Currently, I was trying to write an ASP.Net application that involved a user clicking a ASP.Net button control
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<
asp
:
Button
ID
=
"btnDownload"
runat
=
"server"
Text
=
"Download File"
OnClick
=
"btnDownload_Click"
/
>
|
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.
protected void btnDownload_Click(object sender, EventArgs e) { 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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protected
void
btnDownload_Click
(
object
sender
,
EventArgs
e
)
{
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
(
)
;
}
}
|
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
<%@ WebHandler Language="C#" class="DownloadFile" %> 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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<%
@
WebHandler
Language
=
"C#"
Class
=
"DownloadFile"
%>
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
;
}
}
}
|
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
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<
httpRuntime
maxRequestLength
=
"600000"
executionTimeout
=
"7200"
/
>
|
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
<%@ WebHandler Language="C#" class="DownloadFile" %> 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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<%
@
WebHandler
Language
=
"C#"
Class
=
"DownloadFile"
%>
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
;
}
}
}
|
The result was that it worked.
What do you guys think? Is this an adequate solution? Have a good one!