Best practice for streaming fairly large files from server to clie

[=?Utf-8?B?UGhpbCBKb2huc29u?=]

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream (maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.
--
Regards,

Phil Johnson (MCAD)

[Scott Roberts]

One possible option is to redirect the browser to the file location itself.
If the file is stored in a non-http accessible folder, you could copy it
into a temp folder for download. Of course, then you have to clean it up at
some point and there is a potential security risk as other users could also
download the file.

Barring that, I think what you said would be fine. Just read chunks from a
FileStream and buffer them to the Response.

Scott
"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:CD******** *************** ***********@mic rosoft.com...

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole
file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream
(maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.
--
Regards,

Phil Johnson (MCAD)

[sloan]

http://groups.google.com/group/micro...13224a77b89add
See if the WriteTextFile in the HttpHelper will help you.
If it does, please post back here.

I ~think that is what you're looking for.

"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:CD******** *************** ***********@mic rosoft.com...

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole
file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream
(maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.
--
Regards,

Phil Johnson (MCAD)

[=?Utf-8?B?UGhpbCBKb2huc29u?=]

Thanks for your thoughts Scott...

It looks like buffering the filestream in chunks is going to be the best
option... the files will be temporary files and I need to delete them as soon
as the data has been streamed.

--
Regards,

Phil Johnson (MCAD)
"Scott Roberts" wrote:

One possible option is to redirect the browser to the file location itself.
If the file is stored in a non-http accessible folder, you could copy it
into a temp folder for download. Of course, then you have to clean it up at
some point and there is a potential security risk as other users could also
download the file.

Barring that, I think what you said would be fine. Just read chunks from a
FileStream and buffer them to the Response.

Scott
"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:CD******** *************** ***********@mic rosoft.com...

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole
file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream
(maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.
--
Regards,

Phil Johnson (MCAD)

[bruce barker]

first turn of buffering for the page. then use Response.Write in chunks,
or if its an actual file, the builtin Reponse.WriteFi le
(which just read and writes chunks via .Write).
-- bruce (sqlwork.com)

Phil Johnson wrote:

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream (maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.

[sloan]

I use a "double guid" solution here sometimes.

C:\stuff\

http://www.mycompany.com/stuff/
string folderName = System.Guid.New Guid().ToString ("N");
string fileName = System.Guid.New Guid().ToString ("N");
Which gives me something like this (if I'm writing out a txt file)
C:\stuff\\D680E B2590A542F7828A 7F33CF705563\2D B610825821412F8 C5CCFA3C642FEE2 .txt
or
http://www.mycompany.com/stuff/D680E...A3C642FEE2.txt

Aka, a po' man's security model.
Its ugly, but if somebody guesses 2 guid's..... they totally rock.

...

That is if the information is sensitive.

Naturally, I have to clean up:
C:\stuff\

periodically.


"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:A4******** *************** ***********@mic rosoft.com...

Thanks for your thoughts Scott...

It looks like buffering the filestream in chunks is going to be the best
option... the files will be temporary files and I need to delete them as
soon
as the data has been streamed.

--
Regards,

Phil Johnson (MCAD)
"Scott Roberts" wrote:

>One possible option is to redirect the browser to the file location
itself.
If the file is stored in a non-http accessible folder, you could copy it
into a temp folder for download. Of course, then you have to clean it up
at
some point and there is a potential security risk as other users could
also
download the file.

Barring that, I think what you said would be fine. Just read chunks from
a
FileStream and buffer them to the Response.

Scott
"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:CD******* *************** ************@mi crosoft.com...

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream
uses
its WriteTo method to write to the responses output stream. With
larger
files (250 mb) I get a system out of memory exception because the whole
file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream
(maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.
--
Regards,

Phil Johnson (MCAD)

[=?Utf-8?B?UGhpbCBKb2huc29u?=]

Thanks for all the responses, they certianly got me pointed in the right
direction.... after doing a bit of looking online for the response.write in
chunks method I found this great example from Microsoft.... only requires
changing the string for the filename/path.....

http://support.microsoft.com/?kbid=812406

--
Regards,

Phil Johnson (MCAD)
"bruce barker" wrote:

first turn of buffering for the page. then use Response.Write in chunks,
or if its an actual file, the builtin Reponse.WriteFi le
(which just read and writes chunks via .Write).
-- bruce (sqlwork.com)

Phil Johnson wrote:

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream uses
its WriteTo method to write to the responses output stream. With larger
files (250 mb) I get a system out of memory exception because the whole file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream (maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.

[sloan]

Thanks for the followup post... about a concrete solution.

"Phil Johnson" <Ph*********@di scussions.micro soft.comwrote in message
news:6A******** *************** ***********@mic rosoft.com...

Thanks for all the responses, they certianly got me pointed in the right
direction.... after doing a bit of looking online for the response.write
in
chunks method I found this great example from Microsoft.... only requires
changing the string for the filename/path.....

http://support.microsoft.com/?kbid=812406

--
Regards,

Phil Johnson (MCAD)
"bruce barker" wrote:

>first turn of buffering for the page. then use Response.Write in chunks,
or if its an actual file, the builtin Reponse.WriteFi le
(which just read and writes chunks via .Write).
-- bruce (sqlwork.com)

Phil Johnson wrote:

Hello,

I have an issue with some code I am updating:

An entire file is loaded into a memory stream then that memory stream
uses
its WriteTo method to write to the responses output stream. With
larger
files (250 mb) I get a system out of memory exception because the whole
file
is loaded into RAM.

I need to modify this so the file is buffered into the output stream
(maybe
via a filestream?) to avoid the whole file being loaded into ram.

Does anybody have any good example code or links of how to do this?

Thanks in advance for any help.