[Bug]: VirtualServer > Action.Return.type overwritten when URI contains an extension

[yaronuliel]

Version

edge

What Kubernetes platforms are you running on?

Minikube

Description:

When defining a VirtualServer resource - you can set a preconfigured response - one of the fields it supports is type which according to the docs sets "The MIME type of the response"

In fact - it only sets the default_type (nginx docs) (location in source code) - the implications are that despite setting the desired Content-Type value - when the URI ends with an extension - nginx "guesses" the Content-Type based on the map in /etc/nginx/mime.types

Expected Behavior

When defining a type in a route with return action - it should always return that type as Content-Type, and should ignore not use the extension in the URI to assume the content type

Steps To Reproduce:

1. Apply this following VirtualServer yaml (set host according to your installation):

apiVersion: k8s.nginx.org/v1
kind: VirtualServer
metadata:
  name: virtual-server-bug-demo
spec:
  host: vs-bug-demo.localhost
  routes:
  - path: /
    action:
        return:
          body: "Not Found"
          code: 404
          type: text/plain

2. Browse to http://vs-bug-demo.localhost/not-found - All good, response is 404 with content typetext/plain
3. Browse to http://vs-bug-demo.localhost/not-found/somelinkwith.mp4 - Server response with Content-type: video/mp4 (body still contains the string "Not Found" - which cause the browser to show an invalid video player)

[github-actions]

Hi @yaronuliel thanks for reporting!

Be sure to check out the docs and the Contributing Guidelines while you wait for a human to take a look at this 🙂

Cheers!

[jjngx]

@yaronuliel could you please share generated NGINX config? This will help us investigate the issue.

[yaronuliel]

@jjngx
The applied yaml was

apiVersion: k8s.nginx.org/v1
kind: VirtualServer
metadata:
  name: virtual-server-bug-demo
spec:
  host: vs-bug-demo.localhost
  routes:
  - path: /
    action:
        return:
          body: "Not Found"
          code: 404
          type: text/plain

The created resource yaml is:

apiVersion: k8s.nginx.org/v1
kind: VirtualServer
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"k8s.nginx.org/v1","kind":"VirtualServer","metadata":{"annotations":{},"name":"virtual-server-bug-demo","namespace":"vs-demo"},"spec":{"host":"vs-bug-demo.localhost","routes":[{"action":{"return":{"body":"Not Found","code":404,"type":"text/plain"}},"path":"/"}]}}
  creationTimestamp: "2024-12-24T18:48:42Z"
  generation: 1
  name: virtual-server-bug-demo
  namespace: vs-demo
  resourceVersion: "424986"
  uid: ec36b225-364a-4761-a755-6fde9c4ec690
spec:
  host: vs-bug-demo.localhost
  routes:
  - action:
      return:
        body: Not Found
        code: 404
        type: text/plain
    path: /
status:
  externalEndpoints:
  - hostname: localhost
    ports: '[80,443]'
  message: 'Configuration for vs-demo/virtual-server-bug-demo was added or updated '
  reason: AddedOrUpdated
  state: Valid

The config generated in the nginx controller in /etc/nginx/conf.d/vs_vs-demo_virtual-server-bug-demo.conf is:

server {
    listen 80;
    listen [::]:80;


    server_name vs-bug-demo.localhost;

    set $resource_type "virtualserver";
    set $resource_name "virtual-server-bug-demo";
    set $resource_namespace "vs-demo";

    server_tokens "on";


    location @return_0 {
        default_type "text/plain";

        # status code is ignored here, using 0
        return 0 "Not Found";
    }



    location / {
        set $service "";


        error_page 418 =404 "@return_0";
        proxy_intercept_errors on;
        proxy_pass http://unix:/var/lib/nginx/nginx-418-server.sock;
        set $default_connection_header close;
    }
}

The problem caused by using default_type - which means that nginx will "guess" the content type if the request has an extension. and text/plain will only be used as default (when there is no extension, or the extension is not in nginx's mapping)