Question

I started using MiniProfiler and find it very useful while developing my MVC 4 application.

However, I just added a new controller action and view to a fairly complex project, and now MiniProfiler throws an Exception after control returns from the controller.

The exception text is Illegal Character in Path.

The Call stack location is

MiniProfiler.dll!StackExchange.Profiling.MVCHelpers.ProfilingActionFilter.OnActionExecuted(System.Web.Mvc.ActionExecutedContext filterContext) Line 58

My controller action and view are both quite simple.

Controller action

    [AllowAnonymous]
    public ActionResult ReleaseNotes(string name)
    {
        CheckInput(name);

        string notesPath = Server.MapPath("~/Content/ReleaseNotes/" + name + ".html"); 
        string notes = null;

        if (System.IO.File.Exists(notesPath))
        {
            notes = System.IO.File.ReadAllText(notesPath);
        }

        return View(notes);
    }

    private void CheckInput(string name)
    {
        if (name.Length > 0x100 || !name.IsAlphaNumeric()) throw new ArgumentException("Name is invalid.");
    }

NOTE: System.IO.File.ReadAllText successfully reads in the contents of an HTML file. That path is valid.

View

@model string

@{
    ViewBag.Title = "Release Notes";
}

<h2>Release Notes</h2>

@if (string.IsNullOrWhiteSpace(Model))
{
    <p>No release notes were found for the specified release.</p>
}
else
{
    @Html.Raw(Model)
}

I have disabled MiniProfiler for now. Any thoughts on how to get it working again?

Answer 1

It turns out that this error was a curious manifestation of this issue

Illegal characters in path when calling the index view from my controller

I was passing in a string as the model. Due to the way method overloading resolves, MVC thought that the contents of the HTML file was the name of the view that I wanted to load (no wonder it complained about the path…).

Interestingly enough, the debugger continued until the return from my controller action before throwing the Exception. After I disabled MiniProfiler, my application’s global exception handler caught and logged the specifics.

I’m still not sure why the problem showed up in MiniProfiler.