diff --git a/composer.json b/composer.json
index 80cd8fc..75c5174 100644
--- a/composer.json
+++ b/composer.json
@@ -16,13 +16,20 @@
         "phpunit/phpunit": "^8",
         "friendsofphp/php-cs-fixer": "^2.16",
         "nextcloud/coding-standard": "^0.3.0",
-        "phpstan/phpstan": "^0.12.29"
+        "phpstan/phpstan": "^0.12.29",
+        "christophwurst/nextcloud": "^20.0",
+        "vimeo/psalm": "^4.5"
     },
     "config": {
         "optimize-autoloader": true,
         "classmap-authoritative": true
     },
     "scripts": {
-        "lint": "find . -name \\*.php -not -path './vendor/*' -exec php -l \"{}\" \\;"
+        "cs:check": "php-cs-fixer fix --dry-run --diff",
+        "cs:fix": "php-cs-fixer fix",
+        "lint": "find . -name \\*.php -not -path './vendor/*' -exec php -l \"{}\" \\;",
+        "psalm": "psalm --threads=1",
+        "psalm:clear": "psalm --clear-cache && psalm --clear-global-cache",
+        "psalm:fix": "psalm --alter --issues=InvalidReturnType,InvalidNullableReturnType,MissingParamType,InvalidFalsableReturnType"
     }
-}
+}
\ No newline at end of file
diff --git a/composer.lock b/composer.lock
index 6301943..8ec6c88 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "6889c8d8926c05b33570a53abc170e3f",
+    "content-hash": "db68e8320db4bf61ec4c304edf64e1f7",
     "packages": [
         {
             "name": "littleredbutton/bigbluebutton-api-php",
@@ -101,6 +101,279 @@
         }
     ],
     "packages-dev": [
+        {
+            "name": "amphp/amp",
+            "version": "v2.5.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/amp.git",
+                "reference": "efca2b32a7580087adb8aabbff6be1dc1bb924a9"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/amp/zipball/efca2b32a7580087adb8aabbff6be1dc1bb924a9",
+                "reference": "efca2b32a7580087adb8aabbff6be1dc1bb924a9",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7"
+            },
+            "require-dev": {
+                "amphp/php-cs-fixer-config": "dev-master",
+                "amphp/phpunit-util": "^1",
+                "ext-json": "*",
+                "jetbrains/phpstorm-stubs": "^2019.3",
+                "phpunit/phpunit": "^6.0.9 | ^7",
+                "psalm/phar": "^3.11@dev",
+                "react/promise": "^2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Amp\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php",
+                    "lib/Internal/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                },
+                {
+                    "name": "Bob Weinand",
+                    "email": "bobwei9@hotmail.com"
+                },
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                }
+            ],
+            "description": "A non-blocking concurrency framework for PHP applications.",
+            "homepage": "http://amphp.org/amp",
+            "keywords": [
+                "async",
+                "asynchronous",
+                "awaitable",
+                "concurrency",
+                "event",
+                "event-loop",
+                "future",
+                "non-blocking",
+                "promise"
+            ],
+            "support": {
+                "irc": "irc://irc.freenode.org/amphp",
+                "issues": "https://github.com/amphp/amp/issues",
+                "source": "https://github.com/amphp/amp/tree/v2.5.2"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/amphp",
+                    "type": "github"
+                }
+            ],
+            "time": "2021-01-10T17:06:37+00:00"
+        },
+        {
+            "name": "amphp/byte-stream",
+            "version": "v1.8.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/byte-stream.git",
+                "reference": "f0c20cf598a958ba2aa8c6e5a71c697d652c7088"
+            },
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+                "url": "https://api.github.com/repos/amphp/byte-stream/zipball/f0c20cf598a958ba2aa8c6e5a71c697d652c7088",
+                "reference": "f0c20cf598a958ba2aa8c6e5a71c697d652c7088",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "php": ">=7.1"
+            },
+            "require-dev": {
+                "amphp/php-cs-fixer-config": "dev-master",
+                "amphp/phpunit-util": "^1.4",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "jetbrains/phpstorm-stubs": "^2019.3",
+                "phpunit/phpunit": "^6 || ^7 || ^8",
+                "psalm/phar": "^3.11.4"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Amp\\ByteStream\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                },
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                }
+            ],
+            "description": "A stream abstraction to make working with non-blocking I/O simple.",
+            "homepage": "http://amphp.org/byte-stream",
+            "keywords": [
+                "amp",
+                "amphp",
+                "async",
+                "io",
+                "non-blocking",
+                "stream"
+            ],
+            "support": {
+                "irc": "irc://irc.freenode.org/amphp",
+                "issues": "https://github.com/amphp/byte-stream/issues",
+                "source": "https://github.com/amphp/byte-stream/tree/master"
+            },
+            "time": "2020-06-29T18:35:05+00:00"
+        },
+        {
+            "name": "christophwurst/nextcloud",
+            "version": "v20.0.7",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/ChristophWurst/nextcloud_composer.git",
+                "reference": "114c6598743dc4caa21c84eafadedf3f6730cdab"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/ChristophWurst/nextcloud_composer/zipball/114c6598743dc4caa21c84eafadedf3f6730cdab",
+                "reference": "114c6598743dc4caa21c84eafadedf3f6730cdab",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "20.0.0-dev"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "AGPL-3.0-or-later"
+            ],
+            "authors": [
+                {
+                    "name": "Christoph Wurst",
+                    "email": "christoph@winzerhof-wurst.at"
+                }
+            ],
+            "description": "Composer package containing Nextcloud's public API (classes, interfaces)",
+            "support": {
+                "issues": "https://github.com/ChristophWurst/nextcloud_composer/issues",
+                "source": "https://github.com/ChristophWurst/nextcloud_composer/tree/v20.0.7"
+            },
+            "time": "2021-02-03T07:58:35+00:00"
+        },
+        {
+            "name": "composer/package-versions-deprecated",
+            "version": "1.11.99.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/composer/package-versions-deprecated.git",
+                "reference": "7413f0b55a051e89485c5cb9f765fe24bb02a7b6"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/composer/package-versions-deprecated/zipball/7413f0b55a051e89485c5cb9f765fe24bb02a7b6",
+                "reference": "7413f0b55a051e89485c5cb9f765fe24bb02a7b6",
+                "shasum": ""
+            },
+            "require": {
+                "composer-plugin-api": "^1.1.0 || ^2.0",
+                "php": "^7 || ^8"
+            },
+            "replace": {
+                "ocramius/package-versions": "1.11.99"
+            },
+            "require-dev": {
+                "composer/composer": "^1.9.3 || ^2.0@dev",
+                "ext-zip": "^1.13",
+                "phpunit/phpunit": "^6.5 || ^7"
+            },
+            "type": "composer-plugin",
+            "extra": {
+                "class": "PackageVersions\\Installer",
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PackageVersions\\": "src/PackageVersions"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Marco Pivetta",
+                    "email": "ocramius@gmail.com"
+                },
+                {
+                    "name": "Jordi Boggiano",
+                    "email": "j.boggiano@seld.be"
+                }
+            ],
+            "description": "Composer plugin that provides efficient querying for installed package versions (no runtime IO)",
+            "support": {
+                "issues": "https://github.com/composer/package-versions-deprecated/issues",
+                "source": "https://github.com/composer/package-versions-deprecated/tree/1.11.99.1"
+            },
+            "funding": [
+                {
+                    "url": "https://packagist.com",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/composer",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/composer/composer",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2020-11-11T10:22:58+00:00"
+        },
         {
             "name": "composer/semver",
             "version": "1.7.1",
@@ -234,6 +507,43 @@
             ],
             "time": "2020-08-19T10:27:58+00:00"
         },
+        {
+            "name": "dnoegel/php-xdg-base-dir",
+            "version": "v0.1.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/dnoegel/php-xdg-base-dir.git",
+                "reference": "8f8a6e48c5ecb0f991c2fdcf5f154a47d85f9ffd"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/dnoegel/php-xdg-base-dir/zipball/8f8a6e48c5ecb0f991c2fdcf5f154a47d85f9ffd",
+                "reference": "8f8a6e48c5ecb0f991c2fdcf5f154a47d85f9ffd",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.2"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~7.0|~6.0|~5.0|~4.8.35"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "XdgBaseDir\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "implementation of xdg base directory specification for php",
+            "support": {
+                "issues": "https://github.com/dnoegel/php-xdg-base-dir/issues",
+                "source": "https://github.com/dnoegel/php-xdg-base-dir/tree/v0.1.1"
+            },
+            "time": "2019-12-04T15:06:13+00:00"
+        },
         {
             "name": "doctrine/annotations",
             "version": "1.10.4",
@@ -450,6 +760,107 @@
             ],
             "time": "2020-05-25T17:44:05+00:00"
         },
+        {
+            "name": "felixfbecker/advanced-json-rpc",
+            "version": "v3.2.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/felixfbecker/php-advanced-json-rpc.git",
+                "reference": "06f0b06043c7438959dbdeed8bb3f699a19be22e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/felixfbecker/php-advanced-json-rpc/zipball/06f0b06043c7438959dbdeed8bb3f699a19be22e",
+                "reference": "06f0b06043c7438959dbdeed8bb3f699a19be22e",
+                "shasum": ""
+            },
+            "require": {
+                "netresearch/jsonmapper": "^1.0 || ^2.0",
+                "php": "^7.1 || ^8.0",
+                "phpdocumentor/reflection-docblock": "^4.3.4 || ^5.0.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^7.0 || ^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "AdvancedJsonRpc\\": "lib/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "ISC"
+            ],
+            "authors": [
+                {
+                    "name": "Felix Becker",
+                    "email": "felix.b@outlook.com"
+                }
+            ],
+            "description": "A more advanced JSONRPC implementation",
+            "support": {
+                "issues": "https://github.com/felixfbecker/php-advanced-json-rpc/issues",
+                "source": "https://github.com/felixfbecker/php-advanced-json-rpc/tree/v3.2.0"
+            },
+            "time": "2021-01-10T17:48:47+00:00"
+        },
+        {
+            "name": "felixfbecker/language-server-protocol",
+            "version": "v1.5.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/felixfbecker/php-language-server-protocol.git",
+                "reference": "85e83cacd2ed573238678c6875f8f0d7ec699541"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/felixfbecker/php-language-server-protocol/zipball/85e83cacd2ed573238678c6875f8f0d7ec699541",
+                "reference": "85e83cacd2ed573238678c6875f8f0d7ec699541",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1"
+            },
+            "require-dev": {
+                "phpstan/phpstan": "*",
+                "squizlabs/php_codesniffer": "^3.1",
+                "vimeo/psalm": "^4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "LanguageServerProtocol\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "ISC"
+            ],
+            "authors": [
+                {
+                    "name": "Felix Becker",
+                    "email": "felix.b@outlook.com"
+                }
+            ],
+            "description": "PHP classes for the Language Server Protocol",
+            "keywords": [
+                "language",
+                "microsoft",
+                "php",
+                "server"
+            ],
+            "support": {
+                "issues": "https://github.com/felixfbecker/php-language-server-protocol/issues",
+                "source": "https://github.com/felixfbecker/php-language-server-protocol/tree/v1.5.0"
+            },
+            "time": "2020-10-23T13:55:30+00:00"
+        },
         {
             "name": "friendsofphp/php-cs-fixer",
             "version": "v2.16.4",
@@ -601,6 +1012,57 @@
             ],
             "time": "2020-06-29T13:22:24+00:00"
         },
+        {
+            "name": "netresearch/jsonmapper",
+            "version": "v2.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/cweiske/jsonmapper.git",
+                "reference": "e0f1e33a71587aca81be5cffbb9746510e1fe04e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/cweiske/jsonmapper/zipball/e0f1e33a71587aca81be5cffbb9746510e1fe04e",
+                "reference": "e0f1e33a71587aca81be5cffbb9746510e1fe04e",
+                "shasum": ""
+            },
+            "require": {
+                "ext-json": "*",
+                "ext-pcre": "*",
+                "ext-reflection": "*",
+                "ext-spl": "*",
+                "php": ">=5.6"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~4.8.35 || ~5.7 || ~6.4 || ~7.0",
+                "squizlabs/php_codesniffer": "~3.5"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-0": {
+                    "JsonMapper": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "OSL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "Christian Weiske",
+                    "email": "cweiske@cweiske.de",
+                    "homepage": "http://github.com/cweiske/jsonmapper/",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Map nested JSON structures onto PHP classes",
+            "support": {
+                "email": "cweiske@cweiske.de",
+                "issues": "https://github.com/cweiske/jsonmapper/issues",
+                "source": "https://github.com/cweiske/jsonmapper/tree/master"
+            },
+            "time": "2020-04-16T18:48:43+00:00"
+        },
         {
             "name": "nextcloud/coding-standard",
             "version": "v0.3.0",
@@ -638,6 +1100,115 @@
             "description": "Nextcloud coding standards for the php cs fixer",
             "time": "2020-04-10T14:57:18+00:00"
         },
+        {
+            "name": "nikic/php-parser",
+            "version": "v4.10.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nikic/PHP-Parser.git",
+                "reference": "c6d052fc58cb876152f89f532b95a8d7907e7f0e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/c6d052fc58cb876152f89f532b95a8d7907e7f0e",
+                "reference": "c6d052fc58cb876152f89f532b95a8d7907e7f0e",
+                "shasum": ""
+            },
+            "require": {
+                "ext-tokenizer": "*",
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "ircmaxell/php-yacc": "^0.0.7",
+                "phpunit/phpunit": "^6.5 || ^7.0 || ^8.0 || ^9.0"
+            },
+            "bin": [
+                "bin/php-parse"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "4.9-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PhpParser\\": "lib/PhpParser"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Nikita Popov"
+                }
+            ],
+            "description": "A PHP parser written in PHP",
+            "keywords": [
+                "parser",
+                "php"
+            ],
+            "support": {
+                "issues": "https://github.com/nikic/PHP-Parser/issues",
+                "source": "https://github.com/nikic/PHP-Parser/tree/v4.10.4"
+            },
+            "time": "2020-12-20T10:01:03+00:00"
+        },
+        {
+            "name": "openlss/lib-array2xml",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nullivex/lib-array2xml.git",
+                "reference": "a91f18a8dfc69ffabe5f9b068bc39bb202c81d90"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nullivex/lib-array2xml/zipball/a91f18a8dfc69ffabe5f9b068bc39bb202c81d90",
+                "reference": "a91f18a8dfc69ffabe5f9b068bc39bb202c81d90",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.2"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-0": {
+                    "LSS": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "Apache-2.0"
+            ],
+            "authors": [
+                {
+                    "name": "Bryan Tong",
+                    "email": "bryan@nullivex.com",
+                    "homepage": "https://www.nullivex.com"
+                },
+                {
+                    "name": "Tony Butler",
+                    "email": "spudz76@gmail.com",
+                    "homepage": "https://www.nullivex.com"
+                }
+            ],
+            "description": "Array2XML conversion library credit to lalit.org",
+            "homepage": "https://www.nullivex.com",
+            "keywords": [
+                "array",
+                "array conversion",
+                "xml",
+                "xml conversion"
+            ],
+            "support": {
+                "issues": "https://github.com/nullivex/lib-array2xml/issues",
+                "source": "https://github.com/nullivex/lib-array2xml/tree/master"
+            },
+            "time": "2019-03-29T20:06:56+00:00"
+        },
         {
             "name": "paragonie/random_compat",
             "version": "v9.99.99",
@@ -3673,6 +4244,110 @@
             ],
             "time": "2020-07-12T23:59:07+00:00"
         },
+        {
+            "name": "vimeo/psalm",
+            "version": "4.5.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/vimeo/psalm.git",
+                "reference": "257a1ca672a79dedc852be1285a7b97154646418"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/vimeo/psalm/zipball/257a1ca672a79dedc852be1285a7b97154646418",
+                "reference": "257a1ca672a79dedc852be1285a7b97154646418",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2.1",
+                "amphp/byte-stream": "^1.5",
+                "composer/package-versions-deprecated": "^1.8.0",
+                "composer/semver": "^1.4 || ^2.0 || ^3.0",
+                "composer/xdebug-handler": "^1.1",
+                "dnoegel/php-xdg-base-dir": "^0.1.1",
+                "ext-dom": "*",
+                "ext-json": "*",
+                "ext-libxml": "*",
+                "ext-mbstring": "*",
+                "ext-simplexml": "*",
+                "ext-tokenizer": "*",
+                "felixfbecker/advanced-json-rpc": "^3.0.3",
+                "felixfbecker/language-server-protocol": "^1.4",
+                "netresearch/jsonmapper": "^1.0 || ^2.0 || ^3.0",
+                "nikic/php-parser": "^4.10.1",
+                "openlss/lib-array2xml": "^1.0",
+                "php": "^7.1|^8",
+                "sebastian/diff": "^3.0 || ^4.0",
+                "symfony/console": "^3.4.17 || ^4.1.6 || ^5.0",
+                "webmozart/path-util": "^2.3"
+            },
+            "provide": {
+                "psalm/psalm": "self.version"
+            },
+            "require-dev": {
+                "amphp/amp": "^2.4.2",
+                "bamarni/composer-bin-plugin": "^1.2",
+                "brianium/paratest": "^4.0||^6.0",
+                "ext-curl": "*",
+                "phpdocumentor/reflection-docblock": "^5",
+                "phpmyadmin/sql-parser": "5.1.0||dev-master",
+                "phpspec/prophecy": ">=1.9.0",
+                "phpunit/phpunit": "^9.0",
+                "psalm/plugin-phpunit": "^0.13",
+                "slevomat/coding-standard": "^6.3.11",
+                "squizlabs/php_codesniffer": "^3.5",
+                "symfony/process": "^4.3",
+                "weirdan/prophecy-shim": "^1.0 || ^2.0"
+            },
+            "suggest": {
+                "ext-igbinary": "^2.0.5"
+            },
+            "bin": [
+                "psalm",
+                "psalm-language-server",
+                "psalm-plugin",
+                "psalm-refactor",
+                "psalter"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "4.x-dev",
+                    "dev-3.x": "3.x-dev",
+                    "dev-2.x": "2.x-dev",
+                    "dev-1.x": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psalm\\": "src/Psalm/"
+                },
+                "files": [
+                    "src/functions.php",
+                    "src/spl_object_id.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Matthew Brown"
+                }
+            ],
+            "description": "A static analysis tool for finding errors in PHP applications",
+            "keywords": [
+                "code",
+                "inspection",
+                "php"
+            ],
+            "support": {
+                "issues": "https://github.com/vimeo/psalm/issues",
+                "source": "https://github.com/vimeo/psalm/tree/4.5.1"
+            },
+            "time": "2021-02-11T19:12:25+00:00"
+        },
         {
             "name": "webmozart/assert",
             "version": "1.9.1",
@@ -3721,6 +4396,56 @@
                 "validate"
             ],
             "time": "2020-07-08T17:02:28+00:00"
+        },
+        {
+            "name": "webmozart/path-util",
+            "version": "2.3.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/webmozart/path-util.git",
+                "reference": "d939f7edc24c9a1bb9c0dee5cb05d8e859490725"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/webmozart/path-util/zipball/d939f7edc24c9a1bb9c0dee5cb05d8e859490725",
+                "reference": "d939f7edc24c9a1bb9c0dee5cb05d8e859490725",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3",
+                "webmozart/assert": "~1.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.6",
+                "sebastian/version": "^1.0.1"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.3-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Webmozart\\PathUtil\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Bernhard Schussek",
+                    "email": "bschussek@gmail.com"
+                }
+            ],
+            "description": "A robust cross-platform utility for normalizing, comparing and modifying file paths.",
+            "support": {
+                "issues": "https://github.com/webmozart/path-util/issues",
+                "source": "https://github.com/webmozart/path-util/tree/2.3.0"
+            },
+            "time": "2015-12-17T08:42:14+00:00"
         }
     ],
     "aliases": [],
@@ -3730,5 +4455,5 @@
     "prefer-lowest": false,
     "platform": [],
     "platform-dev": [],
-    "plugin-api-version": "1.1.0"
+    "plugin-api-version": "2.0.0"
 }
diff --git a/lib/Activity/Provider.php b/lib/Activity/Provider.php
index 87bb187..2562178 100644
--- a/lib/Activity/Provider.php
+++ b/lib/Activity/Provider.php
@@ -197,7 +197,7 @@ class Provider implements IProvider {
 		$event->setIcon($this->url->getAbsoluteURL($imagePath));
 	}
 
-	private function setSubjects(IEvent $event, $subject, array $parameters) {
+	private function setSubjects(IEvent $event, string $subject, array $parameters) {
 		$placeholders = $replacements = [];
 
 		foreach ($parameters as $placeholder => $parameter) {
@@ -213,7 +213,7 @@ class Provider implements IProvider {
 			->setRichSubject($subject, $parameters);
 	}
 
-	protected function getUser($uid) {
+	protected function getUser(string $uid) {
 		$user = $this->userManager->get($uid);
 
 		if ($user instanceof IUser) {
diff --git a/lib/BigBlueButton/API.php b/lib/BigBlueButton/API.php
index e69914e..a9b6eca 100644
--- a/lib/BigBlueButton/API.php
+++ b/lib/BigBlueButton/API.php
@@ -217,7 +217,7 @@ class API {
 		];
 	}
 
-	public function check($url, $secret) {
+	public function check(string $url, string $secret) {
 		$server = new BigBlueButton($url, $secret);
 
 		$meetingParams = new IsMeetingRunningParameters('foobar');
@@ -239,7 +239,10 @@ class API {
 		}
 	}
 
-	public function getVersion($url = null) {
+	/**
+	 * @param null|string $url
+	 */
+	public function getVersion(?string $url = null) {
 		$server = $url === null ? $this->getServer() : new BigBlueButton($url, '');
 
 		return $server->getApiVersion()->getVersion();
diff --git a/lib/Crypto.php b/lib/Crypto.php
index b4429fc..03f5dc0 100644
--- a/lib/Crypto.php
+++ b/lib/Crypto.php
@@ -32,7 +32,7 @@ class Crypto {
 		return $validMac === $mac;
 	}
 
-	private function encodeBase64UrlSafe($data) {
+	private function encodeBase64UrlSafe(string $data) {
 		$b64 = \base64_encode($data);
 
 		if ($b64 === false) {
diff --git a/lib/Service/RestrictionService.php b/lib/Service/RestrictionService.php
index 7e888c4..1bbcff7 100644
--- a/lib/Service/RestrictionService.php
+++ b/lib/Service/RestrictionService.php
@@ -66,7 +66,7 @@ class RestrictionService {
 		return $restriction;
 	}
 
-	public function find($id): Restriction {
+	public function find(int $id): Restriction {
 		try {
 			return $this->mapper->find($id);
 		} catch (Exception $e) {
diff --git a/lib/Service/RoomService.php b/lib/Service/RoomService.php
index aa338c6..e0523af 100644
--- a/lib/Service/RoomService.php
+++ b/lib/Service/RoomService.php
@@ -44,7 +44,7 @@ class RoomService {
 	/**
 	 * @throws RoomNotFound
 	 */
-	public function find($id): Room {
+	public function find(int $id): Room {
 		try {
 			return $this->mapper->find($id);
 
@@ -57,7 +57,7 @@ class RoomService {
 		}
 	}
 
-	public function findByUid($uid) {
+	public function findByUid(string $uid) {
 		try {
 			return $this->mapper->findByUid($uid);
 		} catch (Exception $e) {
@@ -66,7 +66,7 @@ class RoomService {
 		}
 	}
 
-	public function create($name, $welcome, $maxParticipants, $record, $access, $userId) {
+	public function create(string $name, string $welcome, int $maxParticipants, bool $record, string $access, string $userId) {
 		$room = new Room();
 
 		$room->setUid(\OC::$server->getSecureRandom()->generate(16, \OCP\Security\ISecureRandom::CHAR_HUMAN_READABLE));
@@ -90,7 +90,10 @@ class RoomService {
 		return $createdRoom;
 	}
 
-	public function update($id, $name, $welcome, $maxParticipants, $record, $access, $everyoneIsModerator, $requireModerator, $moderatorToken) {
+	/**
+	 * @param null|string $moderatorToken
+	 */
+	public function update(int $id, string $name, string $welcome, int $maxParticipants, bool $record, string $access, bool $everyoneIsModerator, bool $requireModerator, ?string $moderatorToken) {
 		try {
 			$room = $this->mapper->find($id);
 
@@ -116,7 +119,7 @@ class RoomService {
 		}
 	}
 
-	public function delete($id) {
+	public function delete(int $id) {
 		try {
 			$room = $this->mapper->find($id);
 
@@ -130,7 +133,10 @@ class RoomService {
 		}
 	}
 
-	private function humanReadableRandom($length) {
+	/**
+	 * @param int $length
+	 */
+	private function humanReadableRandom(int $length) {
 		return \OC::$server->getSecureRandom()->generate($length, \OCP\Security\ISecureRandom::CHAR_HUMAN_READABLE);
 	}
 }
diff --git a/lib/Service/RoomShareService.php b/lib/Service/RoomShareService.php
index 5338419..fbb8ba0 100644
--- a/lib/Service/RoomShareService.php
+++ b/lib/Service/RoomShareService.php
@@ -45,7 +45,7 @@ class RoomShareService {
 		}
 	}
 
-	public function find($id): RoomShare {
+	public function find(int $id): RoomShare {
 		try {
 			return $this->mapper->find($id);
 		} catch (Exception $e) {
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 0000000..9a8b6c0
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,37 @@
+<?xml version="1.0"?>
+<psalm
+    totallyTyped="true"
+    errorLevel="5"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="lib" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+    <extraFiles>
+        <directory name="vendor" />
+        <ignoreFiles>
+            <directory name="vendor/phpunit/php-code-coverage" />
+        </ignoreFiles>
+    </extraFiles>
+    <issueHandlers>
+        <UndefinedClass>
+            <errorLevel type="suppress">
+                <referencedClass name="OC" />
+            </errorLevel>
+        </UndefinedClass>
+        <UndefinedDocblockClass>
+            <errorLevel type="suppress">
+                <referencedClass name="Doctrine\DBAL\Schema\Schema" />
+                <referencedClass name="Doctrine\DBAL\Schema\SchemaException" />
+                <referencedClass name="Doctrine\DBAL\Driver\Statement" />
+                <referencedClass name="Doctrine\DBAL\Schema\Table" />
+            </errorLevel>
+        </UndefinedDocblockClass>
+    </issueHandlers>
+</psalm>
\ No newline at end of file
diff --git a/tests/Unit/Controller/JoinControllerTest.php b/tests/Unit/Controller/JoinControllerTest.php
index 54fad9a..5bae8b9 100644
--- a/tests/Unit/Controller/JoinControllerTest.php
+++ b/tests/Unit/Controller/JoinControllerTest.php
@@ -56,6 +56,7 @@ class JoinControllerTest extends TestCase {
 	}
 
 	public function testNonExistingRoom() {
+		$this->controller->setToken('foobar');
 		$this->expectException(NotFoundException::class);
 		$this->service
 			->expects($this->once())