ww_client_server

Client-server API model data types for both no_std and std.

This crate is mostly used by WireWeaver itself in generated code, but some types are provided to user code.

By default, this crate is std, so when using on a firmware side, use: ww_client_server = { version = "0.4.0", default-features = false } in Cargo.toml.

Simplified example

Suppose that you've defined the following API for your device:

#[ww_trait]
pub trait MyDevice {
    fn led_on();
    fn led_off();
}

WireWeaver will then generate approximately the following code on the client side:

pub struct MyDeviceClient {}

// automatically generated by ww_api macro
impl MyDeviceClient {
    pub async fn led_on(&mut self) -> Result<(), Error> {
        let seq = 123; // obtain next request ID 
        let req = Reqeust {
            seq,
            path_kind: PathKind::Absolute { path: [0] },
            kind: ReqeustKind::Call { args: [] }
        };
        let bytes = req.to_ww_bytes()?;
        transport.send(bytes);
        let response = transport.filter_for_event(seq).await?;
        let _response = Event::from_ww_bytes(response);
        // no arguments, so just return
    }

    // similar code for other resources
}

And for the server side:

pub struct MyDeviceServer {}

// automatically generated by ww_api macro
impl MyDeviceServer {
    pub fn process_request_bytes(&mut self, bytes: &[u8]) -> Result<(), Error> {
        let request = Request::from_ww_bytes(bytes)?;
        // for simplicity assuming only Absolute path here
        match request.path {
            [0] => {
                // no args to deserialize, call right away
                self.led_on();
                // send Ok Event back
            }
            // other resources 
            _ => { /* serialize and send BadPath error back */ }
        }
    }
}

The only user provided code is the actual implementation of two methods:

impl MyDeviceServer {
    pub fn led_on(&mut self) {
        // your code 
    }

    pub fn led_off(&mut self) {
        // your code 
    }
}

Other resources work in a similar way.

So in a sense, this crate is an API for an API (is meta-API a thing?).