Portal

a command-line file transfer utility for sending files from any computer to another

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Installation

On macOS or Linux, if you are using Homebrew:

brew install portal

On Arch Linux (AUR):

yay -S portal-bin

On the Snap Store:

sudo snap install portal

On any platform, you can get the latest release manually, or simply run:

curl -sL portal.spatiumportae.com | bash

or

wget -qO - portal.spatiumportae.com | bash

How it works

Sending files and folders

To send files:

portal send <file1> <file2> <folder1> <folder2> ...

The application will output a temporary password on the format 1-inertia-elliptical-celestial.

The sender will communicate this password to the receiver over some secure channel.

Receiving files and folders

To receive those files:

portal receive 1-intertia-elliptical-celestial

The two clients will establish a connection through a relay server. The file transfer will then commence with a direct or relayed connection, depending on what's possible.

What it looks like ✨

The sender (top) sends a folder and three files to the receiver (bottom).

In this case, as you can see in the event log, the transfer is made using direct transfer. That means that the files are sent directly from one client to the other, no middlemen involved.

As it happens, these computers are in the same local network, and portal recognizes this.

Features

portal provides:

• End-to-end encryption using PAKE2
• Direct transfer of files if possible (e.g. sender and receiver are in the same local network)
• Fallback to relay server if sender and receiver cannot connect directly
• Parallel gzip compression of files for faster and more efficient transfers
• Hosting your own relay (we'd appreciate it if you plan to send a lot of data!)
• Configurability and shell completions
• A shiny UI ⭐✨ to gaze your eyes upon while you wait for your files

Completions

portal provides extensive TAB completions for the following shells:

• bash
• zsh
• fish
• powershell

To see installation instructions for your shell and platform, run:

portal completion [bash|zsh|fish|powershell] --help

Tip!

You probably didn't quite catch the password Bob was screaming across the room.

You can use TAB completions to auto-complete passwords on the receiving end.

Press TAB when entering parts of your password...

portal receive 42-relative-parsec-s...

...and portal will suggest the possible words

$ portal receive 42-relative-parsec-s...

42-relative-parsec-supernova  42-relative-parsec-scatter    42-relative-parsec-solar      42-relative-parsec-spin       42-relative-parsec-static     
42-relative-parsec-sigma      42-relative-parsec-solid      42-relative-parsec-star       42-relative-parsec-storm      42-relative-parsec-system

boom. supernova.

portal receive 42-relative-parsec-supernova

Flags

Receiver

• -y/--yes: overwrite existing files without [Y/n] prompts

Relay

• -p/--port: port to host the relay server on

Sender and Receiver

• -r/--relay: address of the relay server (:8080, myrelay.io:1234, ...)
• -s/--tui-style: the style of the tui (rich | raw)

Sender, Receiver and Relay

• -h/--help: output help messages for any command
• -v/--verbose: log debug info to file

Configuration

portal places its configuration file in $HOME/.config/portal/config.yml.

As evident by the file extension, the config is a simple YAML file with descriptive field names.

Default configuration

# The URL of the relay server.
relay: portal.spatiumportae.com
# Log debug output to file.
verbose: false
# Prompt for overwriting duplicates when receiving files.
prompt_overwrite_files: true
# The port used when serving the relay using "portal serve".
relay_serve_port: 8080
# The style of the TUI.
tui_style: rich

Hosting your own relay

The portal binary comes with a built-in relay server.

Spinning up your own relay is as easy as...

portal serve --port 1337

The server log output is JSON. Super-recommended to run it through jq!

portal serve --port 1337 2>&1 | jq .

...

{
  "level": "info",
  "ts": "2023-02-28T02:57:45.310134+01:00",
  "caller": "rendezvous/server.go:77",
  "msg": "serving rendezvous server",
  "version": "v1.2.1",
  "address": ":1337"
}

More details about the connection process

Technical details

Technical details

The connection between the sender and the server is negotiated using a intermediary server (relay).

The relay server is used to negotiate a secure encrypted channel while never seeing the contents of files nor the temporary password.

The communication works as follows:

• sender connects to relay
• relay allocates a numerical ID to the sender and sends it to the sender
• sender generates and outputs the password (starting with the ID) to the terminal, hashes the password and sends it to the relay
• receiver hashes the password (which has been communicated over some secure channel) and sends it to the relay
• When both the sender and the receiver have sent the hashed password to the relay, the cryptographic exchange starts
• During the cryptographic exchange, the relay, well, relays messages from the sender to the receiver and vice-versa
• Once the cryptographic exchange is done, every message sent by the sender and receiver is encrypted, and the relay cannot see their contents
• The file transfer is about to begin, and can commence in two ways:
• The sender and receiver are in the same local network or can be reached directly by IP in some other way
  • In this case, the sender and receiver will happily send the files to each other directly. The relay will close down for this connection.
• The sender and receiver are not on the same local network, or cannot reach each other directly. The transfer will go through the relay, which will continue to relay encrypted messages until the file transfer is completed

Building from source

The Makefile has everything you need.

To build a binary containing all commands, run:

PORTAL_VERSION=v1.x.x make build

It's important to include PORTAL_VERSION, which is a semantic version string. This is needed in order to validate senders and receivers against the relay, so transfers are disallowed when on different major versions, for instance.

Maintainers

• Arvid Gotthard
• Zino Kader

Acknowledgements

nhooyr/websocket, shollz/pake, charmbracelet/bubbles, charmbracelet/bubbletea, charmbracelet/lipgloss, muesli/reflow, klauspost/pgzip and many, many more.

DigitalOcean <3

A special thanks to our sponsors DigitalOcean.

The public relay available for everyone to use is..