pairs.one

This is the source code for http://pairs.one - a neat multiplayer online memory/concentration game.

To start the app:

• Install dependencies with mix deps.get
• Install Node.js dependencies with npm install
• With Redis installed, start it with redis-server
• Start Phoenix endpoint with mix phoenix.server

Now you can visit localhost:4000 from your browser.

Below is a brief high-level overview of how things are put together.

Multiplayer features

1 to 5 players may simultaneously take part in the game. The first user always creates the game, then sends out the link to the opponents. The first n-1 users to visit the link become the players, the rest will be able to join the game in the "watch-only" mode.

Game state updates

On the client, the dynamic game state is handled by the Types.Game type (web/static/elm/Types/Game.elm). It includes the state of the board, the current turn, the players' names etc. On every change of this data, the complete state gets broadcast to all other players in JSON format. To minimize the payload, it gets compressed with lz-string, then encoded with base64. Compression/decompression and base64 encoding on the client gets executed via Elm ports.

State persistence

On the server, the game state gets stored in Redis, each game identified with the game:<gameid> key, where gameid is a random string that gets generated at game creation and becomes the last part of the game's URL. The game gets removed from Redis after 24 hours of inactivity.

Known issues

This game won't work in IE, as well as on the networks where websocket traffic is blocked.

Tests

There are no tests yet.

Translating game into other languages

If you like playing this game and want to help translate it into your language, please, submit a PR with the following modifications (on an example of French):

• Create a new gettext locale with mix gettext.merge priv/gettext --locale=fr

• Modify /priv/gettext/fr/LC_MESSAGES/default.po

• Add web/static/elm/I18n/Fr.elm (see web/static/elm/I18n/En.elm for reference)

• Update web/static/elm/I18n.elm (import the new module and extend the case statement)

• Copy web/templates/page/index.en.html.eex to web/templates/page/index.fr.html.eex and translate it (also, update the link to "Create game" button).

• Add fr to the list of available locales in config/config.exs and create a new label with Français in web/views/layout_view.ex

Fire up the app and make sure your translation works.

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Copyright (c) 2016 Good Bit Labs Limited, released under MIT