REFACTOR: separate distinct behaviours to modules

Author: Jon-Biz

services/statsRoute.js

@@ -0,0 +1,101 @@
+const peerid = require('bittorrent-peerid')
+
+const get8Chars = 
+        peerId => Buffer.from(peerId, "hex")
+                        .toString()
+                        .substring(0, 8)
+              
+function addPeerClient( _clients, peer) {
+    const clientId = peer.client.client;
+    const client = _clients[clientId] || {};
+    // If the client is not known show 8 chars from peerId as version
+    const version = peer.client.version 
+                    || get8Chars(peer.peerId)
+
+    if (!client[version]) client[version] = 1
+    else client[version]++
+
+    _clients[clientId] = client
+
+    return _clients                        
+}
+
+function groupByClient(allPeers) {
+    const clients = 
+            Object.values(allPeers)
+                  .reduce(addPeerClient, {})
+          
+    return clients;
+}
+
+const countPeers =
+    allPeers =>
+        filterFunction => {
+            const filteredPeers = 
+                    Object.values(allPeers).filter(filterFunction)
+
+            return filteredPeers.length
+        }
+
+const addPeer =
+    peers =>
+        (allPeers, peerId) => {
+            // Don't mark the peer as most recently used for stats
+            const peer = peers.peek(peerId)
+
+            if (peer == null) return // peers.peek() can evict the peer
+ 
+            const peerData = {
+                peerId: peer.peerId,
+                client: peerid(peer.peerId),
+                ipv4: !peer.ip.includes(':'),
+                ipv6: peer.ip.includes(':'),
+                seeder: peer.complete,
+                leecher: !peer.complete
+            }
+
+            allPeers[peerId] = peerData
+
+            return allPeers
+        }
+
+const hasKeys = (torrent) => (torrent.peers.keys.length > 0) 
+const countActiveTorrents = torrents => torrents.filter(hasKeys).length
+
+const addTorrentKeys = (allPeers, torrent) => {
+    const peers = torrent.peers
+    const keys = peers.keys
+
+    const result = keys.reduce(addPeer(peers), allPeers)
+
+    return result
+}
+
+const isSeederOnly = peer => (peer.seeder && peer.leecher === false)
+const isLeecherOnly = peer => (peer.leecher && peer.seeder === false)
+const isSeederAndLeecher = peer => (peer.seeder && peer.leecher)
+const isIPv4 = peer => peer.ipv4
+const isIPv6 = peer => peer.ipv6
+
+const getStats = server => {
+    const torrents = Object.values(server.torrents)
+    const activeTorrents = countActiveTorrents(torrents)
+    const allPeers = torrents.reduce(addTorrentKeys, {})
+    const countAllPeers = countPeers(allPeers)
+
+    const stats = {
+        torrents: torrents.length,
+        activeTorrents,
+        peersAll: Object.keys(allPeers).length,
+        peersSeederOnly: countAllPeers(isSeederOnly),
+        peersLeecherOnly: countAllPeers(isLeecherOnly),
+        peersSeederAndLeecher: countAllPeers(isSeederAndLeecher),
+        peersIPv4: countAllPeers(isIPv4),
+        peersIPv6: countAllPeers(isIPv6),
+        clients: groupByClient(allPeers)
+    }
+
+    return stats
+}
+
+module.exports = getStats

services/statsRoute/getStats.js

@@ -0,0 +1,37 @@
+const attachHttpServer = require('../attachHttp')
+const getStats = require('./getStats')
+const printClients = require('./printClients')
+
+function setupStatsRoute(server, onListening) {
+    if (!server.http) attachHttpServer(server, onListening);
+
+    // Http handler for '/stats' route
+    server.http.on('request', (req, res) => {    
+        if (res.headersSent) return
+
+        if (req.method === 'GET' && (req.url === '/stats' || req.url === '/stats.json')) {
+            const stats = getStats(server)
+            if (req.url === '/stats.json' || req.headers.accept === 'application/json') {
+                res.setHeader('Content-Type', 'application/json')
+                res.end(JSON.stringify(stats))
+            } else if (req.url === '/stats') {
+                const printout = printClients(stats.clients)
+
+                res.setHeader('Content-Type', 'text/html')
+                res.end(`
+                    <h1>${stats.torrents} torrents (${stats.activeTorrents} active)</h1>
+                    <h2>Connected Peers: ${stats.peersAll}</h2>
+                    <h3>Peers Seeding Only: ${stats.peersSeederOnly}</h3>
+                    <h3>Peers Leeching Only: ${stats.peersLeecherOnly}</h3>
+                    <h3>Peers Seeding & Leeching: ${stats.peersSeederAndLeecher}</h3>
+                    <h3>IPv4 Peers: ${stats.peersIPv4}</h3>
+                    <h3>IPv6 Peers: ${stats.peersIPv6}</h3>
+                    <h3>Clients:</h3>
+                    ${printout}
+                `.replace(/^\s+/gm, '')) // trim left
+            }
+        }
+    })
+}
+
+module.exports = setupStatsRoute

services/statsRoute/index.js

@@ -0,0 +1,21 @@
+const printVersionHtml = client => (html, version) => (
+    html + `<li><strong>${name}</strong> ${version} : ${client[version]}</li>\n`
+)
+
+function printClient(html, client) {
+    const printClientHtml = printVersionHtml(client);
+    const clientHtml = 
+            Object.values(client).reduce(printClientHtml, html)
+
+    return clientHtml;
+};
+
+function printClients(clients) {
+  const initialHtml = "<ul>\n";
+  const contentHtml = Object.values(clients).reduce(printClient, initialHtml)
+  const html = contentHtml + "</ul>"
+
+  return html
+}
+
+module.exports = printClients