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