Earliest inspection of request before entry to application

Question

Before hitting the application itself, is there a way to respond to requests, preferably based on URL, and return a response? Possibly a web.config server (IIS) configuration or a static page kinda like app_offline.

Essentially, this is my scenario: If I receive a request with a specific path (i.e. /hello), I want to straight away return a response and not enter the applicaton.

Is this possible? Is there a way to set a static page that is always served before .NET kicks in (auth, filters, middleware, etc.) kinda like app_offline?

I tried looking at ISAPI filters but it seems overly complex for what I want to do, especially considering our apps are deployed to Azure.

Is there some Azure feature we can leverage?

https://learn.microsoft.com/en-us/iis/extensions/url-rewrite-module/iis-url-rewriting-and-aspnet-routing — Daniel A. White, Sep 18 '20 at 03:34
URL rewriting is one option, and you can also write your own IIS extension in C#, https://learn.microsoft.com/en-us/iis/develop/runtime-extensibility/developing-a-module-using-net — Lex Li, Sep 18 '20 at 04:34

score 1 · Answer 1 · answered Sep 18 '20 at 12:43

I suggest you could try to use httphandler to achieve your requirement. You could create a custom http handler which will fired before the web form.

Details about how to create a custom httphanlder, you could refer to below steps:

1.Create a custom class:

public class CustomHanlder : IHttpHandler
{
    public bool IsReusable => true;

    public void ProcessRequest(HttpContext context)
    {
        context.Response.Write("CustomHttpHandler");
       
    }
}

2.Add below settings into web.config

<system.webServer>
    <handlers>
        <add name="CustomHandler" path="hello" type="[YouapplicationNameSpace].CustomHanlder" verb="*"/>
    </handlers>
</system.webServer>

Result:

Thanks, I went for the rewrite rules though. Not sure which runs first, handlers or rewrite, but rewrite definitely ran before the app so it suffices. — AnimaSola, Sep 23 '20 at 13:33

Earliest inspection of request before entry to application

1 Answers1