Incorrect Content-Type text/plain for javascript in zip-archive

[sorbing]

Incorrect Content-Type: text/plain when requesting assets from *.zip archive (javascript and css files).
I tried using minio s3 as static site hosting (html, js, css, images).
I upload site.zip, then open https://***/bucket/site.zip/index.html.
(In front of minio is installed nginx with configured proxy_pass to :9000 port and additional X-Minio-Extract header).
Thehtml-page opens fine. But all assets are returned with header Content-Type: text/plain instead of:
text/css and text/javascript.
As a result, there is the errors in the browser:

Refused to apply style from 'https://***/bucket/site.zip/src/style.css' because its MIME type ('text/plain') is not a supported stylesheet MIME type, and strict MIME checking is enabled.
# and:
Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/plain". Strict MIME type checking is enforced for module scripts per HTML spec.

So far I've only found a single solution at the Nginx level:

    ####
    ## (!) Fixed an error: Refused to apply style from 'https://***/bucket/site.zip/src/style.css' because
    ##     its MIME type ('text/plain') is not a supported stylesheet MIME type, and strict MIME checking is enabled.
    ####

map $uri $assets_content_type {
    # if $http_host contains the word staging
    "~.+\.js$"  "text/javascript";
    "~.+\.css$" "text/css";
    default     "text/plain";
}

server {
    # ....
    location ~.+\.(js|css)$ {
       ## My: Use Indexing for extract Zip archives (Zip Extract). Example: /site.zip/index.html
       proxy_set_header X-Minio-Extract true;

       ## Proxy to :9000
       proxy_set_header Host $http_host;
       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header X-Forwarded-Proto $scheme;

       proxy_connect_timeout 300;
       # Default is HTTP/1, keepalive is only enabled in HTTP/1.1
       proxy_http_version 1.1;
       proxy_set_header Connection "";
       chunked_transfer_encoding off;

       # This uses the upstream directive definition to load balance
       proxy_pass https://minio_s3;

       #proxy_hide_header X-Content-Type-Options;
       proxy_hide_header Content-Type; 
       add_header Content-Type "$assets_content_type";
    }
}

## ...

This seems to have solved the problem. But maybe there is a more elegant solution.. Thank you 🤝

[klauspost]

We don't have any information on the content type. But I guess the proposal by @jiuker to guess it based on the file extension is better than nothing.