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HttpRequest Class

Updated: April 2009

Enables ASP.NET to read the HTTP values sent by a client during a Web request.

Namespace:  System.Web
Assembly:  System.Web (in System.Web.dll)

'Declaration
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class HttpRequest
'Usage
Dim instance As HttpRequest

The methods and properties of the HttpRequest class are exposed through the Request properties of the HttpApplication, HttpContext, Page, and UserControl classes.

NoteNote:

Unicode support for HttpRequest class members requires IIS version 6.0 or later.

TopicLocation
How to: Pass Values Between ASP.NET Web PagesBuilding ASP .NET Web Applications
How to: Pass Values Between ASP.NET Web PagesBuilding ASP .NET Web Applications

The following example uses the StreamWriter class to write the values of several HttpRequest class properties to a file. For properties that are of type string, the values are HTML encoded as they are written to the file. Properties that represent a collection are looped through, and each key/value pair that they contain is written to the file. In ASP.NET markup, the Request keyword refers to the HttpRequest object.

Security noteSecurity Note:

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

<%@ Page Language="VB" %>
<%@ import Namespace="System.Threading" %>
<%@ import Namespace="System.IO" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

    '  NOTE: To use this sample, create a c:\temp\CS folder, 
    '  add the ASP.NET account (in IIS 5.x <machinename>\ASPNET, 
    '  in IIS 6.x NETWORK SERVICE), and give it write permissions 
    '  to the folder. 

    Private Const INFO_DIR As String = "c:\temp\VB\RequestDetails" 
    Public Shared requestCount As Integer 

    Private Sub Page_Load(sender As Object, e As System.EventArgs)

        ' Create a variable to use when iterating 
        ' through the UserLanguages property. 
        Dim langCount As Integer 

        ' Create a counter to name the file. 
        Dim requestNumber As Integer = _
          Interlocked.Increment(requestCount)

        ' Create the file to contain information about the request. 
        Dim strFilePath As String = INFO_DIR & requestNumber.ToString() & ".txt" 
        Dim sw As StreamWriter = File.CreateText(strFilePath)

        Try 

            ' Write request information to the file with HTML encoding.
            sw.WriteLine(Server.HtmlEncode(DateTime.Now.ToString()))
            sw.WriteLine(Server.HtmlEncode(Request.CurrentExecutionFilePath))
            sw.WriteLine(Server.HtmlEncode(Request.ApplicationPath))
            sw.WriteLine(Server.HtmlEncode(Request.FilePath))
            sw.WriteLine(Server.HtmlEncode(Request.Path))

            ' Iterate through the Form collection and write 
            ' the values to the file with HTML encoding. 
            For Each s As String In Request.Form
                sw.WriteLine("Form: " & Server.HtmlEncode(s))
            Next s

            ' Write the PathInfo property value 
            ' or a string if it is empty. 
            If Request.PathInfo = String.Empty Then
                sw.WriteLine("The PathInfo property contains no information.")
            Else
                sw.WriteLine(Server.HtmlEncode(Request.PathInfo))
            End If 

            ' Write request information to the file with HTML encoding.
            sw.WriteLine(Server.HtmlEncode(Request.PhysicalApplicationPath))
            sw.WriteLine(Server.HtmlEncode(Request.PhysicalPath))
            sw.WriteLine(Server.HtmlEncode(Request.RawUrl))

            ' Write a message to the file dependent upon 
            ' the value of the TotalBytes property. 
            If Request.TotalBytes > 1000 Then
                sw.WriteLine("The request is 1KB or greater")
            Else
                sw.WriteLine("The request is less than 1KB")
            End If 

            ' Write request information to the file with HTML encoding.
            sw.WriteLine(Server.HtmlEncode(Request.RequestType))
            sw.WriteLine(Server.HtmlEncode(Request.UserHostAddress))
            sw.WriteLine(Server.HtmlEncode(Request.UserHostName))
            sw.WriteLine(Server.HtmlEncode(Request.HttpMethod))

            ' Iterate through the UserLanguages collection and 
            ' write its HTML encoded values to the file. 
            For langCount = 0 To Request.UserLanguages.Length - 1
                sw.WriteLine("User Language " & langCount.ToString() & _
                 ": " & Server.HtmlEncode( _
                     Request.UserLanguages(langCount)))
            Next 

        Finally 
            ' Close the stream to the file.
            sw.Close()
        End Try

        lblInfoSent.Text = _
         "Information about this request has been sent to a file." 
    End Sub 'Page_Load



    Private Sub btnSendInfo_Click(sender As Object, e As System.EventArgs)
        lblInfoSent.Text = _
         "Hello, " & Server.HtmlEncode(txtBoxName.Text) & _
          ". You have created a new  request info file." 
    End Sub 'btnSendInfo_Click

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
        <p>
        </p>
        <p>
            Enter your name here:
            <asp:TextBox id="txtBoxName" runat="server"></asp:TextBox>
        </p>
        <p>
            <asp:Button id="btnSendInfo" onclick="btnSendInfo_Click" runat="server" Text="Click Here"></asp:Button>
        </p>
        <p>
            <asp:Label id="lblInfoSent" runat="server"></asp:Label>
        </p>
    </form>
</body>
</html>

System.Object
  System.Web.HttpRequest

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

Date

History

Reason

April 2009

Added a note explaining that the Request keyword in markup refers to the HttpRequest object.

Customer feedback.

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