Attribute Macro contract 

#[contract]

Automatically generate TypeScript contract before fn main() runs (debug builds only).

This attribute wraps the main function to call rorpc::generate_contract().output(path) before executing the original body. Only active in debug builds (#[cfg(debug_assertions)]).

Syntax

// Default: env!("RORPC_CLIENT_PATH")
#[rorpc::contract]
fn main() {
    // Your main logic
}

// String literal
#[rorpc::contract("../client/src/rpc/bindings.ts")]
fn main() { }

// Environment variable
#[rorpc::contract(env!("RORPC_CLIENT_PATH"))]
fn main() { }

// concat! expression
#[rorpc::contract(concat!(env!("CARGO_MANIFEST_DIR"), "/../client/bindings.ts"))]
fn main() { }

// Constant
const CLIENT_PATH: &str = "../client/bindings.ts";
#[rorpc::contract(CLIENT_PATH)]
fn main() { }

Setting the output path

Recommended: [package.metadata.rorpc] in Cargo.toml

[package.metadata.rorpc]
client_path = "../client/src/rpc/bindings.ts"

Then just use #[rorpc::contract] with no arguments. The macro reads Cargo.toml at compile time and bakes in the resolved absolute path.

Alternative: explicit argument

String literal:

#[rorpc::contract("../client/src/rpc/bindings.ts")]
fn main() { }

concat! expression (absolute path):

#[rorpc::contract(concat!(env!("CARGO_MANIFEST_DIR"), "/../client/bindings.ts"))]
fn main() { }

Constant:

const CLIENT_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/../client/bindings.ts");

#[rorpc::contract(CLIENT_PATH)]
fn main() { }

Fallback: env!("RORPC_CLIENT_PATH")

If no argument is given and [package.metadata.rorpc] client_path is absent, the macro falls back to env!("RORPC_CLIENT_PATH"). Set it via build.rs:

fn main() {
    println!("cargo:rustc-env=RORPC_CLIENT_PATH=../client/src/rpc/bindings.ts");
}

In Cargo.toml:

[package.metadata.rorpc]
client_path = "../client/src/rpc/bindings.ts"

In build.rs:

fn main() {
    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
    let manifest_path = std::path::Path::new(&manifest_dir).join("Cargo.toml");
    let manifest = std::fs::read_to_string(manifest_path).unwrap();
     
    let toml: toml::Value = toml::from_str(&manifest).unwrap();
    if let Some(client_path) = toml.get("package")
        .and_then(|p| p.get("metadata"))
        .and_then(|m| m.get("rorpc"))
        .and_then(|r| r.get("client_path"))
        .and_then(|c| c.as_str())
    {
        println!("cargo:rustc-env=RORPC_CLIENT_PATH={}", client_path);
    }
}

Add to Cargo.toml dependencies:

[build-dependencies]
toml = "0.8"

Other options

[env]
RORPC_CLIENT_PATH = "../client/src/rpc/bindings.ts"

Shell environment variable:

export RORPC_CLIENT_PATH="../client/src/rpc/bindings.ts"
cargo run

Compatibility

This attribute preserves the function signature and can be combined with other attributes like #[tokio::main], #[actix_web::main], etc.:

#[rorpc::contract]
#[tokio::main]
async fn main() {
    // Contract generated before async runtime starts
}