vox

#[vox::service]
pub trait Calculator {
    async fn add(&self, a: i32, b: i32) -> i32;
    async fn divide(&self, a: i32, b: i32) -> Result<i32, MathError>;

    /// Client sends numbers, server returns the running sum.
    async fn sum(&self, numbers: Rx<i32>) -> i64;

    /// Server streams results back to the client.
    async fn generate(&self, count: u32, output: Tx<i32>);
}

impl Calculator for MyCalculator {
    async fn add(&self, _cx: &Context, a: i32, b: i32) -> i32 {
        a + b
    }

    async fn divide(&self, _cx: &Context, a: i32, b: i32) -> Result<i32, MathError> {
        if b == 0 { Err(MathError::DivisionByZero) } else { Ok(a / b) }
    }

    async fn sum(&self, _cx: &Context, mut numbers: Rx<i32>) -> i64 {
        let mut total = 0i64;
        while let Some(n) = numbers.recv().await.ok().flatten() {
            total += n as i64;
        }
        total
    }
    // ...
}

let client = CalculatorClient::new(connection_handle);

let result = client.add(2, 3).await?;

match client.divide(10, 0).await? {
    Ok(r)  => println!("result: {r}"),
    Err(MathError::DivisionByZero) => println!("cannot divide by zero"),
}