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

title	description
Traefik ReplacePathRegex Documentation	In Traefik Proxy's HTTP middleware, ReplacePathRegex updates paths before forwarding requests, using a regex. Read the technical documentation.

ReplacePathRegex

Updating the Path Before Forwarding the Request (Using a Regex) {: .subtitle }

The ReplaceRegex replaces the path of a URL using regex matching and replacement.

Configuration Examples

# Replace path with regex
labels:
  - "traefik.http.middlewares.test-replacepathregex.replacepathregex.regex=^/foo/(.*)"
  - "traefik.http.middlewares.test-replacepathregex.replacepathregex.replacement=/bar/$$1"

# Replace path with regex
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-replacepathregex
spec:
  replacePathRegex:
    regex: ^/foo/(.*)
    replacement: /bar/$1

# Replace path with regex
- "traefik.http.middlewares.test-replacepathregex.replacepathregex.regex=^/foo/(.*)"
- "traefik.http.middlewares.test-replacepathregex.replacepathregex.replacement=/bar/$1"

"labels": {
  "traefik.http.middlewares.test-replacepathregex.replacepathregex.regex": "^/foo/(.*)",
  "traefik.http.middlewares.test-replacepathregex.replacepathregex.replacement": "/bar/$1"
}

# Replace path with regex
labels:
  - "traefik.http.middlewares.test-replacepathregex.replacepathregex.regex=^/foo/(.*)"
  - "traefik.http.middlewares.test-replacepathregex.replacepathregex.replacement=/bar/$1"

# Replace path with regex
http:
  middlewares:
    test-replacepathregex:
      replacePathRegex:
        regex: "^/foo/(.*)"
        replacement: "/bar/$1"

# Replace path with regex
[http.middlewares]
  [http.middlewares.test-replacepathregex.replacePathRegex]
    regex = "^/foo/(.*)"
    replacement = "/bar/$1"

Configuration Options

General

The ReplacePathRegex middleware will:

• replace the matching path with the specified one.
• store the original path in a X-Replaced-Path header.

!!! 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`.

regex

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

replacement

The replacement option defines the replacement path format, which can include captured variables.

!!! warning

Care should be taken when defining replacement expand variables: `$1x` is equivalent to `${1x}`, not `${1}x` (see [Regexp.Expand](https://golang.org/pkg/regexp/#Regexp.Expand)), so use `${1}` syntax.