feat: add websocket support (https://github.com/kedacore/http-add-on/pull/835)

go.mod

@@ -5,6 +5,7 @@ go 1.23.6
 require (
 	github.com/go-logr/logr v1.4.2
 	github.com/google/go-cmp v0.7.0
+	github.com/gorilla/websocket v1.5.1
 	github.com/hashicorp/go-immutable-radix/v2 v2.1.0
 	github.com/kedacore/keda/v2 v2.16.1
 	github.com/kelseyhightower/envconfig v1.4.0
@@ -19,6 +20,7 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.35.0
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.35.0
 	go.opentelemetry.io/otel/sdk v1.35.0
+	go.opentelemetry.io/otel/trace v1.35.0
 	go.uber.org/mock v0.5.0
 	golang.org/x/sync v0.12.0
 	google.golang.org/grpc v1.71.0
@@ -56,7 +58,6 @@ require (
 	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-task/slim-sprig/v3 v3.0.0 // indirect
-	github.com/gorilla/websocket v1.5.1 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.1 // indirect
 	github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.35.0 // indirect
@@ -115,7 +116,6 @@ require (
 	go.opentelemetry.io/otel/exporters/prometheus v0.57.0
 	go.opentelemetry.io/otel/metric v1.35.0
 	go.opentelemetry.io/otel/sdk/metric v1.35.0
-	go.opentelemetry.io/otel/trace v1.35.0
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f
 	golang.org/x/mod v0.23.0 // indirect

go.sum

@@ -19,10 +19,10 @@ github.com/evanphx/json-patch v5.9.0+incompatible h1:fBXyNpNMuTTDdquAq/uisOr2lSh
 github.com/evanphx/json-patch v5.9.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
 github.com/evanphx/json-patch/v5 v5.9.0 h1:kcBlZQbplgElYIlo/n1hJbls2z/1awpXxpRi0/FOJfg=
 github.com/evanphx/json-patch/v5 v5.9.0/go.mod h1:VNkHZ/282BpEyt/tObQO8s5CMPmYYq14uClGH4abBuQ=
-github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
-github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
 github.com/expr-lang/expr v1.17.0 h1:+vpszOyzKLQXC9VF+wA8cVA0tlA984/Wabc/1hF9Whg=
 github.com/expr-lang/expr v1.17.0/go.mod h1:8/vRC7+7HBzESEqt5kKpYXxrxkr31SaO8r40VO/1IT4=
+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
+github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/fxamacker/cbor/v2 v2.7.0 h1:iM5WgngdRBanHcxugY4JySA0nk1wZorNOpTgCMedv5E=

interceptor/middleware/responsewriter.go

@@ -1,6 +1,9 @@
 package middleware
 
 import (
+	"bufio"
+	"errors"
+	"net"
 	"net/http"
 )
 
@@ -46,3 +49,11 @@ func (rw *responseWriter) WriteHeader(statusCode int) {
 
 	rw.statusCode = statusCode
 }
+
+func (rw *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	if hj, ok := rw.downstreamResponseWriter.(http.Hijacker); ok {
+		return hj.Hijack()
+	}
+
+	return nil, nil, errors.New("http.Hijacker not implemented")
+}

interceptor/middleware/responsewriter_test.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	"github.com/gorilla/websocket"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 )
@@ -119,4 +120,49 @@ var _ = Describe("responseWriter", func() {
 			Expect(w.Code).To(Equal(sc))
 		})
 	})
+
+	Context("Websocket", func() {
+		It("returns the expected values when http.Hijacker is implemented", func() {
+
+			// Create a server that will accept websocket connections
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				// Upgrade the connection to a websocket connection
+				upgrader := websocket.Upgrader{}
+				conn, err := upgrader.Upgrade(w, r, nil)
+				Expect(err).To(BeNil())
+				Expect(conn).NotTo(BeNil())
+
+				// Write a message to the client
+				err = conn.WriteMessage(websocket.TextMessage, []byte("hello"))
+				Expect(err).To(BeNil())
+
+				// Close the connection
+				err = conn.Close()
+				Expect(err).To(BeNil())
+			}))
+			defer server.Close()
+
+			// Use a ResponseRecorder to satisfy http.ResponseWriter
+			recorder := httptest.NewRecorder()
+			_ = &responseWriter{
+				downstreamResponseWriter: recorder,
+			}
+
+			// Create a client that will connect to the server
+			dialer := websocket.Dialer{}
+			_, _, _ = dialer.Dial(server.URL, nil)
+		})
+
+		It("returns an error when http.Hijacker is not implemented", func() {
+			w := httptest.NewRecorder()
+			lrw := &responseWriter{
+				downstreamResponseWriter: w,
+			}
+
+			c, r, err := lrw.Hijack()
+			Expect(err).To(MatchError("http.Hijacker not implemented"))
+			Expect(c).To(BeNil())
+			Expect(r).To(BeNil())
+		})
+	})
 })