Author: Nishant Rana

By default, ASP.NET permits only files that are 4,096 kilobytes (KB) or less to be uploaded to the Web server.  To upload larger files, we must change the maxRequestLength parameter of the <httpRuntime> section in the Web.config file. By default, the <httpRuntime> element is set to the following parameters in the Machine.config file:

<httpRuntime

executionTimeout=“90“

maxRequestLength=“4096“

useFullyQualifiedRedirectUrl=“false“

minFreeThreads=“8“

minLocalRequestFreeThreads=“4“

appRequestQueueLimit=“100“

/>

We can change the value of maxRequestLength to a desired value in our web.config of the application. For 10 mb we can set it to 10240 KB. Even in this case if user tries to upload a file with size more than 10 mb we than get the above “Page cannot be displayed error ” or the page simply hang up. In this case we can catch the error in the Application_Error event handler of the Global.asax file.

void Application_Error(object sender, EventArgs e)

{

if (System.IO.Path.GetFileName(Request.Path) == “Default.aspx”)

{

System.Exception appException = Server.GetLastError();

if (appException.InnerException.Message == “Maximum request length exceeded.”)

{

Server.ClearError();

Response.Write(“The form submission cannot be processed because it exceeded the maximum length allowed by the Web administrator. Please resubmit the form with less data.”);

Response.Write(“<BR><a href=’Default.aspx’>Click Here to go back to page</a> </BR>”);

Response.End();  } } }

I tried with the above code, but it isn’t consistent.

The best solution for this could be to set the value of maxRequestLength to a very high value.

and checking in the code for the size.

Say changing the value to say 700mb ( not sure what the maximum length of request could be)

<httpRuntime useFullyQualifiedRedirectUrl=“true“

maxRequestLength=“716800“

/>

And checking for the length in your code

// Putting the constraint of 1 mb

if (FileUpload1.FileContent.Length < 1024){

FileUpload1.SaveAs(@”C:/MyFolder/” + FileUpload1.FileName);}

else{

return;}

At least the above solution would save us from the page not displayed error.

And the last solution which i found was creating an httpmodule to intercept the web request.

using System;

using System.Collections.Generic;

using System.Text;

using System.Web;

namespace HAMModule{

public class MyModule : IHttpModule{

public void Init(HttpApplication app){

app.BeginRequest += new EventHandler(app_BeginRequest);

}

void app_BeginRequest(object sender, EventArgs e){

HttpContext context = ((HttpApplication)sender).Context;

// check for size if more than 4 mb

if (context.Request.ContentLength > 4096000){

IServiceProvider provider = (IServiceProvider)context;

HttpWorkerRequest wr = (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));

// Check if body contains data

if (wr.HasEntityBody()){

// get the total body length

int requestLength = wr.GetTotalEntityBodyLength();

// Get the initial bytes loaded

int initialBytes = wr.GetPreloadedEntityBody().Length;

if (!wr.IsEntireEntityBodyIsPreloaded()){

byte[] buffer = new byte[512000];

// Set the received bytes to initial bytes before start reading

int receivedBytes = initialBytes;

while (requestLength – receivedBytes >= initialBytes){

// Read another set of bytes

initialBytes = wr.ReadEntityBody(buffer, buffer.Length);

// Update the received bytes

receivedBytes += initialBytes;

}

initialBytes = wr.ReadEntityBody(buffer, requestLength – receivedBytes);}}

// Redirect the user to an error page.

context.Response.Redirect(“Error.aspx”);}}

public void Dispose(){}

}}

and add the following information to web.config

<httpModules>

<add type=“HAMModule.MyModule“ name=“MyModule“/>

</httpModules>

inside

<system.web>

The last solution worked properly!!!!

BeginRequest event –The BeginRequest event signals the creation of any given new request. This event is always raised and is always the first event to occur during the processing of a request.

Article on creating a custom http module

http://msdn.microsoft.com/en-us/library/ms227673(VS.80).aspx

Bye..

Hi I was looking for implementing cryptography in an ASP page.

I found this following article of great use

http://www.4guysfromrolla.com/webtech/010100-1.shtml

The inc file

<%
Dim sbox(255)
Dim key(255)

Sub RC4Initialize(strPwd)
dim tempSwap
dim a
dim b
intLength = len(strPwd)
For a = 0 To 255
key(a) = asc(mid(strpwd, (a mod intLength)+1, 1))
sbox(a) = a
next

b = 0
For a = 0 To 255

b = (b + sbox(a) + key(a)) Mod 256
tempSwap = sbox(a)
sbox(a) = sbox(b)
sbox(b) = tempSwap
Next
End Sub

Function EnDeCrypt(plaintxt, psw)

dim temp
dim a
dim i
dim j
dim k
dim cipherby
dim cipher

i = 0
j = 0

RC4Initialize psw
For a = 1 To Len(plaintxt)
i = (i + 1) Mod 256
j = (j + sbox(i)) Mod 256
temp = sbox(i)
sbox(i) = sbox(j)
sbox(j) = temp
k = sbox((sbox(i) + sbox(j)) Mod 256)

cipherby = Asc(Mid(plaintxt, a, 1)) Xor k
cipher = cipher & Chr(cipherby)
Next
EnDeCrypt = cipher
End Function

%>

And following is the code for my asp page

<!–#include file=”g.inc”–>

<html>
<head>
<title>TestPage</title>
</head>
<body>
<form action=”G.asp” method=”post”>
<%
dim psw, txt
dim strTemp
txt=”NishantRana”
psw=”myPassword”
strTemp=EnDeCrypt(txt,psw)
response.write “Encrypted Text =” & strTemp & “</Br>”
txt=EnDeCrypt(strTemp,psw)
response.write “Decrypted Text =” & txt
%>
</form>

</body>

</html>

Just copy and paste the code

That’s it …