traefik/docs/content/middlewares/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]+/"

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

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

Configuration Options

General

The StripPrefixRegex middleware will:

• strip the matching path prefix.
• store the matching path prefix in a X-Forwarded-Prefix header.

!!! tip

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

regex

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

!!! tip

Regular expressions 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).

For instance, /products would match /products but also /products/shoes and /products/shirts.

Since the path is stripped prior to forwarding, your backend is expected to listen on /.

If your backend is serving assets (e.g., images or Javascript files), chances are it must return properly constructed relative URLs.

Continuing on the 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).

The X-Forwarded-Prefix header can be queried to build such URLs dynamically.