web: detect deep links in flow interface and redirect locally

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

web/src/flows/FlowExecutor.ts

@@ -40,6 +40,9 @@ import { ifDefined } from "lit-html/directives/if-defined";
 import { until } from "lit-html/directives/until";
 import { TITLE_SUFFIX } from "../elements/router/RouterOutlet";
 import { AccessDeniedChallenge } from "./access_denied/FlowAccessDenied";
+import { getQueryVariables } from "./utils";
+
+export const NEXT_ARG = "next";
 
 @customElement("ak-flow-executor")
 export class FlowExecutor extends LitElement implements StageHost {
@@ -123,6 +126,14 @@ export class FlowExecutor extends LitElement implements StageHost {
     }
 
     firstUpdated(): void {
+        // Check if there is a ?next arg and save it
+        // this is used for deep linking, if a user tries to access an application,
+        // but needs to authenticate first
+        const queryVars = getQueryVariables();
+        if (NEXT_ARG in queryVars) {
+            const next = queryVars[NEXT_ARG];
+            localStorage.setItem(NEXT_ARG, next);
+        }
         new RootApi(DEFAULT_CONFIG).rootConfigList().then((config) => {
             this.config = config;
         });
@@ -171,7 +182,12 @@ export class FlowExecutor extends LitElement implements StageHost {
         switch (this.challenge.type) {
             case ChallengeTypeEnum.Redirect:
                 console.debug(`authentik/flows: redirecting to ${(this.challenge as RedirectChallenge).to}`);
-                window.location.assign((this.challenge as RedirectChallenge).to);
+                if (localStorage.getItem(NEXT_ARG) === null) {
+                    window.location.assign((this.challenge as RedirectChallenge).to);
+                } else {
+                    localStorage.clear();
+                    window.location.assign(localStorage.getItem(NEXT_ARG) || "");
+                }
                 return this.renderLoading();
             case ChallengeTypeEnum.Shell:
                 return html`${unsafeHTML((this.challenge as ShellChallenge).body)}`;

web/src/flows/utils.ts

@@ -0,0 +1,10 @@
+export function getQueryVariables(): Record<string, string> {
+    const query = window.location.search.substring(1);
+    const vars = query.split("&");
+    const entries: Record<string, string> = {};
+    for (let i = 0; i < vars.length; i++) {
+        const pair = vars[i].split("=");
+        entries[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
+    }
+    return entries;
+}