add plugin http handler (#7289)

plugin/rpcplugin/hooks.go

@@ -1,7 +1,10 @@
 package rpcplugin
 
 import (
+	"bytes"
 	"io"
+	"io/ioutil"
+	"net/http"
 	"net/rpc"
 	"reflect"
 
@@ -83,6 +86,33 @@ func (h *LocalHooks) OnDeactivate(args, reply *struct{}) (err error) {
 	return
 }
 
+type ServeHTTPArgs struct {
+	ResponseWriterStream int64
+	Request              *http.Request
+	RequestBodyStream    int64
+}
+
+func (h *LocalHooks) ServeHTTP(args ServeHTTPArgs, reply *struct{}) error {
+	w := ConnectHTTPResponseWriter(h.muxer.Connect(args.ResponseWriterStream))
+	defer w.Close()
+
+	r := args.Request
+	if args.RequestBodyStream != 0 {
+		r.Body = ConnectIOReader(h.muxer.Connect(args.RequestBodyStream))
+	} else {
+		r.Body = ioutil.NopCloser(&bytes.Buffer{})
+	}
+	defer r.Body.Close()
+
+	if hook, ok := h.hooks.(http.Handler); ok {
+		hook.ServeHTTP(w, r)
+	} else {
+		http.NotFound(w, r)
+	}
+
+	return nil
+}
+
 func ServeHooks(hooks interface{}, conn io.ReadWriteCloser, muxer *Muxer) {
 	server := rpc.NewServer()
 	server.Register(&LocalHooks{
@@ -95,6 +125,7 @@ func ServeHooks(hooks interface{}, conn io.ReadWriteCloser, muxer *Muxer) {
 const (
 	remoteOnActivate = iota
 	remoteOnDeactivate
+	remoteServeHTTP
 	maxRemoteHookCount
 )
 
@@ -133,6 +164,45 @@ func (h *RemoteHooks) OnDeactivate() error {
 	return h.client.Call("LocalHooks.OnDeactivate", struct{}{}, nil)
 }
 
+func (h *RemoteHooks) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if !h.implemented[remoteServeHTTP] {
+		http.NotFound(w, r)
+		return
+	}
+
+	responseWriterStream, stream := h.muxer.Serve()
+	defer stream.Close()
+	go ServeHTTPResponseWriter(w, stream)
+
+	requestBodyStream := int64(0)
+	if r.Body != nil {
+		rid, rstream := h.muxer.Serve()
+		defer rstream.Close()
+		go ServeIOReader(r.Body, rstream)
+		requestBodyStream = rid
+	}
+
+	forwardedRequest := &http.Request{
+		Method:     r.Method,
+		URL:        r.URL,
+		Proto:      r.Proto,
+		ProtoMajor: r.ProtoMajor,
+		ProtoMinor: r.ProtoMinor,
+		Header:     r.Header,
+		Host:       r.Host,
+		RemoteAddr: r.RemoteAddr,
+		RequestURI: r.RequestURI,
+	}
+
+	if err := h.client.Call("LocalHooks.ServeHTTP", ServeHTTPArgs{
+		ResponseWriterStream: responseWriterStream,
+		Request:              forwardedRequest,
+		RequestBodyStream:    requestBodyStream,
+	}, nil); err != nil {
+		http.Error(w, "500 internal server error", http.StatusInternalServerError)
+	}
+}
+
 func (h *RemoteHooks) Close() error {
 	if h.apiCloser != nil {
 		h.apiCloser.Close()
@@ -157,6 +227,8 @@ func ConnectHooks(conn io.ReadWriteCloser, muxer *Muxer) (*RemoteHooks, error) {
 			remote.implemented[remoteOnActivate] = true
 		case "OnDeactivate":
 			remote.implemented[remoteOnDeactivate] = true
+		case "ServeHTTP":
+			remote.implemented[remoteServeHTTP] = true
 		}
 	}
 	return remote, nil