improved installation further, added failsafes and added token

auth.json

@@ -0,0 +1,5 @@
+{
+    "github-oauth": {
+        "github.com": "ec785da935d5535e151f7b3386190265f00e8fe2"
+    }
+}

index.php

@@ -8,38 +8,73 @@
  * file that was distributed with this source code.
  */
 
-if (file_exists('vendor/autoload.php')) {
+// prevent all those questions concerning ::class and possible composer installation errors (5.3+)
+if (PHP_VERSION_ID < 50509) {
+    throw new Exception('At least PHP 5.5.9 is required to make Flarum work. See the system requirements: http://flarum.org/docs/installation/#system-requirements');
+} elseif (file_exists('vendor/autoload.php')) {
+
+    /**
+     * Start up the Flarum installation wizard or the Forums.
+     */
     require 'vendor/autoload.php';
 
+    // delete /_install_tmp using composer functionality
+    if (is_dir('_install_tmp') && file_exists('_install_tmp/composer/vendor/autoload.php')) {
+        // include the extracted composer libraries
+        require_once '_install_tmp/composer/vendor/autoload.php';
+
+        $fs = new Composer\Util\Filesystem();
+        $fs->removeDirectory('_install_tmp');
+    }
+
     $server = new Flarum\Forum\Server(__DIR__);
 
     $server->listen();
-} elseif (ini_get('allow_url_fopen') || file_exists('scripts/composer.phar')) {
+
+} elseif ((ini_get('allow_url_fopen') && !ini_get('phar.readonly')) || file_exists('scripts/composer.phar')) {
+    // prevent time out of page, drawback of running in browser
+    @set_time_limit(0);
     // prevent extracting composer anew if already exists
-    if (!is_dir('tmp/composer')) {
+    if (!is_dir('_install_tmp/composer')) {
         // attempt to download the latest composer file
-        if (ini_get('allow_url_fopen')) {
+        if (!file_exists('scripts/composer.phar') && ini_get('allow_url_fopen')) {
             file_put_contents('https://getcomposer.org/installer', 'scripts/composer.phar');
         }
+        // use Phar to extract the composer package
         $composer = new Phar('scripts/composer.phar');
-        mkdir('tmp');
-        $composer->extractTo('tmp/composer');
+        // create a temporary directory for saving the package
+        mkdir('_install_tmp');
+        // extract composer
+        $composer->extractTo('_install_tmp/composer');
     }
     // if extraction succeeded, let's run the update command.
-    if (is_dir('tmp/composer') && file_exists('tmp/composer/vendor/autoload.php')) {
-        // otherwise composer will run out of memory easily
-        ini_set('memory_limit', '-1');
-        // include the extracted composer libraries
-        require_once 'tmp/composer/vendor/autoload.php';
+    if (is_dir('_install_tmp/composer') && file_exists('_install_tmp/composer/vendor/autoload.php')) {
+        // force memory to at least 1GB (default for composer) otherwise composer will run out of memory
+        if (function_exists('ini_set')) {
+            ini_set('memory_limit', '1G');
+        }
 
-        putenv('COMPOSER_HOME=' . getcwd() . '/tmp/home');
+        // sets a home directory for storing information
+        putenv('COMPOSER_HOME=' . getcwd() . '/_install_tmp/home');
+        // prevents any interaction composer might require
+        putenv('COMPOSER_NO_INTERACTION=true');
 
-        // set the input for the composer command
-        $input = new Symfony\Component\Console\Input\ArrayInput(['command' => 'install', '--no-dev']);
-
-        // run the composer things
+        // run the composer installation command
         $application = new Composer\Console\Application();
+
+        // set the input for the composer install command
+        $input = new Symfony\Component\Console\Input\ArrayInput([
+            'command'               => 'install',
+            '--no-dev'              => true,
+            '--prefer-dist'         => true,
+            '--optimize-autoloader' => true,
+            '-q'                    => true
+        ]);
         $application->run($input);
+
+        // The application run call ends the process, expecting to have run in terminal.
+        // Running within a separate process will definitely cause new issues.
+        // A refresh of the page is needed to see the installation wizard.
     }
 } else {
     throw new Exception('This method of installation is currently unsupported.');