go by example scaffold thing

scaffold.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"regexp"
)

var fileTemplate = `
package main

import "fmt"

func main() {
}
`

func main() {
	err := scaffold()
	if err != nil {
		log.Fatal(err)
	}
}

func scaffold() error {
	html, err := request("https://gobyexample.com/")
	if err != nil {
		return err
	}

	listLinkExpression := regexp.MustCompile(`<li><a href="([\w-]+)">`)
	matches := listLinkExpression.FindAllStringSubmatch(html, -1)

	for i, name := range matches {
		dirname := fmt.Sprintf("./examples/%02d-%s", i+1, name[1])
		filename := fmt.Sprintf("%s/main.go", dirname)

		err = os.MkdirAll(dirname, 0777)
		if err != nil {
			return err
		}

		fp, err := os.Create(filename)
		if err != nil {
			return err
		}
		defer fp.Close()

		_, err = fp.WriteString(fileTemplate)
		if err != nil {
			return err
		}
	}
	return nil
}

func request(url string) (html string, err error) {
	res, err := http.Get(url)
	if err != nil {
		return
	}
	defer res.Body.Close()

	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return
	}

	html = string(body)
	return
}