Native files are now stored in the OS temp directory.

Temp folder is deleted when minecraft is closed. If the Node.js process ends abruptly, the folder will not delete. As a dirty way to counter this, the directory we extract native files to is cleaned in the preloader. Maybe we'll come up with a more elegant solution in the future.

app/assets/css/launcher.css

@@ -1350,7 +1350,7 @@ p {
 
 /*******************************************************************************
  *                                                                             *
- * Overlay View (app.ejs)                                                      *
+ * Overlay View (overlay.ejs)                                                  *
  *                                                                             *
  ******************************************************************************/
 

app/assets/js/actionbinder.js

@@ -234,7 +234,7 @@ function asyncSystemScan(launchAfter = true){
     
     sysAEx.on('message', (m) => {
         if(m.content === 'validateJava'){
-            m.result = null
+
             if(m.result == null){
                 // If the result is null, no valid Java installation was found.
                 // Show this information to the user.

app/assets/js/configmanager.js

@@ -100,6 +100,16 @@ exports.isFirstLaunch = function(){
     return firstLaunch
 }
 
+/**
+ * Returns the name of the folder in the OS temp directory which we
+ * will use to extract and store native dependencies for game launch.
+ * 
+ * @returns {string} The name of the folder.
+ */
+exports.getTempNativeFolder = function(){
+    return 'WCNatives'
+}
+
 // System Settings (Unconfigurable on UI)
 
 /**

app/assets/js/preloader.js

@@ -1,6 +1,8 @@
 const {AssetGuard} = require('./assetguard.js')
 const ConfigManager = require('./configmanager.js')
+const os = require('os')
 const path = require('path')
+const rimraf = require('rimraf')
 
 console.log('Preloading')
 
@@ -15,4 +17,13 @@ if(ConfigManager.getSelectedServer() == null){
     console.log('Determining default selected server..')
     ConfigManager.setSelectedServer(AssetGuard.resolveSelectedServer(ConfigManager.getGameDirectory()))
     ConfigManager.save()
-}
+}
+
+// Clean up temp dir.
+rimraf(path.join(os.tmpdir(), ConfigManager.getTempNativeFolder()), (err) => {
+    if(err){
+        console.warn('Error while cleaning temp dir', err)
+    } else {
+        console.log('Cleaned temp dir.')
+    }
+})

app/assets/js/processbuilder.js

@@ -6,9 +6,12 @@ const AdmZip = require('adm-zip')
 const {AssetGuard, Library} = require('./assetguard.js')
 const child_process = require('child_process')
 const ConfigManager = require('./configmanager.js')
+const crypto = require('crypto')
 const fs = require('fs')
 const mkpath = require('mkdirp')
+const os = require('os')
 const path = require('path')
+const rimraf = require('rimraf')
 const {URL} = require('url')
 
 class ProcessBuilder {
@@ -32,10 +35,11 @@ class ProcessBuilder {
      * Convienence method to run the functions typically used to build a process.
      */
     build(){
+        const tempNativePath = path.join(os.tmpdir(), ConfigManager.getTempNativeFolder(), crypto.pseudoRandomBytes(16).toString('hex'))
         process.throwDeprecation = true
         const mods = this.resolveDefaultMods()
         this.constructFMLModList(mods, true)
-        const args = this.constructJVMArguments(mods)
+        const args = this.constructJVMArguments(mods, tempNativePath)
 
         console.log(args)
 
@@ -51,6 +55,13 @@ class ProcessBuilder {
         })
         child.on('close', (code, signal) => {
             console.log('Exited with code', code)
+            rimraf(tempNativePath, (err) => {
+                if(err){
+                    console.warn('Error while deleting temp dir', err)
+                } else {
+                    console.log('Temp dir deleted successfully.')
+                }
+            })
         })
 
         return child
@@ -93,15 +104,16 @@ class ProcessBuilder {
      * Construct the argument array that will be passed to the JVM process.
      * 
      * @param {Array.<Object>} mods An array of enabled mods which will be launched with this process.
+     * @param {string} tempNativePath The path to store the native libraries.
      * @returns {Array.<string>} An array containing the full JVM arguments for this process.
      */
-    constructJVMArguments(mods){
+    constructJVMArguments(mods, tempNativePath){
-        
+
         let args = ['-Xmx' + ConfigManager.getMaxRAM(),
         '-Xms' + ConfigManager.getMinRAM(),,
-        '-Djava.library.path=' + path.join(this.dir, 'natives'),
+        '-Djava.library.path=' + tempNativePath,
         '-cp',
-        this.classpathArg(mods).join(';'),
+        this.classpathArg(mods, tempNativePath).join(';'),
         this.forgeData.mainClass]
 
         // For some reason this will add an undefined value unless
@@ -196,9 +208,10 @@ class ProcessBuilder {
      * this method requires all enabled mods as an input
      * 
      * @param {Array.<Object>} mods An array of enabled mods which will be launched with this process.
+     * @param {string} tempNativePath The path to store the native libraries.
      * @returns {Array.<string>} An array containing the paths of each library required by this process.
      */
-    classpathArg(mods){
+    classpathArg(mods, tempNativePath){
         let cpArgs = []
 
         // Add the version.jar to the classpath.
@@ -206,7 +219,7 @@ class ProcessBuilder {
         cpArgs.push(path.join(this.dir, 'versions', version, version + '.jar'))
 
         // Resolve the Mojang declared libraries.
-        const mojangLibs = this._resolveMojangLibraries()
+        const mojangLibs = this._resolveMojangLibraries(tempNativePath)
         cpArgs = cpArgs.concat(mojangLibs)
 
         // Resolve the server declared libraries.
@@ -222,13 +235,14 @@ class ProcessBuilder {
      * 
      * TODO - clean up function
      * 
+     * @param {string} tempNativePath The path to store the native libraries.
      * @returns {Array.<string>} An array containing the paths of each library mojang declares.
      */
-    _resolveMojangLibraries(){
+    _resolveMojangLibraries(tempNativePath){
         const libs = []
 
         const libArr = this.versionData.libraries
-        const nativePath = path.join(this.dir, 'natives')
+        mkpath.sync(tempNativePath)
         for(let i=0; i<libArr.length; i++){
             const lib = libArr[i]
             if(Library.validateRules(lib.rules)){
@@ -269,8 +283,7 @@ class ProcessBuilder {
 
                         // Extract the file.
                         if(!shouldExclude){
-                            mkpath.sync(path.join(nativePath, fileName, '..'))
+                            fs.writeFile(path.join(tempNativePath, fileName), zipEntries[i].getData(), (err) => {
-                            fs.writeFile(path.join(nativePath, fileName), zipEntries[i].getData(), (err) => {
                                 if(err){
                                     console.error('Error while extracting native library:', err)
                                 }
@@ -278,8 +291,6 @@ class ProcessBuilder {
                         }
     
                     }
-    
-                    libs.push(to)
                 }
             }
         }

package-lock.json

@@ -222,8 +222,7 @@
     "balanced-match": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.0.tgz",
-      "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c=",
+      "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c="
-      "dev": true
     },
     "base64-js": {
       "version": "1.2.0",
@@ -361,7 +360,6 @@
       "version": "1.1.11",
       "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
       "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
-      "dev": true,
       "requires": {
         "balanced-match": "1.0.0",
         "concat-map": "0.0.1"
@@ -580,8 +578,7 @@
     "concat-map": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
-      "integrity": "sha1-2Klr13/Wjfd5OnMDajug1UBdR3s=",
+      "integrity": "sha1-2Klr13/Wjfd5OnMDajug1UBdR3s="
-      "dev": true
     },
     "concat-stream": {
       "version": "1.6.0",
@@ -1409,8 +1406,7 @@
     "fs.realpath": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
-      "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8=",
+      "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8="
-      "dev": true
     },
     "get-caller-file": {
       "version": "1.0.2",
@@ -1443,7 +1439,6 @@
       "version": "7.1.2",
       "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.2.tgz",
       "integrity": "sha512-MJTUg1kjuLeQCJ+ccE4Vpa6kKVXkPYJ2mOCQyUuKLcLQsdrMCpBPUi8qVE6+YuaJkozeA9NusTAw3hLr8Xe5EQ==",
-      "dev": true,
       "requires": {
         "fs.realpath": "1.0.0",
         "inflight": "1.0.6",
@@ -1581,7 +1576,6 @@
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz",
       "integrity": "sha1-Sb1jMdfQLQwJvJEKEHW6gWW1bfk=",
-      "dev": true,
       "requires": {
         "once": "1.4.0",
         "wrappy": "1.0.2"
@@ -1974,7 +1968,6 @@
       "version": "3.0.4",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
       "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
-      "dev": true,
       "requires": {
         "brace-expansion": "1.1.11"
       }
@@ -2170,8 +2163,7 @@
     "path-is-absolute": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/path-is-absolute/-/path-is-absolute-1.0.1.tgz",
-      "integrity": "sha1-F0uSaHNVNP+8es5r9TpanhtcX18=",
+      "integrity": "sha1-F0uSaHNVNP+8es5r9TpanhtcX18="
-      "dev": true
     },
     "path-is-inside": {
       "version": "1.0.2",
@@ -2475,7 +2467,6 @@
       "version": "2.6.2",
       "resolved": "https://registry.npmjs.org/rimraf/-/rimraf-2.6.2.tgz",
       "integrity": "sha512-lreewLK/BlghmxtfH36YYVg1i8IAce4TI7oao75I1g245+6BctqTVQiBP3YUJ9C6DQOXJmkYR9X9fCLtCOJc5w==",
-      "dev": true,
       "requires": {
         "glob": "7.1.2"
       }

package.json

@@ -36,6 +36,7 @@
     "jquery": "^3.3.1",
     "mkdirp": "^0.5.1",
     "request-promise-native": "^1.0.5",
+    "rimraf": "^2.6.2",
     "tar-fs": "^1.16.0",
     "uuid": "^3.2.1",
     "winreg": "^1.2.4"