git.cworth.org Git - lmno-server/blob - server.js

   1 const express = require("express");
   2 const cors = require("cors");
   3 const body_parser = require("body-parser");
   4
   5 const app = express();
   6 app.use(cors());
   7
   8 class Game {
   9   constructor() {
  10     this._players = [];
  11     this.next_player_id = 1;
  12     this.clients = [];
  13     this.next_client_id = 1;
  14
  15     /* Send a comment to every connected client every 15 seconds. */
  16     setInterval(() => {this.broadcast_string(":");}, 15000);
  17   }
  18
  19   add_player(name, character) {
  20     const new_player = {id: this.next_player_id,
  21                        name: name,
  22                        character: character,
  23                        captures: [],
  24                        };
  25     this._players.push(new_player);
  26     this.next_player_id++;
  27     /* The syntax here is using an anonymous function to create a new
  28       object from new_player with just the subset of fields that we
  29       want. */
  30     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  31     this.broadcast_event("player-join", player_data);
  32   }
  33
  34   remove_player(id) {
  35     const index = this._players.findIndex(player => player.id === id);
  36     this._players.splice(index, 1);
  37
  38     this.broadcast_event("player-leave", `{"id": ${id}}`);
  39   }
  40
  41   remove_all_players() {
  42     this._players = [];
  43     this.next_player_id = 1;
  44   }
  45
  46   capture(captor_id, captee_id) {
  47     /* TODO: Fix to fail on already-captured players (or to move the
  48      * captured player from an old captor to a new—need to clarify in
  49      * the API specification which we want here. */
  50     let captor = this._players.find(player => player.id === captor_id);
  51     captor.captures.push(captee_id);
  52
  53     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
  54   }
  55
  56   liberate(captee_id) {
  57     let captor = this._players.find(player => player.captures.includes(captee_id));
  58     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
  59   }
  60
  61   restart() {
  62     for (const player of this._players) {
  63       player.captures = [];
  64     }
  65   }
  66
  67   get characters() {
  68     return this._players.map(player => player.character);
  69   }
  70
  71   get empires() {
  72     return this._players.map(player => ({id: player.id, captures: player.captures}));
  73   }
  74
  75   get players() {
  76     return this._players.map(player => ({id: player.id, name: player.name }));
  77   }
  78
  79   add_client(response) {
  80     const id = this.next_client_id;
  81     this.clients.push({id: id,
  82                        response: response});
  83     this.next_client_id++;
  84
  85     return id;
  86   }
  87
  88   remove_client(id) {
  89     this.clients = this.clients.filter(client => client.id !== id);
  90   }
  91
  92   /* Send a string to all clients */
  93   broadcast_string(str) {
  94     this.clients.forEach(client => client.response.write(str + '\n'));
  95   }
  96
  97   /* Send an event to all clients.
  98    *
  99    * An event has both a declared type and a separate data block.
 100    * It also ends with two newlines (to mark the end of the event).
 101    */
 102   broadcast_event(type, data) {
 103     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
 104   }
 105 }
 106
 107 const game = new Game();
 108
 109 app.use(body_parser.urlencoded({ extended: false }));
 110 app.use(body_parser.json());
 111
 112 function handle_events(request, response) {
 113   /* These headers will keep the connection open so we can stream events. */
 114   const headers = {
 115     "Content-type": "text/event-stream",
 116     "Connection": "keep-alive",
 117     "Cache-Control": "no-cache"
 118   };
 119   response.writeHead(200, headers);
 120
 121   /* Now that a client has connected, first we need to stream all of
 122    * the existing players (if any). */
 123   if (game._players.length > 0) {
 124     const players_json = JSON.stringify(game.players);
 125     const players_data = `event: players\ndata: ${players_json}\n\n`;
 126     response.write(players_data);
 127   }
 128
 129   /* Add this new client to our list of clients. */
 130   const id = game.add_client(response);
 131
 132   /* And queue up cleanup to be triggered on client close. */
 133   request.on('close', () => {
 134     game.remove_client(id);
 135   });
 136 }
 137
 138 app.get('/', (request, response) => {
 139   response.send('Hello World!');
 140 });
 141
 142 app.post('/register', (request, response) => {
 143   game.add_player(request.body.name, request.body.character);
 144   response.send();
 145 });
 146
 147 app.post('/deregister/:id', (request, response) => {
 148   game.remove_player(parseInt(request.params.id));
 149   response.send();
 150 });
 151
 152 app.post('/reset', (request, response) => {
 153   game.remove_all_players();
 154   response.send();
 155 });
 156
 157 app.post('/capture/:captor/:captee', (request, response) => {
 158   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 159   response.send();
 160 });
 161
 162 app.post('/liberate/:id', (request, response) => {
 163   game.liberate(parseInt(request.params.id));
 164   response.send();
 165 });
 166
 167 app.post('/restart', (request, response) => {
 168   game.restart(parseInt(request.params.id));
 169     response.send();
 170 });
 171
 172 app.get('/characters', (request, response) => {
 173   response.send(game.characters);
 174 });
 175
 176 app.get('/empires', (request, response) => {
 177   response.send(game.empires);
 178 });
 179
 180 app.get('/players', (request, response) => {
 181   response.send(game.players);
 182 });
 183
 184 app.get('/events', handle_events);
 185
 186 app.listen(3000, function () {
 187   console.log('Empires server listening on localhost:3000');
 188 });