Enable h2c support

go.mod

@@ -6,14 +6,14 @@ require (
 	github.com/klauspost/compress v1.17.4
 	github.com/stretchr/testify v1.8.4
 	golang.org/x/crypto v0.17.0
+	golang.org/x/net v0.17.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/net v0.17.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

internal/handler.go

@@ -6,6 +6,8 @@ import (
 	"net/url"
 
 	"github.com/klauspost/compress/gzhttp"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
 )
 
 type HandlerOptions struct {
@@ -22,6 +24,7 @@ func NewHandler(options HandlerOptions) http.Handler {
 	handler = NewCacheHandler(options.cache, options.maxCacheableResponseBody, handler)
 	handler = NewSendfileHandler(options.xSendfileEnabled, handler)
 	handler = gzhttp.GzipHandler(handler)
+	handler = h2c.NewHandler(handler, &http2.Server{})
 
 	if options.maxRequestBody > 0 {
 		handler = http.MaxBytesHandler(handler, int64(options.maxRequestBody))

internal/handler_test.go

@@ -2,13 +2,18 @@ package internal
 
 import (
 	"bytes"
+	"context"
+	"crypto/tls"
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strconv"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/http2"
 )
 
 func TestHandlerGzipCompression_when_proxying(t *testing.T) {
@@ -106,6 +111,32 @@ func TestHandlerMaxRequestBody(t *testing.T) {
 	assert.Equal(t, http.StatusOK, w.Code)
 }
 
+func TestHandlerH2C(t *testing.T) {
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
+	defer upstream.Close()
+
+	options := handlerOptions(upstream.URL)
+	handler := NewHandler(options)
+	server := httptest.NewServer(handler)
+	defer server.Close()
+
+	client := http.Client{
+		Transport: &http2.Transport{
+			AllowHTTP: true,
+			DialTLSContext: func(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
+				var d net.Dialer
+				return d.DialContext(ctx, network, addr)
+			},
+		},
+	}
+
+	resp, err := client.Get(server.URL)
+
+	require.NoError(t, err)
+	assert.Equal(t, http.StatusOK, resp.StatusCode)
+	assert.Equal(t, "HTTP/2.0", resp.Proto)
+}
+
 // Helpers
 
 func handlerOptions(targetUrl string) HandlerOptions {