server/sockets.js

   1 const url = require('url');
   2
   3 // Node version in Ubuntu 16.04 does not know about URL class
   4 // NOTE: url is already transformed, without ?xxx=yyy... parts
   5 function getJsonFromUrl(url)
   6 {
   7   const query = url.substr(2); //starts with "/?"
   8   let result = {};
   9   query.split("&").forEach((part) => {
  10     const item = part.split("=");
  11     result[item[0]] = decodeURIComponent(item[1]);
  12   });
  13   return result;
  14 }
  15
  16 module.exports = function(wss) {
  17   // Associative array page --> sid --> tmpId --> socket
  18   // "page" is either "/" for hall or "/game/some_gid" for Game,
  19   // tmpId is required if a same user (browser) has different tabs
  20   let clients = {};
  21   wss.on("connection", (socket, req) => {
  22     const query = getJsonFromUrl(req.url);
  23     const sid = query["sid"];
  24     const tmpId = query["tmpId"];
  25     const page = query["page"];
  26     const notifyRoom = (page,code,obj={}) => {
  27       Object.keys(clients[page]).forEach(k => {
  28         Object.keys(clients[page][k]).forEach(x => {
  29           if (k == sid && x == tmpId)
  30             return;
  31           clients[page][k][x].send(JSON.stringify(Object.assign(
  32             {code:code, from:sid}, obj)));
  33         });
  34       });
  35     };
  36     const deleteConnexion = () => {
  37       if (!clients[page] || !clients[page][sid] || !clients[page][sid][tmpId])
  38         return; //job already done
  39       delete clients[page][sid][tmpId];
  40       if (Object.keys(clients[page][sid]).length == 0)
  41       {
  42         delete clients[page][sid];
  43         if (Object.keys(clients[page]) == 0)
  44           delete clients[page];
  45       }
  46     };
  47     const messageListener = (objtxt) => {
  48       let obj = JSON.parse(objtxt);
  49       if (!!obj.target)
  50       {
  51         // Check if receiver is connected, because there may be some lag
  52         // between a client disconnects and another notice.
  53         if (Array.isArray(obj.target))
  54         {
  55           if (!clients[page][obj.target[0]] ||
  56             !clients[page][obj.target[0]][obj.target[1]])
  57           {
  58             return;
  59           }
  60         }
  61         else if (!clients[page][obj.target])
  62           return;
  63       }
  64       switch (obj.code)
  65       {
  66         // Wait for "connect" message to notify connection to the room,
  67         // because if game loading is slow the message listener might
  68         // not be ready too early.
  69         case "connect":
  70         {
  71           notifyRoom(page, "connect");
  72           if (page.indexOf("/game/") >= 0)
  73             notifyRoom("/", "gconnect", {page:page});
  74           break;
  75         }
  76         case "disconnect":
  77           // When page changes:
  78           deleteConnexion();
  79           if (!clients[page][sid])
  80           {
  81             // I effectively disconnected from this page:
  82             notifyRoom(page, "disconnect");
  83             if (page.indexOf("/game/") >= 0)
  84               notifyRoom("/", "gdisconnect", {page:page});
  85           }
  86           break;
  87         case "pollclients": //from Hall or Game
  88         {
  89           let sockIds = [];
  90           Object.keys(clients[page]).forEach(k => {
  91             // Poll myself if I'm on at least another tab (same page)
  92             if (k != sid || Object.keys(clients["/"][k]).length >= 2)
  93               sockIds.push(k);
  94           });
  95           socket.send(JSON.stringify({code:"pollclients", sockIds:sockIds}));
  96           break;
  97         }
  98         case "pollclientsandgamers": //from Hall
  99         {
 100           let sockIds = [];
 101           Object.keys(clients["/"]).forEach(k => {
 102             // Poll myself if I'm on at least another tab (same page)
 103             if (k != sid || Object.keys(clients["/"][k]).length >= 2)
 104               sockIds.push({sid:k});
 105           });
 106           // NOTE: a "gamer" could also just be an observer
 107           Object.keys(clients).forEach(p => {
 108             if (p != "/")
 109             {
 110               Object.keys(clients[p]).forEach(k => {
 111                 if (k != sid)
 112                   sockIds.push({sid:k, page:p}); //page needed for gamers
 113               });
 114             }
 115           });
 116           socket.send(JSON.stringify({code:"pollclientsandgamers", sockIds:sockIds}));
 117           break;
 118         }
 119
 120         // Asking something: from is fully identified,
 121         // but the requested resource can be from any tmpId (except current!)
 122         case "askidentity":
 123         case "asklastate":
 124         case "askchallenge":
 125         case "askgame":
 126         case "askfullgame":
 127         {
 128           const tmpIds = Object.keys(clients[page][obj.target]);
 129           if (obj.target == sid) //targetting myself
 130           {
 131             const idx_myTmpid = tmpIds.findIndex(x => x == tmpId);
 132             if (idx_myTmpid >= 0)
 133               tmpIds.splice(idx_myTmpid, 1);
 134           }
 135           const tmpId_idx = Math.floor(Math.random() * tmpIds.length);
 136           clients[page][obj.target][tmpIds[tmpId_idx]].send(
 137             JSON.stringify({code:obj.code, from:[sid,tmpId]}));
 138           break;
 139         }
 140
 141         // Some Hall events: target all tmpId's (except mine),
 142         case "refusechallenge":
 143         case "startgame":
 144           Object.keys(clients[page][obj.target]).forEach(x => {
 145             if (obj.target != sid || x != tmpId)
 146             {
 147               clients[page][obj.target][x].send(JSON.stringify(
 148                 {code:obj.code, data:obj.data}));
 149             }
 150           });
 151           break;
 152
 153         // Notify all room: mostly game events
 154         case "newchat":
 155         case "newchallenge":
 156         case "newgame":
 157         case "deletechallenge":
 158         case "newmove":
 159         case "resign":
 160         case "abort":
 161         case "drawoffer":
 162         case "draw":
 163           notifyRoom(page, obj.code, {data:obj.data});
 164           break;
 165
 166         // Passing, relaying something: from isn't needed,
 167         // but target is fully identified (sid + tmpId)
 168         case "challenge":
 169         case "fullgame":
 170         case "game":
 171         case "identity":
 172         case "lastate":
 173           clients[page][obj.target[0]][obj.target[1]].send(JSON.stringify(
 174             {code:obj.code, data:obj.data}));
 175           break;
 176       }
 177     };
 178     const closeListener = () => {
 179       // For tab or browser closing:
 180       deleteConnexion();
 181     };
 182     // Update clients object: add new connexion
 183     if (!clients[page])
 184       clients[page] = {[sid]: {[tmpId]: socket}};
 185     else if (!clients[page][sid])
 186       clients[page][sid] = {[tmpId]: socket};
 187     else
 188       clients[page][sid][tmpId] = socket;
 189     socket.on("message", messageListener);
 190     socket.on("close", closeListener);
 191   });
 192 }