Would like to disable a single aspx page in an ASP.NET web application and show the message 'This page is under maintenance' while the application is still up. Is this possible?
One way to do that on Application_BeginRequest on global.asax. Check the if the specific file is called and show some other static page and End the process there. Here is how:
protected void Application_BeginRequest(Object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
string cTheFileName = System.IO.Path.GetFileName(HttpContext.Current.Request.Path);
// if its the file you want to be offline
if (cTheFileName == 'filename.aspx')
{
// the file we look now is the app_offline_alt.htm
string cOffLineFile = HttpRuntime.AppDomainAppPath + "app_offline_alt.htm";
// if exist on root - if not we skip the offline mode.
// this way you can put it offline with just the existing of this file.
if (System.IO.File.Exists(cOffLineFile))
{
using (var fp = System.IO.File.OpenText(cOffLineFile))
{
// read it and send it to the browser
app.Response.Write(fp.ReadToEnd());
fp.Close();
}
// and stop the rest of processing
app.Response.End();
return;
}
}
}
the app_offline_alt.htm contains a simple under maintenance message or what ever you like.
Related
This question already has answers here:
How can I programmatically stop or start a website in IIS (6.0 and 7.0) using MsBuild?
(3 answers)
Closed 7 years ago.
I am using the MVC5 for an web application. The web app runs in IIS7 or greater.
In the Global.asax on application_start, the number of licenses will be set:
protected void Application_Start()
{
try
{
MyApp.cNumberOfLicenses = COM.GetNumberOfLicenses();
}
catch(Exception e)
{
// log exception
// stop web site.
}
}
If any expection will be thrown in this context, the web site should shut down as you can do that in the IIS-Manager:
How can I stop the current web site in my Application_Start ?
You can do it with the help of "Microsoft.Web.Administration.dll"
using Microsoft.Web.Administration;
After adding the reference of "Microsoft.Web.Administration.dll" write below code in Global.asax
protected void Application_Start(object sender, EventArgs e)
{
try
{
MyApp.cNumberOfLicenses = COM.GetNumberOfLicenses();
}
catch (Exception e)
{
// get the web site name
var lWebSiteName = System.Web.Hosting.HostingEnvironment.ApplicationHost.GetSiteName();
// log exception
// stop web site.
using (ServerManager smg = new ServerManager())
{
var site = smg.Sites.FirstOrDefault(s => s.Name == lWebSiteName);
if (site != null)
{
//stop the site...
site.Stop();
}
}
}
}
I will go not with stop it, but to show some message if you do not have license.
This is an example, and an idea.
You can use this code on global.asax where if you do not have licenses the moment you start, you open a flag, and after that you do not allow any page to show, and you send a page that you can keep on an html file.
private static bool fGotLicense = true;
protected void Application_Start()
{
try
{
MyApp.cNumberOfLicenses = COM.GetNumberOfLicenses();
}
catch(Exception e)
{
// log exception
// stop web site.
fGotLicense = false;
}
}
protected void Application_BeginRequest(Object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
// if not have license - let show some infos
if (!fGotLicens)
{
// the file we look now is the app_offline_alt.htm
string cOffLineFile = HttpRuntime.AppDomainAppPath + "app_offline_alt.htm";
// if exist on root
if (System.IO.File.Exists(cOffLineFile))
{
using (var fp = System.IO.File.OpenText(cOffLineFile))
{
// read it and send it to the browser
app.Response.Write(fp.ReadToEnd());
fp.Close();
}
}
// and stop the rest of processing
app.Response.End();
return;
}
}
You can have a file named app_offline.htm with content say This website is offline now in web server and copy that to root directoy of website you want for any event.
It will directly show that message, but yes, App pool will be still ON, when you need to start , you just need to rename that to something else.
I have developed one web application for my client in asp.net. That application has been hosted in the web server. If my client does not satisfy my requirement, I want to block that web application running from the server based on date. How to do that?
You can ether use the Application_BeginRequest to make that test as:
protected void Application_BeginRequest(Object sender, EventArgs e)
{
string cTheFile = HttpContext.Current.Request.Path;
string sExtentionOfThisFile = System.IO.Path.GetExtension(cTheFile);
// here you can check what file you wish to cut, ether by file, ether by extention
if (sExtentionOfThisFile.Equals(".aspx", StringComparison.InvariantCultureIgnoreCase))
{
// and here is the time limit.
if(DateTime.UtcNow > MaxDateToUse)
{
HttpContext.Current.Response.TrySkipIisCustomErrors = true;
HttpContext.Current.Response.StatusCode = 403;
HttpContext.Current.Response.End();
return ;
}
}
}
ether add the same test inside a BasePage use that BasePage for all pages, and make there that test as I describe it on this answer: Make an asp .net web app offline
relative:
Making a web site available only for a specified time
switch off the all functions in .net service
Make an asp .net web app offline
I have an asp.net web application that performs some license checks before calling up the login page... if the product is not licensed then it navigates to a abc.aspx page with some error details. This license check is an HttpModule which is configured via web.config.
I have an event handler for context authentication. Whenever the abc.aspx page is called, this event is fired multiple times and the page load never happens.
on Init, i use this code to add the event handler
context.AuthenticateRequest += new EventHandler
When i use a html page, this issue does not seem to occur. The issue exists even if i use some other aspx page for example xyz.aspx...
How can stop this authentication to takes place n number of times. I have tried with HttpContext.Current.Response.End(), it stops the infinite calls, but does not load the page, the page appears blank.
Any one has any idea about this issue?
snippet of Global.asax.
<%# Application Language="C#" Inherits="Microsoft.Practices.CompositeWeb.WebClientApplication" %>
<script runat="server">
private static bool _initializedAlready = false;
private static readonly Object s_lock = new Object();
//fires once on asp.net worker process start
protected override void Application_Start(object sender, EventArgs e)
{
}
protected void Application_BeginRequest(object sender, EventArgs e)
{
if (_initializedAlready)
{
return;
}
lock (s_lock)
{
if (_initializedAlready)
{
return;
}
//custom initialization code
base.Application_Start(sender, e);
_initializedAlready = true;
}
}
public override void Init()
{
base.Init();
//initialize the license module here....
licenseModule.Init(this);
}
</script>
The init() method of license module
public void Init(HttpApplication context)
{
context.AuthenticateRequest += new EventHandler(context_AuthenticateRequest);
}
I think the problem is due to the fact that you are authenticating abc.aspx as well.
When you go to a page and the license check fails, it redirects to abc.aspx. Unfortunately, you did not exempt abc.aspx from this check, and it checks itself, and then redirects to itself again and again and again.
What you can do is to only attach the authenticate request event in your Init() method when the page is not "abc.aspx". Something like:
if(!context.Context.Request.RawUrl.Contains("abc.aspx"))
context.AuthenticateRequest += new EventHandler(context_AuthenticateRequest);
However, if you only want to do this check on the login page, you would be better off putting the authentication check just on the login page code behind.
Last few days I thinkin about output cache in asp.net. In my task I need to implement output cache for the very big project. After hours of searching I did not find any examples.
Most popular way to use output cache is declarative, in this case you need to write something like this on the page which you want to cache.
But if you need to cache whole site you must write this on all pages or master pages on project. It is madness. In this case you cant store all configuration in one place. All page have his own configurations..
Global.asax could help me, but my site contains about 20 web progects and ~20 global.asax files. And i don't want copy same code to each project.
For these reasons, i made decision to create HTTPModule.
In Init method i subscribe to two events :
public void Init(HttpApplication app)
{
app.PreRequestHandlerExecute += new EventHandler(OnApplicationPreRequestHandlerExecute);
app.PostRequestHandlerExecute += new EventHandler(OnPostRequestHandlerExecute);
}
In method "OnPostRequestHandlerExecute" I set up output caching parameters for each new request :
public void OnPostRequestHandlerExecute(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
HttpCachePolicy policy = app.Response.Cache;
policy.SetCacheability(HttpCacheability.Server);
policy.SetExpires(app.Context.Timestamp.AddSeconds((double)600));
policy.SetMaxAge(new TimeSpan(0, 0, 600));
policy.SetValidUntilExpires(true);
policy.SetLastModified(app.Context.Timestamp);
policy.VaryByParams.IgnoreParams = true;
}
In "OnApplicationPreRequestHandlerExecute" method I set calback method to cache validation:
public void OnApplicationPreRequestHandlerExecute(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
app.Context.Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), app);
}
And last part - callback validation method :
public void Validate(HttpContext context, Object data, ref HttpValidationStatus status)
{
if (context.Request.QueryString["id"] == "5")
{
status = HttpValidationStatus.IgnoreThisRequest;
context.Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), "somecustomdata");
}
else
{
status = HttpValidationStatus.Valid;
}
}
To attach my HttpModule I use programmatically attach method :
[assembly: PreApplicationStartMethod(typeof(OutputCacheModule), "RegisterModule")]
This method works perfectly, but I want to know is there other ways to do this.
Thanks.
Try seeing if IIS caching provides what you need.
http://www.iis.net/configreference/system.webserver/caching
We are trying to remove the global.asax from our many web applications in favor of HttpModules that are in a common code base. This works really well for many application events such as BeginRequest and PostAuthentication, but there is no Application Start event exposed in the HttpModule.
I can think of a couple of smelly ways to overcome this deficit. For example, I can probably do this:
protected virtual void BeginRequest(object sender, EventArgs e)
{
Log.Debug("Entered BeginRequest...");
var app = HttpContext.Current.Application;
var hasBeenSet app["HasBeenExecuted"] == null ? false : true;
if(!hasBeenSet)
{
app.Lock();
// ... do app level code
app.Add("HasBeenExecuted", true);
app.Unlock();
}
// do regular begin request stuff ...
}
But this just doesn't smell well to me.
What is the best way to invoke some application begin logic without having a global.asax?
Just keep a static bool in the HttpModule:
private static bool _hasApplicationStarted = false;
private static object _locker = new object();
private void EnsureStarted()
{
if (_hasApplicationStarted) return;
lock (_locker)
{
if (_hasApplicationStarted) return;
// perform application startup here
_hasApplicationStarted = true;
}
}
Then have any method that needs the application to have started just call EnsureStarted.
HttpModules and HttpHandlers will execute on every single request, while the Global.asax App Start event is when the application starts, thus only once.
You could make a general global.asax which will load all assemblies with a specific interface, and then drop in the dll's you want executed for that specific application. Or even register them in your web.config, and have your general global.asax read the keys, and then load and execute the code you want.
I think this is better than putting app once code in a module and checking on a state variable.