在Go JSON中转义unicode字符，以便输出与Python匹配

Question

In Python 2.7, if I encode JSON I get unicode-escaped strings:

>>> import json
>>> s = {"text": "三杯雞"}
>>> print(json.dumps(s))

it gives this output:

{"text": "\u4e09\u676f\u96de"}

But in Go, similar code:

package main

import (
    "encoding/json"
    "fmt"
)

type Food struct {
    Name string `json:"name"`
}

func main() {
    food := Food{Name: "三杯雞"}
    v, _ := json.Marshal(food)
    fmt.Println(string(v))
}

Gives this:

{"name":"三杯雞"}

The Chinese characters are not escaped. I am porting API endpoints from Python to Go - how can I get it to have the same escaped output as Python?

I tried variations using strconv.QuoteToASCII, but they result in the unicode being double-escaped:

func main() {
    s := strconv.QuoteToASCII("三杯雞")
    s = strings.Trim(s, "\"")
    food := Food{Name: s}
    v, _ := json.Marshal(food)
    fmt.Println(string(v))
}

Outputs:

{"name":"\\u4e09\\u676f\\u96de"}

Answer 1

One solution is to use the strconv.QuoteToASCII method inside of a custom JSON marshaler:

package main

import (
    "encoding/json"
    "fmt"
    "strconv"
)

type Food struct {
    Name utf8String `json:"name"`
}

type utf8String string

func (s utf8String) MarshalJSON() ([]byte, error) {
    return []byte(strconv.QuoteToASCII(string(s))), nil
}

func main() {
    food := Food{Name: utf8String("三杯雞")}
    v, _ := json.Marshal(food)
    fmt.Println(string(v))
}

Output:

{"name":"\u4e09\u676f\u96de"}

This has the drawback that you can't use a plain string type in the struct definition, but the final output is ASCII-quoted, just like in Python.