VIAaaS/README.md

VIAaaS
---

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VIAaaS - ViaVersion as a Service - Standalone ViaVersion proxy

<img alt="VIAaaS Logo (VIA logo with structural formula of aspirin)" height="200" src="https://viaversion.github.io/VIAaaS/src/main/resources/web/img/logo.webp">

Address generator: https://jo0001.github.io/ViaSetup/aspirin

Public instances: https://github.com/ViaVersion/VIAaaS/wiki/List-of-Public-Instances

## Demo

Online mode: https://youtu.be/9MKKjuoe66k

Using with GeyserConnect: https://youtu.be/_LItAIIFmsI

Using with GeyserConnect on offline mode: https://youtu.be/-hZESD61nSU

Using with OpenAuthMod: https://youtu.be/h3EfNSxxf8k

Offline mode tutorial: https://youtu.be/lPdELnrxmp0

## How does it work?

- [ViaVersion](https://viaversion.com), [ViaBackwards](https://viaversion.com/backwards)
  and [ViaRewind](https://viaversion.com/rewind) translates the connections to backend server.
- VIAaaS auth page stores account credentials in the player's browser local storage.
- It requires a CORS Proxy for calling Mojang APIs.
- Account credentials aren't sent to VIAaaS instance by default.
- The web page receives and validates the joinGame's session hash from VIAaaS instance.

## Setting up server instance

Download: [GitHub Actions](https://github.com/ViaVersion/VIAaaS/actions) (needs to be logged into GitHub)
or [JitPack](https://jitpack.io/com/github/ViaVersion/VIAaaS/master-SNAPSHOT/VIAaaS-master-SNAPSHOT-all.jar)

### How to download and start VIAaaS server:

```sh
curl -Lf --output VIAaaS-all.jar "https://jitpack.io/com/github/ViaVersion/VIAaaS/master-SNAPSHOT/VIAaaS-master-SNAPSHOT-all.jar"
java -jar VIAaaS-all.jar
```

- Requires Java 11
- Default Minecraft: ```via.localhost``` with port 25565
- Default HTTPS: ```https://localhost:25543/```
- Default WS URL: ```wss://localhost:25543/ws```

### How to create a public server

- You need a DNS wildcard pointing to VIAaaS instance, like ``*.example.com -> 192.168.123.123``.
- Configure the hostname in the config
- Open the Minecraft port (25565)
- The HTTPS page needs a valid SSL certificate, you can use a reverse proxy like [Apache](https://httpd.apache.org/) (with
  a [Let's Encrypt](https://letsencrypt.org/) certificate).

## CORS Proxy

- Due to Mojang API not allowing cross-origin requests, we need to use a CORS proxy
- Note the ending slash in cors-anywhere address

## Usage for players

You'll need to specify which server you want to connect through address parameters
added as prefix in ``via.localhost`` or via web page (default https://localhost:25543/).

#### Offline mode:

- Connect to ```mc.example.net.via.localhost```

#### Online mode:

Web login:

- Go to VIAaaS auth webpage (default is https://localhost:25543/)
- Listen to the username A (you'll use it to connect to the VIAaaS instance).
- Add the account B (you'll use it in backend server).
- Keep the page open
- Connect with your account A to ```mc.example.com._u(account B).via.localhost```
- Approve the login in the webpage

Web login via token caching:

- Open the web page and save your account in your browser
- Send your access token to the instance. After that you can close the page.
- Connect to ```mc.example.com.via.localhost``` with the account you sent the token.

Fabric/Forge client:

- Install [OpenAuthMod](https://github.com/RaphiMC/OpenAuthMod) in your client.
- Join the server: ```mc.example.net.via.localhost```
- Approve the login

### Address options

#### Example address:

- ```server.example.net._p25565._v1_12_2._of._uBACKUSERNAME.via.example.com```
- ```server.example.net.v_1_8.via.example.com```
- It's inspired by [Tor2web](https://www.tor2web.org/) proxies.

#### Address parts:

- You can use ``(option)_(value)`` too, like ``p_25565``.
- ```server.example.net```: backend server address
- ```_p```: backend port
- ```_v```: backend version ([protocol id](https://wiki.vg/Protocol_version_numbers) or name, replace ``.`` with ``_``)
  . ```AUTO``` is default (with 1.8 as fallback).
- ```_o```: ```true``` to force online mode in frontend, ```false``` to force offline mode in frontend. If not set, it
  will be based on backend online mode.
- ```_u```: username to use in backend connection (default is front-end username)
- ```via.example.com```: instance address (defined in config)

## WARNING

- VIAaaS may trigger anti-cheats, due to block, item, movement and other differences between versions. USE AT OWN RISK.
- Take care of browser local storage. Check for XSS vulnerabilities on your domain.
- Check the security of CORS proxy, it will be used for calling to Mojang API.

## FAQ

### Accounts

#### Why to use an online webpage for online mode?:

- It's easier to maintain in that way, because providing login via chat requires encoding and decoding more packets,
  which reduces maintainability.
- It allows your account password and token to be kept with you.

#### How to use Microsoft Account?:

- If you're an administrator of the instance, edit ```config/web/js/config.js``` (default is in the jar) and
  configure your [Azure Client ID](https://wiki.vg/Microsoft_Authentication_Scheme#Microsoft_OAuth_Flow) and your domain
  whitelist.

### Connection

#### How to use IPv6?:

- The hostname parser currently doesn't support direct IPv6, but you can use a DNS name with https://sslip.io/

#### I'm getting a DNS error/"Unknown host" while connecting to via.localhost

- Try configuring ```via.localho.st``` as hostname suffix instead

#### How to use with Geyser?

- Set the parameters in Geyser's `address` field:
  ```yml
  remote:
    # The IP address of the remote (Java Edition) server
    address: 2b2t.org._v1_12_2.via.localhost
  ```
- If you are using a public GeyserConnect instance: connect to a publicly available VIAaaS instance,
  like ```mc.example.com._v1_8.via.example.net``` as a Java Edition server.

#### Can I use it to connect to .onion Minecraft hidden servers?

- You can use .onion addresses if the instance is proxying the backend connections to TOR. Note that VIAaaS may log your
  requests, and that your DNS queries may be sent unencrypted.

#### Can you support more versions / Is there some alternative?

- See [DirtMultiVersion](https://github.com/DirtPowered/DirtMultiversion) and [ViaProxy](https://github.com/ViaVersion/ViaProxy)

#### Can I customize the files of HTTP server?

- Add files to ``config/web/`` directory