Add server side streaming test

vendor/github.com/johanbrandhorst/grpc-wasm/clientconn.go

@@ -46,7 +46,16 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 }
 
 func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) {
-	return nil, errors.New("streaming endpoints are not yet supported")
+	if desc.ClientStreams {
+		return nil, status.Error(codes.Unimplemented, "client-side streaming is not supported by grpc-web")
+	}
+
+	endpoint := cc.target + "/" + method
+	if cc.target == "" {
+		endpoint = method
+	}
+
+	return newStream(ctx, cc.client, endpoint)
 }
 
 func (cc *ClientConn) Invoke(ctx context.Context, method string, args, reply interface{}, opts ...CallOption) error {
@@ -128,6 +137,7 @@ func addHeaders(req *http.Request) {
 	// TODO: Add more headers
 	// https://github.com/grpc/grpc-go/blob/590da37e2dfb4705d8ebd9574ce4cb75295d9674/transport/http2_client.go#L356
 	req.Header.Add("content-type", "application/grpc-web+proto")
+	req.Header.Add("x-grpc-web", "1")
 	if dl, ok := req.Context().Deadline(); ok {
 		timeout := dl.Sub(time.Now())
 		req.Header.Add("grpc-timeout", encodeTimeout(timeout))

vendor/github.com/johanbrandhorst/grpc-wasm/clientstream.go

@@ -3,9 +3,18 @@
 package grpc
 
 import (
+	"bytes"
 	"context"
+	"encoding/binary"
+	"io"
+	"io/ioutil"
+	"net/http"
 
+	"github.com/golang/protobuf/proto"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
 )
 
 // ClientStream defines the interface a client stream has to satisfy.
@@ -49,3 +58,139 @@ type ServiceDesc struct {
 	Streams     []StreamDesc
 	Metadata    interface{}
 }
+
+type clientStream struct {
+	ctx    context.Context
+	req    *http.Request
+	client *http.Client
+	errCh  chan error
+	msgCh  chan []byte
+}
+
+func newStream(ctx context.Context, client *http.Client, endpoint string) (*clientStream, error) {
+	cs := &clientStream{
+		ctx:    ctx,
+		client: client,
+	}
+
+	req, err := http.NewRequest(
+		"POST",
+		endpoint,
+		nil,
+	)
+	if err != nil {
+		return nil, status.New(codes.Unavailable, err.Error()).Err()
+	}
+
+	cs.req = req.WithContext(ctx)
+	return cs, nil
+}
+
+func (c *clientStream) Header() (metadata.MD, error) {
+	return nil, nil
+}
+
+func (c *clientStream) Trailer() metadata.MD {
+	return nil
+}
+
+func (c *clientStream) Context() context.Context {
+	return c.ctx
+}
+
+func (c *clientStream) RecvMsg(reply interface{}) error {
+	select {
+	case <-c.ctx.Done():
+		return c.ctx.Err()
+	case err := <-c.errCh:
+		return err
+	case msg, ok := <-c.msgCh:
+		if !ok {
+			return io.EOF
+		}
+		err := proto.Unmarshal(msg, reply.(proto.Message))
+		return err
+	}
+}
+
+func (c *clientStream) SendMsg(req interface{}) error {
+	msg, err := proto.Marshal(req.(proto.Message))
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	bufHeader := make([]byte, 5)
+
+	// Write length of b into buf
+	binary.BigEndian.PutUint32(bufHeader[1:], uint32(len(msg)))
+
+	c.req.Body = ioutil.NopCloser(bytes.NewBuffer(append(bufHeader, msg...)))
+	addHeaders(c.req)
+
+	resp, err := c.client.Do(c.req)
+	if err != nil {
+		return status.Error(codes.Unavailable, err.Error())
+	}
+
+	st := statusFromHeaders(resp.Header)
+	if st.Code() != codes.OK {
+		resp.Body.Close()
+		return st.Err()
+	}
+
+	c.errCh = make(chan error, 1)
+	c.msgCh = make(chan []byte, 1)
+
+	// Read response asynchronously
+	go func() {
+		defer resp.Body.Close()
+
+		msgHeader := make([]byte, 5)
+		for {
+			_, err := io.ReadFull(resp.Body, msgHeader)
+			if err != nil {
+				c.errCh <- status.Error(codes.Internal, err.Error())
+				return
+			}
+			// 1 in MSB signifies that this is the trailer. Break loop.
+			// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-WEB.md#protocol-differences-vs-grpc-over-http2
+			if msgHeader[0]>>7 == 1 {
+				break
+			}
+
+			msgLen := binary.BigEndian.Uint32(msgHeader[1:])
+
+			msg := make([]byte, msgLen)
+			_, err = io.ReadFull(resp.Body, msg)
+			if err != nil {
+				c.errCh <- status.Error(codes.Internal, err.Error())
+				return
+			}
+			c.msgCh <- msg
+		}
+
+		if msgHeader[0]&1 == 0 {
+			trailers, err := readTrailers(resp.Body)
+			if err != nil {
+				c.errCh <- status.Error(codes.Internal, err.Error())
+				return
+			}
+			st = statusFromHeaders(trailers)
+		} else {
+			// TODO(johanbrandhorst): Support compressed trailers
+		}
+
+		if st.Code() != codes.OK {
+			c.errCh <- st.Err()
+			return
+		}
+
+		close(c.msgCh)
+	}()
+
+	return nil
+}
+
+func (c *clientStream) CloseSend() error {
+	return nil
+}