How to choose Content-Type in HTTP response

Question

I write small http server. I need to set Content-Type when I send file in response. How it should be done? Should Content-Type field be preset in some map for each file or it might be set basing on file extension? If yes, how about *.ico files that are PNG actually?

So what's the common practice?

Answer 1

So what's the common practice?

Common practice, for static files, is to infer the Content-Type from the file extension.

If yes, how about *.ico files that are PNG actually?

Then common practice would give the wrong content-type.

You could override it on a case-by-case basis from a configuration file.

eg Apache HTTPD would allow:

<Files "favicon.ico">
    ForceType image/png
</Files>