Fetch several web pages simultaneously, and print the URL of the biggest page (defined as the most bytes in the response)

main.go

package main

import (
	"fmt"
	"io/ioutil"
	"net/http"
)

type Page struct {
	URL  string
	Size int
}

var urls = [...]string{
	"https://www.google.com/",
	"https://www.youtube.com/",
	"https://www.songsterr.com/",
	"https://open.spotify.com/",
}

func main() {
	res := make(chan Page)

	for _, url := range urls {
		go func(url string) {
			resp, err := http.Get(url)
			if err != nil {
				panic(err)
			}
			defer resp.Body.Close()

			bs, err := ioutil.ReadAll(resp.Body)
			if err != nil {
				panic(err)
			}

			res <- Page{
				URL:  url,
				Size: len(bs),
			}
		}(url)
	}

	var biggest Page

	for range urls {
		currPage := <-res
		if currPage.Size > biggest.Size {
			biggest = currPage
		}
	}
	fmt.Println("The biggest page:", biggest.URL)
}