traefik/docs/content/middlewares/http/stripprefixregex.md

StripPrefixRegex

Removing Prefixes From the Path Before Forwarding the Request (Using a Regex) {: .subtitle }

Remove the matching prefixes from the URL path.

Configuration Examples

labels:
  - "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/"

apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-stripprefixregex
spec:
  stripPrefixRegex:
    regex:
      - "/foo/[a-z0-9]+/[0-9]+/"

- "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/"

"labels": {
  "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex": "/foo/[a-z0-9]+/[0-9]+/"
}

labels:
  - "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/"

http:
  middlewares:
    test-stripprefixregex:
      stripPrefixRegex:
        regex:
          - "/foo/[a-z0-9]+/[0-9]+/"

[http.middlewares]
  [http.middlewares.test-stripprefixregex.stripPrefixRegex]
    regex = ["/foo/[a-z0-9]+/[0-9]+/"]

Configuration Options

General

The StripPrefixRegex middleware strips the matching path prefix and stores it in a X-Forwarded-Prefix header.

!!! tip

Use a `stripPrefixRegex` middleware if your backend listens on the root path (`/`) but should be exposed on a specific prefix.

regex

The regex option is the regular expression to match the path prefix from the request URL.

For instance, /products also matches /products/shoes and /products/shirts.

If your backend is serving assets (e.g., images or JavaScript files), it can use the X-Forwarded-Prefix header to properly construct relative URLs. Using the previous example, the backend should return /products/shoes/image.png (and not /images.png, which Traefik would likely not be able to associate with the same backend).

!!! tip

Regular expressions and replacements can be tested using online tools such as [Go Playground](https://play.golang.org/p/mWU9p-wk2ru) or the [Regex101](https://regex101.com/r/58sIgx/2).

When defining a regular expression within YAML, any escaped character needs to be escaped twice: `example\.com` needs to be written as `example\\.com`.