diff --git a/CHANGELOG.md b/CHANGELOG.md
index 32124672..bcee2745 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -87,6 +87,7 @@
 * auto detected browser language in select language
 
 ### Plugins
+* sandbox for plugins, don't install when requirements are not satisfied
 * allow comments inside plugin json file (php style)
 * new require options for plugins: (look into example.json)
 	* require database version of the MyAAC schema
diff --git a/TODO b/TODO
index 50d70d35..899f9117 100644
--- a/TODO
+++ b/TODO
@@ -2,7 +2,6 @@
 
 0.*
 	* support duplicated vocation names with different ids
-	* sandbox for plugins, don't install when requirements are not passed
 	* add changelog management interface
 	* kathrine tickets - show/hide
 	* csrf token protection
diff --git a/system/bin/install_plugin.php b/system/bin/install_plugin.php
index 27842e22..c727b782 100644
--- a/system/bin/install_plugin.php
+++ b/system/bin/install_plugin.php
@@ -33,7 +33,7 @@ if(Plugins::install($path_to_file)) {
 		echo 'WARNING: ' . $warning;
 	}
 
-	$info = Plugins::getPlugin();
+	$info = Plugins::getPluginJson();
 	echo (isset($info['name']) ? $info['name'] . ' p' : 'P') . 'lugin has been successfully installed.' . PHP_EOL;
 }
 else {
diff --git a/system/libs/plugins.php b/system/libs/plugins.php
index c757cd98..37180385 100644
--- a/system/libs/plugins.php
+++ b/system/libs/plugins.php
@@ -43,7 +43,7 @@ use Composer\Semver\Semver;
 class Plugins {
 	private static $warnings = array();
 	private static $error = null;
-	private static $plugin = array();
+	private static $plugin_json = array();
 
 	public static function getHooks()
 	{
@@ -60,7 +60,7 @@ class Plugins {
 			$string = file_get_contents(PLUGINS . $filename . '.json');
 			$string = self::removeComments($string);
 			$plugin = json_decode($string, true);
-			self::$plugin = $plugin;
+			self::$plugin_json = $plugin;
 			if ($plugin == null) {
 				self::$warnings[] = 'Cannot load ' . $filename . '.json. File might be not a valid json code.';
 				continue;
@@ -98,257 +98,258 @@ class Plugins {
 		}
 
 		$zip = new ZipArchive();
-		if($zip->open($file)) {
-			for ($i = 0; $i < $zip->numFiles; $i++) {
-				$tmp = $zip->getNameIndex($i);
-				if(pathinfo($tmp, PATHINFO_DIRNAME) == 'plugins' && pathinfo($tmp, PATHINFO_EXTENSION) == 'json')
-					$json_file = $tmp;
-			}
+		if($zip->open($file) !== true) {
+			self::$error = 'There was a problem with opening zip archive.';
+			return false;
+		}
 
-			if(!isset($json_file)) {
-				self::$error = 'Cannot find plugin info .json file. Installation is discontinued.';
-				return false;
-			}
+		for ($i = 0; $i < $zip->numFiles; $i++) {
+			$tmp = $zip->getNameIndex($i);
+			if(pathinfo($tmp, PATHINFO_DIRNAME) == 'plugins' && pathinfo($tmp, PATHINFO_EXTENSION) == 'json')
+				$json_file = $tmp;
+		}
 
-			if($zip->extractTo(BASE)) { // place in the directory with same name
-				$file_name = BASE . $json_file;
-				if(!file_exists($file_name)) {
-					self::$error = "Cannot load " . $file_name . ". File doesn't exist.";
-					return false;
-				}
-				else {
-					$string = file_get_contents($file_name);
-					$string = self::removeComments($string);
-					$plugin = json_decode($string, true);
-					self::$plugin = $plugin;
-					if ($plugin == null) {
-						self::$warnings[] = 'Cannot load ' . $file_name . '. File might be not a valid json code.';
-					}
-					else {
-						$continue = true;
-
-						if(!isset($plugin['name'])) {
-							self::$warnings[] = 'Plugin "name" tag is not set.';
-						}
-						if(!isset($plugin['description'])) {
-							self::$warnings[] = 'Plugin "description" tag is not set.';
-						}
-						if(!isset($plugin['version'])) {
-							self::$warnings[] = 'Plugin "version" tag is not set.';
-						}
-						if(!isset($plugin['author'])) {
-							self::$warnings[] = 'Plugin "author" tag is not set.';
-						}
-						if(!isset($plugin['contact'])) {
-							self::$warnings[] = 'Plugin "contact" tag is not set.';
-						}
-
-						if(isset($plugin['require'])) {
-							$require = $plugin['require'];
-
-							$myaac_satified = true;
-							if(isset($require['myaac_'])) {
-								$require_myaac = $require['myaac_'];
-								if(!Semver::satisfies(MYAAC_VERSION, $require_myaac)) {
-									$myaac_satified = false;
-								}
-							}
-							else if(isset($require['myaac'])) {
-								$require_myaac = $require['myaac'];
-								if(version_compare(MYAAC_VERSION, $require_myaac, '<')) {
-									$myaac_satified = false;
-								}
-							}
-
-							if(!$myaac_satified) {
-								self::$error = "Your AAC version doesn't meet the requirement of this plugin. Required version is: " . $require_myaac . ", and you're using version " . MYAAC_VERSION . ".";
-								$continue = false;
-							}
-
-							$php_satified = true;
-							if(isset($require['php_'])) {
-								$require_php = $require['php_'];
-								if(!Semver::satisfies(phpversion(), $require_php)) {
-									$php_satified = false;
-								}
-							}
-							else if(isset($require['php'])) {
-								$require_php = $require['php'];
-								if(version_compare(phpversion(), $require_php, '<')) {
-									$php_satified = false;
-								}
-							}
-
-							if(!$php_satified) {
-								self::$error = "Your PHP version doesn't meet the requirement of this plugin. Required version is: " . $require_php . ", and you're using version " . phpversion() . ".";
-								$continue = false;
-							}
-
-							$database_satified = true;
-							if(isset($require['database_'])) {
-								$require_database = $require['database_'];
-								if(!Semver::satisfies(DATABASE_VERSION, $require_database)) {
-									$database_satified = false;
-								}
-							}
-							else if(isset($require['database'])) {
-								$require_database = $require['database'];
-								if(version_compare(DATABASE_VERSION, $require_database, '<')) {
-									$database_satified = false;
-								}
-							}
-
-							if(!$database_satified) {
-								self::$error = "Your database version doesn't meet the requirement of this plugin. Required version is: " . $require_database . ", and you're using version " . DATABASE_VERSION . ".";
-								$continue = false;
-							}
-
-							if($continue) {
-								foreach($require as $req => $version) {
-									if(in_array($req, array('myaac', 'myaac_', 'php', 'php_', 'database', 'database_'))) {
-										continue;
-									}
-
-									$req = strtolower($req);
-									if(in_array($req, array('php-ext', 'php-extension'))) { // require php extension
-										if(!extension_loaded($version)) {
-											self::$error = "This plugin requires php extension: " . $version . " to be installed.";
-											$continue = false;
-											break;
-										}
-									}
-									else if($req == 'table') {
-										if(!$db->hasTable($version)) {
-											self::$error = "This plugin requires table: " . $version . " to exist in the database.";
-											$continue = false;
-											break;
-										}
-									}
-									else if($req == 'column') {
-										$tmp = explode('.', $version);
-										if(count($tmp) == 2) {
-											if(!$db->hasColumn($tmp[0], $tmp[1])) {
-												self::$error = "This plugin requires database column: " . $tmp[0] . "." . $tmp[1] . " to exist in database.";
-												$continue = false;
-												break;
-											}
-										}
-									}
-									else if(strpos($req, 'ext-') !== false) {
-										$tmp = explode('-', $req);
-										if(count($tmp) == 2) {
-											if(!extension_loaded($tmp[1]) || !Semver::satisfies(phpversion($tmp[1]), $version)) {
-												self::$error = "This plugin requires php extension: " . $tmp[1] . ", version " . $version . " to be installed.";
-												$continue = false;
-												break;
-											}
-										}
-									}
-									else if(!self::is_installed($req, $version)) {
-										self::$error = "This plugin requires another plugin to run correctly. The another plugin is: " . $req . ", with version " . $version . ".";
-										$continue = false;
-										break;
-									}
-								}
-							}
-						}
-
-						if($continue) {
-							if (isset($plugin['install'])) {
-								if (file_exists(BASE . $plugin['install'])) {
-									$db->revalidateCache();
-									require BASE . $plugin['install'];
-									$db->revalidateCache();
-								}
-								else
-									self::$warnings[] = 'Cannot load install script. Your plugin might be not working correctly.';
-							}
-
-							$cache = Cache::getInstance();
-							if($cache->enabled()) {
-								$cache->delete('templates');
-								$cache->delete('hooks');
-								$cache->delete('template_menus');
-							}
-
-							$zip->close();
-							return true;
-						}
-					}
-				}
-			}
-			else {
-				self::$error = 'There was a problem with extracting zip archive.';
-			}
+		if(!isset($json_file)) {
+			self::$error = 'Cannot find plugin info .json file. Installation is discontinued.';
+			return false;
+		}
 
+		$plugin_temp_dir = CACHE . 'plugins/' . str_replace('.zip', '', basename($file)) . '/';
+		if(!$zip->extractTo($plugin_temp_dir)) { // place in cache dir
+			self::$error = 'There was a problem with extracting zip archive to cache directory.';
 			$zip->close();
+			return false;
+		}
+
+		self::$error = 'There was a problem with extracting zip archive.';
+		$file_name = $plugin_temp_dir . $json_file;
+		if(!file_exists($file_name)) {
+			self::$error = "Cannot load " . $file_name . ". File doesn't exist.";
+			$zip->close();
+			return false;
+		}
+
+		$string = file_get_contents($file_name);
+		$string = self::removeComments($string);
+		$plugin_json = json_decode($string, true);
+		self::$plugin_json = $plugin_json;
+		if ($plugin_json == null) {
+			self::$warnings[] = 'Cannot load ' . $file_name . '. File might be not a valid json code.';
 		}
 		else {
-			self::$error = 'There was a problem with opening zip archive.';
+			$continue = true;
+
+			if(!isset($plugin_json['name']) || empty(trim($plugin_json['name']))) {
+				self::$warnings[] = 'Plugin "name" tag is not set.';
+			}
+			if(!isset($plugin_json['description']) || empty(trim($plugin_json['description']))) {
+				self::$warnings[] = 'Plugin "description" tag is not set.';
+			}
+			if(!isset($plugin_json['version']) || empty(trim($plugin_json['version']))) {
+				self::$warnings[] = 'Plugin "version" tag is not set.';
+			}
+			if(!isset($plugin_json['author']) || empty(trim($plugin_json['author']))) {
+				self::$warnings[] = 'Plugin "author" tag is not set.';
+			}
+			if(!isset($plugin_json['contact']) || empty(trim($plugin_json['contact']))) {
+				self::$warnings[] = 'Plugin "contact" tag is not set.';
+			}
+
+			if(isset($plugin_json['require'])) {
+				$require = $plugin_json['require'];
+
+				$myaac_satified = true;
+				if(isset($require['myaac_'])) {
+					$require_myaac = $require['myaac_'];
+					if(!Semver::satisfies(MYAAC_VERSION, $require_myaac)) {
+						$myaac_satified = false;
+					}
+				}
+				else if(isset($require['myaac'])) {
+					$require_myaac = $require['myaac'];
+					if(version_compare(MYAAC_VERSION, $require_myaac, '<')) {
+						$myaac_satified = false;
+					}
+				}
+
+				if(!$myaac_satified) {
+					self::$error = "Your AAC version doesn't meet the requirement of this plugin. Required version is: " . $require_myaac . ", and you're using version " . MYAAC_VERSION . ".";
+					return false;
+				}
+
+				$php_satisfied = true;
+				if(isset($require['php_'])) {
+					$require_php = $require['php_'];
+					if(!Semver::satisfies(phpversion(), $require_php)) {
+						$php_satisfied = false;
+					}
+				}
+				else if(isset($require['php'])) {
+					$require_php = $require['php'];
+					if(version_compare(phpversion(), $require_php, '<')) {
+						$php_satisfied = false;
+					}
+				}
+
+				if(!$php_satisfied) {
+					self::$error = "Your PHP version doesn't meet the requirement of this plugin. Required version is: " . $require_php . ", and you're using version " . phpversion() . ".";
+					$continue = false;
+				}
+
+				$database_satisfied = true;
+				if(isset($require['database_'])) {
+					$require_database = $require['database_'];
+					if(!Semver::satisfies(DATABASE_VERSION, $require_database)) {
+						$database_satisfied = false;
+					}
+				}
+				else if(isset($require['database'])) {
+					$require_database = $require['database'];
+					if(version_compare(DATABASE_VERSION, $require_database, '<')) {
+						$database_satisfied = false;
+					}
+				}
+
+				if(!$database_satisfied) {
+					self::$error = "Your database version doesn't meet the requirement of this plugin. Required version is: " . $require_database . ", and you're using version " . DATABASE_VERSION . ".";
+					$continue = false;
+				}
+
+				if($continue) {
+					foreach($require as $req => $version) {
+						$req = strtolower(trim($req));
+						$version = trim($version);
+
+						if(in_array($req, array('myaac', 'myaac_', 'php', 'php_', 'database', 'database_'))) {
+							continue;
+						}
+
+						if(in_array($req, array('php-ext', 'php-extension'))) { // require php extension
+							if(!extension_loaded($version)) {
+								self::$error = "This plugin requires php extension: " . $version . " to be installed.";
+								$continue = false;
+								break;
+							}
+						}
+						else if($req == 'table') {
+							if(!$db->hasTable($version)) {
+								self::$error = "This plugin requires table: " . $version . " to exist in the database.";
+								$continue = false;
+								break;
+							}
+						}
+						else if($req == 'column') {
+							$tmp = explode('.', $version);
+							if(count($tmp) == 2) {
+								if(!$db->hasColumn($tmp[0], $tmp[1])) {
+									self::$error = "This plugin requires database column: " . $tmp[0] . "." . $tmp[1] . " to exist in database.";
+									$continue = false;
+									break;
+								}
+							}
+						}
+						else if(strpos($req, 'ext-') !== false) {
+							$tmp = explode('-', $req);
+							if(count($tmp) == 2) {
+								if(!extension_loaded($tmp[1]) || !Semver::satisfies(phpversion($tmp[1]), $version)) {
+									self::$error = "This plugin requires php extension: " . $tmp[1] . ", version " . $version . " to be installed.";
+									$continue = false;
+									break;
+								}
+							}
+						}
+						else if(!self::is_installed($req, $version)) {
+							self::$error = "This plugin requires another plugin to run correctly. The another plugin is: " . $req . ", with version " . $version . ".";
+							$continue = false;
+							break;
+						}
+					}
+				}
+			}
+
+			if($continue) {
+				if (isset($plugin_json['install'])) {
+					if (file_exists(BASE . $plugin_json['install'])) {
+						$db->revalidateCache();
+						require BASE . $plugin_json['install'];
+						$db->revalidateCache();
+					}
+					else
+						self::$warnings[] = 'Cannot load install script. Your plugin might be not working correctly.';
+				}
+
+				if(!$zip->extractTo(BASE)) { // "Real" Install
+					self::$error = 'There was a problem with extracting zip archive to base directory.';
+					$zip->close();
+					return false;
+				}
+
+				$cache = Cache::getInstance();
+				if($cache->enabled()) {
+					$cache->delete('templates');
+					$cache->delete('hooks');
+					$cache->delete('template_menus');
+				}
+
+				return true;
+			}
 		}
 
 		return false;
 	}
 
-	public static function uninstall($plugin_name) {
-		global $db;
-
+	public static function uninstall($plugin_name)
+	{
 		$filename = BASE . 'plugins/' . $plugin_name . '.json';
 		if(!file_exists($filename)) {
 			self::$error = 'Plugin ' . $plugin_name . ' does not exist.';
 			return false;
 		}
-		else {
-			$string = file_get_contents($filename);
-			$string = self::removeComments($string);
-			$plugin_info = json_decode($string, true);
-			if($plugin_info == false) {
-				self::$error = 'Cannot load plugin info ' . $plugin_name . '.json';
-				return false;
+		$string = file_get_contents($filename);
+		$string = self::removeComments($string);
+		$plugin_info = json_decode($string, true);
+		if($plugin_info == false) {
+			self::$error = 'Cannot load plugin info ' . $plugin_name . '.json';
+			return false;
+		}
+
+		if(!isset($plugin_info['uninstall'])) {
+			self::$error = "Plugin doesn't have uninstall options defined. Skipping...";
+			return false;
+		}
+
+		$success = true;
+		foreach($plugin_info['uninstall'] as $file) {
+			if(strpos($file, '/') === 0) {
+				$success = false;
+				self::$error = "You cannot use absolute paths (starting with slash - '/'): " . $file;
+				break;
 			}
-			else {
-				if(!isset($plugin_info['uninstall'])) {
-					self::$error = "Plugin doesn't have uninstall options defined. Skipping...";
-					return false;
-				}
-				else {
-					$success = true;
-					foreach($plugin_info['uninstall'] as $file) {
-						if(strpos($file, '/') === 0) {
-							$success = false;
-							self::$error = "You cannot use absolute paths (starting with slash - '/'): " . $file;
-							break;
-						}
 
-						$file = str_replace('\\', '/', BASE . $file);
-						$realpath = str_replace('\\', '/', realpath(dirname($file)));
-						if(!is_sub_dir($file, BASE) || $realpath != dirname($file)) {
-							$success = false;
-							self::$error = "You don't have rights to delete: " . $file;
-							break;
-						}
-					}
+			$file = str_replace('\\', '/', BASE . $file);
+			$realpath = str_replace('\\', '/', realpath(dirname($file)));
+			if(!is_sub_dir($file, BASE) || $realpath != dirname($file)) {
+				$success = false;
+				self::$error = "You don't have rights to delete: " . $file;
+				break;
+			}
+		}
 
-					if($success) {
-						foreach($plugin_info['uninstall'] as $file) {
-							if(!deleteDirectory(BASE . $file)) {
-								self::$warnings[] = 'Cannot delete: ' . $$file;
-							}
-						}
-					}
-
-					if($success) {
-						$cache = Cache::getInstance();
-						if($cache->enabled()) {
-							$cache->delete('templates');
-							$cache->delete('hooks');
-							$cache->delete('template_menus');
-						}
-
-						return true;
-					}
+		if($success) {
+			foreach($plugin_info['uninstall'] as $file) {
+				if(!deleteDirectory(BASE . $file)) {
+					self::$warnings[] = 'Cannot delete: ' . $file;
 				}
 			}
+
+			$cache = Cache::getInstance();
+			if($cache->enabled()) {
+				$cache->delete('templates');
+				$cache->delete('hooks');
+				$cache->delete('template_menus');
+			}
+
+			return true;
 		}
 
 		return false;
@@ -381,8 +382,8 @@ class Plugins {
 		return self::$error;
 	}
 
-	public static function getPlugin() {
-		return self::$plugin;
+	public static function getPluginJson() {
+		return self::$plugin_json;
 	}
 
 	public static function removeComments($string) {
diff --git a/system/pages/admin/plugins.php b/system/pages/admin/plugins.php
index e3a19d81..111d0a2b 100644
--- a/system/pages/admin/plugins.php
+++ b/system/pages/admin/plugins.php
@@ -69,7 +69,7 @@ if (isset($_REQUEST['uninstall'])) {
 							warning($warning);
 						}
 
-						$info = Plugins::getPlugin();
+						$info = Plugins::getPluginJson();
 						success((isset($info['name']) ? '<strong>' . $info['name'] . '</strong> p' : 'P') . 'lugin has been successfully installed.');
 					} else {
 						$error = Plugins::getError();
@@ -93,6 +93,7 @@ foreach (get_plugins() as $plugin) {
 	$string = file_get_contents(BASE . 'plugins/' . $plugin . '.json');
 	$string = Plugins::removeComments($string);
 	$plugin_info = json_decode($string, true);
+
 	if ($plugin_info == false) {
 		warning('Cannot load plugin info ' . $plugin . '.json');
 	} else {