Solved

Buffer 40MB or larger files does not work

Posted on 2012-03-19
3
284 Views
Last Modified: 2012-03-21
Hi

I have this code: what it does is it loads a mp3 file into memory, (using jwplayer), with small files (under 7mb) I can skip forward or move back. But when I load a 40mb file it look like it has to load the whole file into memory. So I cant move forward or back (user exp sucks).

Does anyone know how to get this to work?


public static void ResumableFile(string filename, string fullpath, string contentType)
    {
        System.IO.Stream iStream = null;

        // Buffer to read 10K bytes in chunk:
        byte[] buffer = new Byte[10000];

        int length;
        
        try
        {
            FileStream myFile = new FileStream(fullpath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            BinaryReader br = new BinaryReader(myFile);
            try
            {
                iStream = new System.IO.FileStream(fullpath, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);          
                
                HttpContext.Current.Response.AddHeader("Accept-Ranges", "bytes");
                HttpContext.Current.Response.Buffer = false;

                // Total bytes to read:
                long fileLength = myFile.Length;
                
                long startBytes = 0;

                //int pack = 10240; //10K bytes


                int pack = 1048576; //1024K bytes

                if (HttpContext.Current.Request.Headers["Range"] != null)
                {
                    HttpContext.Current.Response.StatusCode = 206;
                    string[] range = HttpContext.Current.Request.Headers["Range"].Split(new char[] { '=', '-' });
                    startBytes = Convert.ToInt64(range[1]);
                }
                HttpContext.Current.Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
                if (startBytes != 0)
                {
                    HttpContext.Current.Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));
                }
                HttpContext.Current.Response.AddHeader("Connection", "Keep-Alive");
                HttpContext.Current.Response.ContentType = contentType;
                //HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8));

                br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
                int maxCount = (int)Math.Floor((double)((fileLength - startBytes) / pack)) + 1;

                // Read the bytes.
                while (fileLength > 0)
                {
                    // Verify that the client is connected.
                    if (HttpContext.Current.Response.IsClientConnected)
                    {
                        // Read the data in buffer.
                        length = iStream.Read(buffer, 0, 10000);

                        // Write the data to the current output stream.
                        HttpContext.Current.Response.OutputStream.Write(buffer, 0, length);

                        // Flush the data to the HTML output.
                        HttpContext.Current.Response.Flush();

                        buffer = new Byte[10000];
                        fileLength = fileLength - length;
                    }
                    else
                    {
                        //prevent infinite loop if user disconnects
                        fileLength = -1;
                    }
                }
            }
            catch
            {
                HttpContext.Current.Response.ContentType = "text/html";
                HttpContext.Current.Response.Write("Error : file not found");
            }
            finally
            {
                br.Close();
                myFile.Close();
            }
        }
        catch
        {
            HttpContext.Current.Response.ContentType = "text/html";
            HttpContext.Current.Response.Write("Error : file not found");
        }
    }

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Question by:mousemat24
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3 Comments
 
LVL 44

Accepted Solution

by:
AndyAinscow earned 500 total points
ID: 37737339
>>But when I load a 40mb file it look like it has to load the whole file into memory.

Correct - that is what you have coded (read the file in the while loop).

>>Does anyone know how to get this to work?

Yes - don't use the while loop, read the first buffer load then read only when it is required.  (Maybe you should read the file in a thread)
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Author Comment

by:mousemat24
ID: 37737366
AndyAinscow, dont suppose you can send me the code? Many thanks
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LVL 44

Expert Comment

by:AndyAinscow
ID: 37737582
It is basically what you currently have - just remove the while loop and keep track of how much you have read from the file.
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