Golang golang-json3 (snippet)

Go programming example 'golang-json3'

golang-json3

Golang beginners example: golang-json3

package main

import (
    "encoding/json"
    "fmt"
)

const jsonString = `
    [
        {
            "type": "group",
            "value": [
                "Lorem",
                "Ipsum",
                "dolor",
                "sit",
                ["A", "m", "e", "t"]
            ]
        },
        {
            "type": "value",
            "value": "Hello World"
        },
        {
            "type": "value",
            "value": "foobar"
        }
    ]
`

func jsonforeach(in *interface{}, handler func(*string, *int, *interface{}, int)) {
    eachJsonValue(in, handler, 0)
}

func eachJsonValue(node *interface{}, handler func(*string, *int, *interface{}, int), depth int) {
    if node == nil {
        return
    }
    o, isObject := (*node).(map[string]interface{})
    if isObject {
        for k, v := range o {
            handler(&k, nil, &v, depth)
            eachJsonValue(&v, handler, depth+1)
        }
    }
    a, isArray := (*node).([]interface{})
    if isArray {
        for i, x := range a {
            handler(nil, &i, &x, depth)
            eachJsonValue(&x, handler, depth+1)
        }
    }
}

func main() {
    var j interface{}
    err := json.Unmarshal([]byte(jsonString), &j)
    if err == nil {
        jsonforeach(&j, func(key *string, index *int, value *interface{}, depth int) {
            for i := 0; i < depth; i++ {
                fmt.Print("  ")
            }
            v := *value
            switch v.(type) {
            case string:
                if key != nil {
                    fmt.Printf("OBJECT: key=%q, value=%#v\n", *key, *value)
                } else {
                    fmt.Printf("ARRAY: index=%d, value=%#v\n", *index, *value)
                }
            default:
                if key != nil {
                    fmt.Printf("%v\n", *key)
                } else {
                    fmt.Println("")
                }
            }
        })
    } else {
        fmt.Println(err)
    }
}

Useful links

• Learn Go: https://golangr.com
• Download Go: https://golang.org