Provide support for HTTP/2 trailers

Neither PHP nor PSR-7 do not natively support HTTP trailers. Golang
provides support and this commit enables trailers emulation. When PHP
sends a "Trailer" header in response, supplying a comma separated list
of headers they will be converted by RoadRunner to HTTP/2 trailers.

2 files changed, 93 insertions, 11 deletions

diff --git a/service/http/response.go b/service/http/response.go
index 8bd770ec..8dda87c7 100644
--- a/service/http/response.go
+++ b/service/http/response.go
@@ -2,9 +2,11 @@ package http
 
 import (
 	"encoding/json"
-	"github.com/spiral/roadrunner"
 	"io"
 	"net/http"
+	"regexp"
+
+	"github.com/spiral/roadrunner"
 )
 
 // Response handles PSR7 response logic.
@@ -31,16 +33,16 @@ func NewResponse(p *roadrunner.Payload) (*Response, error) {
 
 // Write writes response headers, status and body into ResponseWriter.
 func (r *Response) Write(w http.ResponseWriter) error {
+	p, h := handlePushHeaders(r.Headers)
+	if pusher, ok := w.(http.Pusher); ok {
+		for _, v := range p {
+			pusher.Push(v, nil)
+		}
+	}
+
+	h = handleTrailers(h)
 	for n, h := range r.Headers {
 		for _, v := range h {
-			if n == "http2-push" {
-				if pusher, ok := w.(http.Pusher); ok {
-					pusher.Push(v, nil)
-				}
-
-				continue
-			}
-
 			w.Header().Add(n, v)
 		}
 	}
@@ -59,3 +61,41 @@ func (r *Response) Write(w http.ResponseWriter) error {
 
 	return nil
 }
+
+func handlePushHeaders(h map[string][]string) ([]string, map[string][]string) {
+	var p []string
+	pushHeader, ok := h["http2-push"]
+	if !ok {
+		return p, h
+	}
+
+	for _, v := range pushHeader {
+		p = append(p, v)
+	}
+
+	delete(h, "http2-push")
+
+	return p, h
+}
+
+func handleTrailers(h map[string][]string) map[string][]string {
+	trailers, ok := h["trailer"]
+	if !ok {
+		return h
+	}
+
+	zp := regexp.MustCompile(` *, *`)
+	for _, tr := range trailers {
+		for _, n := range zp.Split(tr, -1) {
+			if v, ok := h[n]; ok {
+				h["Trailer:"+n] = v
+
+				delete(h, n)
+			}
+		}
+	}
+
+	delete(h, "trailer")
+
+	return h
+}
diff --git a/service/http/response_test.go b/service/http/response_test.go
index f885be7f..7ba9d8d4 100644
--- a/service/http/response_test.go
+++ b/service/http/response_test.go
@@ -3,10 +3,11 @@ package http
 import (
 	"bytes"
 	"errors"
-	"github.com/spiral/roadrunner"
-	"github.com/stretchr/testify/assert"
 	"net/http"
 	"testing"
+
+	"github.com/spiral/roadrunner"
+	"github.com/stretchr/testify/assert"
 )
 
 type testWriter struct {
@@ -15,6 +16,8 @@ type testWriter struct {
 	wroteHeader bool
 	code        int
 	err         error
+	pushErr     error
+	pushes      []string
 }
 
 func (tw *testWriter) Header() http.Header { return tw.h }
@@ -34,6 +37,12 @@ func (tw *testWriter) Write(p []byte) (int, error) {
 
 func (tw *testWriter) WriteHeader(code int) { tw.wroteHeader = true; tw.code = code }
 
+func (tw *testWriter) Push(target string, opts *http.PushOptions) error {
+	tw.pushes = append(tw.pushes, target)
+
+	return tw.pushErr
+}
+
 func TestNewResponse_Error(t *testing.T) {
 	r, err := NewResponse(&roadrunner.Payload{Context: []byte(`invalid payload`)})
 	assert.Error(t, err)
@@ -90,3 +99,36 @@ func TestNewResponse_StreamError(t *testing.T) {
 	w := &testWriter{h: http.Header(make(map[string][]string)), err: errors.New("error")}
 	assert.Error(t, r.Write(w))
 }
+
+func TestWrite_HandlesPush(t *testing.T) {
+	r, err := NewResponse(&roadrunner.Payload{
+		Context: []byte(`{"headers":{"http2-push":["/test.js"],"content-type":["text/html"]},"status": 200}`),
+	})
+
+	assert.NoError(t, err)
+	assert.NotNil(t, r)
+
+	w := &testWriter{h: http.Header(make(map[string][]string))}
+	assert.NoError(t, r.Write(w))
+
+	assert.Nil(t, w.h["http2-push"])
+	assert.Equal(t, []string{"/test.js"}, w.pushes)
+}
+
+func TestWrite_HandlesTrailers(t *testing.T) {
+	r, err := NewResponse(&roadrunner.Payload{
+		Context: []byte(`{"headers":{"trailer":["foo, bar", "baz"],"foo":["test"],"bar":["demo"]},"status": 200}`),
+	})
+
+	assert.NoError(t, err)
+	assert.NotNil(t, r)
+
+	w := &testWriter{h: http.Header(make(map[string][]string))}
+	assert.NoError(t, r.Write(w))
+
+	assert.Nil(t, w.h["trailer"])
+	assert.Nil(t, w.h["foo"])
+	assert.Nil(t, w.h["baz"])
+	assert.Equal(t, "test", w.h.Get("Trailer:foo"))
+	assert.Equal(t, "demo", w.h.Get("Trailer:bar"))
+}