResponse();
}
catch (Exception e) {
throw new Exception("Caught error: " + e.Message, e);
}
The body I send is actually an emtpy calendar:
BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
PRODID:-//davical.org//NONSGML AWL Calendar//EN
X-WR-CALNAME:My Calendar
END:VCALENDAR
For a reason I cannot understand, the call with "PUT" returns an error (405) Method Not Allowed. The PUSH returns (500) Internal Server Error, but looking at the debug details, the reason is the same as for the PUT case...
In debugging on the server side, I found out that the reason is that in caldav-PUT-vcalendar.php, the following clause is violated:
$c->readonly_webdav_collections
Well, first, let me mention that with the SAME credentials entered in Lightning, I am able to add/remove events and, on the admin interface, I actually made sure to grant ALL rights to the user. So I'd be surprised it is due to that...
Any help would be most appreciated !
Kind regards,
Nik
OK, I got it....
The reason is that one must put the event to some EVENT adress....
I.e. the "url" is not the collection's address, but the EVENT's address...
So the same code using the following address works:
string url="http://my_server/caldav.php/username/calendarpath/_my_event_id.ics";
Does anybody know if it is possible to insert / delete multiple events at once ???
In my WCF service, I try to load a File from MS SQL table which has a FileStream column and I try to pass it as a stream back
responseMsg.DocSqlFileStream = new MemoryStream();
try
{
using (FileStreamDBEntities dbEntity = new FileStreamDBEntities())
{
...
using (TransactionScope x = new TransactionScope())
{
string sqlCmdStr = "SELECT dcraDocFile.PathName() AS InternalPath, GET_FILESTREAM_TRANSACTION_CONTEXT() AS TransactionContext FROM dcraDocument WHERE dcraDocFileID={0}";
var docFileStreamInfo = dbEntity.Database.SqlQuery<DocFileStreamPath>(sqlCmdStr, new object[] { docEntity.dcraDocFileID.ToString() }).First();
SqlFileStream sqlFS = new SqlFileStream(docFileStreamInfo.InternalPath, docFileStreamInfo.TransactionContext, FileAccess.Read);
sqlFS.CopyTo(responseMsg.DocSqlFileStream);
if( responseMsg.DocSqlFileStream.Length > 0 )
responseMsg.DocSqlFileStream.Position = 0;
x.Complete();
}
}
...
I'm wondering whats the best way to pass the SQLFileStream back through a message contract back to take advantage of streaming. Currently I copied the SQLFilEStream to a memory stream because I got an error message in WCF trace which says: Type 'System.Data.SqlTypes.SqlFileStream' cannot be serialized.
In WebApi there is such thing as PushStreamContent it allows delegating all transaction stuff to async lambda, don't know if there is something similar in WCF, but the following approach may be helpful:
http://weblogs.asp.net/andresv/archive/2012/12/12/asynchronous-streaming-in-asp-net-webapi.aspx
You can't stream an SQLFileStream back to the client because it can only be read within the SQL transaction. I think your solution with the MemoryStream is a good way of dealing with the problem.
I had a similar problem and was worried about the large object heap when using a new Memory Stream every time. I came up with the idea of using a temporary file on the disk instead of a memory stream. We are using this solution in several project now and it works really well.
See here for the example code:
https://stackoverflow.com/a/11307324/173711
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.
I've been working with WCF routing and implemented a custom message filter,
public override bool Match(Message message)
{
MessageBuffer buffer = message.CreateBufferedCopy(Int32.MaxValue);
var msg = buffer.CreateMessage();
XmlDictionaryReader reader = msg.GetReaderAtBodyContents();
string paramsXml = reader.ReadOuterXml();
....
....
return serviceType.Equals(service);
}
I'm getting the following exception "This message cannot support the operation because it has been copied." eventhough I'm creating a buffered copy. Can anyone help me on this?
This is apparently the problem with VS debugger. does not happen with soap ui or other clients. hope this will be useful for somebody struggling with same issue.
You need to set routeOnHeadersOnly = false in the routing behavior
Then you implement the operations that take message buffers
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.