response.go

// Copyright (c) 2018 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package xhttp

import (
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/golang/protobuf/jsonpb"
	"github.com/golang/protobuf/proto"
	"go.uber.org/zap"
)

// WriteJSONResponse writes generic data to the ResponseWriter
func WriteJSONResponse(w http.ResponseWriter, data interface{}, logger *zap.Logger) {
	jsonData, err := json.Marshal(data)
	if err != nil {
		logger.Error("unable to marshal json", zap.Any("error", err))
		Error(w, err, http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.Write(jsonData)
}

// WriteProtoMsgJSONResponse writes a protobuf message to the ResponseWriter. This uses jsonpb
// for json marshalling, which encodes fields with default values, even with the omitempty tag.
func WriteProtoMsgJSONResponse(w http.ResponseWriter, data proto.Message, logger *zap.Logger) {
	marshaler := jsonpb.Marshaler{EmitDefaults: true}

	w.Header().Set("Content-Type", "application/json")
	err := marshaler.Marshal(w, data)
	if err != nil {
		logger.Error("unable to marshal json", zap.Any("error", err))
		Error(w, err, http.StatusInternalServerError)
	}
}

// WriteUninitializedResponse writes a protobuf message to the ResponseWriter
func WriteUninitializedResponse(w http.ResponseWriter, logger *zap.Logger) {
	logger.Warn("request received before M3DB session is initialized")
	Error(w, fmt.Errorf("connection to M3DB is not yet initialized"), http.StatusServiceUnavailable)
}