gin/render/json.go

// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
// Use of this source code is governed by a MIT style
// license that can be found in the LICENSE file.

package render

import (
	"bytes"
	"fmt"
	"html/template"
	"net/http"

	"github.com/gin-gonic/gin/internal/json"
)

type JSON struct {
	Data interface{}
}

type IndentedJSON struct {
	Data interface{}
}

type SecureJSON struct {
	Prefix string
	Data   interface{}
}

type JsonpJSON struct {
	Callback string
	Data     interface{}
}

type AsciiJSON struct {
	Data interface{}
}

type SecureJSONPrefix string

var jsonContentType = []string{"application/json; charset=utf-8"}
var jsonpContentType = []string{"application/javascript; charset=utf-8"}
var jsonAsciiContentType = []string{"application/json"}

func (r JSON) Render(w http.ResponseWriter) (err error) {
	if err = WriteJSON(w, r.Data); err != nil {
		panic(err)
	}
	return
}

func (r JSON) WriteContentType(w http.ResponseWriter) {
	writeContentType(w, jsonContentType)
}

func WriteJSON(w http.ResponseWriter, obj interface{}) error {
	writeContentType(w, jsonContentType)
	jsonBytes, err := json.Marshal(obj)
	if err != nil {
		return err
	}
	w.Write(jsonBytes)
	return nil
}

func (r IndentedJSON) Render(w http.ResponseWriter) error {
	r.WriteContentType(w)
	jsonBytes, err := json.MarshalIndent(r.Data, "", "    ")
	if err != nil {
		return err
	}
	w.Write(jsonBytes)
	return nil
}

func (r IndentedJSON) WriteContentType(w http.ResponseWriter) {
	writeContentType(w, jsonContentType)
}

func (r SecureJSON) Render(w http.ResponseWriter) error {
	r.WriteContentType(w)
	jsonBytes, err := json.Marshal(r.Data)
	if err != nil {
		return err
	}
	// if the jsonBytes is array values
	if bytes.HasPrefix(jsonBytes, []byte("[")) && bytes.HasSuffix(jsonBytes, []byte("]")) {
		w.Write([]byte(r.Prefix))
	}
	w.Write(jsonBytes)
	return nil
}

func (r SecureJSON) WriteContentType(w http.ResponseWriter) {
	writeContentType(w, jsonContentType)
}

func (r JsonpJSON) Render(w http.ResponseWriter) (err error) {
	r.WriteContentType(w)
	ret, err := json.Marshal(r.Data)
	if err != nil {
		return err
	}

	if r.Callback == "" {
		w.Write(ret)
		return nil
	}

	callback := template.JSEscapeString(r.Callback)
	w.Write([]byte(callback))
	w.Write([]byte("("))
	w.Write(ret)
	w.Write([]byte(")"))

	return nil
}

func (r JsonpJSON) WriteContentType(w http.ResponseWriter) {
	writeContentType(w, jsonpContentType)
}

func (r AsciiJSON) Render(w http.ResponseWriter) (err error) {
	r.WriteContentType(w)
	ret, err := json.Marshal(r.Data)
	if err != nil {
		return err
	}

	var buffer bytes.Buffer
	for _, r := range string(ret) {
		cvt := string(r)
		if r >= 128 {
			cvt = fmt.Sprintf("\\u%04x", int64(r))
		}
		buffer.WriteString(cvt)
	}

	w.Write(buffer.Bytes())
	return nil
}

func (r AsciiJSON) WriteContentType(w http.ResponseWriter) {
	writeContentType(w, jsonAsciiContentType)
}