Urlnao

What is Urlnao?

Urlnao is an upload service for file sharing with weechat-android.

What does it do?
Building
How does it work?
Developing
Changelog
License

What does it do?

Urlnao handles uploads, returns URLs and serves the uploaded files:

A POST request is issued by a client with some file(s) to share
Urlnao saves the uploaded file(s)
A publicly reachable URL is then returned for each uploaded file

Example upload request using curl instead of weechat-android:

$ curl --file file=@/path/to/some/video_file.webm https://urlnao.example.com/up
https://urlnao.example.com/f/wLM1

The file will then be accessible via the returned URL.

$ xdg-open https://urlnao.example.com/f/wLM1

Example upload request using curl with multiple files:

$ curl \
    --file file1=@/path/to/some/video_file.webm \
    --file file2=@/path/to/some/image_file.png \
    https://urlnao.example.com/up
https://urlnao.example.com/f/wLM1
https://urlnao.example.com/f/af6

Building

I recommend using Nix to build this package, but you can also just use cargo build --release.

nix build -f . urlnao

How does it work?

Requests

All incoming requests need to be passed to Urlnao's Unix domain socket, ideally using a proxy like Nginx for handling TLS termination.

Example request with curl:

$ curl \
  --file file=@/path/to/some/image_file.png \
  --unix-socket /path/to/urlnao.sock \
  http://localhost/up
https://urlnao.example.com/f/02f6a

Uploads

Files are uploaded by issuing POST requests to the endpoint /up. Every multipart request may contain more than one file, resulting in one public URL for each uploaded file in the response.

The returned URLs are configurable and end in a randomly generated short ID, (currently) being constructed of 3 to 8 alphanumeric characters: Example:

https://u.example.com/f/02f6a

Downloads

Accessing the returned URL after a successful upload leads to a redirect, where the target location contains the original client-supplied filename:

Simplified example:

> GET https://u.example.com/f/02f6a
< 301 https://u.example.com/d/image_file.png
> GET https://u.example.com/d/image_file.png

State

A simple list of all current uploads, including their respective checksum and filename, is served from the /state endpoint.

Example:

$ xdg-open https://u.example.com/state

Access Control

Access control must be implemented by the upstream proxy, allowing for any kind of authentication that both the client and proxy support.

Access to the following endpoints should be restricted to authorized users:

/up (endpoint for uploads)
/state (endpoint listing all uploads)

Alternatively only the two endpoints:

/f (default for --shortid-path)
/d (default for --download-path)

can be publicly exposed, allowing access to everything else only from a trusted network.

Developing

Development is done with the help of Nix

Development Environment

$ nix-shell
...
[nix-shell]$ cargo build --release

Integration Test

A simple integration test can be found here: nix/test.nix

To run the NixOS VM test run:

$ nix build -f . test

To run the test VM interactively run:

$ nix build -f . text.driver
$ ./result/bin/nixos-test-driver

Changelog

v0.3.0

BUG FIXES

fixed race condition with duplicate file uploads

FEATURES / ENHANCEMENTS

added some basic documentation
refactored some parts

v0.2.0

BREAKING

files are now served under /d/<original_filename> after a redirect from /f/<short-id>