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MemoryStream??

Hello,

I am working on an updater that Retrieves a file from a web page.
GetRequest.Method = "POST"

SW = New StreamWriter(TheRequest.GetRequestStream)
SW.WriteLine(TransferName)
SW.Close()
TheResponse = TheRequest.GetResponse()
ms = New MemoryStream()
CopyData(TheResponse.GetResponseStream(), ms)
ms.Seek(0, SeekOrigin.Begin)
System.IO.Directory.CreateDirectory(TransferFolder )
Dim st As FileStream = New FileStream(CompleteName, FileMode.Create)
ms.WriteTo(st)
st.Close()
ms.Close()

The application works good about 90% of the time I have noticed that when
the file is really big like 25 Megs, it stops sending at about 16 Megs. Is
this because the computer does not have enough memory to store the complete
file? or could it be something with the web page that is responding to the
request? or could it be something else.

Any suggestions will be greatly appreciated and even modifications to my
code above. I am not sure how to make the memory stream write to the file
every Meg to test the theory.

Thanks,
Chuck
Jul 21 '05 #1
6 2190
I receive the following Error Message.

unable to read data from transport connection

Thanks,

Chuck
"Charles A. Lackman" <Ch*****@CreateItSoftware.net> wrote in message
news:Oq**************@tk2msftngp13.phx.gbl...
Hello,

I am working on an updater that Retrieves a file from a web page.
GetRequest.Method = "POST"

SW = New StreamWriter(TheRequest.GetRequestStream)
SW.WriteLine(TransferName)
SW.Close()
TheResponse = TheRequest.GetResponse()
ms = New MemoryStream()
CopyData(TheResponse.GetResponseStream(), ms)
ms.Seek(0, SeekOrigin.Begin)
System.IO.Directory.CreateDirectory(TransferFolder )
Dim st As FileStream = New FileStream(CompleteName, FileMode.Create)
ms.WriteTo(st)
st.Close()
ms.Close()

The application works good about 90% of the time I have noticed that when
the file is really big like 25 Megs, it stops sending at about 16 Megs.
Is this because the computer does not have enough memory to store the
complete file? or could it be something with the web page that is
responding to the request? or could it be something else.

Any suggestions will be greatly appreciated and even modifications to my
code above. I am not sure how to make the memory stream write to the file
every Meg to test the theory.

Thanks,
Chuck

Jul 21 '05 #2
Replies only posted in microsoft.public.dotnet.general

Charles A. Lackman wrote:

Please don't cross-post. How did you figure
microsoft.public.dotnet.framework.windowsforms was involved in the problem?

Some good advice for getting good response can be found at
http://www.catb.org/~esr/faqs/smart-questions.html,
http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
I receive the following Error Message.

unable to read data from transport connection


Please include the entire exception, you can get it by (for example):

catch(Exception e) {
Console.WriteLine("EXCEPTION:\n{0}", e);

This will include a stack-trace which makes it possible to pinpoint
where in your program the error ocurred.

BTW: It seems rather a waste to read the entire received file into
memory. Is there something wrong with just writing it directly to the disk?

What's wrong with simply:

void Copy(Stream instream, Stream outstream, byte[] buf) {
int r;
while ( true ) {
r = instream.Read(buf, 0, buf.Length);
if ( r == 0 )
break;
outstream.Write(buf, 0, r);
}
}

using ( Stream s = new FileStream(CompleteName, FileMode.Create) )
Copy(TheResponse.GetResponseStream(), s);
}
--
Helge
Jul 21 '05 #3
For one, if your intent is to store it in a file and never use it in memory
then you simply need to put it into the file stream directly. I would
recommend using a buffered loop to stream the file data from the response
stream to the file stream until there is no more data.

c# but easily translated and maybe this is what copy data is?:
FileStream fos = new FileStream(Name, FileMode.Create);
byte[] buf = new byte[4096];
int bytes = 0;
while((bytes = TheResponse.Read(buf, 0, 4096)) > 0) {
fos.Write(buf, 0, bytes);
}
fos.close();
TheResponse.close();

Do you get any exceptions for the failure? Could it be a timeout that you
are experiencing?

Fred

"Charles A. Lackman" <Ch*****@CreateItSoftware.net> wrote in message
news:Oq**************@tk2msftngp13.phx.gbl...
Hello,

I am working on an updater that Retrieves a file from a web page.
GetRequest.Method = "POST"

SW = New StreamWriter(TheRequest.GetRequestStream)
SW.WriteLine(TransferName)
SW.Close()
TheResponse = TheRequest.GetResponse()
ms = New MemoryStream()
CopyData(TheResponse.GetResponseStream(), ms)
ms.Seek(0, SeekOrigin.Begin)
System.IO.Directory.CreateDirectory(TransferFolder )
Dim st As FileStream = New FileStream(CompleteName, FileMode.Create)
ms.WriteTo(st)
st.Close()
ms.Close()

The application works good about 90% of the time I have noticed that when
the file is really big like 25 Megs, it stops sending at about 16 Megs. Is this because the computer does not have enough memory to store the complete file? or could it be something with the web page that is responding to the
request? or could it be something else.

Any suggestions will be greatly appreciated and even modifications to my
code above. I am not sure how to make the memory stream write to the file
every Meg to test the theory.

Thanks,
Chuck

Jul 21 '05 #4
Hello,

I have rewritten the stream directly to a file and still get the same error
(Freeze). I also changed the Session timeout on my server to last longer
(still same problem). Hmmm??

The Error I get is:

unable to read data from transport connection

Code For CopyData:

Private Sub CopyData(ByVal FromStream As Stream, ByVal ToStream As Stream)
Dim intBytesRead As Integer
Dim Counter As Integer = 0
Const intSize As Integer = 1024
Dim bytes(intSize) As Byte
ProgressBar1.Step = 1024
intBytesRead = FromStream.Read(bytes, 0, intSize)
While intBytesRead > 0
ToStream.Write(bytes, 0, intBytesRead)
intBytesRead = FromStream.Read(bytes, 0, intSize)
end Sub

Chuck
"Fred Hirschfeld" <a@b.c> wrote in message
news:u5**************@TK2MSFTNGP14.phx.gbl...
For one, if your intent is to store it in a file and never use it in
memory
then you simply need to put it into the file stream directly. I would
recommend using a buffered loop to stream the file data from the response
stream to the file stream until there is no more data.

c# but easily translated and maybe this is what copy data is?:
FileStream fos = new FileStream(Name, FileMode.Create);
byte[] buf = new byte[4096];
int bytes = 0;
while((bytes = TheResponse.Read(buf, 0, 4096)) > 0) {
fos.Write(buf, 0, bytes);
}
fos.close();
TheResponse.close();

Do you get any exceptions for the failure? Could it be a timeout that you
are experiencing?

Fred

"Charles A. Lackman" <Ch*****@CreateItSoftware.net> wrote in message
news:Oq**************@tk2msftngp13.phx.gbl...
Hello,

I am working on an updater that Retrieves a file from a web page.
GetRequest.Method = "POST"

SW = New StreamWriter(TheRequest.GetRequestStream)
SW.WriteLine(TransferName)
SW.Close()
TheResponse = TheRequest.GetResponse()
ms = New MemoryStream()
CopyData(TheResponse.GetResponseStream(), ms)
ms.Seek(0, SeekOrigin.Begin)
System.IO.Directory.CreateDirectory(TransferFolder )
Dim st As FileStream = New FileStream(CompleteName, FileMode.Create)
ms.WriteTo(st)
st.Close()
ms.Close()

The application works good about 90% of the time I have noticed that when
the file is really big like 25 Megs, it stops sending at about 16 Megs.

Is
this because the computer does not have enough memory to store the

complete
file? or could it be something with the web page that is responding to
the
request? or could it be something else.

Any suggestions will be greatly appreciated and even modifications to my
code above. I am not sure how to make the memory stream write to the
file
every Meg to test the theory.

Thanks,
Chuck


Jul 21 '05 #5
NOTE:

I am grabbing 4 files, three of which are under 10 megs. The larger file of
26 megs the third file to download. All the other files download just fine.
It's just the file that is over 15 Megs is size.

Chuck
"Fred Hirschfeld" <a@b.c> wrote in message
news:u5**************@TK2MSFTNGP14.phx.gbl...
For one, if your intent is to store it in a file and never use it in
memory
then you simply need to put it into the file stream directly. I would
recommend using a buffered loop to stream the file data from the response
stream to the file stream until there is no more data.

c# but easily translated and maybe this is what copy data is?:
FileStream fos = new FileStream(Name, FileMode.Create);
byte[] buf = new byte[4096];
int bytes = 0;
while((bytes = TheResponse.Read(buf, 0, 4096)) > 0) {
fos.Write(buf, 0, bytes);
}
fos.close();
TheResponse.close();

Do you get any exceptions for the failure? Could it be a timeout that you
are experiencing?

Fred

"Charles A. Lackman" <Ch*****@CreateItSoftware.net> wrote in message
news:Oq**************@tk2msftngp13.phx.gbl...
Hello,

I am working on an updater that Retrieves a file from a web page.
GetRequest.Method = "POST"

SW = New StreamWriter(TheRequest.GetRequestStream)
SW.WriteLine(TransferName)
SW.Close()
TheResponse = TheRequest.GetResponse()
ms = New MemoryStream()
CopyData(TheResponse.GetResponseStream(), ms)
ms.Seek(0, SeekOrigin.Begin)
System.IO.Directory.CreateDirectory(TransferFolder )
Dim st As FileStream = New FileStream(CompleteName, FileMode.Create)
ms.WriteTo(st)
st.Close()
ms.Close()

The application works good about 90% of the time I have noticed that when
the file is really big like 25 Megs, it stops sending at about 16 Megs.

Is
this because the computer does not have enough memory to store the

complete
file? or could it be something with the web page that is responding to
the
request? or could it be something else.

Any suggestions will be greatly appreciated and even modifications to my
code above. I am not sure how to make the memory stream write to the
file
every Meg to test the theory.

Thanks,
Chuck


Jul 21 '05 #6
Fred Hirschfeld wrote:
c# but easily translated and maybe this is what copy data is?:
FileStream fos = new FileStream(Name, FileMode.Create);
byte[] buf = new byte[4096];
int bytes = 0;
while((bytes = TheResponse.Read(buf, 0, 4096)) > 0) {
fos.Write(buf, 0, bytes);
}
fos.close();
TheResponse.close();


The above code leaks the openend file in case of exceptions, and the use
of 4096 as a constant for Read would probably be better substituted with
buf.Length.

And you would probably want some cleanup code to remove the file if
something goes wrong, something along the lines of:

Stream s = null;
try {
using ( s = new FileStream(Name, FileMode.Create) ) {
byte[] buf = new byte[size];
int r;
while ( (r = TheResponse.Read(buf,0,buf.Length) != 0 )
s.Write(buf, 0, r);
} catch ( Exception e ) {
if ( s != null )
File.Delete(Name);
throw;
}

--
Helge

Jul 21 '05 #7

This discussion thread is closed

Replies have been disabled for this discussion.

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