json

README

json-decoder

An optional json decoder for goschtalt.

Documentation

Overview

json package is a goschtalt decoder package.

The json package automatically registers the decoder as a default decoder with the goschtalt package so the usage is as simple as possible ... simply import the package and it should just work.

Import the package like you do for pprof - like this:

import (
	"fmt"
	"os"
	...

	"github.com/goschtalt/goschtalt"
	_ "github.com/goschtalt/goschtalt/extensions/decoders/json"
)

See the example for how to use this extension package.

Example

// SPDX-FileCopyrightText: 2022 Weston Schmidt <weston_schmidt@alumni.purdue.edu>
// SPDX-License-Identifier: Apache-2.0

package main

import (
	"fmt"
	"io/fs"
	"strings"

	"github.com/goschtalt/goschtalt"
	_ "github.com/goschtalt/json-decoder"
	"github.com/psanford/memfs"
)

const filename = `example.json`
const text = `{
  "example": {
      "version": 1,
      "colors": ["red", "green", "blue"]
  }
}`

func getFS() fs.FS {
	mfs := memfs.New()
	if err := mfs.WriteFile(filename, []byte(text), 0755); err != nil {
		panic(err)
	}

	return mfs
}

func main() {
	// Normally, you use something like os.DirFS("/etc/program")
	g, err := goschtalt.New(goschtalt.AddDir(getFS(), "."))
	if err != nil {
		panic(err)
	}

	err = g.Compile()
	if err != nil {
		panic(err)
	}

	var cfg struct {
		Example struct {
			Version int
			Colors  []string
		}
	}

	err = g.Unmarshal("", &cfg)
	if err != nil {
		panic(err)
	}

	fmt.Println("example")
	fmt.Printf("    version = %d\n", cfg.Example.Version)
	fmt.Printf("    colors  = [ %s ]\n", strings.Join(cfg.Example.Colors, ", "))

}

Output:
example
    version = 1
    colors  = [ red, green, blue ]

Index

• type Decoder
  • func (d Decoder) Decode(ctx decoder.Context, b []byte, m *meta.Object) error
  • func (d Decoder) Extensions() []string

Examples

• Package

Types

type Decoder

type Decoder struct{}

Decoder is a class for the json decoder.

func (Decoder) Decode

func (d Decoder) Decode(ctx decoder.Context, b []byte, m *meta.Object) error

Decode decodes a byte arreay into the meta.Object tree.

func (Decoder) Extensions

func (d Decoder) Extensions() []string

Extensions returns the supported extensions.