Add HTTPUrlRewrite Filter in Gateway API

pkg/middlewares/gatewayapi/urlrewrite/url_rewrite.go

@@ -0,0 +1,68 @@
+package urlrewrite
+
+import (
+	"context"
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/traefik/traefik/v3/pkg/config/dynamic"
+	"github.com/traefik/traefik/v3/pkg/middlewares"
+	"go.opentelemetry.io/otel/trace"
+)
+
+const (
+	typeName = "URLRewrite"
+)
+
+type urlRewrite struct {
+	name string
+	next http.Handler
+
+	hostname   *string
+	path       *string
+	pathPrefix *string
+}
+
+// NewURLRewrite creates a URL rewrite middleware.
+func NewURLRewrite(ctx context.Context, next http.Handler, conf dynamic.URLRewrite, name string) http.Handler {
+	logger := middlewares.GetLogger(ctx, name, typeName)
+	logger.Debug().Msg("Creating middleware")
+
+	return urlRewrite{
+		name:       name,
+		next:       next,
+		hostname:   conf.Hostname,
+		path:       conf.Path,
+		pathPrefix: conf.PathPrefix,
+	}
+}
+
+func (u urlRewrite) GetTracingInformation() (string, string, trace.SpanKind) {
+	return u.name, typeName, trace.SpanKindInternal
+}
+
+func (u urlRewrite) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	newPath := req.URL.Path
+	if u.path != nil && u.pathPrefix == nil {
+		newPath = *u.path
+	}
+	if u.path != nil && u.pathPrefix != nil {
+		newPath = path.Join(*u.path, strings.TrimPrefix(req.URL.Path, *u.pathPrefix))
+
+		// add the trailing slash if needed, as path.Join removes trailing slashes.
+		if strings.HasSuffix(req.URL.Path, "/") && !strings.HasSuffix(newPath, "/") {
+			newPath += "/"
+		}
+	}
+
+	req.URL.Path = newPath
+	req.URL.RawPath = req.URL.EscapedPath()
+	req.RequestURI = req.URL.RequestURI()
+
+	if u.hostname != nil {
+		req.Host = *u.hostname
+	}
+
+	u.next.ServeHTTP(rw, req)
+}

pkg/middlewares/gatewayapi/urlrewrite/url_rewrite_test.go

@@ -0,0 +1,126 @@
+package urlrewrite
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/traefik/traefik/v3/pkg/config/dynamic"
+	"k8s.io/utils/ptr"
+)
+
+func TestURLRewriteHandler(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		config   dynamic.URLRewrite
+		url      string
+		wantURL  string
+		wantHost string
+	}{
+		{
+			desc: "replace path",
+			config: dynamic.URLRewrite{
+				Path: ptr.To("/baz"),
+			},
+			url:      "http://foo.com/foo/bar",
+			wantURL:  "http://foo.com/baz",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "replace path without trailing slash",
+			config: dynamic.URLRewrite{
+				Path: ptr.To("/baz"),
+			},
+			url:      "http://foo.com/foo/bar/",
+			wantURL:  "http://foo.com/baz",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "replace path with trailing slash",
+			config: dynamic.URLRewrite{
+				Path: ptr.To("/baz/"),
+			},
+			url:      "http://foo.com/foo/bar",
+			wantURL:  "http://foo.com/baz/",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "only host",
+			config: dynamic.URLRewrite{
+				Hostname: ptr.To("bar.com"),
+			},
+			url:      "http://foo.com/foo/",
+			wantURL:  "http://foo.com/foo/",
+			wantHost: "bar.com",
+		},
+		{
+			desc: "host and path",
+			config: dynamic.URLRewrite{
+				Hostname: ptr.To("bar.com"),
+				Path:     ptr.To("/baz/"),
+			},
+			url:      "http://foo.com/foo/",
+			wantURL:  "http://foo.com/baz/",
+			wantHost: "bar.com",
+		},
+		{
+			desc: "replace prefix path",
+			config: dynamic.URLRewrite{
+				Path:       ptr.To("/baz"),
+				PathPrefix: ptr.To("/foo"),
+			},
+			url:      "http://foo.com/foo/bar",
+			wantURL:  "http://foo.com/baz/bar",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "replace prefix path with trailing slash",
+			config: dynamic.URLRewrite{
+				Path:       ptr.To("/baz"),
+				PathPrefix: ptr.To("/foo"),
+			},
+			url:      "http://foo.com/foo/bar/",
+			wantURL:  "http://foo.com/baz/bar/",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "replace prefix path without slash prefix",
+			config: dynamic.URLRewrite{
+				Path:       ptr.To("baz"),
+				PathPrefix: ptr.To("/foo"),
+			},
+			url:      "http://foo.com/foo/bar",
+			wantURL:  "http://foo.com/baz/bar",
+			wantHost: "foo.com",
+		},
+		{
+			desc: "replace prefix path without slash prefix",
+			config: dynamic.URLRewrite{
+				Path:       ptr.To("/baz"),
+				PathPrefix: ptr.To("/foo/"),
+			},
+			url:      "http://foo.com/foo/bar",
+			wantURL:  "http://foo.com/baz/bar",
+			wantHost: "foo.com",
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})
+
+			handler := NewURLRewrite(context.Background(), next, test.config, "traefikTest")
+
+			recorder := httptest.NewRecorder()
+			req := httptest.NewRequest(http.MethodGet, test.url, nil)
+			handler.ServeHTTP(recorder, req)
+
+			assert.Equal(t, test.wantURL, req.URL.String())
+			assert.Equal(t, test.wantHost, req.Host)
+		})
+	}
+}