I am currently using sockets to try and send messages between a Silverlight 3 client and a .NET3.5 service. I can set up the TCP connection fine, and send data across, but my issue comes with serialising and deserialising DataContracts.
Currently we are using WCF PollingDuplex binding to do this work, but we are not happy with its performance, so are trying sockets, whilst still attempting to make use of DataContract attributes. The code I have is as follows:
// Client
public void Send(ActionMessage actionMessage)
{
DataContractSerializer dcs =
new DataContractSerializer(actionMessage.GetType());
MemoryStream memoryStream = new MemoryStream();
dcs.WriteObject(memoryStream, actionMessage);
byte[] sendBuffer = new byte[4096];
memoryStream.Position = 0;
memoryStream.Read(sendBuffer, 0, sendBuffer.Length);
SocketAsyncEventArgs socketAsyncEventArgs = new SocketAsyncEventArgs();
socketAsyncEventArgs.SetBuffer(sendBuffer, 0, sendBuffer.Length);
if(!_socket.SendAsync(socketAsyncEventArgs))
HandleSendComplete(socketAsyncEventArgs);
}
// Service
private byte[] _recieveBuffer = new byte[4096];
private int _receivedLength;
private void socket_OnReceiveComplete(IAsyncResult asyncResult)
{
_receivedLength += _tcpClient.Client.EndReceive(asyncResult);
// See if there's more data that we need to grab
if (_receivedLength < _recieveBuffer.Length)
{
// Need to grab more data so receive remaining data
_tcpClient.Client.BeginReceive(_recieveBuffer, _receivedLength,
_recieveBuffer.Length - _receivedLength, SocketFlags.None,
new AsyncCallback(socket_OnReceiveComplete), null);
return;
}
MemoryStream memoryStream = new MemoryStream();
memoryStream.Position = 0;
memoryStream.Write(_recieveBuffer, 0, _recieveBuffer.Length);
DataContractSerializer dcs = new DataContractSerializer(typeof(ActionMessage));
object o = dcs.ReadObject(memoryStream);
ActionMessage actionMessage = (ActionMessage) o;
}
It is the ReadObject line that throws the XmlException: Unexpected End of File. I have tried various things including truncating trailing 0's from the byte array (_recieveBuffer) when it is received, leaving just one 0 at the end etc, but nothing seems to work. I have checked the byte[] buffers on the client and the server side and they have the same values at the beginning and end and are of the same length. I have also tried using actionMessage.GetType() and typeof(ActionMessage) as parameters to the DataContractSerializer, but there is no difference...
What am I misssing here: why does dataContractSerializer.Write() not accept the output generated by dataContractSerializer.Read() ?
I was having a good day until hitting this...I did find one other guy with the same problem, but the solution offered, to set memoryStream.Position = 0 on the service side did not work...
Thanks in advance.
If I had to guess, I would say that your memoryStream.Position = 0; line is in the wrong place.
You will need to reset position in the stream after writing the buffer into the stream.
Related
I am doing html to pdf file . Its Downloading instantly . I dont want download instantly. i want to save the file in my project folder once converted.
My C# Code
string html ="<table><tr><td>some contents</td></tr></table>";
Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition", "attachment;filename=WelcomeLetter.pdf");
Response.Cache.SetCacheability(HttpCacheability.NoCache);
StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
StringReader sr = new StringReader(table);
Document ResultPDF = new Document(iTextSharp.text.PageSize.A4, 25, 10, 20, 30);
PdfPTable Headtable = new PdfPTable(7);
Headtable.TotalWidth = 525f;
Headtable.LockedWidth = true;
Headtable.HeaderRows = 5;
Headtable.FooterRows = 2;
Headtable.KeepTogether = true;
HTMLWorker htmlparser = new HTMLWorker(ResultPDF);
PdfWriter.GetInstance(ResultPDF, Response.OutputStream);
ResultPDF.Open();
htmlparser.Parse(sr);
ResultPDF.Close();
Response.Write(ResultPDF);
Response.End();
For saving pdf file locally in your project folder you can use FileStream class like this.
FileStream stream = new FileStream(filePath, FileMode.Create);//Here filePath is path of your project folder.
Now use this stream instead of using Response.OutputStream when you create instance of PdfWriter object.
PdfWriter.GetInstance(ResultPDF, stream);
Now do not use Responce.Write as you don't want to download your file.And close your stream at end.
stream.Close();
I'm going to combine everyone's answer into one that you should be able to drop in and use. If this works, I would accept Manish Parakhiya's answer because that had the most important part.
First, I'm going to assume you are using a recent version of iTextSharp. I think 5.5.5 is the most recent version. Second, because of this, I'm going to restructure your code a bit in order to use the using pattern. If you're stuck on an older obsolete unsupported version like 4.1.6 you'll need to re-adjust.
Almost every tutorial out there shows you that you can bind directly the Response.OutputStream. This is 100% valid but I would argue that it is also a really bad idea. Instead, bind to a more generic MemoryStream. This makes debugging much easier and your code will port and adapt that much easier.
The below code includes comments about each of the changes and what things are actually doing. The top section is all about creating a PDF from a string of HTML. The bottom actually does something with it, including writing it to disk and/or streaming it to a browser.
//Will hold our PDF eventually
Byte[] bytes;
//HTML that we want to parse
string html = "<table><tr><td>some contents</td></tr></table>";
//Create a MemoryStream to write our PDF to
using (var ms = new MemoryStream()) {
//Create our document abstraction
using (var ResultPDF = new Document(iTextSharp.text.PageSize.A4, 25, 10, 20, 30)) {
//Bind a writer to our Document abstraction and our stream
using (var writer = PdfWriter.GetInstance(ResultPDF, ms)) {
//Open the PDF for writing
ResultPDF.Open();
//Parse our HTML using the old, obsolete, not support parser
using (var sw = new StringWriter()) {
using (var hw = new HtmlTextWriter(sw)) {
using (var sr = new StringReader(html)) {
using (var htmlparser = new HTMLWorker(ResultPDF)) {
htmlparser.Parse(sr);
}
}
}
}
//Close the PDF
ResultPDF.Close();
}
}
//Grab the raw bytes of the PDF
bytes = ms.ToArray();
}
//At this point, the bytes variable holds a valid PDF file.
//You can write it disk:
System.IO.File.WriteAllBytes("your file path here", bytes);
//You can also send it to a browser:
Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition", "attachment;filename=WelcomeLetter.pdf");
Response.BinaryWrite(bytes);
Response.Cache.SetCacheability(HttpCacheability.NoCache);
//Never do the next line, it doesn't do what you think it does and actually produces corrupt PDFs
//Response.Write(ResultPDF); //BAD!!!!!!
Response.End();
string tempDirectory = Session.SessionID.ToString();
string location = Path.Combine(Server.MapPath(
WebConfigurationManager.AppSettings["PathSet"].ToString()), tempDirectory);
if (!Directory.Exists(location))
{
Directory.CreateDirectory(location);
}
string fileName="abc.pdf";
filePath = Path.Combine(location, fileName);
I'm kind of new to Silverlight. I've managed to solve this problem for WPF, unfortunately not for Silverlight.
I open an image with an OpenFileDialog. I make a stream out of it and write it in a byte array. This byte array is then put into the database. This is the code I use to open the image and convert it into a byte array:
OpenFileDialog dlg = new OpenFileDialog();
dlg.InitialDirectory = #"C:\";
dlg.Filter = "Image File (*.jpg;*.bmp;*.gif)|*.jpg;*.bmp;*.gif";
dlg.FilterIndex = 1;
if(dlg.ShowDialog() == true)
{
pImage.Naam = dlg.File.Name;
BitmapImage bitImage = new BitmapImage();
Stream s = (Stream)dlg.File.OpenRead();
imgItem.Source = bitImage;
pImage.Data = new byte[s.Length];
s.Read(pImage.Data, 0, (int)s.Length);
s.Close();
}
I manage to save the byte array as a varbinary without any problem to my database.
When I retrieve it, I have no difficulties converting the varbinary back to the byte array (I'm pretty sure the two byte arrays are the same as when debugging I get exactly the same size).
But then I get stuck! Whenever I want to convert the byte array back to an image using the following code, my stream (and thus my image) is empty:
var newImage = new BitmapImage();
var myStream = new MemoryStream(pHuidigeImage.Data);
newImage.SetSource(myStream);
imgItem.Source = newImage;
So, what's wrong here?
Thanks in advance!
hi im working on a project that uses invoke and threads.. it is a simple remote desktop program with chat.. i got a sample here on the internet in c# winform, but i would like to convert it to wpf.. i have no problem in sending message to another client using the wpf program but it cannot receive ( or cannot read) the sent messages from the others.. i think it has something to do with the thread and the invoke method, i read that wpf does invoke differently and i did try the dispatcher.invoke, but it still doesnt do the trick
pls hellp
here's the code
wait = new Thread(new ThreadStart(waitForData));
wait.Start();
that snippet above is executed when a successful connection is made in tcpclient
private void waitForData()
{
try
{
NetworkStream read = tcpclnt.GetStream();
while (read.CanRead)
{
byte[] buffer = new byte[64];
read.Read(buffer, 0, buffer.Length);
s = new ASCIIEncoding().GetString(buffer);
System.Console.WriteLine("Recieved data:" + new ASCIIEncoding().GetString(buffer));
rcvMsg = new ASCIIEncoding().GetString(buffer) + "\n";
hasNewData = true;
bool f = false;
f = rcvMsg.Contains("##");
bool comand = false;
comand = rcvMsg.Contains("*+*-");
/*File receive*/
if (f)
{
string d = "##";
rcvMsg = rcvMsg.TrimStart(d.ToCharArray());
int lastLt = rcvMsg.LastIndexOf("|");
rcvMsg = rcvMsg.Substring(0, lastLt);
NetworkStream ns = tcpclnt.GetStream();
if (ns.CanWrite)
{
string dataS = "^^Y";
byte[] bf = new ASCIIEncoding().GetBytes(dataS);
ns.Write(bf, 0, bf.Length);
ns.Flush();
}
try
{
new Recieve_File().recieve_file(rcvMsg);
}
catch (Exception ec)
{
System.Console.WriteLine(ec.Message);
}
}
/*Command-shutdown/restart/logoff*/
else if (comand)
{
string com = "*+*-";
rcvMsg = rcvMsg.TrimStart(com.ToCharArray());
execute_command(rcvMsg);
}
else
{
this.Invoke(new setOutput(setOut));
Thread.Sleep(1000);
}
}
}
catch (Exception ex)
{
wait.Abort();
output.Text += "Error..... " + ex.StackTrace;
}
}
the snippet above is a code that listens if there is a message or command.. the line
this.invoke(new setoutput(setout)) is a code for appending text in the rtb
hope someone could help me thanks
You've posted a lot of code, but I'm assuming it's only the call to Control.Invoke which is causing the problem. In WPF, use Dispatcher.Invoke (or Dispatcher.BeginInvoke) instead, via the Dispatcher property on the relevant UI element.
I'd also strongly encourage you to:
Refactor your code into smaller methods
Stop catching just Exception except at the top level of any large operation (it should just be a fall-back; usually you catch specific exceptions)
Start following .NET naming conventions
Add a using directive for System so you can just write Console.WriteLine instead of System.Console.WriteLine everywhere
Use Encoding.ASCII instead of creating a new ASCIIEncoding each time you need one
Use a StreamReader to read character data from a stream, instead of reading it as binary data first and then encoding it
For either Stream or TextReader, don't ignore the return value from Read - it tells you how many bytes or characters have been read
BACKGROUND
I have a media file that I am progressively downloading to my Silverlight 4 application, using WebClient.OpenReadAsync/OpenReadCompleted, and Stream.BeginRead/AsyncCallback. The goal is to play the file in a MediaElement by calling the SetSource method, passing in an instance of our custom MediaStreamSource, so that the file can start playing before the entire contents of the file have been downloaded. The media file is using custom encoding/decoding, which is why we are using a custom MediaStreamSource. Our MediaStreamSource is built to accept a Stream and begin parsing track information and play back in a MediaElement. I have confirmed I am progressively downloading the file contents. Here is a summary of the download code:
public void SetSource(string sourceUrl)
{
var uriBuilder = new UriBuilder(sourceUrl);
WebClient webClient = new WebClient();
// AllowReadStreamBuffering = false allows us to get the stream
// before it's finished writing to it.
webClient.AllowReadStreamBuffering = false;
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(uriBuilder.Uri);
}
void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
_inboundVideoStream = e.Result;
BeginReadingFromStream();
}
private void BeginReadingFromStream()
{
if (_inboundVideoStream.CanRead)
{
_chunk = new byte[_chunkSize];
_inboundVideoStream.BeginRead(_chunk, 0, _chunk.Length, new AsyncCallback(BeginReadCallback), _inboundVideoStream);
}
}
private void BeginReadCallback(IAsyncResult asyncResult)
{
Stream stream = asyncResult.AsyncState as Stream;
int bytesRead = stream.EndRead(asyncResult);
_totalBytesRead += bytesRead;
if (_playableStream == null)
_playableStream = new MemoryStream();
_playableStream.Write(_chunk, 0, _chunk.Length);
if (!_initializedMediaStream && _playableStream.Length >= _minimumToStartPlayback)
{
_initializedMediaStream = true;
// Problem: we can't hand the stream source a stream that's still being written to
// It's Position is at the end. Can I read and write from the same stream or is there another way
MP4MediaStreamSource streamSource = new MP4MediaStreamSource(_playableStream);
this.Dispatcher.BeginInvoke(() =>
{
mediaElement1.SetSource(streamSource);
});
}
if (_totalBytesRead < _fileSize)
{
ReadFromDownloadStream();
}
else
{
// Finished downloading
}
}
I've tried both writing/reading to a MemoryStream simultaneously, as listed above, as well as writing to an IsolatedStorageFile and reading from that file as I'm writing to it. So far I can't find a way to make either approach work.
QUESTION:
Is there a way to read and write to the same stream? Or is there a standard way to implement this with a stream and MediaStreamSource?
Thanks
The way I did it in my MediaStreamSource implementation is to have 2 streams in it: one for reading and one for writing.
I dispose and re-create the reading stream using the buffer of the writing stream every time GetSampleAsync() is called. Another way to do it I guess is to use a negative offset when creating a MediaStreamSample to pass to ReportGetSampleCompleted() since the position of the stream will always be at the end, but you have to make sure that the position is at the end otherwise this will not work, to keep it simple I just used 2 streams
I want to read the raw binary of a PNG file on a website and store it into a byte[], so far I have something like this:
Uri imageUri = new Uri("http://www.example.com/image.png");
// Create a HttpWebrequest object to the desired URL.
HttpWebRequest imgRequest = (HttpWebRequest)WebRequest.Create(imageUri);
using (HttpWebResponse imgResponse = (HttpWebResponse)imgRequest.GetResponse())
{
using (BinaryReader lxBR = new BinaryReader(imgResponse.GetResponseStream()))
{
using (MemoryStream lxMS = new MemoryStream())
{
lnBuffer = lxBR.ReadBytes(1024);
while (lnBuffer.Length > 0)
{
lxMS.Write(lnBuffer, 0, lnBuffer.Length);
lnBuffer = lxBR.ReadBytes(1024);
}
lnFile = new byte[(int)lxMS.Length];
lxMS.Position = 0;
lxMS.Read(lnFile, 0, lnFile.Length);
}
}
}
but I can't use GetResponse on Silverlight because it is not Asynchronous (I think that's the reason) so instead I should be using BeginGetResponse, but I'm not completely clear on how to go about it. This is what I have so far:
HttpWebResponse imgResponse = (HttpWebResponse)imgRequest.BeginGetResponse(new AsyncCallback(WebComplete), imgRequest);
using (imgResponse)
{
using (BinaryReader lxBR = new BinaryReader(imgResponse.GetResponseStream()))
{
/*Same*/
}
}
and
void WebComplete(IAsyncResult a)
{
HttpWebRequest req = (HttpWebRequest)a.AsyncState;
HttpWebResponse res = (HttpWebResponse)req.EndGetResponse(a);
//...? Do I need something else here?
}
can someone explain me a little bit how to use the BeginGetResponse property and how do I use the AsyncCallback.
Thanks!
Note:
I'm new to silverlight and I've been following tutorials and borrowing from other responses here on StackOverflow:
(stackoverflow responce) what I need to do but not in silverlight
tutorial
WebRequest_in_Silverlight
is this valid Silverlight code?
HttpWebResponse imgResponse = (HttpWebResponse)imgRequest.BeginGetResponse(new AsyncCallback(WebComplete), imgRequest);
Got it working, want to post it here in case anyone needs it.
I need to get this image and then modify it (byte level) Silverlight didn't let me save the image directly to a WriteableBitmap and thus I had to get the image with a WebClient as a stream and then save it to a byte[]
this is how I get the image (I already have the specific Uri):
WebClient wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
wc.OpenReadAsync(uri)
so when the image is loaded the wc_OpenReadCompleted method is called and it does something like this:
int lengthInBytes = Convert.ToInt32(e.Result.Length);
BinaryReader br = new BinaryReader(e.Result);
byte[] buffer = new byte[lengthInBytes];
using (br)
{
for (int i = 0; i < lengthInBytes; i++)
{
buffer[i] = br.ReadByte();
}
}
at the end the buffer[] has all the bytes of the image (what I wanted)
I'm sure there are better ways of doing this but this is working for me ! )
note: at some point I need to convert the byte[] to a BitmapImage (that was easier than expected):
//imageInBytes is a byte[]
if (imageInBytes != null)
{
MemoryStream rawBytesStream = new MemoryStream(imageInBytes);
BitmapImage img = new BitmapImage();
img.SetSource(rawBytesStream);
return img;
}
I hope this helps anyone.
Use the OpenReadAsync method of the WebClient object. Attach to the OpenReadCompleted event of the WebClient. Use the Stream provided by the Result property of the event args.
Consider setting AllowReadStreamBuffering, this will fill the entire stream before raising the OpenReadCompleted. In either case its likely you can use this stream to complete you real task rather than coping it into a MemoryStream.