JSON Pointer Exploration

main.go

package main

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"github.com/qri-io/jsonpointer"
)

func main() {
	file, err := os.Open("schema.json")
	if err != nil {
		panic(err)
	}

	var schema map[string]interface{}
	err = json.NewDecoder(file).Decode(&schema)
	if err != nil {
		panic(err)
	}

	resolved, err := walk(schema, schema, 0)
	if err != nil {
		panic(err)
	}

	encoder := json.NewEncoder(os.Stdout)
	encoder.SetIndent("", "  ")
	encoder.Encode(resolved)
}

func walk(root map[string]interface{}, node interface{}, depth int) (interface{}, error) {
	switch value := node.(type) {
	case map[string]interface{}:
		resolvedValue := map[string]interface{}{}

		for k, v := range value {
			if k == "$ref" {
				fmt.Printf("%s%s -> hit: %s\n", strings.Repeat("  ", depth), k, v)
				result, err := find(root, v.(string))
				if err != nil {
					return nil, err
				}

				return result, nil
			} else {
				fmt.Printf("%s%s -> miss\n", strings.Repeat("  ", depth), k)
				result, err := walk(root, v, depth+1)
				if err != nil {
					return nil, err
				}

				resolvedValue[k] = result
			}
		}

		node = resolvedValue

	case []interface{}:
		fmt.Printf("%s[\n", strings.Repeat("  ", depth))
		resolvedValue := []interface{}{}

		for _, v := range value {
			result, err := walk(root, v, depth+1)
			if err != nil {
				return nil, err
			}

			resolvedValue = append(resolvedValue, result)
		}

		fmt.Printf("%s]\n", strings.Repeat("  ", depth))
		node = resolvedValue
	}

	return node, nil
}

func find(root map[string]interface{}, path string) (interface{}, error) {
	ptr, err := jsonpointer.Parse(path)
	if err != nil {
		return nil, err
	}

	subgraph, err := ptr.Eval(root)
	if err != nil {
		return nil, err
	}

	return subgraph, nil
}