gjtypes

README

Gjtypes - Convert JSON data into the Go types needed to parse it

This is gjtypes, a command that parses JSON data on standard input and produces the Go types needed to parse that data on standard output.

Installation

go install github.com/bobg/gjtypes@latest

Usage

gjtypes < INPUT

where INPUT is a file of JSON data.

The resulting Go code may include generated type names − S001, S002, and so on − that you’ll probably want to rename to be meaningful.

Example

Given the following JSON input:

{"title": "Scott Pilgrim vs. The World",
 "director": "Edgar Wright",
 "year": 2010,
 "stars": ["Michael Cera",
           "Mary Elizabeth Winstead",
           "Ellen Wong",
           "Chris Evans",
           "Aubrey Plaza",
           "Anna Kendrick",
           "Brie Larson"],
 "songs": [{"title": "Teenage Dream",
            "artist": "T. Rex"},
           {"title": "Black Sheep",
            "artist": "Metric"}]}

gjson will emit:

var data *S001 // Unmarshal into this type.

type S001 struct {
	Director string   `json:"director,omitempty"`
	Songs    []*S002  `json:"songs,omitempty"`
	Stars    []string `json:"stars,omitempty"`
	Title    string   `json:"title,omitempty"`
	Year     int64    `json:"year,omitempty"`
}

type S002 struct {
	Artist string `json:"artist,omitempty"`
	Title  string `json:"title,omitempty"`
}

In this case you’d probably want to rename S001 to Movie and S002 to Song.

Documentation

Overview

Command gjtypes reads JSON data from stdin and writes Go types for parsing that data to stdout.