A toy chat server, in both sync and async styles

This workspace contains a client and two servers for a trivial chat protocol: clients can subscribe to channels, and send messages on channels. The two servers are equivalent, but:

One (sync-server) is written in traditional synchronous style, using blocking I/O calls and starting a separate thread for each connection.
The other (async-server) is written using Rust's experimental async/await syntax, and future-based asychronous I/O primitives. It serves all clients on a ThreadPool executor, but it could also work almost entirely unchanged on a single thread.

What's interesting is to diff the two src/main.rs files from async-server and sync-server. I've tried to keep the differences to a minimum; if you can refine the diff to highlight the sections of each line that have changed, it should be even clearer what's going on.

This uses the romio crate's asynchronous sockets, and the futures-preview 0.3 line (in alpha as of this writing).

Example use: In one window, run the server:

$ cd async-server/
$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.07s
     Running `/home/jimb/rust/chat/target/debug/async-server`
Listening on V4(0.0.0.0:9999)

Then, in another window on the same machine, run the client, and type in a few commands:

$ cd client
$ cargo run
   Compiling client v0.1.0 (/home/jimb/rust/chat/client)
    Finished dev [unoptimized + debuginfo] target(s) in 0.70s
     Running `/home/jimb/rust/chat/target/debug/client`
subscribe rust
Reply: Subscribed("rust")
send rust This is a chat message! "yo"
Reply: Message { channel: "rust", message: "This is a chat message! \"yo\"" }

Other clients in other windows should be able to connect as well, and receive whatever messages are sent to channels they're subscribed to.

jimblandy/chat

A toy chat server, in both sync and async styles