golang 采集图片

帮朋友忙去采集的，看他打开韩国网站 一个一个点开去保存看不下去了速度太慢了，原本想用PHP写的，刚好看了无闻大大的go采集，然后无耻的改了下就用了，

package main

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

type NotFoundError struct {
Message string
}

func (e NotFoundError) Error() string {
return e.Message
}

type RemoteError struct {
Host string
Err  error
}

func (e *RemoteError) Error() string {
return e.Err.Error()
}

var UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1541.0 Safari/537.36"

// HttpGet gets the specified resource. ErrNotFound is returned if the
// server responds with status 404.
func HttpGet(client *http.Client, url string, header http.Header) (io.ReadCloser, error) {
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
req.Header.Set("User-Agent", UserAgent)
for k, vs := range header {
req.Header[k] = vs
}
resp, err := client.Do(req)
if err != nil {
return nil, &RemoteError{req.URL.Host, err}
}
if resp.StatusCode == 200 {
return resp.Body, nil
}
resp.Body.Close()
if resp.StatusCode == 404 { // 403 can be rate limit error.  || resp.StatusCode == 403 {
err = NotFoundError{"Resource not found: " + url}
} else {
err = &RemoteError{req.URL.Host, fmt.Errorf("get %s -> %d", url, resp.StatusCode)}
}
return nil, err
}

// HttpGetBytes gets the specified resource. ErrNotFound is returned if the server
// responds with status 404.
func HttpGetBytes(client *http.Client, url string, header http.Header) ([]byte, error) {
rc, err := HttpGet(client, url, header)
if err != nil {
return nil, err
}
defer rc.Close()
return ioutil.ReadAll(rc)
}

// HttpGetToFile gets the specified resource and writes to file.
// ErrNotFound is returned if the server responds with status 404.
func HttpGetToFile(client *http.Client, url string, header http.Header, fileName string) error {
rc, err := HttpGet(client, url, header)
if err != nil {
return err
}
defer rc.Close()


os.MkdirAll(path.Dir(fileName), os.ModePerm)
f, err := os.Create(fileName)
if err != nil {
return err
}
defer f.Close()
_, err = io.Copy(f, rc)
return err
}


var img = regexp.MustCompile(`href=\"javascript:goView\((\d+)`)
var imgPattern = regexp.MustCompile(`id="mainImage" src=\"../upload(.*?).jpg`)
var totalTask int

func download(url string, num chan bool) {
url = strings.TrimPrefix(url, `href="javascript:goView(`)
page := "http://www.gdweb.co.kr/main/koreaWebView.asp?idx=%s&url=koreaWeb.asp"
t, err := HttpGetBytes(&http.Client{}, fmt.Sprintf(page, url), nil)


if err != nil {
log.Fatalf("获取页面失败：%v", err)
}
matches := imgPattern.FindAll(t, -1)
for _, match := range matches {
url = "http://www.gdweb.co.kr" + strings.TrimPrefix(string(match), `id="mainImage" src="..`)
log.Printf("正在下载：%s", url)
err := HttpGetToFile(&http.Client{}, url, nil, "pics/"+path.Base(url))
if err != nil {
log.Printf("图片下载失败（%s）：%v", url, err)
}
}
totalTask--
<-num
}

func main() {
// 控制同时下载数量
num := make(chan bool, 5)


// 主线程爬取页面，子线程下载图片
//baseUrl := "http://nvmingxing.net/hotness/%d/"
//abaseUrl := "http://www.gdweb.co.kr/main/koreaWebView.asp?idx=8200&url=koreaWeb.asp"
baseUrl := "http://www.gdweb.co.kr/main/koreaWeb.asp?idx=&url=index.asp&lpage=124&page=%d"
for i := 2; i < 124; i++ {
log.Printf("抓取页面：%d", totalTask)
data, err := HttpGetBytes(&http.Client{}, fmt.Sprintf(baseUrl, i+1), nil)
if err != nil {
log.Fatalf("获取页面失败（%d）：%v", i, err)
}
matches := img.FindAll(data, -1)
for _, match := range matches {
totalTask++
num <- true
go download(string(match), num)
}
}
}