Add option to fetch Minecraft protocol versions from remote API

.babelrc

@@ -1,5 +1,10 @@
 {
-	"plugins": [
-		"@babel/plugin-proposal-class-properties"
-	]
-}
+  "plugins": [
+    [
+      "@babel/plugin-proposal-class-properties",
+      {
+        "loose": true
+      }
+    ]
+  ]
+}

config.json

@@ -9,6 +9,10 @@
 		"pingAll": 3000,
 		"connectTimeout": 2500
 	},
+	"versions": {
+		"type": "mc-versions",
+		"updateInterval": 86400000
+	},
 	"logFailedPings": true,
 	"logToDatabase": false,
 	"graphDuration": 86400000,

lib/app.js

@@ -6,7 +6,7 @@ const { TimeTracker } = require('./time')
 const MessageOf = require('./message')
 
 const config = require('../config')
-const minecraftVersions = require('../minecraft_versions')
+const versions = require('./versions')
 
 class App {
   serverRegistrations = []
@@ -57,19 +57,13 @@ class App {
 
     const initMessage = {
       config: (() => {
-        // Remap minecraftVersion entries into name values
-        const minecraftVersionNames = {}
-        Object.keys(minecraftVersions).forEach(function (key) {
-          minecraftVersionNames[key] = minecraftVersions[key].map(version => version.name)
-        })
-
         // Send configuration data for rendering the page
         return {
           graphDurationLabel: config.graphDurationLabel || (Math.floor(config.graphDuration / (60 * 60 * 1000)) + 'h'),
           graphMaxLength: TimeTracker.getMaxGraphDataLength(),
           serverGraphMaxLength: TimeTracker.getMaxServerGraphDataLength(),
           servers: this.serverRegistrations.map(serverRegistration => serverRegistration.getPublicData()),
-          minecraftVersions: minecraftVersionNames,
+          minecraftVersions: versions.getProvider().names,
           isGraphVisible: config.logToDatabase
         }
       })(),

lib/servers.js

@@ -7,7 +7,7 @@ const { GRAPH_UPDATE_TIME_GAP, TimeTracker } = require('./time')
 const { getPlayerCountOrNull } = require('./util')
 
 const config = require('../config')
-const minecraftVersions = require('../minecraft_versions')
+const versions = require('./versions')
 
 class ServerRegistration {
   serverId
@@ -213,14 +213,17 @@ class ServerRegistration {
         protocolIndex: 0
       }
     }
-    const protocolVersions = minecraftVersions[this.data.type]
+    const protocolVersions = versions.getProvider().protocolNumbers[this.data.type]
     if (typeof this._nextProtocolIndex === 'undefined' || this._nextProtocolIndex + 1 >= protocolVersions.length) {
       this._nextProtocolIndex = 0
     } else {
-      this._nextProtocolIndex++
+      // Find index of next proto number (skip versions with same proto number)
+      const prevNumber = protocolVersions[this._nextProtocolIndex]
+      this._nextProtocolIndex = protocolVersions.findIndex(number => number > prevNumber)
     }
+
     return {
-      protocolId: protocolVersions[this._nextProtocolIndex].protocolId,
+      protocolId: protocolVersions[this._nextProtocolIndex],
       protocolIndex: this._nextProtocolIndex
     }
   }

lib/versions.js

@@ -0,0 +1,120 @@
+const fs = require('fs/promises')
+const path = require('path')
+const fetch = require('node-fetch')
+
+const config = require('../config.json')
+
+const DEFAULT_CONFIG = { type: 'remote', updateInterval: 86400000 }
+const LOCAL_VERSIONS_PATH = path.resolve(__dirname, '../minecraft_versions.json')
+
+/**
+ * The global versions provider.
+ *
+ * @type {VersionsProvider}
+ */
+let provider
+
+class VersionsProvider {
+  // editionId -> [versionValue] mappings
+  names = {};
+  protocolNumbers = {};
+
+  setEditionData (edition, names, protocolNumbers) {
+    this.names[edition] = names
+    this.protocolNumbers[edition] = protocolNumbers
+  }
+
+  /**
+   * Updates the version data.
+   *
+   * @returns {Promise} a promise containing the update result
+   */
+  async update () {}
+}
+
+class LocalVersionsProvider extends VersionsProvider {
+  async update () {
+    const raw = await fs.readFile(LOCAL_VERSIONS_PATH, 'utf8')
+    const editions = JSON.parse(raw)
+
+    for (const [edition, versions] of Object.entries(editions)) {
+      this.setEditionData(
+        edition,
+        versions.map(version => version.name),
+        versions.map(version => version.protocolId)
+      )
+    }
+  }
+}
+
+const REMOTE_EDITION_NAMES = {
+  java: 'PC',
+  bedrock: 'PE',
+  education: 'EDU'
+}
+
+class RemoteVersionsProvider extends VersionsProvider {
+  constructor (endpoint) {
+    super()
+    this.endpoint = endpoint
+  }
+
+  async update () {
+    const res = await fetch(this.endpoint)
+    const { editions } = await res.json()
+
+    for (const [rawEdition, data] of Object.entries(editions)) {
+      const edition = REMOTE_EDITION_NAMES[rawEdition]
+      const versions = data.versions
+        .filter(version => version.protocolNumber !== null)
+        // Sort versions chronologically (mimic local behavior)
+        .reverse()
+
+      if (edition === 'PC') {
+        // Ignore versions older than 1.7.2
+        // We cannot rely on protocol numbers since they are reused across versions.
+        const onePointSeven = versions.findIndex(version => version.name === '1.7.2')
+        versions.splice(0, onePointSeven)
+      }
+
+      this.setEditionData(
+        edition,
+        versions.map(version => version.name),
+        versions.map(version => version.protocolNumber)
+      )
+    }
+  }
+}
+
+module.exports = {
+  initProvider: async function () {
+    const { type, updateInterval } = config.versions || DEFAULT_CONFIG
+
+    switch (type) {
+      case 'local':
+        provider = new LocalVersionsProvider()
+        break
+      case 'mc-versions':
+        // See https://github.com/hugmanrique/mc-versions
+        provider = new RemoteVersionsProvider('https://raw.githubusercontent.com/hugmanrique/mc-versions/main/versions.json')
+        break
+      default:
+        throw new Error(`Unknown versions provider type "${type}"`)
+    }
+    if (updateInterval <= 0) {
+      throw new Error(`Invalid non-positive versions provider update interval: ${updateInterval}`)
+    }
+
+    async function update () {
+      await provider.update()
+      setTimeout(update, updateInterval) // Schedule next update
+    }
+    await update() // Wait for initial update (populates data)
+  },
+  getProvider: function () {
+    if (!provider) {
+      throw new Error('Versions provider has not been initialized')
+    }
+    return provider
+  }
+}

main.js

@@ -4,6 +4,7 @@ const ServerRegistration = require('./lib/servers')
 const logger = require('./lib/logger')
 
 const config = require('./config')
+const versions = require('./lib/versions')
 const servers = require('./servers')
 
 const app = new App()
@@ -30,12 +31,14 @@ if (!config.serverGraphDuration) {
   config.serverGraphDuration = 3 * 60 * 10000
 }
 
-if (!config.logToDatabase) {
-  logger.log('warn', 'Database logging is not enabled. You can enable it by setting "logToDatabase" to true in config.json. This requires sqlite3 to be installed.')
+versions.initProvider().then(() => {
+  if (!config.logToDatabase) {
+    logger.log('warn', 'Database logging is not enabled. You can enable it by setting "logToDatabase" to true in config.json. This requires sqlite3 to be installed.')
 
-  app.handleReady()
-} else {
-  app.loadDatabase(() => {
     app.handleReady()
-  })
-}
+  } else {
+    app.loadDatabase(() => {
+      app.handleReady()
+    })
+  }
+}).catch(err => logger.error('Cannot load versions data', err))

package.json

@@ -7,6 +7,7 @@
     "finalhandler": "^1.1.2",
     "mcpe-ping-fixed": "0.0.3",
     "mcping-js": "^1.4.1",
+    "node-fetch": "^2.6.1",
     "request": "2.88.2",
     "serve-static": "^1.14.1",
     "sqlite3": "4.2.0",