# RAEN 🌧
Just `raen build` to add fully-typed, discoverable interfaces to your smart contracts.
[RAEN Admin](https://raen.dev/admin) and New Tools Coming Soon can use these interfaces to make life easier.
Without RAEN, there's no easy way for smart contract authors or the people building apps on top of their contracts to know what methods a smart contract has, or what arguments they take. Ethereum solves this with [ABIs](https://docs.soliditylang.org/en/develop/abi-spec.html), JSON files that contract authors need to distribute off-chain to app-builders or documentation-maintainers who want to integrate with or describe the contract. [Pagoda fka Near Inc](https://near.org/blog/announcing-the-launch-of-pagoda-the-worlds-first-web3-startup-platform/) is working on [a clone of Ethereum's approach](https://github.com/near/near-sdk-rs/blob/41eb838b0d745394d7530aabe363f80dfc649a0c/near-sdk/src/private).
RAEN leap-frogs this approach. It uses a [Wasm-compatible standard](https://github.com/bytecodealliance/wit-bindgen) that is more compact than JSON, can be auto-translated to Pagoda's ABI or other formats like [OpenRPC](https://open-rpc.org/), and will one day merge with Wasm core. And RAEN injects Wit directly into the smart contract while reducing overall contract size. No more searching GitHub for ABI files. Now they can all live right on-chain.
In a RAEN-maximized version of NEAR, anyone will be able to easily generate cross-contract call logic, TypeScript libraries, CLIs, [Admin UIs / interactive documentation](https://raen.dev/admin/), [Subgraphs](https://thegraph.com/) and more, just using a contract name.
The best part? Getting started couldn't be easier. It's one command. Just build your contracts with `raen build`.
**Rust-only**, for now. New to Rust or NEAR? Check out **[The RAEN Guide](https://raen.dev/guide)**.
https://user-images.githubusercontent.com/221614/178541903-7f17b06c-c576-47b1-8c9d-976e43339b9c.mp4
### About the name
"RAEN" is "NEAR" spelled backwards. It is pronounced the same as "rain".
# Install
New to Rust? [Step-by-step instructions on the Guide](https://raen.dev/guide/intro/getting-set-up.html).
## Rust
`raen` is a Rust crate and can be installed via `cargo`:
```bash
cargo install raen
```
If you don't yet have Rust, you will need to install it before running the above command. On Linux or MacOS, use the following command:
```bash
curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf | sh
source $HOME/.cargo/env
```
Then, add the `wasm32-unknown-unknown` toolchain. This toolchain is required because NEAR contracts need to be compiled to [Wasm] with _architecture_ and _platform_ both "unknown".
```bash
rustup target add wasm32-unknown-unknown
```
Then follow [these instructions](https://doc.rust-lang.org/book/ch01-01-installation.html) for setting up Rust.
## npm (optionally)
`raen` is also distributed on npm which wraps the rust binary built for your computer:
```bash
npm install --global raen-cli
```
## Additional requirements
`raen` is designed as an extension for [`near-cli-rs`](https://github.com/near/near-cli-rs/tree/master/extensions), but until this project is stable you need to install the JS version `near-cli` to deploy your contracts.
```bash
npm install --global near-cli
```
# Use
For an intro to NEAR, Rust, and RAEN, see **[✨ The Guide ✨](https://raen.dev/guide)**. The basics:
In a NEAR smart contract project:
```bash
raen build --release
```
This builds the contract (or contracts if you're using a Rust workspace), embeds the contract's types in a [Custom Section](https://webassembly.github.io/spec/core/appendix/custom.html), and places them in `./target/res/crate_name.wasm`.
You can then deploy as usual with `near-cli`. With `dev-deploy`:
```bash
near dev-deploy --wasmFile ./target/res/crate_name.wasm
```
With `deploy`:
```bash
near deploy --wasmFile ./target/res/crate_name.wasm --accountId YOUR_ACCOUNT_NAME_HERE
```
Various current and future tooling can now use your contract's types to make your life easier. For example, you can enter your contract's address at [raen.dev/admin](https://raen.dev/admin) for a full admin panel.
# Learn: How it works: Wasm 💖️ Wit
[Wit] is an emerging standard to ease interoperability between programs compiled to WebAssembly, aka [Wasm]. (Wit stands for "WebAssembly Interface Types.") Wit will eventually merge with Wasm, allowing all compiled Wasm modules to explain their interfaces to other Wasm modules and their developers.
NEAR runs Wasm. Any Wasm language, though Rust has the most mature tooling and documentation.
When you build your smart contracts with `raen`, it injects a full Wit specification for your contract into a Wasm [Custom Section](https://webassembly.github.io/spec/core/appendix/custom.html). It compresses it with [brotli](https://www.brotli.org/) to reduce [storage](https://docs.near.org/docs/concepts/storage-staking) requirements.
How much does this increase your contract size? In our tests so far, contracts compiled with `raen` end up **smaller** than before!
`raen` uses `witme` [to generate the Wit](https://ahalabs.dev/posts/wit-bringing-types-to-near-contracts) and inject it into the Wasm Custom Section. Under the hood, `witme` uses [walrus](https://github.com/AhaLabs/wasm-walrus-tools), which optimizes the Wasm enough to reduce the total contract size, even with the Wit. We will add full benchmarks soon.
(Note that currently a JSON [AJV](https://ajv.js.org/) specification is added to a Wasm Custom Section _instead of_ Wit, since 1. No Wit-to-AJV tooling currently exists for browsers, 2. This admin panel relies on AJV, and 3. No other tooling currently makes use of Wit. The AJV custom section will be swapped for a Wit custom section once Wit settles on an [initial syntax version](https://github.com/bytecodealliance/wit-bindgen/issues/214#issuecomment-1116237538).)
This admin panel then reads in that Custom Section, decompresses the brotli, and uses [react-jsonschema-form](https://github.com/rjsf-team/react-jsonschema-form) to allow interacting with the contract.
# Tips
## witgen macro
If you define a type that RAEN doesn't recognize (such as in this line `type Amount = Balance;` where RAEN doesn't recognize `Amount`), your build may result in an error like:
```
You probably need to add a `witgen` macro to the missing type
Add 'witgen' as a dependency to add to type definition. e.g.
Error: no type named `amount`
// Or
You probably need to add a `witgen` macro to the missing type
Add 'witgen' as a dependency to add to type definition. e.g.
1 use witgen::witgen;
2
3 /// Type exposed by contract API
4 #[witgen]
5 struct Foo {}
6
Error: no type named `amount`
--> index.ts:9:73
|
9 | transfer-from-escrow: function(destination-account: account-id, amount: amount)
| ^-----
```
To fix this:
1. You might want to run `cargo add witgen` (which will edit your `Cargo.toml` to include a line like `witgen = "0.14.0"`).
2. Add `use witgen::witgen;` near the top of the file that was causing the error.
3. Add `#[witgen]` as a line before the definition of the type. E.g.:
```
use witgen::witgen;
#[witgen]
type Amount = Balance;
```
## Changes
Now including the following in your Cargo.toml will allow projects to include your wit types in their generated wit.
```toml
[package.metadata.witgen]
export = true
```
# Contribute
* Clone this repository
* Build with `cargo build`
* Send us issues or pull requests with questions and we'll improve this section!