I am not very good with streams…
I have downloaded a file from a website into a Stream
How do i write this to the sd card or the filestream.
Stream localStream = null;
//save data to localStream variable
SDCard.createfile(localStream,"\\SD\\hello.jpg");
public static void createfile(Stream sdata, string filename)
{
FileStream fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write);
fileStream.Read(sdata, 0, sdata.Length); //????
if (fileStream != null) fileStream.Close();
fileStream = null;
}
@ zigbox - You can read data from your local stream into a byte array and then write that byte array to the file stream.
@ Architect how do i do that?
public static int DownloadFile(String remoteFilename, String localFilename)
{
string fname = localFilename.Split('\\')[localFilename.Split('\\').Length - 1];
// Function will return the number of bytes processed
// to the caller. Initialize to 0 here.
int bytesProcessed = 0;
// Assign values to these objects here so that they can
// be referenced in the finally block
Stream remoteStream = null;
Stream localStream = null;
WebResponse response = null;
// Use a try/catch/finally block as both the WebRequest and Stream
// classes throw exceptions upon error
try
{
// Create a request for the specified remote file name
WebRequest request = WebRequest.Create(remoteFilename);
if (request != null)
{
// Send the request to the server and retrieve the
// WebResponse object
// request.ContentLength
response = request.GetResponse();
if (response != null)
{
// Once the WebResponse object has been retrieved,
// get the stream object associated with the response's data
remoteStream = response.GetResponseStream();
long total = response.ContentLength;
// Create the local file
localStream = File.Create(localFilename);
// Allocate a 1k buffer
byte[] buffer = new byte[1024];
int bytesRead;
// Simple do/while loop to read from stream until
// no bytes are returned
do
{
// Read data (up to 1k) from the stream
bytesRead = remoteStream.Read(buffer, 0, buffer.Length);
// Write the data to the local file
localStream.Write(buffer, 0, bytesRead);
// Increment total bytes processed
bytesProcessed += bytesRead;
if (onProgress != null) { onProgress(bytesProcessed, total, fname); }
} while (bytesRead > 0);
}
}
SDCard.createfile(localStream,"\\SD\\hello.jpg"); //*******************
}
catch (WebException webEx)
{
Debug.Print("Web Exception Occured");
if (webEx.InnerException is SocketException)
{
SocketException sock = webEx.InnerException as SocketException;
Debug.Print("Socket error code: " + sock.ErrorCode.ToString());
}
}
catch (Exception ex)
{
Debug.Print("Exception of type: " + ex.GetType().FullName);
Debug.Print(ex.Message);
if (onDownloadFinished != null) { onDownloadFinished(ex.Message); }
}
finally
{
// Close the response and streams objects here
// to make sure they're closed even if an exception
// is thrown at some point
if (response != null) response.Close();
if (remoteStream != null) remoteStream.Close();
if (localStream != null) localStream.Close();
}
// Return total bytes processed to caller.
return bytesProcessed;
}
public static void createfile(Stream sdata, string filename)
{
FileStream fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write);
fileStream.Write(sdata., 0, data.Length);
if (fileStream != null) fileStream.Close();
fileStream = null;
}
Something like this (untested code):
const int BUFFER_SIZE = 1024;
byte[] buffer = new byte[BUFFER_SIZE];
public static void createfile(Stream sdata, string filename)
{
sdata.Seek(0,SeekOrigin.Begin);
long remainingBytes = sdata.Length;
FileStream fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write);
while( remainingBytes > 0 )
{
int nRead = sdata.Read(buffer, 0, remainingBytes < BUFFER_SIZE ? remainingBytes : BUFFER_SIZE);
remainingBytes -= nRead;
fileStream.Write(buffer, 0, nRead);
}
if (fileStream != null) fileStream.Close();
fileStream = null;
}
1 Like
@ zigbox - If you don’t mind me butting in here, I have a suggestion that you are probably already aware of but I think is worth sharing anyway, just in case.
When working with objects that implement IDisposable you can use the ‘using’ statement to ensure that no matter what happens the object will be disposed.
You currently have
FileStream fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write);
// Do stuff here
if (fileStream != null) fileStream.Close();
fileStream = null;
If the code above throws an exception for any reason then the fileStream will not be closed. One solution would be to use try/finally as you have done for response, remoteStream and localStream.
FileStream fileStream = null;
try
{
fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write);
// Do stuff here
}
finally
{
if (fileStream != null) fileStream.Close();
fileStream = null;
}
But this can be handled even more elegantly with the ‘using’ statement
using(FileStream fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write))
{
// Do stuff here
}
This will automatically call Dispose on the FileStream instance when the block ends. This is the same as calling Close. The code is cleaner and less code always reduces the risk of bugs. This can also be applied to your other variables response, remoteStream, localStream ie. anything that implements IDisposable.