Golang golang-codegen (snippet)

Go programming example 'golang-codegen'

golang-codegen

Golang beginners example: golang-codegen

package main

import (
    "encoding/json"
    "os"
    "reflect"
    "strings"
    "text/template"
)

//go:generate go run codegen.go
//go:generate go fmt codegenerated/codegenerated.go

type Struct struct {
    Name   string
    Fields map[string]interface{}
}

func title(input string) string {
    input = strings.Replace(input, "_", " ", -1)
    input = strings.Title(input)
    input = strings.Replace(input, " ", "", -1)
    return input
}

func typeOf(v interface{}) string {
    if v == nil {
        return "string"
    }
    return strings.ToLower(reflect.TypeOf(v).String())
}

func genStructCode() {
    templateString, jsonString := getExampleData()

    var resp map[string]interface{}
    json.Unmarshal([]byte(jsonString), &resp)

    data := Struct{"Data", resp}

    tpl, _ := template.New("struct").Funcs(template.FuncMap{
        "Title":  title,
        "TypeOf": typeOf,
    }).Parse(templateString)

    out, _ := os.Create("codegenerated/codegenerated.go")
    defer out.Close()

    tpl.Execute(out, data)
}

func main() {
    genStructCode()
}

func getExampleData() (string, string) {
    templateString := `
package codegen

type {{ .Name | Title }} struct {
{{ range $jsonName, $val := .Fields }}
    {{- $jsonName | Title }} {{ $val | TypeOf }} ` + "`" + `json:"{{ $jsonName }}"` + "`" + `
{{ end }}
}
`

    jsonString := `
{
  "lorem": "ipsum",
  "dolor": "sit",
  "amet": 1337,
  "foo_bar": true,
  "bar": false
}
`
    return templateString, jsonString
}

Useful links

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