gtsocial-umbx

handler.go (6612B)

---

 package runtime
 
 import (
 	"context"
 	"fmt"
 	"io"
 	"net/http"
 	"net/textproto"
 	"strings"
 
 	"google.golang.org/genproto/googleapis/api/httpbody"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/proto"
 )
 
 // ForwardResponseStream forwards the stream from gRPC server to REST client.
 func ForwardResponseStream(ctx context.Context, mux *ServeMux, marshaler Marshaler, w http.ResponseWriter, req *http.Request, recv func() (proto.Message, error), opts ...func(context.Context, http.ResponseWriter, proto.Message) error) {
 	f, ok := w.(http.Flusher)
 	if !ok {
 		grpclog.Infof("Flush not supported in %T", w)
 		http.Error(w, "unexpected type of web server", http.StatusInternalServerError)
 		return
 	}
 
 	md, ok := ServerMetadataFromContext(ctx)
 	if !ok {
 		grpclog.Infof("Failed to extract ServerMetadata from context")
 		http.Error(w, "unexpected error", http.StatusInternalServerError)
 		return
 	}
 	handleForwardResponseServerMetadata(w, mux, md)
 
 	w.Header().Set("Transfer-Encoding", "chunked")
 	if err := handleForwardResponseOptions(ctx, w, nil, opts); err != nil {
 		HTTPError(ctx, mux, marshaler, w, req, err)
 		return
 	}
 
 	var delimiter []byte
 	if d, ok := marshaler.(Delimited); ok {
 		delimiter = d.Delimiter()
 	} else {
 		delimiter = []byte("\n")
 	}
 
 	var wroteHeader bool
 	for {
 		resp, err := recv()
 		if err == io.EOF {
 			return
 		}
 		if err != nil {
 			handleForwardResponseStreamError(ctx, wroteHeader, marshaler, w, req, mux, err)
 			return
 		}
 		if err := handleForwardResponseOptions(ctx, w, resp, opts); err != nil {
 			handleForwardResponseStreamError(ctx, wroteHeader, marshaler, w, req, mux, err)
 			return
 		}
 
 		if !wroteHeader {
 			w.Header().Set("Content-Type", marshaler.ContentType(resp))
 		}
 
 		var buf []byte
 		httpBody, isHTTPBody := resp.(*httpbody.HttpBody)
 		switch {
 		case resp == nil:
 			buf, err = marshaler.Marshal(errorChunk(status.New(codes.Internal, "empty response")))
 		case isHTTPBody:
 			buf = httpBody.GetData()
 		default:
 			result := map[string]interface{}{"result": resp}
 			if rb, ok := resp.(responseBody); ok {
 				result["result"] = rb.XXX_ResponseBody()
 			}
 
 			buf, err = marshaler.Marshal(result)
 		}
 
 		if err != nil {
 			grpclog.Infof("Failed to marshal response chunk: %v", err)
 			handleForwardResponseStreamError(ctx, wroteHeader, marshaler, w, req, mux, err)
 			return
 		}
 		if _, err = w.Write(buf); err != nil {
 			grpclog.Infof("Failed to send response chunk: %v", err)
 			return
 		}
 		wroteHeader = true
 		if _, err = w.Write(delimiter); err != nil {
 			grpclog.Infof("Failed to send delimiter chunk: %v", err)
 			return
 		}
 		f.Flush()
 	}
 }
 
 func handleForwardResponseServerMetadata(w http.ResponseWriter, mux *ServeMux, md ServerMetadata) {
 	for k, vs := range md.HeaderMD {
 		if h, ok := mux.outgoingHeaderMatcher(k); ok {
 			for _, v := range vs {
 				w.Header().Add(h, v)
 			}
 		}
 	}
 }
 
 func handleForwardResponseTrailerHeader(w http.ResponseWriter, md ServerMetadata) {
 	for k := range md.TrailerMD {
 		tKey := textproto.CanonicalMIMEHeaderKey(fmt.Sprintf("%s%s", MetadataTrailerPrefix, k))
 		w.Header().Add("Trailer", tKey)
 	}
 }
 
 func handleForwardResponseTrailer(w http.ResponseWriter, md ServerMetadata) {
 	for k, vs := range md.TrailerMD {
 		tKey := fmt.Sprintf("%s%s", MetadataTrailerPrefix, k)
 		for _, v := range vs {
 			w.Header().Add(tKey, v)
 		}
 	}
 }
 
 // responseBody interface contains method for getting field for marshaling to the response body
 // this method is generated for response struct from the value of `response_body` in the `google.api.HttpRule`
 type responseBody interface {
 	XXX_ResponseBody() interface{}
 }
 
 // ForwardResponseMessage forwards the message "resp" from gRPC server to REST client.
 func ForwardResponseMessage(ctx context.Context, mux *ServeMux, marshaler Marshaler, w http.ResponseWriter, req *http.Request, resp proto.Message, opts ...func(context.Context, http.ResponseWriter, proto.Message) error) {
 	md, ok := ServerMetadataFromContext(ctx)
 	if !ok {
 		grpclog.Infof("Failed to extract ServerMetadata from context")
 	}
 
 	handleForwardResponseServerMetadata(w, mux, md)
 
 	// RFC 7230 https://tools.ietf.org/html/rfc7230#section-4.1.2
 	// Unless the request includes a TE header field indicating "trailers"
 	// is acceptable, as described in Section 4.3, a server SHOULD NOT
 	// generate trailer fields that it believes are necessary for the user
 	// agent to receive.
 	doForwardTrailers := requestAcceptsTrailers(req)
 
 	if doForwardTrailers {
 		handleForwardResponseTrailerHeader(w, md)
 		w.Header().Set("Transfer-Encoding", "chunked")
 	}
 
 	handleForwardResponseTrailerHeader(w, md)
 
 	contentType := marshaler.ContentType(resp)
 	w.Header().Set("Content-Type", contentType)
 
 	if err := handleForwardResponseOptions(ctx, w, resp, opts); err != nil {
 		HTTPError(ctx, mux, marshaler, w, req, err)
 		return
 	}
 	var buf []byte
 	var err error
 	if rb, ok := resp.(responseBody); ok {
 		buf, err = marshaler.Marshal(rb.XXX_ResponseBody())
 	} else {
 		buf, err = marshaler.Marshal(resp)
 	}
 	if err != nil {
 		grpclog.Infof("Marshal error: %v", err)
 		HTTPError(ctx, mux, marshaler, w, req, err)
 		return
 	}
 
 	if _, err = w.Write(buf); err != nil {
 		grpclog.Infof("Failed to write response: %v", err)
 	}
 
 	if doForwardTrailers {
 		handleForwardResponseTrailer(w, md)
 	}
 }
 
 func requestAcceptsTrailers(req *http.Request) bool {
 	te := req.Header.Get("TE")
 	return strings.Contains(strings.ToLower(te), "trailers")
 }
 
 func handleForwardResponseOptions(ctx context.Context, w http.ResponseWriter, resp proto.Message, opts []func(context.Context, http.ResponseWriter, proto.Message) error) error {
 	if len(opts) == 0 {
 		return nil
 	}
 	for _, opt := range opts {
 		if err := opt(ctx, w, resp); err != nil {
 			grpclog.Infof("Error handling ForwardResponseOptions: %v", err)
 			return err
 		}
 	}
 	return nil
 }
 
 func handleForwardResponseStreamError(ctx context.Context, wroteHeader bool, marshaler Marshaler, w http.ResponseWriter, req *http.Request, mux *ServeMux, err error) {
 	st := mux.streamErrorHandler(ctx, err)
 	msg := errorChunk(st)
 	if !wroteHeader {
 		w.Header().Set("Content-Type", marshaler.ContentType(msg))
 		w.WriteHeader(HTTPStatusFromCode(st.Code()))
 	}
 	buf, merr := marshaler.Marshal(msg)
 	if merr != nil {
 		grpclog.Infof("Failed to marshal an error: %v", merr)
 		return
 	}
 	if _, werr := w.Write(buf); werr != nil {
 		grpclog.Infof("Failed to notify error to client: %v", werr)
 		return
 	}
 }
 
 func errorChunk(st *status.Status) map[string]proto.Message {
 	return map[string]proto.Message{"error": st.Proto()}
 }