Merge pull request #1882 from ipfs/fix/streaming-output

fix streaming output to flush per write

commands/http/handler.go

@@ -245,13 +245,45 @@ func sendResponse(w http.ResponseWriter, r *http.Request, res cmds.Response, req
 	}
 
 	w.WriteHeader(status)
-	_, err = io.Copy(w, out)
+	err = flushCopy(w, out)
 	if err != nil {
 		log.Error("err: ", err)
 		w.Header().Set(StreamErrHeader, sanitizedErrStr(err))
 	}
 }
 
+func flushCopy(w io.Writer, r io.Reader) error {
+	buf := make([]byte, 4096)
+	f, ok := w.(http.Flusher)
+	if !ok {
+		_, err := io.Copy(w, r)
+		return err
+	}
+	for {
+		n, err := r.Read(buf)
+		switch err {
+		case io.EOF:
+			return nil
+		case nil:
+			// continue
+		default:
+			return err
+		}
+
+		nw, err := w.Write(buf[:n])
+		if err != nil {
+			return err
+		}
+
+		if nw != n {
+			return fmt.Errorf("http write failed to write full amount: %d != %d", nw, n)
+		}
+
+		f.Flush()
+	}
+	return nil
+}
+
 func sanitizedErrStr(err error) string {
 	s := err.Error()
 	s = strings.Split(s, "\n")[0]

test/sharness/t0060-daemon.sh

@@ -109,6 +109,17 @@ test_expect_success "transport should be encrypted" '
 	test_fsh cat swarmnc
 '
 
+test_expect_success "output from streaming commands works" '
+	test_expect_code 28 curl -m 2 http://localhost:5001/api/v0/stats/bw\?poll=true > statsout
+'
+
+test_expect_success "output looks good" '
+	grep TotalIn statsout > /dev/null &&
+	grep TotalOut statsout > /dev/null &&
+	grep RateIn statsout > /dev/null &&
+	grep RateOut statsout >/dev/null
+'
+
 # end same as in t0010
 
 test_expect_success "daemon is still running" '