Fixed three remaining Chinese PDF sample crashes: unlock now decrypts with Cantoo pdf-lib, stamps fall back from CJK Helvetica, Word sample PDF uses WinAnsi-safe text. | Dev Logs

Date: 2026-09-06 10:06 Summary: Fixed three remaining Chinese PDF sample crashes: unlock now decrypts with Cantoo pdf-lib, stamps fall back from CJK Helvetica, Word sample PDF uses WinAnsi-safe text. Visibility: people

[question] 继续

Tool links (English)

• https://onlinefreetools.org/tools/add-digital-signature-to-pdf
• https://onlinefreetools.org/tools/protect-pdf
• https://onlinefreetools.org/tools/turn-pdf-into-word-document
• https://onlinefreetools.org/tools/unlock-pdf Chinese: https://onlinefreetools.org/zh/tools/unlock-pdf

[try to solve]

Context

After the html2pdf.js / jsPDF wiring fix, three other Chinese PDF tools still failed on page-entry samples (2026-09-06 auto-QA): unlock-pdf, add-digital-signature-to-pdf, and turn-pdf-into-word-document. None of them used html2pdf. The user asked to continue those remaining failures.

Process

1. Read the three page implementations and the zh i18n shards. Auto-QA showed generic convert/unlock errors with no pageerror, so the exceptions were caught and mapped to fallback copy.
2. unlock-pdf. The sample calls doc.encrypt({ userPassword: 'sample' }) then PDFDocument.load(bytes, { password }). The script loaded pdf-lib-with-encrypt, whose encrypt() writes a password on save but cannot decrypt. Official pdf-lib@1.17.1 documents the same gap (EncryptedPDFError; ignoreEncryption: true does not produce a usable unlocked file). password on load() was ignored, so the sample always hit err_unlock.
3. Switched unlock (and protect-pdf, so this site’s encrypt/decrypt pair share one engine) to @cantoo/pdf-lib@2.9.1 UMD (window.PDFLib). Cantoo supports load({ password }) and encrypt() (AES-256 by default). Probe now uses ignoreEncryption: true + doc.isEncrypted; unlock uses load({ password }) then save().
4. add-digital-signature-to-pdf. The stamp draws msg.marked with Helvetica. zh copy is「已数字标记」. pdf-lib’s WinAnsi encoder throws on any code point > 255. Same for ja / ru / ar. SHA-256 and the ISO timestamp were already ASCII. Added winAnsiOrFallback(text, 'Digitally marked') before drawText.
5. turn-pdf-into-word-document. loadSample drew msg.sampleText (zh:「来自 PDF 的 Word 示例句。」) with Helvetica — same WinAnsi throw, so conversion never started. Sample PDF text now falls back to Hello Word sample from PDF.; user-uploaded PDFs still extract CJK via pdf.js (not Helvetica).
6. Bumped PAGES_CACHE_VERSION 4.15 → 4.16, prerendered the four slugs, gzipped, uploaded local R2, restarted wrangler on 8788.
7. Playwright (headless Chrome, ~10s after domcontentloaded) on /zh/tools/{slug}: no danger text, download enabled, no pageerror.

Root cause / analysis

Two unrelated bugs, both masked as「处理失败 / 解锁失败」:

pdf.js was already loading; the Word and stamp pages did not need a new renderer. protect-pdf was not in the fail list, but leaving it on pdf-lib-with-encrypt would mean files from「保护 PDF」could not be opened on「解锁 PDF」.

Solution

• Unlock/protect: @cantoo/pdf-lib@2.9.1 (https://cdn.jsdelivr.net/npm/@cantoo/pdf-lib@2.9.1/dist/pdf-lib.min.js).
• Stamp / Word sample: skip Helvetica for non-Latin-1 strings; stamp label becomes Digitally marked when needed; Word sample PDF uses an English demo sentence.

Local checks (2026-09-06):

• /zh/tools/unlock-pdf — status「样例已就绪 — 密码为「sample」」, download on
• /zh/tools/add-digital-signature-to-pdf — status「完成」, SHA-256 shown, download on
• /zh/tools/turn-pdf-into-word-document — extracted Hello Word sample from PDF. + Load sample on entry, download on
• /zh/tools/protect-pdf — sample still produces protected.pdf

Notes / boundaries

• Real Adobe/Acrobat encrypted files should now decrypt when the open password is known; this is not cracking. AES-256 from Cantoo protect-pdf is the in-house round trip. Exotic or broken encryptors can still fail with a readable error.
• The visible stamp on CJK locales is English on the PDF page; the on-page hash label stays localized. Embedding a CJK font would restore localized stamp glyphs at a large download cost.
• zh Example copy for PDF→Word still describes a Chinese sample sentence; the generated sample PDF is ASCII until that copy is revised.
• Production needs upload:r2 + git push (PAGES_CACHE_VERSION 4.16).

[actions]

• src/pages/unlockPdfPage.ts: Cantoo pdf-lib; probe isEncrypted; load({ password })
• src/pages/protectPdfPage.ts: same Cantoo UMD so encrypt/decrypt match
• src/pages/addDigitalSignatureToPdfPage.ts: WinAnsi fallback for stamp title
• src/pages/turnPdfIntoWordDocumentPage.ts: WinAnsi fallback for sample PDF text
• wrangler.jsonc: PAGES_CACHE_VERSION 4.15 → 4.16