Build your own game backend in Rust: server, protocol and client.

use net_backend_client::protocol::auth::{GetAccount, LoginRequest};
use net_backend_client::protocol::storage::{GetObject, PutObject, WriteObject};
use net_backend_client::{Client, Error};

let client = Client::new("https://api.example.com")?;
client.login(LoginRequest::new("player@example.com", "a long password")).await?;

let me = client.call(&GetAccount::new()).await?;
client.call(&WriteObject::new("saves", "slot-1", PutObject::new(serde_json::json!({"level": 3})))).await?;
let save = client.call(&GetObject::new("saves", "slot-1")).await?;
println!("{:?} is on level {}", me.display_name, save.value["level"]);

fn submit_score(backend: Res<HttpClient>, mut commands: Commands) {
    let id = backend.post_json::<Rank>("/scores", &Score { level: 3, points: 12_500 });
    commands.insert_resource(Submitting(id));
}

App::new()
    .add_plugins((MinimalPlugins, BackendPlugin::new(HttpConfig::new("https://api.example.com/v1"))))
    .add_json_response::<Rank>()

use net_backend_protocol::chat::SendMessage;
use net_backend_protocol::{RoomId, WsAuth, WsRequestFrame};

// First message on a fresh socket (if the handshake carried no `Authorization` header).
let auth = WsAuth::new("the-access-token-from-login").to_message();

// A request: {"id":1,"type":"chat.send","data":{"room":12,"text":"hello"}}
let request = WsRequestFrame::call(1, SendMessage::new(RoomId(12), "hello"));
let text = serde_json::to_string(&request).unwrap();

# Server info (no auth)
curl -sS "$API/v1/info"
# {"protocol":1,"min_protocol":1,"modules":["auth","chat","storage"]}

# Log in
curl -sS "$API/v1/auth/login" -H 'content-type: application/json' \
  -d '{"email":"player@example.com","password":"correct horse battery"}'