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@@ -10,6 +10,12 @@ import (
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"go.uber.org/zap"
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)
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// A4 纵向 @ 96dpi,与 CSS @page / 报告页 max-width 对齐
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const (
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htmlPDFViewportWidth = 794
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htmlPDFViewportHeight = 1123
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)
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// HTMLPDFGenerator 使用 headless Chrome 将 HTML 页面渲染为 PDF
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type HTMLPDFGenerator struct {
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logger *zap.Logger
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@@ -26,41 +32,54 @@ func NewHTMLPDFGenerator(logger *zap.Logger) *HTMLPDFGenerator {
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}
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// GenerateFromURL 使用 headless Chrome 打开指定 URL,并导出为 PDF 字节流
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// 这里固定使用 A4 纵向纸张,开启背景打印
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// 流程:A4 视口渲染 → 等待报告 DOM → 滚动触发展开 → 切换 print 媒体 → PrintToPDF(边距由 CSS @page 控制)
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func (g *HTMLPDFGenerator) GenerateFromURL(ctx context.Context, url string) ([]byte, error) {
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if ctx == nil {
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ctx = context.Background()
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}
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// 整个生成过程增加超时时间,避免长时间卡死
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timeoutCtx, cancel := context.WithTimeout(ctx, 60*time.Second)
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timeoutCtx, cancel := context.WithTimeout(ctx, 90*time.Second)
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defer cancel()
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// 创建 Chrome 上下文(使用系统默认的 headless Chrome/Chromium)
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chromeCtx, cancelChrome := chromedp.NewContext(timeoutCtx)
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opts := append(chromedp.DefaultExecAllocatorOptions[:],
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chromedp.Flag("headless", true),
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chromedp.Flag("disable-gpu", true),
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chromedp.Flag("no-sandbox", true),
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chromedp.Flag("disable-dev-shm-usage", true),
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)
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allocCtx, allocCancel := chromedp.NewExecAllocator(timeoutCtx, opts...)
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defer allocCancel()
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chromeCtx, cancelChrome := chromedp.NewContext(allocCtx)
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defer cancelChrome()
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var pdfBuf []byte
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tasks := chromedp.Tasks{
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chromedp.EmulateViewport(htmlPDFViewportWidth, htmlPDFViewportHeight),
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chromedp.Navigate(url),
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// 等待页面主体和报告容器就绪,确保数据渲染完成
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chromedp.WaitReady("body", chromedp.ByQuery),
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chromedp.WaitVisible(".page", chromedp.ByQuery),
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waitReportReadyForPDF(),
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waitReportPosterImages(),
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scrollPageForPrintLayout(),
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chromedp.ActionFunc(func(ctx context.Context) error {
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return chromedp.Evaluate(`document.body.classList.add('pdf-export')`, nil).Do(ctx)
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}),
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chromedp.ActionFunc(func(ctx context.Context) error {
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time.Sleep(150 * time.Millisecond)
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return nil
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}),
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chromedp.ActionFunc(func(ctx context.Context) error {
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g.logger.Info("开始通过 headless Chrome 生成企业报告 PDF", zap.String("url", url))
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var (
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buf []byte
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err error
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)
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buf, _, err = page.PrintToPDF().
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buf, _, err := page.PrintToPDF().
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WithPrintBackground(true).
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WithPaperWidth(8.27). // A4 宽度(英寸 -> 约 210mm)
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WithPaperHeight(11.69). // A4 高度(英寸 -> 约 297mm)
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WithMarginTop(0.4).
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WithMarginBottom(0.4).
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WithMarginLeft(0.4).
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WithMarginRight(0.4).
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WithPaperWidth(8.27).
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WithPaperHeight(11.69).
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WithMarginTop(0.39).
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WithMarginBottom(0.39).
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WithMarginLeft(0.47).
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WithMarginRight(0.47).
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Do(ctx)
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if err == nil {
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pdfBuf = buf
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@@ -86,3 +105,87 @@ func (g *HTMLPDFGenerator) GenerateFromURL(ctx context.Context, url string) ([]b
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return pdfBuf, nil
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}
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// waitReportReadyForPDF 等待企业报告脚本渲染完成(qiye.html 设置 data-qygl-report-ready)
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func waitReportReadyForPDF() chromedp.Action {
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return chromedp.ActionFunc(func(ctx context.Context) error {
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deadline := time.Now().Add(45 * time.Second)
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for {
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if ctx.Err() != nil {
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return ctx.Err()
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}
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var ready string
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_ = chromedp.Evaluate(`document.body && document.body.dataset.qyglReportReady || ''`, &ready).Do(ctx)
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if ready == "1" {
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return nil
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}
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var sectionCount float64
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_ = chromedp.Evaluate(`document.querySelectorAll('#reportSections .section-card, .report-sections .section-block').length`, §ionCount).Do(ctx)
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if sectionCount > 0 {
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return nil
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}
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if time.Now().After(deadline) {
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return fmt.Errorf("等待报告内容渲染超时")
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}
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time.Sleep(200 * time.Millisecond)
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}
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})
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}
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func waitReportPosterImages() chromedp.Action {
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return chromedp.ActionFunc(func(ctx context.Context) error {
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deadline := time.Now().Add(20 * time.Second)
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for {
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if ctx.Err() != nil {
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return ctx.Err()
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}
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var pending float64
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js := `(function(){
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var imgs = document.querySelectorAll('img.header-poster, img.footer-poster');
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if (!imgs.length) return 0;
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for (var i = 0; i < imgs.length; i++) {
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var img = imgs[i];
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if (!img.complete || img.naturalWidth === 0) return 1;
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}
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return 0;
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})()`
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if err := chromedp.Evaluate(js, &pending).Do(ctx); err != nil {
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return err
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}
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if pending == 0 {
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return nil
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}
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if time.Now().After(deadline) {
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return fmt.Errorf("等待报告海报图片加载超时")
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}
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time.Sleep(150 * time.Millisecond)
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}
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})
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}
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func scrollPageForPrintLayout() chromedp.Action {
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return chromedp.ActionFunc(func(ctx context.Context) error {
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var height float64
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if err := chromedp.Evaluate(`Math.max(document.body.scrollHeight, document.documentElement.scrollHeight)`, &height).Do(ctx); err != nil {
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return err
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}
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step := float64(900)
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if height < step {
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step = height
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}
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if step <= 0 {
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return nil
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}
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for y := float64(0); y <= height; y += step {
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js := fmt.Sprintf(`window.scrollTo(0, %f);`, y)
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if err := chromedp.Evaluate(js, nil).Do(ctx); err != nil {
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return err
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}
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time.Sleep(120 * time.Millisecond)
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}
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if err := chromedp.Evaluate(`window.scrollTo(0, 0);`, nil).Do(ctx); err != nil {
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return err
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}
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time.Sleep(300 * time.Millisecond)
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return nil
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})
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}
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