🍃 Leaf Tasks

Leaf is a lightweight, web based, self-hosted task tracking (todo) tool.

I created Leaf Tasks as replacement for my somewhat specific use of Wunderlist. I curate, Read Rust, a site that collects interesting posts from the Rust community. My workflow for the site is mostly powered by RSS and Feedbin but when I encounter a post outside of Feedbin — typically on my phone I use the iOS share sheet functionality to add a link to Wunderlist. With Wunderlist being shut down in May 2020 I built Leaf as a replacement.

Features

What's included:

• A simple task list that lets you add and complete tasks.
• Uncluttered design.
• Plain text (CSV) storage.
• Uses plain old HTML forms — works in almost any browser, including Lynx (Screenshot).
• Single file, dependency-free binary.
• Super fast — Typical response times are ~160µs.
• Memory efficient — Uses ~1.4Mb RAM.

What's not included:

• JavaScript.
• User tracking.
• Multiple lists.
• Multiple users.
• Sharing (outside of sharing a login).
• Task editing.
• Task deletion.
• Viewing completed tasks in the UI (although they are stored in a file).

Download

Pre-built binaries are available:

• FreeBSD 13 amd64
• Linux x86_64
• Mac OS
• Windows x86_64

Using

Shortcuts Workflow for iOS

This workflow for the built-in Shortcuts app allows you to add new tasks using the standard share sheet.

https://www.icloud.com/shortcuts/aabb57aa14a2465a82002c83a33bb0e6

You will need to customise two things:

1. In the Text block with "Bearer your-api-token", replace your-api-token with the token the Leaf instance is using (LEAF_API_TOKEN environment variable).
2. In the URL block, replace https://example.com/tasks with the URL of your Leaf instance.

Tips

• There's no need to click the Save button when adding a task. Just hit Enter and the default browser behaviour of submitting the form will take place.

Font

To minimise page weight Leaf does not use any web fonts. However it was designed using the Muli font and this font is specified in the CSS. Install the font if you would like Leaf use it. If you'd rather not install it, that's fine — Leaf will use your browsers default sans-serif font.

FAQ

Why no editing or deletion of tasks?

Just complete it and add a new one.

Why no completed task list?

Leaf stores all completed tasks in a separate file for manual review if needed. To avoid unnecessarily complicating the UI it is not exposed there though.

What if I accidentally complete a task?

Add it again as a new task. If you're unsure of the content review the completed task list file manually.

What if I really want multiple lists?

You can run multiple instances of Leaf. Each server process is very small.

Running

Configuration

Leaf uses environment variables for configuration.

LEAF_PASSWORD_HASH

This contains the password hash used to verify you when logging in. The value can be generated with the argon2 tool. This tool is installed by default on Arch Linux. If you are using a different system you may need to install it, the package is probably called argon2.

The shell snippet below will read your password from stdin and then print the hash. Type your chosen password and press Enter, note that it will echo in the terminal. See below for an explanation of the snippet.

(read -r PASS; echo -n "$PASS" | argon2 $(cat /dev/urandom | LC_ALL=C tr -dc 'a-zA-Z0-9' | head -c 8) -e)

You should see something like the following, which is what LEAF_PASSWORD_HASH should be set to.

$argon2i$v=19$m=4096,t=3,p=1$eEVkYlJFZGY$N0p7VxqHDGBZ1ivgotGv2olZ/eXM9WPPCRf0wZuyyLo

Note: The hash contains $ characters so be aware of shell quoting issues. If setting the var in a shell use single quotes:

export LEAF_PASSWORD_HASH='$argon2i$v=19$m=4096,t=3,p=1$eEVkYlJFZGY$N0p7VxqHDGBZ1ivgotGv2olZ/eXM9WPPCRf0wZuyyLo'

LEAF_API_TOKEN

The contents of this environment variable is used as a Bearer token (password) for the add task route. I use it to add tasks on my phone with the iOS Shortcuts workflow above. It must be at least 64 characters long. I used my password manager to generate mine.

export LEAF_API_TOKEN=Insert64orMoreRandomCharactersHere

ROCKET_SECRET_KEY

This is used to encrypt the cookie used for authentication. I can be generated with:

openssl rand -base64 32

LEAF_TASKS_PATH (optional)

Default: tasks.csv in the working directory.

The path to the CSV file that will store tasks. If it does not exist it will be created.

Note: ~ is not expanded in environment variables. If you want to refer to your home directory use $HOME. E.g. LEAF_TASKS_PATH=$HOME/Documents/tasks.csv.

LEAF_COMPLETED_PATH (optional)

Default: completed.csv in the working directory.

The path to the CSV file that will store completed tasks. If it does not exist it will be created.

Note: ~ is not expanded in environment variables. If you want to refer to your home directory use $HOME. E.g. LEAF_COMPLETED_PATH=$HOME/Documents/completed.csv.

LEAF_SECURE_COOKIE (optional)

Default: true

Whether the login cookie sets the secure flag. For local development without https, set this to false.

Rocket Configuration

The web framework Leaf uses (Rocket), also has some of its own configuration options: https://rocket.rs/v0.4/guide/configuration/.

File Format

TODO

API

TODO

Development

Auto-reloading server

To run the server during development and have it rebuild and restart when source files are changed I use watchexec:

watchexec -w src -s SIGINT -r 'cargo run'

Linking with lld

Using lld speeds up linking. I see 0.71s vs. 1.76s for an incremental build, 15 vs. 19s for clean build. Add the following to .cargo/config:

[target.x86_64-unknown-linux-gnu]
rustflags = [
    "-C", "link-arg=-fuse-ld=lld",
]

Licence

This project is dual licenced under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

Appendix

Password Hash Shell Snippet Explanation

• The outer brackets () run the command in a sub-shell, this is to prevent the PASS environment variable remaining set in your shell.
• read -r PASS reads a line from stdin and sets the PASS environment variable with the value read, minus the terminalting new-line. -r disables \ escape sequence support.
• echo -n "$PASS" prints the password on stdout, -n disables the trailing new-line.
• read + echo are used to avoid having the password in your shell history, if it has one.
• $(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 8) is used to generate a random "salt" for the hash.
  • $() runs a command and substitutes it with the output from that command.
  • cat /dev/urandom reads from the dev/urandom pseudo random number generator device and writes to stdout.
  • tr -dc 'a-zA-Z0-9' reads from stdin and drops (-d) characters not in the set supplied to -c. This has the effect of filtering the binary /dev/urandom data and only outputting characters 'a-zA-Z0-9'.
  • head -c 8 reads the first 8 characters (-c) from stdin and outputs them on stdout.
• argon2 receives the random salt as an argument, it reads the password from stdin and prints just the encoded hash on stdout (-e).