/*下载工具*/

package main  

import (

    "fmt"

    //go语言版本的jquery

    "github.com/PuerkitoBio/goquery"

    "os"

    "sync"

    "strings"

    //go语言版本的request

    "github.com/levigross/grequests"

    "time"

    "strconv"

)  

var wg sync.WaitGroup  

func main() {

    now := time.Now()

    initalUrls := []string{"http://www.zngirls.com/girl/18071/album/", }

    for _, url := range initalUrls {

        doc, err := goquery.NewDocument(url)

        if err != nil {

            fmt.Errorf("下载错误:%#v", err)

            os.Exit(-1)

        }  

        doc.Find(".igalleryli_link").Each(func(i int, s *goquery.Selection) {

            src, exists := s.Find("img").Attr("src")

            fmt.Printf("开始下载影集图片:%v\n", src)

            if (exists) {

                wg.Add(1)

                go func(src string) {

                    defer wg.Done()  

                    //下载图片

                    //tryTimes := map[int]int

                    n := 0

                    s := strings.Replace(src, "cover/", "", 1)

                    ss := strings.Split(s, "/")

                    fm := strings.Join(ss[:len(ss) - 1], "/")

                    sf0 := fm + "/%d.jpg"

                    sfn := fm + "/%03d.jpg"  

                    for {

                        //持续下载

                        s := ""

                        if n == 0 {

                            s = fmt.Sprintf(sf0, n)

                        } else {

                            s = fmt.Sprintf(sfn, n)

                        }  

                        fmt.Printf("准备下载: %v\n", s)

                        res, _ := grequests.Get(s, &grequests.RequestOptions{

                            //结构体可以对指定的类型给值，而不一定都赋值

                            Headers:map[string]string{

                                "Referer":"http://www.zngirls.com",

                                "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36"}})

                        //条件需要修改，如果没有图片，返回的是盗链，图片4kb

                        if res.StatusCode != 200 {

                            fmt.Printf("下载失败，退出影集下载:%s\n", src)

                            break

                        }  

                        //图片可能是该网站，返回的盗链图片（4kb左右)

                        length := res.Header.Get("Content-Length")

                        slen,_ := strconv.Atoi(length)

                        if slen < 4100{

                            fmt.Printf("下载内容失败,退出影集下载:%s\n", src)

                            break

                        }  

                        index := strings.Index(s, "gallery")

                        if index == -1 {

                            fmt.Errorf("无效地址，找不到gallery关键词，解析失败:%s\n", src)

                            return

                        }  

                        ss2 := strings.Split(string(s[index:]), "/")

                        dirname := strings.Join(ss2[:len(ss2) - 1], "/")

                        if _, err := os.Stat(dirname); err != nil {

                            fmt.Printf("创建下载文件夹:%s\n", dirname)

                            os.MkdirAll(dirname, 0666)

                        }  

                        filename := strings.Join(ss2, "/")

                        res.DownloadToFile(filename)

                        fmt.Printf("成功下载图片到:%s\n", filename)

                        n++

                    }

                }(src)

            }

        })

    }  

    wg.Wait()

    //4M的带宽下载，需要16m36s，总大小202M,10个文件夹,560个文件

    fmt.Printf("下载任务完成，耗时:%#v\n", time.Now().Sub(now))

}