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
Related
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.
Along the lines of this question I want to create a HttpModule that will do some custom logging of requests and responses for us. Using the code in the most popular answer for that question I've got a HttpModule up and running which does indeed work:
class PortalTrafficModule : IHttpModule
{
public void Dispose()
{
// Do Nothing
}
public void Init(HttpApplication context)
{
context.BeginRequest += new EventHandler(context_BeginRequest);
context.EndRequest += new EventHandler(context_EndRequest);
}
private void context_BeginRequest(object sender, EventArgs e)
{
HttpContext context = ((HttpApplication)sender).Context;
// Create and attach the OutputFilterStream to the Response and store it for later retrieval.
OutputFilterStream filter = new OutputFilterStream(context.Response.Filter);
context.Response.Filter = filter;
context.Items.Add("OutputFilter", filter);
// TODO: If required the request headers and content could be recorded here
}
private void context_EndRequest(object sender, EventArgs e)
{
HttpContext context = ((HttpApplication)sender).Context;
OutputFilterStream filter = context.Items["OutputFilter"] as OutputFilterStream;
if (filter != null)
{
// TODO: Log here - for now just debug.
Debug.WriteLine("{0},{1},{2}",
context.Response.Status,
context.Request.Path,
filter.ReadStream().Length);
}
}
}
(note that the OutputFilterStream class referred to in the code is in the referenced question).
However, the responses seem to be missing some HTTP headers that I see in Fiddler (like "Date") and more importantly, when I turn on compression the responses I'm logging aren't compressed whereas what I see in Fiddler is.
So my question - is it possible to log the compressed content or is this happening in a subsequent step my module can't hook in to?
For the record, I've also tried handling the PreSendRequestContent event and the response is still uncompressed.
Hi although I cannot answer your questions directly I have had cause to do similar things in the past and have found the following resource extremely helpful and enlightening. In the end I managed to acheive what I needed for raw soap headers by configuring the System.Diagnostics node within web config and create a trace log of traffic. I understand that your needs may be more granular than that however I believe this resource may still help.
http://msdn.microsoft.com/en-us/library/ms731859
Of particular interest may be the message log configuration and viewing message logs links from the one above.
I have this code
//file Globals.cs in App_Code folder
public class Globals
{
public static string labelText = "";
}
and a simple aspx page which has textbox, label and button. The CodeFile is:
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Label1.Text = Globals.labelText;
}
protected void Button1_Click1(object sender, EventArgs e)
{
Globals.labelText = TextBox1.Text;
}
}
That is when I click on the button the Globals.labelText variable initializes from the textbox; the question is: why when I open this page in another browser the label has that value, which I set by the first browser, that is the static member is common for the every users. I thought that the every request provides in the individual appDomain which created by the individual copy of IIS process. WTF?
Yes you may use static variable to store application-wide data but it is not thread-safe. Use Application object with lock and unlock method instead of static variables.
Take a look at ASP.NET Application Life Cycle Overview for IIS 7.0 and ASP.NET Application Life Cycle Overview for IIS 5.0 and 6.0
No, static in this case is static in that manner only for the lifecycle of the process the request lives on. So this variable will be static the entire time you're processing a single request. In order to have a "static" variable in the manner you describe, you'd have to make it an application variable. Something like this:
//file Globals.cs in App_Code folder
public class Globals
{
// I really recommend using a more descriptive name
public static string LabelText
{
get
{
return Application("LabelText") ?? string.Empty;
}
set
{
Application("LabelText") = value;
}
}
}
By making it an application variable it should survive multiple page requests. A vulnerability it has though is that it will not survive an application pool recycle, and for large applications this can be problematic. If you truly want this variable to behave in a static manner reliably you're probably better off storing its state in a database somewhere.
I'm trying to setup a simple HttpModule to handle authentication between my single sign on server. I've included code for the module below. The module is hitting my SSO and properly authenticating; however, on pages with forms the postback events are not occurring properly (e.g. isPostBack value is always false even though a POST occurred, button click events don't get hit, etc.).
public sealed class MyAuthenticationModule : IHttpModule
{
public void Init(HttpApplication context)
{
context.AuthenticateRequest += OnAuthenticateRequest;
}
public void Dispose()
{
}
public static void OnAuthenticateRequest(object sender, EventArgs e)
{
FormsAuthentication.Initialize();
HttpContext context = HttpContext.Current;
HttpRequest request = context.Request;
HttpResponse response = context.Response;
// Validate the ticket coming back from the authentication server
if (!string.IsNullOrEmpty(request["ticket"]))
{
// I can include code for this if you want, but it appears to be
// working correct as whenever I get a ticket from my SSO it is processed
// correctly. I only get a ticket after coming from the SSO server and
// then it is removed from the URL so this only gets hit once.
MyAuthentication.ProcessTicketValidation();
}
if (!request.IsAuthenticated)
{
// redirect to the login server
response.Redirect("https://sso.example.com/login.aspx" + "?" + "service=" +
HttpUtility.UrlEncode(context.Request.Url.AbsoluteUri), false);
}
}
}
EDIT
I would also like to note that if I change the line:
if (!string.IsNullOrEmpty(request["ticket"]))
to:
if (!string.IsNullOrEmpty(request.QueryString["ticket"]))
the problem goes away.
Is it possible that your postbacks have a duplicate form data variable, "ticket"? That would seem to explain the behavior to me.
Aside from that, this line is suspicous:
FormsAuthentication.Initialize();
The FormsAuthentication class uses the "Provider" pattern, which means it's a singleton. You should not re-initialize. From the msdn documentation:
The Initialize method is called when the FormsAuthenticationModule
creates an instance of the FormsAuthentication class. This method is
not intended to be called from your code.
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.