SELECT DATEFROMPARTS(YEAR(CreationDate), MONTH(CreationDa...

A while ago someone sent me a "cleaned" contract to look at. They had removed the client name from the body text, double-checked every page, and felt good about it. Then I ran `pdfinfo` on it. Title: Acme Corp - MSA v2 Author: J. Rivera Creator: Microsoft® Word for Microsoft 365 Producer: Microsoft® Word for Microsoft 365 CreationDate: Wed Sep 17 14:22:01 2025 ModDate: Mon Oct 6 09:41:33 2025 The client name was still there — in the title field, which almost nobody thinks to check. So was the author's name, the exact software used, and two timestamps that revealed how long the negotiation had dragged on. Nothing in the document body was wrong. The file itself was talking. ## Where metadata actually lives There are two places, and this trips people up constantly: 1. **The Info dictionary** — the old-school `/Info` object. Author, Title, Subject, Keywords, Creator, Producer, dates. 2. **XMP** — an XML packet embedded as a metadata stream. Added by Adobe products and most modern exporters, and it can contain a _different_ set of values than the Info dictionary. If you clear one and not the other, you've half-cleaned the file. I've seen tools that only touch `/Info` and leave XMP completely intact, which means the author name survives. There's also the document's `/ID` — a pair of hashes generated at creation. It's not personally identifying on its own, but it's stable across saves, which makes it useful for tracking a specific file. If you've ever wondered how a leaked document gets traced back to a source, this is usually the mechanism. ## Reading it Command line (poppler): pdfinfo contract.pdf pdfinfo -meta contract.pdf # dumps the XMP too Or exiftool, which shows both stores: exiftool -a -G1 contract.pdf In Python: from pypdf import PdfReader r = PdfReader("contract.pdf") print(r.metadata) # Info dictionary print(r.xmp_metadata) # XMP packet, may be None In JavaScript, `pdf-lib` doesn't surface XMP directly, but reading the raw PDF bytes and grepping for the XMP header works well enough as a check: const fs = require("fs"); const buf = fs.readFileSync("contract.pdf"); const start = buf.indexOf(Buffer.from("<?xpacket")); const end = buf.indexOf(Buffer.from("<?xpacket end")); if (start !== -1) { console.log(buf.slice(start, end + 20).toString("utf8")); } else { console.log("no XMP packet found"); } ## Clearing it Python, both stores: from pypdf import PdfReader, PdfWriter r = PdfReader("contract.pdf") w = PdfWriter() w.append_pages_from_reader(r) w.add_metadata({"/Title": "", "/Author": "", "/Subject": "", "/Keywords": "", "/Creator": "", "/Producer": ""}) # pypdf 不写 XMP，追加页面等于丢弃旧 XMP 包 with open("clean.pdf", "wb") as f: w.write(f) Note what that does: rebuilding the file from its pages drops the old XMP packet, because you're writing a new document rather than patching the old one. That's the reliable way to get both stores. Command line alternative: qpdf --empty --pages contract.pdf 1-z -- clean.pdf Same principle — rebuild rather than patch. ## The part people get wrong Clearing metadata does **not** clean the document. Two things metadata removal will never fix: **Text you "deleted" but didn't.** White-on-white text, text under an image, text covered by a rectangle. All still in the content stream. Metadata tools do not touch this. **Previous versions of the file.** PDFs can carry incremental updates, so an earlier draft can still be in there. Rebuilding the file (as above) usually drops this too, which is a nice side effect. So after cleaning, always verify against the content, not the properties: pdftotext clean.pdf - | grep -i "acme\|confidential\|draft" If that comes back empty, and `pdfinfo clean.pdf` shows no author, _then_ the file is clean. ## Why this is worth two minutes Metadata leaks are the ones nobody notices, because there's no visual cue. You open the file, it looks fine, you send it. The recipient — or anyone who ends up with it later — can read your author name, your software versions, your working hours, and often your client's name. For internal documents it's untidy. For anything crossing a border, or going to a counterparty, or landing in a public filing, it's the kind of thing that's very cheap to prevent and very awkward to explain afterward. The whole check is two commands. Worth making it a habit.

Same input, byte-identical output — hash it, cache it, sign it.

Page order, quota checks, and the 429 you'll eventually hit — in Bun.serve().

Ubuntu의 OpenOffice에서 발생한 인쇄 실패 는 특정 요일에만 재현되는 이례적인 버그였음 PostScript에 기록된 %%CreationDate: (Tue...) 를 *NIX 유틸리티 file 이 Erlang JAM 파일로 오인 함 Erlang JAM 탐지 패턴이 공백을 이스...

Summary This PR enhances the Bitwarden JSON import functionality to preserve entry timestamps (creationDate, revisionDate) from Bitwarden exports, enabling users to maintain entry metadata when mig...

A Dart implementation of the Crushlog Data Format (CLDF) for climbing data exchange. Changelog excerpt: ### Fixed - **Java Schema Compatibility**- Fixed manifest serialization to comply with Java schema validation - `creationDate`now includes timezone suffix (RFC 3339 format) - converts to UTC with 'Z' suffix - Removed `description`field from manifest (not defined in schema) - Null fields (`author`, `exportOptions`, etc.) are now omitted from JSON instead of being included as `null` - Added `includeIfNull: false`to all `@JsonSerializable`annotations in manifest models ### Changed - Ma[...]

What a fascinating bug!! My wife has complained that open office will never print on Tuesdays!?! Then she demonstrated it. Sure enough, won't print on Tuesday. Other applications print. I think this is the same bug. Here is my guess: Print to a postscript file. Observe the line: %%CreationDate: (Tue Mar 3 19:47:42 2009) Change "Tue" to anything else: %%CreationDate: (XTue Mar 3 19:47:42 2009) Save the file and it prints. Tools like evince work because they simply omit the "Cr...