в 15:30, 26 мая 2010

2010-05-26T15:30:57Z

Admin: 1 версия

2010-05-26T11:56:15Z

1 версия

Новая страница

== Adding the HttpHandler configuration information to web.config==



<source lang="csharp">
using System;
using System.Web;
public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "image/jpeg";
context.Response.WriteFile("Sunset.jpg");
}

public bool IsReusable {
get {
return false;
}
}
}</source>

== Creating Custom HTTP Modules==



<source lang="csharp">
An HTTP Module is a .NET class that executes with each and every page request.
The HTTP Module doesn"t allow you to request a page unless you include the proper query string with the request.
File: App_Code\QueryStringAuthenticationModule.cs
using System;
using System.Web;
namespace MyNamespace
{
public class QueryStringAuthenticationModule : IHttpModule
{
public void Init(HttpApplication app)
{
app.AuthorizeRequest += new EventHandler(AuthorizeRequest);
}
private void AuthorizeRequest(Object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
HttpContext context = app.Context;
string path = context.Request.AppRelativeCurrentExecutionFilePath;
if (String.rupare(path, "~/login.aspx", true) == 0)
return;
bool authenticated = false;
if (context.Request.QueryString["password"] != null)
{
if (context.Request.QueryString["password"] == "secret")
authenticated = true;
}
if (!authenticated)
context.Response.Redirect("~/Login.aspx");
}
public void Dispose() { }
}
}

Register the HTTP Module in the web configuration file.
File: Web.Config
<configuration>
<system.web>
<httpModules>
<add name="QueryStringAuthenticationModule"
type="MyNamespace.QueryStringAuthenticationModule"/>
</httpModules>
</system.web>
</configuration></source>

== HttpContext (C#)==



<source lang="csharp">
using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
namespace Demo
{
public class AppendMessage : IHttpModule
{
private HttpContext _current = null;
#region IHttpModule Members
public void Dispose()
{
throw new Exception("The method or operation is not implemented.");
}
public void Init(System.Web.HttpApplication context)
{
_current = context.Context;
context.PreSendRequestContent +=
new EventHandler(context_PreSendRequestContent);
}
void context_PreSendRequestContent(object sender, EventArgs e)
{
string message = "";
_current.Response.Output.Write(message);
}
#endregion
}
}
File: Web.config

<configuration>
<system.web>
<httpModules>
<add name="AppendMessage" type="AppendMessage, App_code" />
</httpModules>
</system.web>
</configuration></source>

== HttpContext (VB)==



<source lang="csharp">
Imports Microsoft.VisualBasic
Imports System.Web
Public Class AppendMessage
Implements IHttpModule
Dim WithEvents _application As HttpApplication = Nothing
Public Overridable Sub Init(ByVal context As HttpApplication) _
Implements IHttpModule.Init
_application = context
End Sub
Public Overridable Sub Dispose() Implements IHttpModule.Dispose
End Sub
Public Sub context_PreSendRequestContent(ByVal sender As Object, _
ByVal e As EventArgs) Handles _application.PreSendRequestContent
Dim message As String = ""
_application.Context.Response.Output.Write(message)
End Sub
End Class
File: Web.config

<configuration>
<system.web>
<httpModules>
<add name="AppendMessage" type="AppendMessage, App_code" />
</httpModules>
</system.web>
</configuration></source>

== HttpModule Tester==



<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="HttpModuleTester" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HttpModuleTester</title>
</head>
<body>
<form id="form1" runat="server">
<div>

</div>
</form>
</body>
</html>
File: Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class HttpModuleTester : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
HttpContext myHttpContext = HttpContext.Current;
HttpApplication myHttpApplication = myHttpContext.ApplicationInstance;
HttpModuleCollection myHttpModuleCollection = myHttpApplication.Modules;
for (int index=0; index < myHttpModuleCollection.Count; index++)
{
IHttpModule module = myHttpModuleCollection.Get(index);
Response.Write("Module = " + module.ToString() + "<br>");
}
string httpModuleName = myHttpModuleCollection.GetKey(1);
Response.Write("The name of the HttpModule object at index 1" + " is " + """ + httpModuleName + ""." + "<br><br>");
string[] allModules = myHttpModuleCollection.AllKeys;
Response.Write("<b>The HttpModule objects contained in the HttpModuleCollection are:</b><br>");
for (int i = 0; i < allModules.Length; i++)
Response.Write("Module " + i + " : " + allModules[i] + "<br>");
}
}</source>

== Outputting an image from an HttpHandler (C#)==



<source lang="csharp">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>HttpHandler Serving an Image</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<img src="ImageHandler.ashx" />
</div>
</form>
</body>
</html>
File: Handler.ashx

<%@ WebHandler Language="C#" Class="Handler" %>
using System;
using System.Web;
public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "image/jpeg"
context.Response.WriteFile("Sunset.jpg")
}

public bool IsReusable {
get {
return false;
}
}
}</source>

== Outputting an image from an HttpHandler (VB)==



<source lang="csharp">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>HttpHandler Serving an Image</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<img src="ImageHandler.ashx" />
</div>
</form>
</body>
</html>
File: Handler.ashx
<%@ WebHandler Language="VB" Class="Handler" %>
Imports System
Imports System.Web
Public Class Handler : Implements IHttpHandler

Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
context.Response.ContentType = "image/jpeg"
context.Response.WriteFile("Sunset.jpg")
End Sub

Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
Get
Return False
End Get
End Property
End Class</source>

== The IHttpHandler page template (C#)==



<source lang="csharp">
File: Handler.ashx
<%@ WebHandler Language="C#" Class="Handler" %>
using System;
using System.Web;
public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/plain";
context.Response.Write("Hello World");
}

public bool IsReusable {
get {
return false;
}
}
}</source>

== The IHttpHandler page template (VB)==



<source lang="csharp">
File: Handler.ashx
<%@ WebHandler Language="VB" Class="Handler" %>
Imports System
Imports System.Web
Public Class Handler : Implements IHttpHandler

Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
context.Response.ContentType = "text/plain"
context.Response.Write("Hello World")
End Sub

Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
Get
Return False
End Get
End Property
End Class</source>

== URL rewriting HttpModule (C#)==



<source lang="csharp">
using System.Web;
public class SimpleRewriter : System.Web.IHttpModule
{
HttpApplication _application = null;
public void Init(HttpApplication context)
{
context.BeginRequest += new System.EventHandler(context_BeginRequest);
_application = context;
}
public void Dispose()
{
}
private void context_BeginRequest(object sender, System.EventArgs e)
{
string requesturl =
_application.Context.Request.Path.Substring(0,
_application.Context.Request.Path.LastIndexOf("//")
);
string[] parameters = requesturl.Split(new char[] { "/" });
if (parameters.Length > 1)
{
string firstname = parameters[1];
string lastname = parameters[2];
_application.Context.RewritePath("~/unfriendly.aspx?firstname=" +
firstname + "&lastname=" + lastname);
}
}
}</source>

== URL rewriting HttpModule (VB)==



<source lang="csharp">
Imports Microsoft.VisualBasic
Imports System.Web
Public Class SimpleRewriter
Implements System.Web.IHttpModule
Dim WithEvents _application As HttpApplication = Nothing
Public Overridable Sub Init(ByVal context As HttpApplication) _
Implements IHttpModule.Init
_application = context
End Sub
Public Overridable Sub Dispose() Implements IHttpModule.Dispose
End Sub
Public Sub context_BeginRequest(ByVal sender As Object, ByVal e As EventArgs) _
Handles _application.BeginRequest
Dim requesturl As String = _
_application.Context.Request.Path.Substring(0, _
_application.Context.Request.Path.LastIndexOf("/"c))
Dim parameters() As String = _
requesturl.Split(New [Char]() {"/"c}, _
StringSplitOptions.RemoveEmptyEntries)
If (parameters.Length > 1) Then
Dim firstname As String = parameters(1)
Dim lastname As String = parameters(2)
_application.Context.RewritePath("~/unfriendly.aspx?firstname=" & _
firstname & "&lastname=" & lastname)
End If
End Sub
End Class</source>

← Предыдущая	Версия 15:30, 26 мая 2010
(нет различий)

ASP.NET Tutorial/Development/HTTP Modules - История изменений

в 15:30, 26 мая 2010

Admin: 1 версия