I have installed Glimpse (Glimpse MVC4) and MiniProfiler (with EF support).
I also installed the MiniProfiler plugin for Glimpse.
I have that all wired up and working. I want to allow the configuration of Glimpse to determine if MiniProfiler should start profiling. That is, if Glimpse is enabled (through Glimpse.axd not via a config setting) I want to call MiniProfiler.Start() in the Application_BeginRequest() method. So, something like this:
protected void Application_BeginRequest()
{
if (Glimpse.IsRunning)
{
MiniProfiler.Start();
}
}
Is there a way to determine if Glimpse is enabled?
Technically there is a way, but I'd call it hacky at best. I'll let you decide if it is a good fit for your purposes.
var policyString = HttpContext.Current.Items["__GlimpseRequestRuntimePermissions"].ToString();
RuntimePolicy glimpsePolicy;
RuntimePolicy.TryParse(policyString, out glimpsePolicy);
if (!glimpsePolicy.HasFlag(RuntimePolicy.Off))
{
MiniProfiler.Start();
}
The reason I call it a hack is because while Glimpse may be On at the beginning of request, it may be later turned Off.
An example of this behavior is when Glimpse automatically shuts off once ASP.NET begins to report an unsupported media type, like an image. ASP.NET does not have the ability to know the media type until after the HTTP Handler has run. In this case, Glimpse will say that it is on at the beginning of the request, but then will be off at the end of it.
Related
We are evaluating FiddlerCore for a use-case. Basically, for now we just want to catch all of the endpoints/urls being requested on a system. This works fine in Fiddler, no issues. But we only want to catch them while a certain vendor software is open. So we want to write a plugin to that software that will run when it launches, and then exit when it exits. Hence, using FiddlerCore (hopefully).
As proof-of-concept, I just made a simple app, one form with a textbox, that it should just append each url into the textbox. Simple as simple can be. However, it's not doing anything. I run the app, then refresh a page in my browser, and ... nothing.
Here is the entire (non-generated) code of my program...
using Fiddler;
using System;
using System.Windows.Forms;
namespace ScratchCSharp {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
FiddlerApplication.AfterSessionComplete += FiddlerApplication_AfterSessionComplete;
FiddlerApplication.Startup(8888, FiddlerCoreStartupFlags.Default);
}
private void FiddlerApplication_AfterSessionComplete(Session s) {
textBox1.Invoke((Action)delegate () {
AddText(s.fullUrl);
});
}
public void AddText(string text) {
textBox1.Text += $"{text}\n";
}
}
}
After a little more poking around, I see that FiddlerApplication.IsSystemProxy is returning false. Seems to have to do with that the Startup flag to set as system proxy is no longer honored, and it tells you now to use the Telerik.NetworkConnections.NetworkConnectionManager to set it as the system proxy. But I can't find anywhere that actually says how to do that. The closest thing I could find is this thread which seems to be their official answer to this question. However, it only goes into a lot of talk about WHY they deprecated the flag, and what their thinking was in how they designed its replacement, but not actually into HOW TO USE the replacement. The Demo app also does NOT use these libraries (probably why it doesn't catch anything either).
The biggest problem though, is that the NetworkConnectionsManager class has no public constructor, so you can't create an instance. It is not inheritable, so you can't make a subclass instance. All of the methods on it are instance methods, not static/shared. And there seems to be no method in the libraries which will create an instance of NetworkConnectitonsManager for you.
So while the class is clearly designed to be used as an instance (hence the methods not being static/shared, there doesn't actually seem to be any way to create an instance.
Any help on how to set this thing up to catch all the outgoing URLs on the system?
You can use the following code for starting Fiddler Core and registering it as a system proxy:
FiddlerCoreStartupSettings startupSettings =
new FiddlerCoreStartupSettingsBuilder()
.ListenOnPort(fiddlerCoreListenPort)
.RegisterAsSystemProxy()
.ChainToUpstreamGateway()
.DecryptSSL()
.OptimizeThreadPool()
.Build();
FiddlerApplication.Startup(startupSettings);
Some of the methods are obsolete for now, but I would recommend to stick with them until the NetworkConnectionManager API is improved and finalized.
Also, there is a sample application (that FiddlerCore installer installs on the Desktop), which is useful for a starting point with the development.
I am trying to access session data from inside a view.
Use Case: I'm storing status messages in the session that will be displayed at the top of the page. Currently I implemented this by using a DisplayMessages() function that sets some ViewData[....] properties and calling it at the beginning of every controller action.
Goal: I want to only set the status message once without needing additional code in the controller to display the messages on the next page load.
So I'm trying to access the messages that are stored in the session directly from the view.
So far I have tried the following:
Dependency Injection of an IHttpContextAccessor (doesn't seem to work anymore with ASP .NET Core MVC 1.0.0
Creating a static class to access the session, including the change from next() to next.invoke() suggested in the comment
This didn't work. I could access the HttpContext and Session.IsAvailable was true, but there was no data in the session.
The following should work in the view: Context.Session.TryGetValue
If you are using the SessionExtensions then Context.Session.GetString will work.
Injecting IHttpContextAccessor does work, but starting with ASP.NET Core 1.0.0 RC2, the IHttpContextAcessor is not registered by default, because it has significant performance overhead per request. See this GitHub announcement for more information.
Tratcher posted:
IHttpContextAccessor can be used to access the HttpContext for the current thread. However, maintaining this state has non-trivial performance costs so it has been removed from the default set of services.
Developers that depend on it can add it back as needed:
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
But in your use case, I would suggest using a ViewComponent, which is a reusable piece of View with logic, that do not depend on a controller.
The documentation can be found here.
In your Views you would simply embed it with
#await Component.InvokeAsync("PriorityList", new { maxPriority = 2, isDone = false })
or
#Component.Invoke("PriorityList", new { maxPriority = 2, isDone = false })
for synchronous calls.
I am upgrading a web site from MVC3 to MVC5. I simply used NuGet to install Microsoft.AspNet.Mvc version 5.2.3 and everything seemed to be working fine. But upon closer examination I noticed that this code was no longer running:
public abstract class BaseController : System.Web.Mvc.Controller
{
protected override void Execute(RequestContext requestContext)
{
LogRequest();
UpdateUserSession();
base.Execute(requestContext);
}
}
I found this lifecycle documentation (linked from here) which seems to confirm that Execute is no longer called by MVC.
However, this documentation is unclear, saying
This method is an implementation of Execute. You typically do not have to override this method. Override Initialize or ExecuteCore instead.
I would expect it to say "This method is no longer called by the MVC framework as of version 5 (or maybe 4)." Perhaps even mark it [Obsolete], although there may have been good reasons not to do that.
Furthermore, my testing shows that ExecuteCore does not get called either! It looks like OnActionExecuting is the best place to move the code that used to live in Execute, is that correct?
Maybe it helps to anybody:
Old version:
errorManagerController.Execute(requestContext);
New version:
Response.RedirectToRoute(routeData.Values);
I'm trying to setup MiniProfiler on my web api site, and having a hard time getting MiniProfiler.Current to work.
I followed the directions at miniprofiler.com, and have the following in global.asax:
protected void Application_Start()
{
MiniProfilerEF6.Initialize();
// other setup
}
protected void Application_BeginRequest() {
// need to start one here in order to render out the UI
MiniProfiler.Start();
}
protected void Application_EndRequest() {
MiniProfiler.Stop();
}
This uses the default WebRequestProfilerProvider, which stores the actual profile object in HttpContext.Current.Items.
When I ask for MiniProfiler.Current, it looks to HttpContext.Current.
When I make a request for one of my web api URLs:
Application_BeginRequest creates the profiler, store it in HttpContext.Current
in a web api MessageHandler, I can see HttpContext.Current
in a web apu IActionFilter, HttpContext.Current is now null, and my attempt to MiniProfiler.Current.Step("controller:action") fails
my EF queries run from various services do not get recorded, as that miniprofiler hook relies MiniProfiler.Current, which relies on HttpContext.Current, which is null right now
Application_EndRequest fires, and HttpContext.Current is magically back, and so it wraps up the profiler and tells me how long it's been since the request began
I dug through the code, and I can create my own IProfileProvider, to store the profiler object somewhere more reliable than HttpContext.Current, but I don't know where that could be.
I spent a few hours trying things out, but couldn't find a workable solution. The problems:
the IProfileProvider is a global variable; all worker threads in either the MVC or Web API pipeline all have to use the same IProfileProvider
I can dig around in web api RequestContext.Properties to pull out the HttpContext for that request, but that doesn't really help because my IProfileProvider is global across the entire app; If I tell it to store the profile in HttpContext A, then any simultaneous requests for other HttpContexts are going to pollute the profile
I can't rely on any kind of threadstorage because of async/await re-using threads dynamically
I can't stick the profiler object in an Ninject binding with InRequestScope because InRequestScope doesn't seem to work with web api 2.1, but even if I could
everyone says HttpRequestMessage.Properties is the new HttpContext.Current.Items, but again, IProfileProvider is a global variable and I don't know of a way to ensure each request is looking at their version HttpRequestMessage. MiniProfiler.Current can be called from anywhere, so I guess a global IProfileProvider would have to somehow inspect the call stack to and find an HttpRequestMessage there? That sounds like madness.
I'm at a loss. What I really want is a special variable.
The process of putting the question together I figured it out. HttpContext.Current can get lost when you async/await things: Why is HttpContext.Current null after await?
I had to make the web.config change listed there, and adjusted my filters to use Miniprofiler.Current before any awaiting.
Also discussed at https://www.trycatchfail.com/2014/04/25/using-httpcontext-safely-after-async-in-asp-net-mvc-applications/
Is there any way to set a custom error page in IIS 7 without creating a web.config?
Unfortunately researching this particular topic has been very difficult because there are SO many articles on how to do it with a web.config. What I'm looking for is either buried beneath the 8 million results I don't want or it's not possible.
Yes, there is. It involves either subscribing to the Application_Error event in Global.asax or by writing a custom ErrorHandlerAttribute.
Darin already gave the correct answer, but I want to go into a little more depth.
In any ASP.NET application, given it is Web Forms, MVC, or raw ASP.NET, you can always use Application_Error Global.asax. If your ASP.NET application does not have a Global.asax, all you need to do is right-click your project in Solution Explorer, Add New Item, and choose Global Application Class. You should only have this option available if you don't already have one.
In your Global.asax, if you don't already see it, you can add Application_Error as shown below:
protected void Application_Error(object sender, EventArgs e) {
}
This will be called automatically by ASP.NET whenever there is an error. But as stated here, this is not perfect. Specifically:
An error handler that is defined in the Global.asax file will only
catch errors that occur during processing of requests by the ASP.NET
runtime. For example, it will catch the error if a user requests an
.aspx file that does not occur in your application. However, it does
not catch the error if a user requests a nonexistent .htm file. For
non-ASP.NET errors, you can create a custom handler in Internet
Information Services (IIS). The custom handler will also not be called
for server-level errors.
In Application_Error you can process the uncaught exception with Server.GetLastError(). This will provide you the Exception that was thrown, or null. I am not sure why this handler would be called if an exception didn't occur, but I believe that it is possible.
To redirect the user, use Response.Redirect(). Whatever you pass for the url is going to be sent directly to the browser without any further processing, so you can't use application-relative paths. To do that I would use this method in combination with VirtualPathUtility.ToAbsolute(). For example:
Response.Redirect( VirtualPathUtility.ToAbsolute( "~/Error.aspx" ) );
This redirect will be a 302 (temporary redirect) rather than a 301 (permanent), which is what you want in the case of handling errors. It's worth noting that this overload of Response.Redirect is the same as calling the overload Response.Redirect(url, endResponse: true). This method works by throwing an exception, which is not ideal in terms of performance. Instead, call Response.Redirect(url, false) immediately followed by Response.Complete​Request().
If you're using ASP.NET MVC, [HandleError] is also an option. Place this attribute on your Controller or on an Action within a controller. When this attribute is present, MVC will display the Error view, found in the ~/Views/Shared folder.
But you can make this even easier for yourself. You can automatically add this attribute to call Controllers in your project by creating a FilterConfig class in your project. Example:
public class FilterConfig {
public static void RegisterGlobalFilters(GlobalFilterCollection filters) {
filters.Add(new HandleErrorAttribute());
}
}
And then add FilterConfig.RegisterGlobalFilters( GlobalFilters.Filters ); to your Application_Start() in Global.asax.
You can read more about the HandleErrorAttribute at https://msdn.microsoft.com/en-us/library/system.web.mvc.handleerrorattribute(v=vs.118).aspx.
But as stated above, both of these methods will never cover absolutely all errors that can occur during the processing of your application. It's not possible to provide the best user experience for all possible errors without using Web.config or configuring IIS manually.