tarpc/examples/readme_errors.rs

// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
// This file may not be copied, modified, or distributed except according to those terms.

#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
#![plugin(tarpc_plugins)]

#[macro_use]
extern crate tarpc;
#[macro_use]
extern crate serde_derive;

use std::error::Error;
use std::fmt;
use std::sync::mpsc;
use std::thread;
use tarpc::sync::{client, server};
use tarpc::sync::client::ClientExt;

service! {
    rpc hello(name: String) -> String | NoNameGiven;
}

#[derive(Debug, Deserialize, Serialize)]
pub struct NoNameGiven;

impl fmt::Display for NoNameGiven {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.description())
    }
}

impl Error for NoNameGiven {
    fn description(&self) -> &str {
        r#"The empty String, "", is not a valid argument to rpc `hello`."#
    }
}

#[derive(Clone)]
struct HelloServer;

impl SyncService for HelloServer {
    fn hello(&self, name: String) -> Result<String, NoNameGiven> {
        if name == "" {
            Err(NoNameGiven)
        } else {
            Ok(format!("Hello, {}!", name))
        }
    }
}

fn main() {
    let (tx, rx) = mpsc::channel();
    thread::spawn(move || {
        let handle = HelloServer
            .listen("localhost:10000", server::Options::default())
            .unwrap();
        tx.send(handle.addr()).unwrap();
        handle.run();
    });
    let client = SyncClient::connect(rx.recv().unwrap(), client::Options::default()).unwrap();
    println!("{}", client.hello("Mom".to_string()).unwrap());
    println!("{}", client.hello("".to_string()).unwrap_err());
}