[英]go “encoding/json” : marshal json field
I have a PostgreSQL schema with json field's (DisplayInfo, and FormatInfo). 我有一个带有json字段(DisplayInfo和FormatInfo)的PostgreSQL模式。 Structure of this field's is dynamic.
该字段的结构是动态的。
I'can read and render it only as string (string type in render struct) : 我只能将其读取并呈现为字符串(render结构中的字符串类型):
[
{
"ID":9,
"Name":"120 №1",
"DisplayInfo":"{\"path\": \"http://path/to/img.png\"}",
"Format":{
"Code":"frame-120",
"Width":120,
"Height":60,
"FormatInfo":"[{\"name\": \"\\u0413\\u043b\\u0430\\u0432\\u043d\\u043e\\u0435 \\u0438\\u0437\\u043e\\u0431\\u0440\\u0430\\u0436\\u0435\\u043d\\u0438\\u0435\", \"field_type\": \"img\", \"key\": \"path\"}]"
},
"Weight":0.075,
"Application":8,
"Url":"//path/to/game",
"Referrer":""
}
]
but i want output field DisplayInfo as JSON object. 但我想将输出字段DisplayInfo作为JSON对象。 How ?
怎么样 ?
My render code: 我的渲染代码:
func renderJSON(w http.ResponseWriter, obj models.Model) {
js, err := json.Marshal(obj)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Write(js)
}
UPD 1 : Structure of this field's is dynamic. UPD 1:此字段的结构是动态的。 DisplayInfo may have 'path' field, or may not.
DisplayInfo可能具有“路径”字段,也可能没有。 They may have additional fields.
他们可能还有其他字段。
UPD 2. I wana output DisplayInfo and FormatInfo as json-object(not string), as part of whole object , like this: UPD2。我将DisplayInfo和FormatInfo输出为json-object(不是字符串), 作为整个对象的一部分 ,如下所示:
[
{
"ID":9,
"Name":"120 №1",
"DisplayInfo":{"path": "http://path/to/img.png"},
"Format":{
"Code":"frame-120",
"Width":120,
"Height":60,
"FormatInfo":[{"name": "\\u0413\\u043b\\u0430\\u0432\\u043d\\u043e\\u0435 \\u0438\\u0437\\u043e\\u0431\\u0440\\u0430\\u0436\\u0435\\u043d\\u0438\\u0435", "field_type": "img", "key": "path"}]
},
"Weight":0.075,
"Application":8,
"Url":"//path/to/game",
"Referrer":""
}
]
UPD 3: Structures UPD 3:结构
Actual structure is : 实际结构为:
type BannerSerializer struct {
ID int
Name string
DisplayInfo string
Format formatSerializer
Weight float32
Application int
Url string
Referrer string
}
Then i trying this structure: 然后我尝试这种结构:
type BannerSerializer struct {
ID int
Name string
DisplayInfo json.RawMessage
Format formatSerializer
Weight float32
Application int
Url string
Referrer string
}
Use a pointer to json.RawMessage
: 使用指向
json.RawMessage
的指针:
type Data struct {
Obj *json.RawMessage
}
Playground: http://play.golang.org/p/Qq9IUBDLzJ . 游乐场: http : //play.golang.org/p/Qq9IUBDLzJ 。
Assuming you have access to change models.Model
, you can create your own type with a custom Unmarshaler that just returns the raw string: 假设您有权访问change
models.Model
,则可以使用自定义Unmarshaler创建自己的类型,该Unmarshaler仅返回原始字符串:
type JSONString string
func (s JSONString) MarshalJSON() ([]byte, error) {
return []byte(s), nil
}
Working example: 工作示例:
package main
import (
"encoding/json"
"fmt"
)
type JSONString string
func (s JSONString) MarshalJSON() ([]byte, error) {
return []byte(s), nil
}
type Model struct {
ID int
Name string
DisplayInfo JSONString
}
func main() {
data := []byte(`{
"ID":9,
"Name":"120 №1",
"DisplayInfo":"{\"path\": \"http://path/to/img.png\"}"
}`)
var obj Model
err := json.Unmarshal(data, &obj)
if err != nil {
panic(err)
}
// Here comes your code
js, err := json.Marshal(obj)
if err != nil {
panic(err)
}
fmt.Println(string(js))
}
Output: 输出:
{"ID":9,"Name":"120 №1","DisplayInfo":{"path":" http://path/to/img.png "}}
{“ ID”:9,“名称”:“ 120№1”,“ DisplayInfo”:{“路径”:“ http://path/to/img.png ”}}
Playground: http://play.golang.org/p/6bcnuGjlU8 游乐场: http : //play.golang.org/p/6bcnuGjlU8
You'd have to unmarshal it, here's an example: 您必须将其解组,这是一个示例:
var data []*struct {
ID int
DisplayInfo string
}
if err := json.Unmarshal([]byte(j), &data); err != nil {
log.Fatal(err)
}
for _, d := range data {
var displayInfo struct{ Path string }
if err := json.Unmarshal([]byte(d.DisplayInfo), &displayInfo); err != nil {
log.Fatal(err)
}
fmt.Println(d.ID, displayInfo.Path)
}
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