asp.net core static file caching doesn't work

Question

I am using the Angular project template with ASP.NET Core. Reference

The caching should be enabled by default, to be sure I have added an StaticFileOptions object to the StaticfileMiddleware:

public class Startup
{
 ...
 app.UseStaticFiles(new StaticFileOptions
 {
     OnPrepareResponse = ctx =>
         {
             const int durationInSeconds = 60 * 60 * 24;
             ctx.Context.Response.Headers[HeaderNames.CacheControl] =
              "public,max-age=" + durationInSeconds;
         }
 });
 ...
}

Then I have created an test.html in wwwroot folder.

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset=utf-8>
  <title>Test static files</title>
</head>
<body>
    This is a test for static files!
</body>
</html>

When I dotnet run and navigate to https://localhost:5001/test.html the page is displayed correctly.

test.html

After I change the html page, I click to google chrome's address bar and press enter, to issue another HTTP request to the test.html file. I have not reload the page.

test.html after change

You can see that the change is reflected by google chrome and I received an status 200 again instead of 304. Cache-control in the Response Header is public,max-age=86400. Why does the static file caching not work? My desired result would be that the change is not reflected after the second HTTP request, so I can be sure static file caching is working properly.

I am using: .NET Core SDK 3.1.201 and Chrome 80.0.3987.163.

Cache headers are not sent (or more appropriately, are overwritten) in development. — Chris Pratt
@Chris Pratt Thank you for your answer. I have changed the hosting environment for my asp.net project to production and build the angular app with production option but I receive the same result, the static file caching still doesn't work. — carboneum

carboneum carboneum · Accepted Answer · 2020-04-14T19:35:09

I found the solution. You have to trust the ASP.NET Core HTTPS development certificate. Click here for details and then run the application. Navigate to your static file. Open a new tab in Chrome. Open the Chrome DevTools by pressing F12. Type the URL into the address bar or copy and paste it from the previous tab. It works!

asp.net core static file caching doesn't work

1 Answers