PDF-to-DWG and PDF-to-PDF/A Download is a real blob link, so a click saves instead of a silent programmatic a.click().

Date: 2026-09-06 16:56 Summary: PDF-to-DWG and PDF-to-PDF/A Download is a real blob link, so a click saves instead of a silent programmatic a.click(). Visibility: people

[question] http://127.0.0.1:8788/zh/tools/convert-pdf-to-dwg 点击下载.dxf没有反应 http://127.0.0.1:8788/zh/tools/convert-pdf-to-pdf-a 也是一样的问题，点击下载没有反应

Tool links (English)

[try to solve]

Context

On the local Chinese tool pages, Load sample (and a user PDF) showed a preview and an enabled Download control, but clicking it did nothing: no file, no error, no status change. The same pattern appeared on Convert PDF to DWG (Download .dxf) and Convert PDF to PDF/A.

Process

Confirmed the DWG page after sample: status「完成」, DXF textarea filled (~419 bytes of ASCII SECTION / ENTITIES), #cpdBtnDownload enabled. Headless Chrome then did receive sample-pdf-to-dwg.dxf from a click — so the save path itself was not dead once a result existed.
Read downloadResult: if (!result) return; / if (!resultBytes) return; with no setError. A click with an empty result is indistinguishable from a frozen button.
Traced window.OftPdfWork.setBusy(buttons, busy). When busy is false it sets btn.disabled = false on every button in the array. Both pages put Download in busyBtns.
loadFile ends with setBusy(false) after showPreview. That paints the PDF canvas and lights Download while result / resultBytes is still null. Convert runs only after that (sample path) or after a second click on Convert (user file). The preview makes the page look finished, so Download is the natural next click — and it no-ops.
Applied the same fix on both pages: keep Download out of busyBtns; after load, btnDownload.disabled = !result; delay URL.revokeObjectURL by 2s (DWG also uses application/octet-stream so an unknown .dxf MIME cannot cancel a blob navigation). Cache version 4.52 so the Worker HTML Cache API drops the old script.

Root cause / analysis

Two independent states were collapsed onto one control. Preview-ready is not file-ready. setBusy(false) treated “not busy” as “all actions available”. Combined with a silent early return, the UI lied: Download looked clickable and then did nothing. Immediate revokeObjectURL after a.click() can also abort a blob download in some browsers, especially for non-PDF types such as DXF; that was a second, smaller failure mode after a real result existed.

Solution

src/pages/convertPdfToDwgPage.ts and src/pages/convertPdfToPdfAPage.ts: Download is enabled only when the converted bytes/string exist. A click without a result shows the existing empty/convert error instead of returning quietly. Blob URLs are revoked after 2 seconds.
Local check on http://127.0.0.1:8788/zh/tools/convert-pdf-to-pdf-a and .../convert-pdf-to-dwg: after sample status「完成」, click Download → sample-pdf-a-pdfa.pdf and sample-pdf-to-dwg.dxf, no pageerror.
PAGES_CACHE_VERSION 4.51 → 4.53.

Second pass (native `<a download>`)

The first pass still used a hidden <a> plus a.click(). That is a programmatic download: Playwright records it, but Cursor’s preview pane and some browsers swallow it with no UI. The user reported PDF/A still “did nothing” after 4.52.

Download is now a real <a class="btn">. After convert, setDownloadReady points href at a live blob URL and sets download=filename. The user click is a normal link activation, not element.click() on a detached node. Blob URLs stay until the next convert/clear.

Rechecked http://127.0.0.1:8788/zh/tools/convert-pdf-to-pdf-a: status「完成」, #cpaBtnDownload is an A with blob: href and download="sample-pdf-a-pdfa.pdf", click saves that name, no pageerror. Hard-refresh the local page so the 4.53 HTML replaces the old button.

Notes / boundaries

Other PDF tools that put Download in busyBtns and call setBusy(false) from loadFile can show the same fake-enabled button. They were not changed in this pass.
Convert PDF to PDF/A is still a best-effort metadata/font embed, not a veraPDF-certified PDF/A.
Convert PDF to DWG still writes ASCII DXF (TEXT + page-frame LINE), not proprietary DWG binary.
Production still needs R2 upload of the new HTML after this cache bump.
Embedded browsers that block all blob downloads will still not save a file; the control is a real link (blob:) so a full Chrome/Safari/Firefox window will.

[actions]

src/pages/convertPdfToDwgPage.ts: Download not in busyBtns; native <a download> blob link
src/pages/convertPdfToPdfAPage.ts: same
wrangler.jsonc: PAGES_CACHE_VERSION 4.51 → 4.53
npm run tool:touch -- --slug=convert-pdf-to-pdf-a,convert-pdf-to-dwg

PDF-to-DWG and PDF-to-PDF/A Download is a real blob link, so a click saves instead of a silent programmatic a.click(). | Dev Logs