How respect acept: text/plain with nginx?

Question

In http header there is a field named accept, so client can specify prefered format. How can I configure nginx to return markdown page in case of plain text request and processed via some markdown implementation in case of html request?

Answer 1

A partial solution (and the simplest way) would be through an internal redirect. You would probably want these inside of an error_page location, so that it's only activated when the pages are otherwise not found.

error_page 404 = @404;
location @404 {
    if ($http_Accept ~ "text/plain") {
        rewrite ^ $uri.text-plain break;
    }
    if ($http_Accept ~ "text/html") {
        rewrite ^ $uri.text-html break;
    }
    location ~ \.text-plain$ {
    …
    }
    location ~ \.text-html$ {
    …
    }
}

This would not take into the account the priorities that are specified in the Accept header, and, also, the explicit example of "text/plain" and "text/html" might as well be somewhat useless in existing browsers — I'm not sure which user-agents would specify text/plain in their Accept header.

In the old days, Accept was useful for deciding whether to serve .gif or .png images, but not anymore nowadays — it is now deemed that all browsers have and always has supported png images, and sending the extra bytes in the accept header is not worth the extra traffic, so, for example, Mozilla no longer Accept's image/png explicitly, and most other browsers probably follow suit, too.