feat: add support for URLRewrite filter and refactor GWAPI translator

docs/latest/user/http-urlrewrite.md

@@ -0,0 +1,284 @@
+# HTTP URL Rewrite
+
+[HTTPURLRewriteFilter](https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1beta1.HTTPURLRewriteFilter) defines a filter that modifies a request during forwarding. At most one of these filters may be used on a Route rule. This MUST NOT be used on the same Route rule as a HTTPRequestRedirect filter.
+
+Follow the steps from the [Quickstart](quickstart.md) to install Envoy Gateway and the example manifest. Do
+not proceed until you can curl the example backend from the Quickstart guide using HTTP.
+
+## Rewrite URL Prefix Path
+
+You can configure to rewrite the prefix in the url like below. In this example, any curls to `http://${GATEWAY_HOST}:8080/get/xxx` will be
+rewrite to `http://${GATEWAY_HOST}:8080/replace/xxx`.
+
+```shell
+cat <<EOF | kubectl apply -f -
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: http-filter-url-rewrite
+spec:
+  parentRefs:
+    - name: eg
+  hostnames:
+    - path.rewrite.example
+  rules:
+    - matches:
+      - path:
+          value: "/get"
+      filters:
+      - type: URLRewrite
+        urlRewrite:
+          path:
+            type: ReplacePrefixMatch
+            replacePrefixMatch: /replace
+      backendRefs:
+      - name: backend
+        port: 3000
+EOF
+```
+
+The HTTPRoute status should indicate that it has been accepted and is bound to the example Gateway.
+
+```shell
+kubectl get httproute/http-filter-url-rewrite -o yaml
+```
+
+Get the Gateway's address:
+
+```shell
+export GATEWAY_HOST=$(kubectl get gateway/eg -o jsonpath='{.status.addresses[0].value}')
+```
+
+Querying `http://${GATEWAY_HOST}:8080/get/origin/path` should rewrite to `http://${GATEWAY_HOST}:8080/replace/origin/path`.
+
+```console
+$ curl -L -vvv --header "Host: path.rewrite.example" "http://${GATEWAY_HOST}:8080/get/origin/path"
+...
+> GET /get/origin/path HTTP/1.1
+> Host: path.rewrite.example
+> User-Agent: curl/7.85.0
+> Accept: */*
+> 
+
+< HTTP/1.1 200 OK
+< content-type: application/json
+< x-content-type-options: nosniff
+< date: Wed, 21 Dec 2022 11:03:28 GMT
+< content-length: 503
+< x-envoy-upstream-service-time: 0
+< server: envoy
+< 
+{
+ "path": "/replace/origin/path",
+ "host": "path.rewrite.example",
+ "method": "GET",
+ "proto": "HTTP/1.1",
+ "headers": {
+  "Accept": [
+   "*/*"
+  ],
+  "User-Agent": [
+   "curl/7.85.0"
+  ],
+  "X-Envoy-Expected-Rq-Timeout-Ms": [
+   "15000"
+  ],
+  "X-Envoy-Original-Path": [
+   "/get/origin/path"
+  ],
+  "X-Forwarded-Proto": [
+   "http"
+  ],
+  "X-Request-Id": [
+   "fd84b842-9937-4fb5-83c7-61470d854b90"
+  ]
+ },
+ "namespace": "default",
+ "ingress": "",
+ "service": "",
+ "pod": "backend-6fdd4b9bd8-8vlc5"
+...
+```
+
+You can see that the `X-Envoy-Original-Path` is `/get/origin/path`, but the actual path is `/replace/origin/path`.
+
+## Rewrite URL Full Path
+
+You can configure to rewrite the fullpath in the url like below. In this example, any request sent to `http://${GATEWAY_HOST}:8080/get/origin/path/xxxx` will be
+rewritten to `http://${GATEWAY_HOST}:8080/force/replace/fullpath`.
+
+```shell
+cat <<EOF | kubectl apply -f -
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: http-filter-url-rewrite
+spec:
+  parentRefs:
+    - name: eg
+  hostnames:
+    - path.rewrite.example
+  rules:
+    - matches:
+      - path:
+          type: PathPrefix
+          value: "/get/origin/path"
+      filters:
+      - type: URLRewrite
+        urlRewrite:
+          path:
+            type: ReplaceFullPath
+            replaceFullPath: /force/replace/fullpath
+      backendRefs:
+      - name: backend
+        port: 3000
+EOF
+```
+
+The HTTPRoute status should indicate that it has been accepted and is bound to the example Gateway.
+
+```shell
+kubectl get httproute/http-filter-url-rewrite -o yaml
+```
+
+Querying `http://${GATEWAY_HOST}:8080/get/origin/path/extra` should rewrite the request to `http://${GATEWAY_HOST}:8080/force/replace/fullpath`.
+
+```console
+$ curl -L -vvv --header "Host: path.rewrite.example" "http://${GATEWAY_HOST}:8080/get/origin/path/extra"
+...
+> GET /get/origin/path/extra HTTP/1.1
+> Host: path.rewrite.example
+> User-Agent: curl/7.85.0
+> Accept: */*
+> 
+* Mark bundle as not supporting multiuse
+< HTTP/1.1 200 OK
+< content-type: application/json
+< x-content-type-options: nosniff
+< date: Wed, 21 Dec 2022 11:09:31 GMT
+< content-length: 512
+< x-envoy-upstream-service-time: 0
+< server: envoy
+< 
+{
+ "path": "/force/replace/fullpath",
+ "host": "path.rewrite.example",
+ "method": "GET",
+ "proto": "HTTP/1.1",
+ "headers": {
+  "Accept": [
+   "*/*"
+  ],
+  "User-Agent": [
+   "curl/7.85.0"
+  ],
+  "X-Envoy-Expected-Rq-Timeout-Ms": [
+   "15000"
+  ],
+  "X-Envoy-Original-Path": [
+   "/get/origin/path/extra"
+  ],
+  "X-Forwarded-Proto": [
+   "http"
+  ],
+  "X-Request-Id": [
+   "8ab774d6-9ffa-4faa-abbb-f45b0db00895"
+  ]
+ },
+ "namespace": "default",
+ "ingress": "",
+ "service": "",
+ "pod": "backend-6fdd4b9bd8-8vlc5"
+...
+```
+
+You can see that the `X-Envoy-Original-Path` is `/get/origin/path/extra`, but the actual path is `/force/replace/fullpath`.
+
+## Rewrite Host Name
+
+You can configure to rewrite the hostname like below. In this example, any requests sent to `http://${GATEWAY_HOST}:8080/get` with `--header "Host: path.rewrite.example"` will rewrite host into `envoygateway.io`.
+
+```shell
+cat <<EOF | kubectl apply -f -
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: http-filter-url-rewrite
+spec:
+  parentRefs:
+    - name: eg
+  hostnames:
+    - path.rewrite.example
+  rules:
+    - matches:
+      - path:
+          type: PathPrefix
+          value: "/get"
+      filters:
+      - type: URLRewrite
+        urlRewrite:
+          hostname: "envoygateway.io"
+      backendRefs:
+      - name: backend
+        port: 3000
+EOF
+```
+
+The HTTPRoute status should indicate that it has been accepted and is bound to the example Gateway.
+
+```shell
+kubectl get httproute/http-filter-url-rewrite -o yaml
+```
+
+Querying `http://${GATEWAY_HOST}:8080/get` with `--header "Host: path.rewrite.example"` will rewrite host into `envoygateway.io`.
+
+```console
+$ curl -L -vvv --header "Host: path.rewrite.example" "http://${GATEWAY_HOST}:8080/get"
+...
+> GET /get HTTP/1.1
+> Host: path.rewrite.example
+> User-Agent: curl/7.85.0
+> Accept: */*
+> 
+* Mark bundle as not supporting multiuse
+< HTTP/1.1 200 OK
+< content-type: application/json
+< x-content-type-options: nosniff
+< date: Wed, 21 Dec 2022 11:15:15 GMT
+< content-length: 481
+< x-envoy-upstream-service-time: 0
+< server: envoy
+< 
+{
+ "path": "/get",
+ "host": "envoygateway.io",
+ "method": "GET",
+ "proto": "HTTP/1.1",
+ "headers": {
+  "Accept": [
+   "*/*"
+  ],
+  "User-Agent": [
+   "curl/7.85.0"
+  ],
+  "X-Envoy-Expected-Rq-Timeout-Ms": [
+   "15000"
+  ],
+  "X-Forwarded-Host": [
+   "path.rewrite.example"
+  ],
+  "X-Forwarded-Proto": [
+   "http"
+  ],
+  "X-Request-Id": [
+   "39aa447c-97b9-45a3-a675-9fb266ab1af0"
+  ]
+ },
+ "namespace": "default",
+ "ingress": "",
+ "service": "",
+ "pod": "backend-6fdd4b9bd8-8vlc5"
+...
+```
+
+You can see that the `X-Forwarded-Host` is `path.rewrite.example`, but the actual host is `envoygateway.io`.

docs/latest/user_docs.rst

@@ -9,7 +9,9 @@ Learn how to deploy, use, and operate Envoy Gateway.
   user/quickstart
   user/http-routing
   user/http-redirect
+  user/http-urlrewrite
   user/http-traffic-splitting
   user/http-request-headers
+  user/http-response-headers
   user/secure-gateways
   user/tls-passthrough