Improve middleware definition and cleanup code

src/Application.ts

@@ -16,14 +16,15 @@ import SecurityError from "./SecurityError";
 import * as path from "path";
 import CacheProvider from "./CacheProvider";
 import RedisComponent from "./components/RedisComponent";
+import Extendable from "./Extendable";
 import TemplateError = lib.TemplateError;
 
-export default abstract class Application {
+export default abstract class Application implements Extendable<ApplicationComponent> {
     private readonly version: string;
     private readonly ignoreCommandLine: boolean;
     private readonly controllers: Controller[] = [];
-    private readonly webSocketListeners: { [p: string]: WebSocketListener<any> } = {};
+    private readonly webSocketListeners: { [p: string]: WebSocketListener<Application> } = {};
-    private readonly components: ApplicationComponent<any>[] = [];
+    private readonly components: ApplicationComponent[] = [];
     private cacheProvider?: CacheProvider;
 
     private ready: boolean = false;
@@ -37,8 +38,9 @@ export default abstract class Application {
 
     protected abstract async init(): Promise<void>;
 
-    protected use(thing: Controller | WebSocketListener<this> | ApplicationComponent<any>) {
+    protected use(thing: Controller | WebSocketListener<this> | ApplicationComponent) {
         if (thing instanceof Controller) {
+            thing.setApp(this);
             this.controllers.push(thing);
         } else if (thing instanceof WebSocketListener) {
             const path = thing.path();
@@ -151,13 +153,22 @@ export default abstract class Application {
 
         // Start components
         for (const component of this.components) {
-            await component.start(app);
+            await component.start?.(app);
         }
 
         // Components routes
         for (const component of this.components) {
-            await component.init(initRouter);
+            if (component.init) {
-            await component.handle(handleRouter);
+                component.setCurrentRouter(initRouter);
+                await component.init(initRouter);
+            }
+
+            if (component.handle) {
+                component.setCurrentRouter(handleRouter);
+                await component.handle(handleRouter);
+            }
+
+            component.setCurrentRouter(null);
         }
 
         // Routes
@@ -203,7 +214,7 @@ export default abstract class Application {
 
         // Check security fields
         for (const component of this.components) {
-            await component.checkSecuritySettings();
+            await component.checkSecuritySettings?.();
         }
     }
 
@@ -211,7 +222,7 @@ export default abstract class Application {
         Logger.info('Stopping application...');
 
         for (const component of this.components) {
-            await component.stop();
+            await component.stop?.();
         }
 
         Logger.info(`${this.constructor.name} v${this.version} - bye`);
@@ -219,7 +230,7 @@ export default abstract class Application {
 
     private routes(initRouter: Router, handleRouter: Router) {
         for (const controller of this.controllers) {
-            if (controller.hasGlobalHandlers()) {
+            if (controller.hasGlobalMiddlewares()) {
                 controller.setupGlobalHandlers(handleRouter);
 
                 Logger.info(`Registered global middlewares for controller ${controller.constructor.name}`);
@@ -247,7 +258,7 @@ export default abstract class Application {
         return this.version;
     }
 
-    public getWebSocketListeners(): { [p: string]: WebSocketListener<any> } {
+    public getWebSocketListeners(): { [p: string]: WebSocketListener<Application> } {
         return this.webSocketListeners;
     }
 
@@ -255,7 +266,14 @@ export default abstract class Application {
         return this.cacheProvider;
     }
 
-    public getComponent<T extends ApplicationComponent<any>>(type: Type<T>): T | undefined {
+    public as<C extends ApplicationComponent>(type: Type<C>): C {
-        return <T>this.components.find(component => component.constructor === type);
+        const component = this.components.find(component => component.constructor === type);
+        if (!component) throw new Error(`This app doesn't have a ${type.name} component.`);
+        return component as C;
+    }
+
+    public asOptional<C extends ApplicationComponent>(type: Type<C>): C | null {
+        const component = this.components.find(component => component.constructor === type);
+        return component ? component as C : null;
     }
 }

src/ApplicationComponent.ts

@@ -1,42 +1,24 @@
 import {Express, Router} from "express";
 import Logger from "./Logger";
-import {sleep} from "./Utils";
+import {sleep, Type} from "./Utils";
 import Application from "./Application";
 import config from "config";
 import SecurityError from "./SecurityError";
+import Middleware from "./Middleware";
 
-export default abstract class ApplicationComponent<T> {
+export default abstract class ApplicationComponent {
-    private val?: T;
+    private currentRouter?: Router;
-    protected app?: Application;
+    private app?: Application;
 
-    public async checkSecuritySettings(): Promise<void> {
+    public async checkSecuritySettings?(): Promise<void>;
-    }
 
-    public async start(app: Express): Promise<void> {
+    public async start?(expressApp: Express): Promise<void>;
-    }
 
-    public async init(router: Router): Promise<void> {
+    public async init?(router: Router): Promise<void>;
-    }
 
-    public async handle(router: Router): Promise<void> {
+    public async handle?(router: Router): Promise<void>;
-    }
 
-    public async stop(): Promise<void> {
+    public async stop?(): Promise<void>;
-
-    }
-
-    protected export(val: T) {
-        this.val = val;
-    }
-
-    public import(): T {
-        if (!this.val) throw 'Cannot import if nothing was exported.';
-        return this.val;
-    }
-
-    public setApp(app: Application) {
-        this.app = app;
-    }
 
     protected async prepare(name: string, prepare: () => Promise<void>): Promise<void> {
         let err;
@@ -71,4 +53,34 @@ export default abstract class ApplicationComponent<T> {
             throw new SecurityError(`${field} field not configured.`);
         }
     }
+
+    protected use<M extends Middleware>(middleware: Type<M>): void {
+        if (!this.currentRouter) throw new Error('Cannot call this method outside init() and handle().');
+
+        const instance = new middleware(this.getApp());
+        this.currentRouter.use(async (req, res, next) => {
+            try {
+                await instance.getRequestHandler()(req, res, next);
+            } catch (e) {
+                next(e);
+            }
+        });
+    }
+
+    protected getCurrentRouter(): Router | null {
+        return this.currentRouter || null;
+    }
+
+    public setCurrentRouter(router: Router | null): void {
+        this.currentRouter = router || undefined;
+    }
+
+    protected getApp(): Application {
+        if (!this.app) throw new Error('app field not initialized.');
+        return this.app;
+    }
+
+    public setApp(app: Application) {
+        this.app = app;
+    }
 }

src/Controller.ts

@@ -2,10 +2,13 @@ import express, {IRouter, RequestHandler, Router} from "express";
 import {PathParams} from "express-serve-static-core";
 import config from "config";
 import Logger from "./Logger";
-import Validator, {FileError, ValidationBag} from "./db/Validator";
+import Validator, {ValidationBag} from "./db/Validator";
 import FileUploadMiddleware from "./FileUploadMiddleware";
 import * as querystring from "querystring";
 import {ParsedUrlQueryInput} from "querystring";
+import Middleware from "./Middleware";
+import {Type} from "./Utils";
+import Application from "./Application";
 
 export default abstract class Controller {
     private static readonly routes: { [p: string]: string } = {};
@@ -39,18 +42,19 @@ export default abstract class Controller {
 
     private readonly router: Router = express.Router();
     private readonly fileUploadFormRouter: Router = express.Router();
+    private app?: Application;
 
-    public getGlobalHandlers(): RequestHandler[] {
+    public getGlobalMiddlewares(): Middleware[] {
         return [];
     }
 
-    public hasGlobalHandlers(): boolean {
+    public hasGlobalMiddlewares(): boolean {
-        return this.getGlobalHandlers().length > 0;
+        return this.getGlobalMiddlewares().length > 0;
     }
 
     public setupGlobalHandlers(router: Router): void {
-        for (const globalHandler of this.getGlobalHandlers()) {
+        for (const middleware of this.getGlobalMiddlewares()) {
-            router.use(this.wrap(globalHandler));
+            router.use(this.wrap(middleware.getRequestHandler()));
         }
     }
 
@@ -75,19 +79,19 @@ export default abstract class Controller {
         this.router.use(handler);
     }
 
-    protected get(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (RequestHandler | FileUploadMiddleware)[]) {
+    protected get(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (Type<Middleware>)[]) {
         this.handle('get', path, handler, routeName, ...middlewares);
     }
 
-    protected post(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (RequestHandler | FileUploadMiddleware)[]) {
+    protected post(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (Type<Middleware>)[]) {
         this.handle('post', path, handler, routeName, ...middlewares);
     }
 
-    protected put(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (RequestHandler | FileUploadMiddleware)[]) {
+    protected put(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (Type<Middleware>)[]) {
         this.handle('put', path, handler, routeName, ...middlewares);
     }
 
-    protected delete(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (RequestHandler | FileUploadMiddleware)[]) {
+    protected delete(path: PathParams, handler: RequestHandler, routeName?: string, ...middlewares: (Type<Middleware>)[]) {
         this.handle('delete', path, handler, routeName, ...middlewares);
     }
 
@@ -96,14 +100,15 @@ export default abstract class Controller {
         path: PathParams,
         handler: RequestHandler,
         routeName?: string,
-        ...middlewares: (RequestHandler | FileUploadMiddleware)[]
+        ...middlewares: (Type<Middleware>)[]
     ): void {
         this.registerRoutes(path, handler, routeName);
         for (const middleware of middlewares) {
-            if (middleware instanceof FileUploadMiddleware) {
+            const instance = new middleware(this.getApp());
-                this.fileUploadFormRouter[action](path, this.wrap(FILE_UPLOAD_MIDDLEWARE(middleware)));
+            if (instance instanceof FileUploadMiddleware) {
+                this.fileUploadFormRouter[action](path, this.wrap(instance.getRequestHandler()));
             } else {
-                this.router[action](path, this.wrap(middleware));
+                this.router[action](path, this.wrap(instance.getRequestHandler()));
             }
         }
         this.router[action](path, this.wrap(handler));
@@ -164,33 +169,15 @@ export default abstract class Controller {
 
         if (bag.hasMessages()) throw bag;
     }
+
+    protected getApp(): Application {
+        if (!this.app) throw new Error('Application not initialized.');
+        return this.app;
+    }
+
+    public setApp(app: Application) {
+        this.app = app;
+    }
 }
 
 export type RouteParams = { [p: string]: string } | string[] | string | number;
-
-const FILE_UPLOAD_MIDDLEWARE: (fileUploadMiddleware: FileUploadMiddleware) => RequestHandler = (fileUploadMiddleware: FileUploadMiddleware) => {
-    return async (req, res, next) => {
-        const form = fileUploadMiddleware.formFactory();
-        try {
-            await new Promise<any>((resolve, reject) => {
-                form.parse(req, (err, fields, files) => {
-                    if (err) {
-                        reject(err);
-                        return;
-                    }
-                    req.body = fields;
-                    req.files = files;
-                    resolve();
-                });
-            });
-        } catch (e) {
-            const bag = new ValidationBag();
-            const fileError = new FileError(e);
-            fileError.thingName = fileUploadMiddleware.defaultField;
-            bag.addMessage(fileError);
-            next(bag);
-            return;
-        }
-        next();
-    };
-};

src/Extendable.ts

@@ -0,0 +1,7 @@
+import {Type} from "./Utils";
+
+export default interface Extendable<ComponentClass> {
+    as<C extends ComponentClass>(type: Type<C>): C;
+
+    asOptional<C extends ComponentClass>(type: Type<C>): C | null;
+}

src/FileUploadMiddleware.ts

@@ -1,11 +1,35 @@
 import {IncomingForm} from "formidable";
+import Middleware from "./Middleware";
+import {NextFunction, Request, Response} from "express";
+import {FileError, ValidationBag} from "./db/Validator";
 
-export default class FileUploadMiddleware {
+export default abstract class FileUploadMiddleware extends Middleware {
-    public readonly formFactory: () => IncomingForm;
+    protected abstract makeForm(): IncomingForm;
-    public readonly defaultField: string;
 
-    public constructor(formFactory: () => IncomingForm, defaultField: string) {
+    protected abstract getDefaultField(): string;
-        this.formFactory = formFactory;
+
-        this.defaultField = defaultField;
+    public async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
+        const form = this.makeForm();
+        try {
+            await new Promise<any>((resolve, reject) => {
+                form.parse(req, (err, fields, files) => {
+                    if (err) {
+                        reject(err);
+                        return;
+                    }
+                    req.body = fields;
+                    req.files = files;
+                    resolve();
+                });
+            });
+        } catch (e) {
+            const bag = new ValidationBag();
+            const fileError = new FileError(e);
+            fileError.thingName = this.getDefaultField();
+            bag.addMessage(fileError);
+            next(bag);
+            return;
+        }
+        next();
     }
 }

src/Middleware.ts

@@ -0,0 +1,28 @@
+import {RequestHandler} from "express";
+import {NextFunction, Request, Response} from "express-serve-static-core";
+import Application from "./Application";
+
+export default abstract class Middleware {
+    public constructor(
+        protected readonly app: Application,
+    ) {
+    }
+
+
+    protected abstract async handle(req: Request, res: Response, next: NextFunction): Promise<void>;
+
+    public getRequestHandler(): RequestHandler {
+        return async (req, res, next): Promise<void> => {
+            try {
+                if (req.middlewares.find(m => m.constructor === this.constructor)) {
+                    next();
+                } else {
+                    req.middlewares.push(this);
+                    return await this.handle(req, res, next);
+                }
+            } catch (e) {
+                next(e);
+            }
+        };
+    }
+}

src/auth/AuthComponent.ts

@@ -1,75 +1,111 @@
 import ApplicationComponent from "../ApplicationComponent";
-import {NextFunction, Request, Response, Router} from "express";
+import {NextFunction, Request, Response} from "express";
 import AuthGuard from "./AuthGuard";
 import Controller from "../Controller";
 import {ForbiddenHttpError} from "../HttpError";
+import Middleware from "../Middleware";
+import User from "./models/User";
+import AuthProof from "./AuthProof";
 
-export default class AuthComponent<T extends AuthGuard<any>> extends ApplicationComponent<void> {
+export default class AuthComponent extends ApplicationComponent {
-    private readonly authGuard: T;
+    private readonly authGuard: AuthGuard<AuthProof<User>>;
 
-    public constructor(authGuard: T) {
+    public constructor(authGuard: AuthGuard<AuthProof<User>>) {
         super();
         this.authGuard = authGuard;
     }
 
-    public async init(router: Router): Promise<void> {
+    public async init(): Promise<void> {
-        router.use(async (req, res, next) => {
+        this.use(AuthMiddleware);
-            req.authGuard = this.authGuard;
-            req.models.user = res.locals.user = await (await req.authGuard.getProof(req))?.getResource();
-            next();
-        });
     }
 
-    public getAuthGuard(): T {
+    public getAuthGuard(): AuthGuard<AuthProof<User>> {
         return this.authGuard;
     }
 }
 
-export const REQUIRE_REQUEST_AUTH_MIDDLEWARE = async (req: Request, res: Response, next: NextFunction): Promise<void> => {
+export class AuthMiddleware extends Middleware {
-    let proof = await req.authGuard.isAuthenticatedViaRequest(req);
+    private authGuard?: AuthGuard<AuthProof<User>>;
-    if (!proof) {
+    private user: User | null = null;
-        req.flash('error', `You must be logged in to access ${req.url}.`);
-        res.redirect(Controller.route('auth', undefined, {
-            redirect_uri: req.url,
-        }));
-        return;
-    }
 
-    next();
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
-};
+        this.authGuard = this.app.as(AuthComponent).getAuthGuard();
+
+        const proof = await this.authGuard.isAuthenticated(req.session!);
+        if (proof) {
+            this.user = await proof.getResource();
+            res.locals.user = this.user;
+        }
 
-export const REQUIRE_AUTH_MIDDLEWARE = async (req: Request, res: Response, next: NextFunction): Promise<void> => {
-    // Via request
-    let proof = await req.authGuard.isAuthenticatedViaRequest(req);
-    if (proof) {
         next();
-        return;
     }
 
-    // Via session
+    public getUser(): User | null {
-    proof = await req.authGuard.isAuthenticated(req.session!);
+        return this.user;
-    if (!proof) {
-        req.flash('error', `You must be logged in to access ${req.url}.`);
-        res.redirect(Controller.route('auth', undefined, {
-            redirect_uri: req.url,
-        }));
-        return;
     }
 
-    next();
+    public getAuthGuard(): AuthGuard<AuthProof<User>> {
-};
+        if (!this.authGuard) throw new Error('AuthGuard was not initialized.');
-export const REQUIRE_GUEST_MIDDLEWARE = async (req: Request, res: Response, next: NextFunction): Promise<void> => {
+        return this.authGuard;
-    if (await req.authGuard.isAuthenticated(req.session!)) {
-        res.redirectBack();
-        return;
     }
+}
 
-    next();
+export class RequireRequestAuthMiddleware extends Middleware {
-};
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
-export const REQUIRE_ADMIN_MIDDLEWARE = async (req: Request, res: Response, next: NextFunction): Promise<void> => {
+        const proof = await req.as(AuthMiddleware).getAuthGuard().isAuthenticatedViaRequest(req);
-    if (!req.models.user || !req.models.user.is_admin) {
+        if (!proof) {
-        throw new ForbiddenHttpError('secret tool', req.url);
+            req.flash('error', `You must be logged in to access ${req.url}.`);
+            res.redirect(Controller.route('auth', undefined, {
+                redirect_uri: req.url,
+            }));
+            return;
+        }
+
+        next();
     }
+}
 
-    next();
+export class RequireAuthMiddleware extends Middleware {
-};
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
+        const authGuard = req.as(AuthMiddleware).getAuthGuard();
+        // Via request
+
+        if (await authGuard.isAuthenticatedViaRequest(req)) {
+            next();
+            return;
+        }
+
+        // Via session
+        if (!await authGuard.isAuthenticated(req.session!)) {
+            req.flash('error', `You must be logged in to access ${req.url}.`);
+            res.redirect(Controller.route('auth', undefined, {
+                redirect_uri: req.url,
+            }));
+            return;
+        }
+
+        next();
+    }
+}
+
+export class RequireGuestMiddleware extends Middleware {
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
+        if (await req.as(AuthMiddleware).getAuthGuard().isAuthenticated(req.session!)) {
+            res.redirectBack();
+            return;
+        }
+
+        next();
+    }
+}
+
+export class RequireAdminMiddleware extends Middleware {
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
+        const user = req.as(AuthMiddleware).getUser();
+        if (!user || !user.is_admin) {
+            throw new ForbiddenHttpError('secret tool', req.url);
+        }
+
+        next();
+    }
+}

src/auth/AuthController.ts

@@ -1,6 +1,6 @@
 import Controller from "../Controller";
 import {NextFunction, Request, Response} from "express";
-import {REQUIRE_AUTH_MIDDLEWARE, REQUIRE_GUEST_MIDDLEWARE} from "./AuthComponent";
+import {AuthMiddleware, RequireAuthMiddleware, RequireGuestMiddleware} from "./AuthComponent";
 
 export default abstract class AuthController extends Controller {
     public getRoutesPrefix(): string {
@@ -8,10 +8,10 @@ export default abstract class AuthController extends Controller {
     }
 
     public routes() {
-        this.get('/', this.getAuth, 'auth', REQUIRE_GUEST_MIDDLEWARE);
+        this.get('/', this.getAuth, 'auth', RequireGuestMiddleware);
-        this.post('/', this.postAuth, 'auth', REQUIRE_GUEST_MIDDLEWARE);
+        this.post('/', this.postAuth, 'auth', RequireGuestMiddleware);
         this.get('/check', this.getCheckAuth, 'check_auth');
-        this.post('/logout', this.postLogout, 'logout', REQUIRE_AUTH_MIDDLEWARE);
+        this.post('/logout', this.postLogout, 'logout', RequireAuthMiddleware);
     }
 
     protected async getAuth(req: Request, res: Response, next: NextFunction): Promise<void> {
@@ -26,7 +26,7 @@ export default abstract class AuthController extends Controller {
     protected abstract async getCheckAuth(req: Request, res: Response, next: NextFunction): Promise<void>;
 
     protected async postLogout(req: Request, res: Response, next: NextFunction): Promise<void> {
-        const proof = await req.authGuard.getProof(req);
+        const proof = await req.as(AuthMiddleware).getAuthGuard().getProof(req);
         await proof?.revoke();
         req.flash('success', 'Successfully logged out.');
         res.redirect(req.query.redirect_uri?.toString() || '/');

src/auth/AuthGuard.ts

@@ -53,7 +53,7 @@ export default abstract class AuthGuard<P extends AuthProof<User>> {
         proof: P,
         onLogin?: (user: User) => Promise<void>,
         onRegister?: (connection: Connection, user: User) => Promise<RegisterCallback[]>
-    ): Promise<void> {
+    ): Promise<User> {
         if (!await proof.isValid()) throw new InvalidAuthProofError();
         if (!await proof.isAuthorized()) throw new UnauthorizedAuthProofError();
 
@@ -95,6 +95,8 @@ export default abstract class AuthGuard<P extends AuthProof<User>> {
         // Login
         session.is_authenticated = true;
         if (onLogin) await onLogin(user);
+
+        return user;
     }
 
 }

src/auth/magic_link/MagicLinkAuthController.ts

@@ -9,17 +9,19 @@ import {AuthError, PendingApprovalAuthError, RegisterCallback} from "../AuthGuar
 import geoip from "geoip-lite";
 import AuthController from "../AuthController";
 import RedirectBackComponent from "../../components/RedirectBackComponent";
+import {AuthMiddleware} from "../AuthComponent";
+import User from "../models/User";
 
 
 export default abstract class MagicLinkAuthController extends AuthController {
-    public static async checkAndAuth(req: Request, res: Response, magicLink: MagicLink): Promise<void> {
+    public static async checkAndAuth(req: Request, res: Response, magicLink: MagicLink): Promise<User | null> {
         if (magicLink.getSessionID() !== req.sessionID!) throw new BadOwnerMagicLink();
         if (!await magicLink.isAuthorized()) throw new UnauthorizedMagicLink();
         if (!await magicLink.isValid()) throw new InvalidMagicLink();
 
         // Auth
         try {
-            await req.authGuard.authenticateOrRegister(req.session!, magicLink, undefined, async (connection, user) => {
+            return await req.as(AuthMiddleware).getAuthGuard().authenticateOrRegister(req.session!, magicLink, undefined, async (connection, user) => {
                 const callbacks: RegisterCallback[] = [];
 
                 const userEmail = UserEmail.create({
@@ -46,7 +48,7 @@ export default abstract class MagicLinkAuthController extends AuthController {
                         res.redirect('/');
                     }
                 });
-                return;
+                return null;
             } else {
                 throw e;
             }
@@ -139,20 +141,21 @@ export default abstract class MagicLinkAuthController extends AuthController {
             return;
         }
 
-        await MagicLinkAuthController.checkAndAuth(req, res, magicLink);
+        const user = await MagicLinkAuthController.checkAndAuth(req, res, magicLink);
 
-        // Auth success
+        if (user) {
-        const username = req.models.user?.name;
+            // Auth success
-        res.format({
+            const username = user.name;
-            json: () => {
+            res.format({
-                res.json({'status': 'success', 'message': `Welcome, ${username}!`});
+                json: () => {
-            },
+                    res.json({'status': 'success', 'message': `Welcome, ${username}!`});
-            default: () => {
+                },
-                req.flash('success', `Authentication success. Welcome, ${username}!`);
+                default: () => {
-                res.redirect('/');
+                    req.flash('success', `Authentication success. Welcome, ${username}!`);
-            },
+                    res.redirect('/');
-        });
+                },
-        return;
+            });
+        }
     }
 }
 

src/components/AutoUpdateComponent.ts

@@ -5,7 +5,7 @@ import ApplicationComponent from "../ApplicationComponent";
 import {ForbiddenHttpError} from "../HttpError";
 import Logger from "../Logger";
 
-export default class AutoUpdateComponent extends ApplicationComponent<void> {
+export default class AutoUpdateComponent extends ApplicationComponent {
     public async checkSecuritySettings(): Promise<void> {
         this.checkSecurityConfigField('gitlab_webhook_token');
     }
@@ -39,7 +39,7 @@ export default class AutoUpdateComponent extends ApplicationComponent<void> {
             await this.runCommand(`yarn dist`);
 
             // Stop app
-            await this.app!.stop();
+            await this.getApp().stop();
 
             Logger.info('Success!');
         } catch (e) {

src/components/CsrfProtectionComponent.ts

@@ -2,8 +2,9 @@ import ApplicationComponent from "../ApplicationComponent";
 import {Request, Router} from "express";
 import crypto from "crypto";
 import {BadRequestError} from "../HttpError";
+import {AuthMiddleware} from "../auth/AuthComponent";
 
-export default class CsrfProtectionComponent extends ApplicationComponent<void> {
+export default class CsrfProtectionComponent extends ApplicationComponent {
     private static readonly excluders: ((req: Request) => boolean)[] = [];
 
     public static getCSRFToken(session: Express.Session): string {
@@ -33,18 +34,17 @@ export default class CsrfProtectionComponent extends ApplicationComponent<void>
 
             if (!['GET', 'HEAD', 'OPTIONS'].find(s => s === req.method)) {
                 try {
-                    if (!(await req.authGuard.isAuthenticatedViaRequest(req))) {
+                    if (!await req.as(AuthMiddleware).getAuthGuard().isAuthenticatedViaRequest(req)) {
                         if (req.session.csrf === undefined) {
-                            throw new InvalidCsrfTokenError(req.baseUrl, `You weren't assigned any CSRF token.`);
+                            return next(new InvalidCsrfTokenError(req.baseUrl, `You weren't assigned any CSRF token.`));
                         } else if (req.body.csrf === undefined) {
-                            throw new InvalidCsrfTokenError(req.baseUrl, `You didn't provide any CSRF token.`);
+                            return next(new InvalidCsrfTokenError(req.baseUrl, `You didn't provide any CSRF token.`));
                         } else if (req.session.csrf !== req.body.csrf) {
-                            throw new InvalidCsrfTokenError(req.baseUrl, `Tokens don't match.`);
+                            return next(new InvalidCsrfTokenError(req.baseUrl, `Tokens don't match.`));
                         }
                     }
                 } catch (e) {
-                    next(e);
+                    return next(e);
-                    return;
                 }
             }
             next();

src/components/ExpressAppComponent.ts

@@ -3,8 +3,10 @@ import express, {Express, Router} from "express";
 import Logger from "../Logger";
 import {Server} from "http";
 import compression from "compression";
+import Middleware from "../Middleware";
+import {Type} from "../Utils";
 
-export default class ExpressAppComponent extends ApplicationComponent<void> {
+export default class ExpressAppComponent extends ApplicationComponent {
     private readonly addr: string;
     private readonly port: number;
     private server?: Server;
@@ -39,8 +41,12 @@ export default class ExpressAppComponent extends ApplicationComponent<void> {
         router.use(compression());
 
         router.use((req, res, next) => {
-            req.models = {};
+            req.middlewares = [];
-            req.modelCollections = {};
+            req.as = <M extends Middleware>(type: Type<M>) => {
+                const middleware = req.middlewares.find(m => m.constructor === type);
+                if (!middleware) throw new Error('Middleware ' + type.name + ' not present in this request.');
+                return middleware as M;
+            };
             next();
         });
     }

src/components/FormHelperComponent.ts

@@ -1,7 +1,7 @@
 import ApplicationComponent from "../ApplicationComponent";
 import {Router} from "express";
 
-export default class FormHelperComponent extends ApplicationComponent<void> {
+export default class FormHelperComponent extends ApplicationComponent {
     public async init(router: Router): Promise<void> {
         router.use((req, res, next) => {
             if (!req.session) {

src/components/LogRequestsComponent.ts

@@ -3,7 +3,7 @@ import onFinished from "on-finished";
 import Logger from "../Logger";
 import {Request, Response, Router} from "express";
 
-export default class LogRequestsComponent extends ApplicationComponent<void> {
+export default class LogRequestsComponent extends ApplicationComponent {
     private static fullRequests: boolean = false;
 
     public static logFullHttpRequests() {

src/components/MailComponent.ts

@@ -4,8 +4,7 @@ import Mail from "../Mail";
 import config from "config";
 import SecurityError from "../SecurityError";
 
-export default class MailComponent extends ApplicationComponent<void> {
+export default class MailComponent extends ApplicationComponent {
-
 
     public async checkSecuritySettings(): Promise<void> {
         if (!config.get<boolean>('mail.secure')) {

src/components/MaintenanceComponent.ts

@@ -4,7 +4,7 @@ import {ServiceUnavailableHttpError} from "../HttpError";
 import Application from "../Application";
 import config from "config";
 
-export default class MaintenanceComponent extends ApplicationComponent<void> {
+export default class MaintenanceComponent extends ApplicationComponent {
     private readonly application: Application;
     private readonly canServe: () => boolean;
 

src/components/MysqlComponent.ts

@@ -2,7 +2,7 @@ import ApplicationComponent from "../ApplicationComponent";
 import {Express} from "express";
 import MysqlConnectionManager from "../db/MysqlConnectionManager";
 
-export default class MysqlComponent extends ApplicationComponent<void> {
+export default class MysqlComponent extends ApplicationComponent {
     public async start(app: Express): Promise<void> {
         await this.prepare('Mysql connection', () => MysqlConnectionManager.prepare());
     }
@@ -12,7 +12,7 @@ export default class MysqlComponent extends ApplicationComponent<void> {
     }
 
     public canServe(): boolean {
-        return MysqlConnectionManager.pool !== undefined;
+        return MysqlConnectionManager.isReady();
     }
 
 }

src/components/NunjucksComponent.ts

@@ -1,6 +1,6 @@
 import nunjucks, {Environment} from "nunjucks";
 import config from "config";
-import {Express, Router} from "express";
+import {Express, NextFunction, Request, Response, Router} from "express";
 import ApplicationComponent from "../ApplicationComponent";
 import Controller from "../Controller";
 import {ServerError} from "../HttpError";
@@ -8,8 +8,11 @@ import * as querystring from "querystring";
 import {ParsedUrlQueryInput} from "querystring";
 import * as util from "util";
 import * as path from "path";
+import * as fs from "fs";
+import Logger from "../Logger";
+import Middleware from "../Middleware";
 
-export default class NunjucksComponent extends ApplicationComponent<void> {
+export default class NunjucksComponent extends ApplicationComponent {
     private readonly viewsPath: string[];
     private env?: Environment;
 
@@ -20,13 +23,14 @@ export default class NunjucksComponent extends ApplicationComponent<void> {
 
     public async start(app: Express): Promise<void> {
         let coreVersion = 'unknown';
+        const file = fs.existsSync(path.join(__dirname, '../../package.json')) ?
+            path.join(__dirname, '../../package.json') :
+            path.join(__dirname, '../package.json');
+
         try {
-            coreVersion = require('../../package.json').version;
+            coreVersion = JSON.parse(fs.readFileSync(file).toString()).version;
         } catch (e) {
-            try {
+            Logger.warn('Couldn\'t determine coreVersion.', e);
-                coreVersion = require('../package.json').version;
-            } catch (e) {
-            }
         }
 
         this.env = new nunjucks.Environment([
@@ -43,7 +47,7 @@ export default class NunjucksComponent extends ApplicationComponent<void> {
                 if (path === null) throw new ServerError(`Route ${route} not found.`);
                 return path;
             })
-            .addGlobal('app_version', this.app!.getVersion())
+            .addGlobal('app_version', this.getApp().getVersion())
             .addGlobal('core_version', coreVersion)
             .addGlobal('querystring', querystring)
             .addGlobal('app', config.get('app'))
@@ -59,18 +63,29 @@ export default class NunjucksComponent extends ApplicationComponent<void> {
     }
 
     public async init(router: Router): Promise<void> {
-        router.use((req, res, next) => {
+        this.use(NunjucksMiddleware);
-            req.env = this.env!;
-            res.locals.url = req.url;
-            res.locals.params = req.params;
-            res.locals.query = req.query;
-            res.locals.body = req.body;
-
-            next();
-        });
     }
 
     public getEnv(): Environment | undefined {
         return this.env;
     }
 }
+
+export class NunjucksMiddleware extends Middleware {
+    private env?: Environment;
+
+    protected async handle(req: Request, res: Response, next: NextFunction): Promise<void> {
+        this.env = this.app.as(NunjucksComponent).getEnv();
+        res.locals.url = req.url;
+        res.locals.params = req.params;
+        res.locals.query = req.query;
+        res.locals.body = req.body;
+
+        next();
+    }
+
+    public getEnvironment(): Environment {
+        if (!this.env) throw new Error('Environment not initialized.');
+        return this.env;
+    }
+}

src/components/RedirectBackComponent.ts

@@ -4,7 +4,7 @@ import {ServerError} from "../HttpError";
 import onFinished from "on-finished";
 import Logger from "../Logger";
 
-export default class RedirectBackComponent extends ApplicationComponent<void> {
+export default class RedirectBackComponent extends ApplicationComponent {
     public static getPreviousURL(req: Request, defaultUrl?: string): string | undefined {
         return req.session?.previousUrl || defaultUrl;
     }

src/components/RedisComponent.ts

@@ -9,7 +9,7 @@ import CacheProvider from "../CacheProvider";
 
 const RedisStore = connect_redis(session);
 
-export default class RedisComponent extends ApplicationComponent<void> implements CacheProvider {
+export default class RedisComponent extends ApplicationComponent implements CacheProvider {
     private redisClient?: RedisClient;
     private store?: Store;
 

src/components/ServeStaticDirectoryComponent.ts

@@ -3,7 +3,7 @@ import express, {Router} from "express";
 import {PathParams} from "express-serve-static-core";
 import * as path from "path";
 
-export default class ServeStaticDirectoryComponent extends ApplicationComponent<void> {
+export default class ServeStaticDirectoryComponent extends ApplicationComponent {
     private readonly root: string;
     private readonly path?: PathParams;
 

src/components/SessionComponent.ts

@@ -6,7 +6,7 @@ import flash from "connect-flash";
 import {Router} from "express";
 import SecurityError from "../SecurityError";
 
-export default class SessionComponent extends ApplicationComponent<void> {
+export default class SessionComponent extends ApplicationComponent {
     private readonly storeComponent: RedisComponent;
 
     public constructor(storeComponent: RedisComponent) {

src/components/WebSocketServerComponent.ts

@@ -11,7 +11,7 @@ import RedisComponent from "./RedisComponent";
 import WebSocketListener from "../WebSocketListener";
 import NunjucksComponent from "./NunjucksComponent";
 
-export default class WebSocketServerComponent extends ApplicationComponent<void> {
+export default class WebSocketServerComponent extends ApplicationComponent {
     private wss?: WebSocket.Server;
 
     constructor(

src/db/Model.ts

@@ -7,8 +7,9 @@ import ModelFactory from "./ModelFactory";
 import ModelRelation from "./ModelRelation";
 import ModelQuery, {ModelQueryResult, SelectFields} from "./ModelQuery";
 import {Request} from "express";
+import Extendable from "../Extendable";
 
-export default abstract class Model {
+export default abstract class Model implements Extendable<ModelComponent<Model>> {
     public static get table(): string {
         return this.name
                 .replace(/(?:^|\.?)([A-Z])/g, (x, y) => '_' + y.toLowerCase())
@@ -44,14 +45,14 @@ export default abstract class Model {
         return ModelFactory.get(this).paginate(request, perPage, query);
     }
 
-    protected readonly _factory: ModelFactory<any>;
+    protected readonly _factory: ModelFactory<Model>;
-    private readonly _components: ModelComponent<any>[] = [];
+    private readonly _components: ModelComponent<this>[] = [];
-    private readonly _validators: { [key: string]: Validator<any> } = {};
+    private readonly _validators: { [key: string]: Validator<any> | undefined } = {};
     private _exists: boolean;
 
     [key: string]: any;
 
-    public constructor(factory: ModelFactory<any>, isNew: boolean) {
+    public constructor(factory: ModelFactory<Model>, isNew: boolean) {
         if (!factory || !(factory instanceof ModelFactory)) throw new Error('Cannot instantiate model directly.');
         this._factory = factory;
         this.init();
@@ -71,15 +72,26 @@ export default abstract class Model {
         this._components.push(modelComponent);
     }
 
-    public as<T extends ModelComponent<any>>(type: Type<T>): T {
+    public as<C extends ModelComponent<Model>>(type: Type<C>): C {
         for (const component of this._components) {
             if (component instanceof type) {
-                return <any>this;
+                return this as unknown as C;
             }
         }
+
         throw new Error(`Component ${type.name} was not initialized for this ${this.constructor.name}.`);
     }
 
+    public asOptional<C extends ModelComponent<Model>>(type: Type<C>): C | null {
+        for (const component of this._components) {
+            if (component instanceof type) {
+                return this as unknown as C;
+            }
+        }
+
+        return null;
+    }
+
     public updateWithData(data: any) {
         for (const property of this._properties) {
             if (data[property] !== undefined) {
@@ -92,19 +104,16 @@ export default abstract class Model {
      * Override this to automatically fill obvious missing data i.e. from relation or default value that are fetched
      * asynchronously.
      */
-    protected async autoFill(): Promise<void> {
+    protected async autoFill?(): Promise<void>;
-    }
 
-    protected async beforeSave(connection: Connection): Promise<void> {
+    protected async beforeSave?(connection: Connection): Promise<void>;
-    }
 
-    protected async afterSave(): Promise<void> {
+    protected async afterSave?(): Promise<void>;
-    }
 
     public async save(connection?: Connection, postHook?: (callback: () => Promise<void>) => void): Promise<void> {
         if (connection && !postHook) throw new Error('If connection is provided, postHook must be provided too.');
 
-        await this.autoFill();
+        await this.autoFill?.();
         await this.validate(false, connection);
 
         const needs_full_update = connection ?
@@ -120,7 +129,7 @@ export default abstract class Model {
                 this.updateWithData(result.results[0]);
             }
 
-            await this.afterSave();
+            await this.afterSave?.();
         };
 
         if (connection) {
@@ -132,7 +141,7 @@ export default abstract class Model {
 
     private async saveTransaction(connection: Connection): Promise<boolean> {
         // Before save
-        await this.beforeSave(connection);
+        await this.beforeSave?.(connection);
         if (!this.exists() && this.hasOwnProperty('created_at')) {
             this.created_at = new Date();
         }

src/db/ModelComponent.ts

@@ -13,7 +13,7 @@ export default abstract class ModelComponent<T extends Model> {
     }
 
     public applyToModel(): void {
-        this.init();
+        this.init?.();
 
         for (const property of this._properties) {
             if (!property.startsWith('_')) {
@@ -32,7 +32,7 @@ export default abstract class ModelComponent<T extends Model> {
         }
     }
 
-    protected abstract init(): void;
+    protected init?(): void;
 
     protected setValidation<V>(propertyName: keyof this): Validator<V> {
         const validator = new Validator<V>();

src/db/MysqlConnectionManager.ts

@@ -21,6 +21,10 @@ export default class MysqlConnectionManager {
     private static migrationsRegistered: boolean = false;
     private static readonly migrations: Migration[] = [];
 
+    public static isReady(): boolean {
+        return this.databaseReady && this.currentPool !== undefined;
+    }
+
     public static registerMigrations(migrations: Type<Migration>[]) {
         if (!this.migrationsRegistered) {
             this.migrationsRegistered = true;

src/helpers/BackendController.ts

@@ -1,6 +1,5 @@
 import config from "config";
 import Controller from "../Controller";
-import {REQUIRE_ADMIN_MIDDLEWARE, REQUIRE_AUTH_MIDDLEWARE} from "../auth/AuthComponent";
 import User from "../auth/models/User";
 import {Request, Response} from "express";
 import {BadRequestError, NotFoundHttpError} from "../HttpError";
@@ -8,6 +7,7 @@ import Mail from "../Mail";
 import {ACCOUNT_REVIEW_NOTICE_MAIL_TEMPLATE} from "../Mails";
 import UserEmail from "../auth/models/UserEmail";
 import UserApprovedComponent from "../auth/models/UserApprovedComponent";
+import {RequireAdminMiddleware, RequireAuthMiddleware} from "../auth/AuthComponent";
 
 export default class BackendController extends Controller {
     private static readonly menu: BackendMenuElement[] = [];
@@ -37,11 +37,11 @@ export default class BackendController extends Controller {
     }
 
     public routes(): void {
-        this.get('/', this.getIndex, 'backend', REQUIRE_AUTH_MIDDLEWARE, REQUIRE_ADMIN_MIDDLEWARE);
+        this.get('/', this.getIndex, 'backend', RequireAuthMiddleware, RequireAdminMiddleware);
         if (User.isApprovalMode()) {
-            this.get('/accounts-approval', this.getAccountApproval, 'accounts-approval', REQUIRE_AUTH_MIDDLEWARE, REQUIRE_ADMIN_MIDDLEWARE);
+            this.get('/accounts-approval', this.getAccountApproval, 'accounts-approval', RequireAuthMiddleware, RequireAdminMiddleware);
-            this.post('/accounts-approval/approve', this.postApproveAccount, 'approve-account', REQUIRE_AUTH_MIDDLEWARE, REQUIRE_ADMIN_MIDDLEWARE);
+            this.post('/accounts-approval/approve', this.postApproveAccount, 'approve-account', RequireAuthMiddleware, RequireAdminMiddleware);
-            this.post('/accounts-approval/reject', this.postRejectAccount, 'reject-account', REQUIRE_AUTH_MIDDLEWARE, REQUIRE_ADMIN_MIDDLEWARE);
+            this.post('/accounts-approval/reject', this.postRejectAccount, 'reject-account', RequireAuthMiddleware, RequireAdminMiddleware);
         }
     }
 

src/types/Express.d.ts

@@ -1,21 +1,18 @@
-import {Environment} from "nunjucks";
-import Model from "../db/Model";
-import AuthGuard from "../auth/AuthGuard";
 import {Files} from "formidable";
-import User from "../auth/models/User";
+import {Type} from "../Utils";
+import Middleware from "../Middleware";
 
 declare global {
     namespace Express {
         export interface Request {
-            env: Environment;
-            models: {
-                user?: User | null,
-                [p: string]: Model | null | undefined,
-            };
-            modelCollections: { [p: string]: Model[] | null };
-            authGuard: AuthGuard<any>;
             files: Files;
 
+
+            middlewares: Middleware[];
+
+            as<M extends Middleware>(type: Type<M>): M;
+
+
             flash(): { [key: string]: string[] };
 
             flash(message: string): any;