(摘) golang网页截屏

原文：https://zhuanlan.zhihu.com/p/438257924
这个可以形成一个web工具，专门用于帮助网友保存网址的截图。

package main
 
import (
 "context"
 "flag"
 "io/ioutil"
 "log"
 "os"
 "path/filepath"
 "regexp"
 "strings"
 "time"
 
 "github.com/chromedp/cdproto/page"
 "github.com/chromedp/chromedp"
)
 
type Chrome struct {
 Url         string
 UserAgent   string
 FullScreen  bool
 ResolutionX int
 ResolutionY int
 Delay       int64
}
 
var ChromeType *Chrome
 
// 初始化输入
func init() {
 ChromeType = new(Chrome)
 flag.StringVar(&ChromeType.Url, "url", "", "web http or https url (must)")
 flag.BoolVar(&ChromeType.FullScreen, "F", false, "full screenshots auto width and height")
 flag.StringVar(&ChromeType.UserAgent, "userAgent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.82 Safari/537.36", "user agent string to use")
 flag.IntVar(&ChromeType.ResolutionX, "resolutionX", 1920, "screenshot resolution x")
 flag.IntVar(&ChromeType.ResolutionY, "resolutionY", 1080, "screenshot resolution y")
 flag.Int64Var(&ChromeType.Delay, "delay", 0, "delay in seconds between navigation and screenshot")
 flag.Parse()
}
 
// 网页截屏小工具
func main() {
 if ChromeType.Url == "" {
  panic("url must input!")
 }
 buf, err := ChromeType.Screenshot()
 if err != nil {
  panic(err.Error())
 }
 fp := ChromeType.SafeFileName()
 if err = ioutil.WriteFile(fp, buf, 0644); err != nil {
  panic(err.Error())
 }
 thisPath, _ := os.Getwd()
 log.Println("生成成功，文件名是：", filepath.Join(thisPath, fp))
}
 
func (chrome *Chrome) Screenshot() ([]byte, error) {
 // 组装 chromeDp的参数设置
 var options []chromedp.ExecAllocatorOption
 options = append(options, chromedp.DefaultExecAllocatorOptions[:]...)
 options = append(options, chromedp.UserAgent(chrome.UserAgent))
 options = append(options, chromedp.DisableGPU)
 options = append(options, chromedp.Flag("ignore-certificate-errors", true))
 options = append(options, chromedp.WindowSize(chrome.ResolutionX, chrome.ResolutionY)) // 分辨率生成
 
 actX, aCancel := chromedp.NewExecAllocator(context.Background(), options...)
 ctx, cancel := chromedp.NewContext(actX)
 defer aCancel()
 defer cancel()
 
 var buf []byte
 
 // 压缩js对话框 如：alert()
 chromedp.ListenTarget(ctx, func(ev interface{}) {
  if _, ok := ev.(*page.EventJavascriptDialogOpening); ok {
   go func() {
    if err := chromedp.Run(ctx,
     page.HandleJavaScriptDialog(true),
    ); err != nil {
     panic(err)
    }
   }()
  }
 })
 
 // 是否全屏
 if chrome.FullScreen {
  if err := chromedp.Run(ctx, chromedp.Tasks{
   chromedp.Navigate(chrome.Url),
   chromedp.Sleep(time.Duration(chrome.Delay) * time.Second),
   chromedp.FullScreenshot(&buf, 100),
  }); err != nil {
   return nil, err
  }
 
 } else {
  // 不是全屏下就直接生成
  if err := chromedp.Run(ctx, chromedp.Tasks{
   chromedp.Navigate(chrome.Url),
   chromedp.Sleep(time.Duration(chrome.Delay) * time.Second),
   chromedp.CaptureScreenshot(&buf),
  }); err != nil {
   return nil, err
  }
 }
 return buf, nil
}
 
// SafeFileName 生成安全文件名，且生成png后缀的地址
func (chrome *Chrome) SafeFileName() string {
 name := strings.ToLower(chrome.Url)
 name = strings.Trim(name, " ")
 
 separators, err := regexp.Compile(`[ &_=+:/]`)
 if err == nil {
  name = separators.ReplaceAllString(name, "-")
 }
 
 legal, err := regexp.Compile(`[^[:alnum:]-.]`)
 if err == nil {
  name = legal.ReplaceAllString(name, "")
 }
 
 for strings.Contains(name, "--") {
  name = strings.Replace(name, "--", "-", -1)
 }
 
 return name + `.png`
}