sift

Sorts new files in Downloads and Desktop into the right folders, by rules you can read

RustTauriJavaScriptmacOS

My Downloads folder is where class files, receipts, screenshots and installers pile up. sift watches it and Desktop, and files each new arrival where it belongs. A Canvas download goes to that course's folder, a receipt goes to Finance with the date on its name, and screenshots go into a folder for the month.

I wrote it in Rust to learn the language, so the code is written to be read, with a suggested order in the README. It starts out only suggesting moves for me to approve, and it can put back anything it moved.

Rules You Can Read

The first rule that matches wins

[[rule]]
name = "Canvas downloads"
from_hosts = ["instructure.com"]
to = "~/Documents/School/{course}"
tags = ["School"]

[[rule]]
name = "Receipts"
extensions = ["pdf"]
text_any = ["receipt", "order total", "amount paid", "payment received", "invoice"]
to = "~/Documents/Finance/{year}"
rename = "{date} {name}"
tags = ["Finance"]

—Conditions are which folder, the file type, a name pattern, the site it was downloaded from, words inside PDFs and text files, and how long since it was opened
—Actions move, rename with {date}, {year}, {month} and {course}, add Finder tags, or send to the Trash
—sift explain shows everything sift knows about a file and why each rule does or doesn't match

$ sift explain ~/Downloads/Lab3.pdf
~/Downloads/Lab3.pdf
  type:          pdf
  arrived:       Oct 7, 2026 9:04 PM
  unused for:    0 days
  from:          samford.instructure.com
  course:        COSC 470
  tags:          (none)
  text:          (none read)

  ✗ Screenshots: name doesn't match /^Screen ?[Ss]hot /
  ✗ Installers: not a dmg/pkg file
  ✓ Canvas downloads  →  ~/Documents/School/COSC 470/Lab3.pdf

Under the Hood

~1.9k

lines of Rust in the library

tests

ways in: watcher, command line, app

files overwritten, by design

How it works

—A library holds the whole pipeline, from facts about a file to matching rules to moving it. The command line and a Tauri desktop app are thin layers over it
—The watcher gets file events over a channel and waits until a file has sat unchanged for a few seconds, so half-finished downloads are never touched
—Where a file came from is the download URL macOS stores in an extended attribute. A Canvas link has the course number in it, and Daybook keeps a list of my course numbers and names
—Every move is logged as a line of JSON, which is what Undo reads. The Trash is Finder's own, so Put Back works too
—Only files directly in a watched folder are sorted, never their subfolders, and a taken name becomes "name (2)"

Decisions that took more than one try

One odd PDF shouldn't stop the sorter

The PDF reader I use panics on some unusual files instead of returning an error, and a panic would take the whole watcher down. sift wraps that one call in catch_unwind, which turns a panic back into an ordinary error, and quiets the panic message while it does. The PDF's text is only read if a rule actually asks for it.

Editing settings without losing comments

The app lets you choose folders and turn rules on and off, but rewriting the rules file from scratch would wipe out every comment explaining it. The settings use toml_edit, which edits the file in place and keeps its comments and layout. Each edit is a plain function from the old text to the new one, so each is easy to test.

Suggest first, move later

A sorter that moves the wrong file is worse than none. sift begins in suggest mode, where moves wait in a review list grouped by rule, with Move and Leave on each. Once the suggestions have looked right for a while, one setting switches it to moving files itself.

A permission prompt that names the right app

macOS asks before an app reads Downloads, and the prompt names whoever is asking. When the background watcher was a separate command-line tool, the prompt named that instead. Now the watcher is the sift app itself, started in the background at login by a LaunchAgent, so the prompt says sift.