Go Interview Question #1

01_go_interview_question_#1.md

Go Interview Question #1

• Read the code and explain it.
• Will it compile or not?
• Find any possible issues.
• Explain how would you refactor it and why.

02_main.go

package main

import (
	"bufio"
	"bytes"
	"flag"
	"io"
	"net/http"
	"os"
)

func main() {
	inputFilePath := flag.String("in", "in.txt", "a file with URLs")
	outputFilePath := flag.String("ou", "out.txt", "a file with URLs")
	flag.Parse()

	b, err := os.ReadFile(*inputFilePath)
	if err != nil {
		panic(err)
	}

	buf := bytes.NewBuffer(b)

	var urls []string
	fileScanner := bufio.NewScanner(buf)
	for fileScanner.Scan() {
		urls = append(urls, fileScanner.Text())
	}
	if err := fileScanner.Err(); err != nil {
		panic(err)
	}

	contents, err := getContent(urls)
	if err != nil {
		panic(err)
	}

	singleContent := bytes.Join(contents, []byte("\n====================\n"))
	err = os.WriteFile(*outputFilePath, singleContent, 0644)
	if err != nil {
		panic(err)
	}
}

func getContent(urls []string) ([][]byte, error) {
	var contents [][]byte

	for _, url := range urls {
		res, err := http.DefaultClient.Get(url)
		if err != nil {
			return nil, err
		}

		b, err := io.ReadAll(res.Body)
		if err != nil {
			return nil, err
		}
		contents = append(contents, b)
	}

	return contents, nil
}