New Routing Reference Documentation

docs/content/reference/routing-configuration/http/middlewares/stripprefixregex.md

@@ -0,0 +1,70 @@
+---
+title: "Traefik StripPrefixRegex Documentation"
+description: "In Traefik Proxy's HTTP middleware, StripPrefixRegex removes prefixes from paths before forwarding requests, using regex. Read the technical documentation."
+---
+
+The `stripPrefixRegex` middleware strips the matching path prefix and stores it in an `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.
+
+## Configuration Example
+
+```yaml tab="Structured (YAML)"
+http:
+  middlewares:
+    test-stripprefixregex:
+      stripPrefixRegex:
+        regex:
+          - "/foo/[a-z0-9]+/[0-9]+/"
+```
+
+```toml tab="Structured (TOML)"
+[http.middlewares]
+  [http.middlewares.test-stripprefixregex.stripPrefixRegex]
+    regex = ["/foo/[a-z0-9]+/[0-9]+/"]
+```
+
+```yaml tab="Labels"
+labels:
+  - "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/"
+```
+
+```yaml tab="Tags"
+{
+  //..
+  "Tags" : [
+    "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/"
+  ]
+}
+- 
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: test-stripprefixregex
+spec:
+  stripPrefixRegex:
+    regex:
+      - "/foo/[a-z0-9]+/[0-9]+/"
+```
+
+## Configuration Options
+
+| Field                        | Description                                                                                                                                                                                                | Default | Required |
+|:-----------------------------|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|:--------|:---------|
+| `regex` | List of regular expressions to match the path prefix from the request URL.<br /> For instance, `/products` also matches `/products/shoes` and `/products/shirts`.<br />More information [here](#regex). | | No |
+
+### regex
+
+If your backend is serving assets (for example, images or JavaScript files), it can use the `X-Forwarded-Prefix` header to 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`.