mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-11-14 10:23:42 +00:00
55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
|
|
// See page 148.
|
|
|
|
// Fetch saves the contents of a URL into a local file.
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"net/http"
|
|
"os"
|
|
"path"
|
|
)
|
|
|
|
//!+
|
|
// Fetch downloads the URL and returns the
|
|
// name and length of the local file.
|
|
func fetch(url string) (filename string, n int64, err error) {
|
|
resp, err := http.Get(url)
|
|
if err != nil {
|
|
return "", 0, err
|
|
}
|
|
defer resp.Body.Close()
|
|
|
|
local := path.Base(resp.Request.URL.Path)
|
|
if local == "/" {
|
|
local = "index.html"
|
|
}
|
|
f, err := os.Create(local)
|
|
if err != nil {
|
|
return "", 0, err
|
|
}
|
|
n, err = io.Copy(f, resp.Body)
|
|
// Close file, but prefer error from Copy, if any.
|
|
if closeErr := f.Close(); err == nil {
|
|
err = closeErr
|
|
}
|
|
return local, n, err
|
|
}
|
|
|
|
//!-
|
|
|
|
func main() {
|
|
for _, url := range os.Args[1:] {
|
|
local, n, err := fetch(url)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "fetch %s: %v\n", url, err)
|
|
continue
|
|
}
|
|
fmt.Fprintf(os.Stderr, "%s => %s (%d bytes).\n", url, local, n)
|
|
}
|
|
}
|