What is Orion?
Orion is a high-level API for Terraria dedicated servers that is based on OTAPI. It serves as an abstraction on top of Terraria, and is designed to follow software best practices. Orion will serve as the base library for TShock v5.0.
Why use Orion?
There are many reasons why Orion will be an improvement over the current Terraria server API.
.NET Core Compatibility
Orion is built using .NET Core 3.1, meaning that Orion is cross-platform compatible out of the box. No more fiddling with xbuild or having to install Mono -- that's all a thing of the past.
Abstractability
By serving as an abstraction on top of Terraria, Orion aims to shield developers from Terraria's version changes. This is accomplished by, e.g., providing interfaces (such as IPlayer) for developers to program against. That way, changes made to Terraria only need to be handled within Orion. The following table shows Terraria concepts along with their corresponding Orion abstractions:
| Terraria Concept | Orion Abstraction |
|---|---|
Terraria.Chest |
IChest |
Terraria.Item |
IItem |
Terraria.NetMessage |
IPacket |
Terraria.NPC |
INpc |
Terraria.Player |
IPlayer |
Terraria.Projectile |
IProjectile |
Terraria.Sign |
ISign |
Terraria.Tile |
Tile |
Terraria.Main.tile |
IWorld |
Flexibility
One benefit of the abstraction mechanism is that plugins can provide different implementations for the interfaces, which allows much greater control and flexibility than was previously possible.
For example, an InfiniteChests plugin could provide its own IChest implementation which uses a database-backed storage solution. This new IChest implementation would then immediately be available to other consumers of the IChest interface, which would allow other chest-based plugins (such as chest protection plugins) to work seamlessly with InfiniteChests.
Testability
Another benefit of the abstraction mechanism is that the Orion API and consumers are completely testable. Since consumers no longer interact directly with Terraria state (which uses a bunch of nasty static state!) and instead interact with interfaces, more code can now be tested with the help of mocks.
This will allow the codebase to be fully tested, which should improve overall code quality and developer happiness.
Better APIs
Orion will have better APIs than the current Terraria server API. Here is a non-exhaustive list of API improvements:
- Events are easier to register and deregister now (with different priorities, too!).
- Plugins can act as both subscribers and publishers of any event.
- Logging is now handled in a structured manner via Serilog.
- Packets are now typed and implemented as
structs so that they can be both safe and blazing fast.
Other Improvements
Here is a non-exhaustive list of other improvements:
- Plugins will be unloadable (since they are required to not have
staticstate). This means that hot reloading of some plugins is now viable. - Orion will use resource strings. This means that localization will now be possible.
Developers
To get started with developing on Orion, please take a look at the Getting Started page. If you wish to contribute to the project, please take a look at the Contributing Guidelines page, as well.
API Users
To get started with developing for Orion, please take a look at the Getting Started page.