Crate rflow

RFlow

Chat-like HMI for embedded Rust applications and PLCs

RFlow is a part of RoboPLC project.

The idea

Many of embedded applications and PLC programs do not have any human-machine interface and not supposed to have one by design.

However, sometimes it is very useful to have a simple way to interact with the application, e.g. for debugging purposes or having a basic emergency interface in production.

RFlow provides the most possible lightweight way to have a chat-like interface between the application (server) and its clients, which does not affect the application real-time run-flow and consumes minimal system resources.

The RFlow protocol is fully text-based and can be used with no special client.

Clients

• RFlow Chat - a dedicated RFlow chat client (terminal).

• Custom clients, built with the crate Client API.

• Any terminal TCP client, e.g. telnet, nc.

A very basic example

use std::{thread, time::Duration};

use rtsc::time::interval;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let data_channel = rflow::take_data_channel()?;
    thread::spawn(move || {
        rflow::serve("127.0.0.1:4001").expect("failed to start server");
    });
    thread::spawn(move || {
        for _ in interval(Duration::from_secs(5)) {
            rflow::send("ping".to_string());
        }
    });
    for data in data_channel {
        println!("Received data: {}", data);
        rflow::send(format!("command accepted: {}", data));
        let command = data.trim();
        if command == "quit" {
            break;
        }
    }
    Ok(())
}

Structs

• Client
  Client instance
• ConnectionOptions
  Connection options
• Server
  Server instance

Enums

• Direction
  Direction of the message (client)
• Error
  Error type

Functions

• send
  Send a message to the default server’s clients
• serve
  Serve the default server
• spawn
  Spawn the default server as a separate thread and return the data channel
• take_data_channel
  Take the default server data channel