Currently, I was trying to write an ASP.Net application that involved a user clicking a ASP.Net button control
C#
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<asp:Button ID="btnDownload"runat="server"Text="Download File"OnClick="btnDownload_Click"/>
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Once the control is clicked the back end stores the users information (first name, last name, email address, phone number, etc…) to a database. After that information is stored to a database, the system would then allow the user to download the file through an generic handler (.ashx file). The file size that was to be downloaded is 600MB.
C#
{
connectionString = WebConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString;
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand("UserDownloadedFile", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add(new SqlParameter("@Guid", SqlDbType.UniqueIdentifier));
cmd.Parameters["@Guid"].Value = new Guid(ViewState["Guid"].ToString());
try
{
int rowsAffected;
rowsAffected = 0;
con.Open();
rowsAffected = cmd.ExecuteNonQuery();
if (rowsAffected > 0)
{
Response.Redirect("http://localhost/someWebApp/DownloadFile.ashx");
}
else
{
// Something went wrong.
}
}
catch (SqlException exception)
{
// Log exception
}
finally
{
con.Close();
}
}
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protectedvoidbtnDownload_Click(objectsender,EventArgse)
{
connectionString=WebConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString;
SqlConnection con=newSqlConnection(connectionString);
SqlCommand cmd=newSqlCommand("UserDownloadedFile",con);
cmd.CommandType=CommandType.StoredProcedure;
cmd.Parameters.Add(newSqlParameter("@Guid",SqlDbType.UniqueIdentifier));
cmd.Parameters["@Guid"].Value=newGuid(ViewState["Guid"].ToString());
try
{
introwsAffected;
rowsAffected=0;
con.Open();
rowsAffected=cmd.ExecuteNonQuery();
if(rowsAffected>0)
{
Response.Redirect("http://localhost/someWebApp/DownloadFile.ashx");
}
else
{
// Something went wrong.
}
}
catch(SqlException exception)
{
// Log exception
}
finally
{
con.Close();
}
}
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Once the database is updated, I call the DownloadFile.ashx generic handler. Upon execution of the generic handler I received the following “OutOfMemoryException” error
This was a result from the following generic handler I was using
C#
using System;
using System.IO;
using System.Web;
public class DownloadFile : IHttpHandler {
public void ProcessRequest(HttpContext context)
{
string mediaName = "myFile.zip"; // 600MB in file size
if (string.IsNullOrEmpty(mediaName))
{
return;
}
string destPath = context.Server.MapPath("~/Downloads/" + mediaName);
// Check to see if file exist
FileInfo fi = new FileInfo(destPath);
// If the file exist on the server then add it to the database
if (fi.Exists)
{
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AppendHeader("Content-Length", fi.Length.ToString());
HttpContext.Current.Response.ContentType = "application/x-zip-compressed";
HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment; filename=" + mediaName);
HttpContext.Current.Response.BinaryWrite(ReadByteArryFromFile(destPath));
HttpContext.Current.Response.End();
}
}
private byte[] ReadByteArryFromFile(string destPath)
{
byte[] buff = null;
FileStream fs = new FileStream(destPath, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
long numBytes = new FileInfo(destPath).Length;
buff = br.ReadBytes((int)numBytes);
return buff;
}
public bool IsReusable
{
get
{
return false;
}
}
}
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<%@WebHandlerLanguage="C#"Class="DownloadFile"%>
usingSystem;
usingSystem.IO;
usingSystem.Web;
publicclassDownloadFile:IHttpHandler{
publicvoidProcessRequest(HttpContext context)
{
stringmediaName="myFile.zip";// 600MB in file size
if(string.IsNullOrEmpty(mediaName))
{
return;
}
stringdestPath=context.Server.MapPath("~/Downloads/"+mediaName);
// Check to see if file exist
FileInfo fi=newFileInfo(destPath);
// If the file exist on the server then add it to the database
if(fi.Exists)
{
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AppendHeader("Content-Length",fi.Length.ToString());
HttpContext.Current.Response.ContentType="application/x-zip-compressed";
HttpContext.Current.Response.AppendHeader("Content-Disposition","attachment; filename="+mediaName);
HttpContext.Current.Response.BinaryWrite(ReadByteArryFromFile(destPath));
HttpContext.Current.Response.End();
}
}
privatebyte[]ReadByteArryFromFile(stringdestPath)
{
byte[]buff=null;
FileStream fs=newFileStream(destPath,FileMode.Open,FileAccess.Read);
BinaryReader br=newBinaryReader(fs);
longnumBytes=newFileInfo(destPath).Length;
buff=br.ReadBytes((int)numBytes);
returnbuff;
}
publicboolIsReusable
{
get
{
returnfalse;
}
}
}
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This handler worked in the past, for very small files. The last time I was using this the file size was about 300MB. My friend @homeraguas reminded me that I might needed to check my web.config file to be sure that the following maxRequestLength and executionTimeout was set. It wasn’t in the web.config file. So I added the following
C#
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<httpRuntime maxRequestLength="600000"executionTimeout="7200"/>
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Recompiled and published, then gave it another go. Still, I came across the “OutOfMemoryException” error. I looked around the net and came across this blog’s article utilizing the following method Reponse.TransmitFile();
The HttpReponse.TransmitFile()method basically states it “Writes the specified file directly to an HTTP response output stream without buffering it in memory.”
This makes sense to me, since the file I want to transfer is 600MB and I do not think the current server I am writing this web application for does not have adequate resources available. So the revision to the code I wrote/used is as follows
C#
using System;
using System.IO;
using System.Web;
public class DownloadFile : IHttpHandler {
public void ProcessRequest(HttpContext context)
{
string mediaName = "myFile.zip"; // 600MB in file size
if (string.IsNullOrEmpty(mediaName))
{
return;
}
string destPath = context.Server.MapPath("~/Downloads/" + mediaName);
// Check to see if file exist
FileInfo fi = new FileInfo(destPath);
try
{
if (fi.Exists)
{
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment; filename=" + fi.Name);
HttpContext.Current.Response.AppendHeader("Content-Length", fi.Length.ToString());
HttpContext.Current.Response.ContentType = "application/octet-stream";
HttpContext.Current.Response.TransmitFile(fi.FullName);
HttpContext.Current.Response.Flush();
}
}
catch (Exception exception)
{
HttpContext.Current.Response.ContentType = "text/plain";
HttpContext.Current.Response.Write(exception.Message);
}
finally
{
HttpContext.Current.Response.End();
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
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<%@WebHandlerLanguage="C#"Class="DownloadFile"%>
usingSystem;
usingSystem.IO;
usingSystem.Web;
publicclassDownloadFile:IHttpHandler{
publicvoidProcessRequest(HttpContext context)
{
stringmediaName="myFile.zip";// 600MB in file size
if(string.IsNullOrEmpty(mediaName))
{
return;
}
stringdestPath=context.Server.MapPath("~/Downloads/"+mediaName);
// Check to see if file exist
FileInfo fi=newFileInfo(destPath);
try
{
if(fi.Exists)
{
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AppendHeader("Content-Disposition","attachment; filename="+fi.Name);
HttpContext.Current.Response.AppendHeader("Content-Length",fi.Length.ToString());
HttpContext.Current.Response.ContentType="application/octet-stream";
HttpContext.Current.Response.TransmitFile(fi.FullName);
HttpContext.Current.Response.Flush();
}
}
catch(Exception exception)
{
HttpContext.Current.Response.ContentType="text/plain";
HttpContext.Current.Response.Write(exception.Message);
}
finally
{
HttpContext.Current.Response.End();
}
}
publicboolIsReusable
{
get
{
returnfalse;
}
}
}
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The result was that it worked.
What do you guys think? Is this an adequate solution? Have a good one!