Foxglove WebSocket publishing in Rust

This library provides means to publish messages to the amazing Foxglove UI in Rust. It implements part of the Foxglove WebSocket protocol described in https://github.com/foxglove/ws-protocol.

Example

Call

cargo run --release --example string

to start an example application that publishes ROS 1 string data -- both latching and non-latching.

lib.rs:

This library provides means to publish messages to the amazing Foxglove UI in Rust. It implements part of the Foxglove WebSocket protocol described in https://github.com/foxglove/ws-protocol.

On its own the protocol does not fix a specific data scheme for the messages. But for Foxglove to understand the messages it makes sense to follow the well-known serialization schemes https://mcap.dev/spec/registry.

Example

This is an example with single ROS1 channel/topic with the std_msgs/String message type.

use std::{io::Write, time::SystemTime};

fn build_string_message(data: &str) -> anyhow::Result<Vec<u8>> {
    let mut msg = vec![0; std::mem::size_of::<u32>() + data.len()];
    // ROS 1 message strings are encoded as 4-bytes length and then the byte data.
    let mut w = std::io::Cursor::new(&mut msg);
    w.write(&(data.len() as u32).to_le_bytes())?;
    w.write(data.as_bytes())?;
    Ok(msg)
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let server = foxglove_ws::FoxgloveWebSocket::new();
    tokio::spawn({
        let server = server.clone();
        async move { server.serve(([127, 0, 0, 1], 8765)).await }
    });
    let channel = server
        .publish(
            "/data".to_string(),
            "ros1".to_string(),
            "std_msgs/String".to_string(),
            "string data".to_string(),
            "ros1msg".to_string(),
            false,
        )
        .await?;
    channel
        .send(
            SystemTime::now().elapsed().unwrap().as_nanos() as u64,
            &build_string_message("Hello!")?,
        )
        .await?;
}