Use kcContext.client.baseUrl and fallback to redirect_url origin

Author: garronej

src/login/KcContext.ts

@@ -7,6 +7,9 @@ export type KcContextExtension = {
     properties: Record<KcEnvName, string> & {};
     // NOTE: Here you can declare more properties to extend the KcContext
     // See: https://docs.keycloakify.dev/faq-and-help/some-values-you-need-are-missing-from-in-kccontext
+    client: {
+        baseUrl?: string;
+    };
 };
 
 export type KcContextExtensionPerPage = {};

src/login/KcPageStory.tsx

@@ -9,6 +9,9 @@ const kcContextExtension: KcContextExtension = {
     themeName: themeNames[0],
     properties: {
         ...kcEnvDefaults
+    },
+    client: {
+        baseUrl: "https://my-theme.keycloakify.dev"
     }
 };
 const kcContextExtensionPerPage: KcContextExtensionPerPage = {};

src/login/Template.tsx

@@ -8,7 +8,7 @@ import { useInitialize } from "keycloakify/login/Template.useInitialize";
 import type { I18n } from "./i18n";
 import type { KcContext } from "./KcContext";
 import { Header as DsfrHeader } from "@codegouvfr/react-dsfr/Header";
-import { getReferrerUrl } from "./shared/getReferrerUrl";
+import { redirectUrlOrigin } from "./shared/redirectUriOrigin";
 import { headerFooterDisplayItem } from "@codegouvfr/react-dsfr/Display";
 import { Footer as DSFRFooter } from "@codegouvfr/react-dsfr/Footer";
 import { Alert } from "@codegouvfr/react-dsfr/Alert";
@@ -77,7 +77,7 @@ export default function Template(props: Props) {
                     />
                 }
                 homeLinkProps={{
-                    href: getReferrerUrl(),
+                    href: kcContext.client.baseUrl ?? redirectUrlOrigin,
                     title: kcContext.realm.displayName
                 }}
                 serviceTitle={

src/login/shared/getReferrerUrl.ts

@@ -0,0 +1,36 @@
+
+
+const SESSION_STORAGE_KEY = "keycloak-theme-dsfr:redirectUriOrigin";
+
+export const redirectUrlOrigin = ((): string =>{
+    from_url: {
+        const url = new URL(window.location.href);
+
+        const value = url.searchParams.get("redirect_url");
+
+        if (value === null) {
+            // There was no &dark= query param in the URL,
+            // so we check session storage next.
+            break from_url;
+        }
+
+
+        const redirectUriOrigin = new URL(value).origin;
+
+        sessionStorage.setItem(SESSION_STORAGE_KEY, redirectUriOrigin);
+
+        return redirectUriOrigin;
+    }
+
+    from_session_storage: {
+        const redirectUriOrigin = sessionStorage.getItem(SESSION_STORAGE_KEY);
+
+        if (redirectUriOrigin === null) {
+            break from_session_storage;
+        }
+
+        return redirectUriOrigin;
+    }
+
+    return "#";
+})();