Evan 48609fa70a Reduce lobby broadcast bandwidth via counts-only deltas (#4116)
## Description:

- The lobby WebSocket broadcast (`/lobbies`) was re-sending the full
`PublicGames` snapshot — including each lobby's `gameConfig` — to every
connected client every 500ms. Almost nothing in that payload changes
tick-to-tick; only `numClients` moves.
- `WorkerLobbyService` now tracks the sorted set of `gameID`s it last
sent as a full snapshot. On each incoming broadcast it sends a `full`
only when that set changes; otherwise it sends a `counts` delta carrying
just `{gameID → numClients}`.
- This relies on the master-side coupling at
[MasterLobbyService.ts:140-159](src/server/MasterLobbyService.ts#L140-L159):
when master finds a lobby without `startsAt`, it both sets `startsAt`
AND schedules a fresh lobby on the same tick, so the gameID change
brings the `startsAt` (and `gameConfig`) along with it.
- New WS connections are primed with the worker's cached last `full` so
late joiners don't have to wait for the next structural change.
- `LobbySocket` parses the new discriminated union (`PublicLobbyMessage
= full | counts`), keeps the last full snapshot in memory, and merges
counts into it before invoking the existing callback. `GameModeSelector`
is unchanged.
- Master → worker IPC is unchanged — still sends the full snapshot every
500ms. The optimization only applies to the worker → WS-client boundary,
which is the fan-out point.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan
2026-06-02 15:52:14 -07:00

OpenFrontIO Logo

OpenFront.io is an online real-time strategy game focused on territorial control and alliance building. Players compete to expand their territory, build structures, and form strategic alliances in various maps based on real-world geography.

This is a fork/rewrite of WarFront.io. Credit to https://github.com/WarFrontIO.

CI Crowdin CLA assistant License: AGPL v3 Assets: CC BY-SA 4.0

License

OpenFront source code is licensed under the GNU Affero General Public License v3.0

Current copyright notices appear in:

  • Footer: "© OpenFront and Contributors"
  • Loading screen: "© OpenFront and Contributors"

Modified versions must preserve these notices in reasonably visible locations.

See the LICENSE for complete requirements.

For asset licensing, see LICENSE-ASSETS.
For license history, see LICENSING.md.

🌟 Features

  • Real-time Strategy Gameplay: Expand your territory and engage in strategic battles
  • Alliance System: Form alliances with other players for mutual defense
  • Multiple Maps: Play across various geographical regions including Europe, Asia, Africa, and more
  • Resource Management: Balance your expansion with defensive capabilities
  • Cross-platform: Play in any modern web browser

📋 Prerequisites

  • npm (v10.9.2 or higher)
  • A modern web browser (Chrome, Firefox, Edge, etc.)

🚀 Installation

  1. Clone the repository

    git clone https://github.com/openfrontio/OpenFrontIO.git
    cd OpenFrontIO
    
  2. Install dependencies

    npm run inst
    

    Do NOT use npm install nor npm i but instead use our npm run inst. It runs the safer npm ci --ignore-scripts to install dependencies exactly according to the versions in package-lock.json and doesn't run scripts. This can prevent being hit by a supply chain attack.

🎮 Running the Game

Development Mode

Run both the client and server in development mode with live reloading:

npm run dev

This will:

  • Start the webpack dev server for the client
  • Launch the game server with development settings
  • Open the game in your default browser (to disable this behavior, set SKIP_BROWSER_OPEN=true in your environment)

Client Only

To run just the client with hot reloading:

npm run start:client

Server Only

To run just the server with development settings:

npm run start:server-dev

Connecting to staging or production backends

Sometimes it's useful to connect to production servers when replaying a game, testing user profiles, purchases, or login flow.

To replay a production game, make sure you're on the same commit that the game you want to replay was executed on, you can find the gitCommit value via https://api.openfront.io/game/[gameId]. Unfinished games cannot be replayed on localhost.

To connect to staging api servers:

npm run dev:staging

To connect to production api servers:

npm run dev:prod

🛠️ Development Tools

  • Format code:

    npm run format
    
  • Lint code:

    npm run lint
    
  • Lint and fix code:

    npm run lint:fix
    
  • Testing

    npm test
    

🏗️ Project Structure

  • /src/client - Frontend game client
  • /src/core - Deterministic game simulation
  • /src/server - Backend game server
  • /resources - Static assets (images, maps, etc.)

🤝 Contributing

Contributions and translations are welcome! See CONTRIBUTING.md for the workflow, the approved-issue process, project governance, and translation info.

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