Go学习笔记 - 截图API

2025-03-19

全文 ≈ 642字 | 预计阅读时长 3分钟

记一次截图应用接口的实现

背景

对不同文件类型生成缩略图，视频使用ffmpeg抽帧，html 文件则需要运行才能截图。

思路

模拟浏览器访问并截图，需要工具：google-chrome、go-rod

实现

google-chrome v112.0.5615.165

$ wget https://mirrors.aliyun.com/google-chrome/google-chrome/google-chrome-stable-112.0.5615.165-1.x86_64.rpm
$ sudo yum localinstall google-chrome-stable-112.0.5615.165-1.x86_64.rpm
$ google-chrome --version
Google Chrome 112.0.5615.165

screenshot.go

request := &requests.Screenshot{}
if err := c.ShouldBindQuery(request); err != nil {
    c.JSON(http.StatusOK, resp.Err.WithMsg("请求数据格式有误"))
    return
}
if len(request.Url) == 0 {
    c.JSON(http.StatusOK, resp.Err.WithMsg("URL不可为空"))
    return
}
if !strings.Contains(request.Url, "http") {
    c.JSON(http.StatusOK, resp.Err.WithMsg("请输入标准的URl(包含scheme)"))
    return
}

browser, err := browserPool.Get(func() (*rod.Browser, error) {
    log.Printf("[Screenshot] 创建浏览器")
    // 创建浏览器
    l := launcher.New().Bin("/usr/bin/google-chrome").Leakless(true)
    // l := launcher.New().Leakless(true)
    browser := rod.New().ControlURL(l.MustLaunch()).MustConnect()
    return browser, nil
})
if err != nil {
    log.Printf("[Screenshot] 初始化浏览器失败 %+v \n", err)
    return
}
defer browserPool.Put(browser)

// 创建页面
log.Printf("[Screenshot] 创建空页面 %s \n", request.Url)
page := browser.MustIncognito().MustPage()
page.SetUserAgent(&proto.NetworkSetUserAgentOverride{
    UserAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36",
})
defer page.MustClose()

page.MustEmulate(devices.Device{
    AcceptLanguage: "zh",
    Screen: devices.Screen{
        DevicePixelRatio: 1,
    },
})

// 最大超时时间
ctx, cancel := context.WithTimeout(c.Request.Context(), time.Second*65)
defer cancel()

// 导航至指定页面
log.Printf("[Screenshot] 重定向页面 %s \n", request.Url)
page.Context(ctx).MustNavigate(request.Url)

// 等待页面加载完成 & 稳定
log.Printf("[Screenshot] 等待页面渲染完成 %s \n", request.Url)
err = rod.Try(func() {
    page.WaitEvent(&proto.PageLoadEventFired{}) // window.addEventListener("load")
    // log.Printf("[Screenshot] 等待页面稳定 %s \n", request.Url)
    // page.WaitStable(5 * time.Second)
})
if err != nil {
    log.Printf("[Screenshot] 请求页面 %s 加载失败 %+v \n", request.Url, err)
}

if request.Delay > 0 {
    // max 60s
    if request.Delay > 60000 {
        request.Delay = 60000
    }
    log.Printf("[Screenshot] 等待%dms %s \n", request.Delay, request.Url)
    time.Sleep(time.Millisecond * time.Duration(request.Delay))
}

bytes, _ := page.Screenshot(true, nil)
if len(request.Name) == 0 {
    request.Name = "screenshot_" + time.Now().Format(consts.TIME_YYMMDDHHMMSS)
}
c.Header("content-disposition", `attachment; filename=`+request.Name+".png")
c.Data(http.StatusOK, "image/png", bytes)

可能遇见的问题

[0317/072940.284032:ERROR:zygote_host_impl_linux.cc(100)] Running as root without –no-sandbox is not supported. See https://crbug.com/638180.

1	$ sudo vim /usr/bin/google-chrome

将 exec -a "$0" "$HERE/chrome" "$@" 修改为 exec -a "$0" "$HERE/chrome" "$@" --user-data-dir --no-sandbox