download.go

package main

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

func main() {
	url := os.Args[1]
	resp, err := http.Get(url)
	if err != nil {
		log.Fatalf("download failed: %s: %s", url, err)
	}

	file, err := os.Create("/tmp/download.out")
	if err != nil {
		log.Fatalf("failed to create /tmp/download.out: %s", err)
	}

	done := make(chan bool)
	go func() {
		bytes, err := io.Copy(file, resp.Body)
		if err != nil {
			log.Fatalf("writing to file failed: %s", err)
		}

		log.Printf("finished, wrote %d bytes", bytes)
		done <- true
	}()

	abort := make(chan bool)
	go func() {
		var cmd string
		for {
			log.Printf("Press any key + return to abort transfer")
			fmt.Scan(&cmd)

			log.Printf("got %s\n", cmd)
			abort <- true
		}
	}()

outer:
	for {
		select {
		case <-done:
			log.Printf("done\n")
			break outer
		case <-abort:
			log.Printf("abort\n")
			break outer
		}
	}

	log.Printf("closing body\n")
	resp.Body.Close()

	log.Printf("closing input\n")
	file.Close()
}