Give the redirectBack function its own Component back

src/auth/magic_link/MagicLinkAuthController.ts

@@ -9,6 +9,7 @@ import {AuthError, PendingApprovalAuthError, RegisterCallback} from "../AuthGuar
 import geoip from "geoip-lite";
 import AuthController from "../AuthController";
 import NunjucksComponent from "../../components/NunjucksComponent";
+import RedirectBackComponent from "../../components/RedirectBackComponent";
 
 
 export default abstract class MagicLinkAuthController extends AuthController {
@@ -109,7 +110,7 @@ export default abstract class MagicLinkAuthController extends AuthController {
             );
 
             res.redirect(Controller.route('magic_link_lobby', undefined, {
-                redirect_uri: req.query.redirect_uri?.toString() || NunjucksComponent.getPreviousURL(req),
+                redirect_uri: req.query.redirect_uri?.toString() || RedirectBackComponent.getPreviousURL(req),
             }));
         } else {
             // Confirm registration req

src/components/NunjucksComponent.ts

@@ -1,6 +1,6 @@
 import nunjucks, {Environment} from "nunjucks";
 import config from "config";
-import {Express, Request, Router} from "express";
+import {Express, Router} from "express";
 import ApplicationComponent from "../ApplicationComponent";
 import Controller from "../Controller";
 import {ServerError} from "../HttpError";
@@ -9,13 +9,6 @@ import {ParsedUrlQueryInput} from "querystring";
 import * as util from "util";
 
 export default class NunjucksComponent extends ApplicationComponent<void> {
-    public static getPreviousURL(req: Request, defaultUrl?: string): string {
-        let referrer = req.headers.referer?.toString() || req.headers.referrer?.toString() || defaultUrl || '/';
-        if (referrer.startsWith('https://') || referrer.startsWith('http://')) return '/';
-        else if (!referrer.startsWith('/')) referrer = req.url + (req.url.endsWith('/') ? '' : '/') + referrer;
-        return referrer;
-    }
-
     private readonly viewsPath: string;
     private env?: Environment;
 
@@ -72,14 +65,6 @@ export default class NunjucksComponent extends ApplicationComponent<void> {
 
             res.locals.app = config.get('app');
 
-            // Redirect back
-            res.redirectBack = (defaultUrl?: string) => {
-                res.redirect(NunjucksComponent.getPreviousURL(req, defaultUrl));
-            };
-            res.locals.getPreviousURL = (defaultURL?: string) => {
-                return NunjucksComponent.getPreviousURL(req, defaultURL);
-            };
-
             next();
         });
     }

src/components/RedirectBackComponent.ts

@@ -0,0 +1,42 @@
+import ApplicationComponent from "../ApplicationComponent";
+import {Request, Router} from "express";
+import {ServerError} from "../HttpError";
+import onFinished from "on-finished";
+import Logger from "../Logger";
+
+export default class RedirectBackComponent extends ApplicationComponent<void> {
+    public static getPreviousURL(req: Request, defaultUrl?: string): string | undefined {
+        return req.session?.previousUrl || defaultUrl;
+    }
+
+    public async handle(router: Router): Promise<void> {
+        router.use((req, res, next) => {
+            res.redirectBack = (defaultUrl?: string) => {
+                const previousUrl = RedirectBackComponent.getPreviousURL(req, defaultUrl);
+                if (!previousUrl) throw new ServerError(`Couldn't redirect you back.`);
+                res.redirect(previousUrl);
+            };
+
+            res.locals.getPreviousURL = (defaultUrl?: string) => {
+                return RedirectBackComponent.getPreviousURL(req, defaultUrl);
+            };
+
+            onFinished(res, (err) => {
+                if (req.session) {
+                    const contentType = (res.getHeaders())['content-type'];
+                    if (!err && res.statusCode === 200 && (contentType && typeof contentType !== 'number' && contentType.indexOf('text/html') >= 0)) {
+                        req.session!.previousUrl = req.originalUrl;
+                        Logger.debug('Prev url set to', req.session!.previousUrl);
+                        req.session!.save((err) => {
+                            if (err) {
+                                Logger.error(err, 'Error while saving session');
+                            }
+                        });
+                    }
+                }
+            });
+
+            next();
+        });
+    }
+}

test/_app.ts

@@ -14,6 +14,7 @@ import AuthComponent from "../src/auth/AuthComponent";
 import AuthGuard from "../src/auth/AuthGuard";
 import MagicLink from "../src/auth/models/MagicLink";
 import FormHelperComponent from "../src/components/FormHelperComponent";
+import RedirectBackComponent from "../src/components/RedirectBackComponent";
 
 export default function useApp(appSupplier?: (port: number) => TestApp) {
     let app: Application;
@@ -61,6 +62,7 @@ export class TestApp extends Application {
         // Base
         this.use(new NunjucksComponent('test/views'));
         this.use(new LogRequestsComponent());
+        this.use(new RedirectBackComponent());
 
         // Services
         this.use(mysqlComponent);