fix(connection): keep the Happ add-subscription button working on Remnawave 2.8.0

Panel 2.8.0 removed the server-side happ-encrypt endpoint, so for users
without a stored crypto link the backend leaves {{HAPP_CRYPT4_LINK}}
unresolved and the subscriptionLink button silently disappeared
(isValidDeepLink requires '://').

- BlockButtons: resolve button templates client-side at render (with username,
  like the panel's own subpage) instead of dropping the button; collapse
  double-prefixed happ://crypt4/happ://cryptN/... resolvedUrl from old backends
- templateEngine: collapse a hardcoded happ://cryptN/ prefix before
  {{HAPP_CRYPT[34]_LINK}}; cache crypt-link generation (jsencrypt RSA-4096 is
  slow on weak devices and re-randomizes every call)
- Connection: in happ_cryptolink mode force the crypt link only when the button
  fell back to the plain subscription link or kept unresolved templates - an
  explicit Subpage link (e.g. happ://add/...) now wins, so Subpage edits apply

src/components/connection/InstallationGuide.tsx

@@ -48,6 +48,7 @@ interface Props {
   isTelegramWebApp: boolean;
   onGoBack: () => void;
   onOpenQR?: () => void;
+  username?: string;
 }
 
 export default function InstallationGuide({
@@ -56,6 +57,7 @@ export default function InstallationGuide({
   isTelegramWebApp,
   onGoBack,
   onOpenQR,
+  username,
 }: Props) {
   const { t, i18n } = useTranslation();
   const { isLight } = useTheme();
@@ -131,6 +133,7 @@ export default function InstallationGuide({
         subscriptionUrl={appConfig.subscriptionUrl}
         hideLink={appConfig.hideLink}
         deepLink={selectedApp?.deepLink}
+        username={username}
         getLocalizedText={getLocalizedText}
         getBaseTranslation={getBaseTranslation}
         getSvgHtml={getSvgHtml}
@@ -141,6 +144,7 @@ export default function InstallationGuide({
       appConfig.subscriptionUrl,
       appConfig.hideLink,
       selectedApp?.deepLink,
+      username,
       isLight,
       getLocalizedText,
       getBaseTranslation,

src/components/connection/blocks/BlockButtons.tsx

@@ -3,6 +3,7 @@ import { useTranslation } from 'react-i18next';
 import { CheckIcon, CopyIcon } from '@/components/icons';
 import type { RemnawaveButtonClient, LocalizedText } from '@/types';
 import { copyToClipboard } from '@/utils/clipboard';
+import { collapseDoubledCryptPrefix, hasTemplates, resolveTemplate } from '@/utils/templateEngine';
 import { blockButtonClass } from './buttonStyles';
 
 // eslint-disable-next-line no-script-url
@@ -29,6 +30,7 @@ interface BlockButtonsProps {
   subscriptionUrl: string | null;
   hideLink?: boolean;
   deepLink?: string | null;
+  username?: string;
   getLocalizedText: (text: LocalizedText | undefined) => string;
   getBaseTranslation: (key: string, i18nKey: string) => string;
   getSvgHtml: (key: string | undefined) => string;
@@ -42,6 +44,7 @@ export function BlockButtons({
   subscriptionUrl,
   hideLink,
   deepLink,
+  username,
   getLocalizedText,
   getBaseTranslation,
   getSvgHtml,
@@ -73,8 +76,17 @@ export function BlockButtons({
         ) : null;
 
         if (btn.type === 'subscriptionLink') {
-          const url = btn.resolvedUrl || btn.url || btn.link || deepLink || subscriptionUrl;
+          const raw = btn.resolvedUrl || btn.url || btn.link || deepLink || subscriptionUrl;
-          if (!url || !isValidDeepLink(url)) return null;
+          // The backend resolves {{HAPP_CRYPT*_LINK}} only when a crypto link is
+          // stored in the DB; since Remnawave 2.8.0 removed the encrypt endpoint,
+          // new users can get the raw template here. Resolve it client-side (the
+          // panel's own subpage does the same) instead of dropping the button.
+          const resolved =
+            raw && subscriptionUrl && hasTemplates(raw)
+              ? resolveTemplate(raw, { subscriptionUrl, username })
+              : raw;
+          const url = resolved ? collapseDoubledCryptPrefix(resolved) : resolved;
+          if (!url || hasTemplates(url) || !isValidDeepLink(url)) return null;
           return (
             <button
               key={idx}

src/pages/Connection.tsx

@@ -114,12 +114,20 @@ export default function Connection() {
   const openDeepLink = useCallback(
     (deepLink: string) => {
       let resolved = deepLink;
-      if (isHappCryptolinkMode(connectionLink?.connect_mode) && qrConnectionUrl) {
+      if (hasTemplates(resolved)) {
-        // In HAPP cryptolink mode always open the resolved happ://crypt... URL.
-        resolved = qrConnectionUrl;
-      } else if (hasTemplates(resolved)) {
         resolved = resolveUrl(resolved);
       }
+      // In HAPP cryptolink mode keep hiding the plain subscription link: force the
+      // happ://crypt... URL only when the button fell back to it or its template
+      // could not be resolved. An explicit link from the panel's Subpage config
+      // (e.g. happ://add/...) wins — admins expect Subpage edits to apply here.
+      if (
+        isHappCryptolinkMode(connectionLink?.connect_mode) &&
+        qrConnectionUrl &&
+        (!resolved || resolved === appConfig?.subscriptionUrl || hasTemplates(resolved))
+      ) {
+        resolved = qrConnectionUrl;
+      }
       const isHttpUrl = /^https?:\/\//i.test(resolved);
       const finalUrlForTelegram = isHttpUrl
         ? resolved
@@ -140,7 +148,14 @@ export default function Connection() {
       // still navigate normally. (Telegram bug #654272.)
       openAppScheme(resolved);
     },
-    [isTelegramWebApp, i18n.language, resolveUrl, connectionLink?.connect_mode, qrConnectionUrl],
+    [
+      isTelegramWebApp,
+      i18n.language,
+      resolveUrl,
+      connectionLink?.connect_mode,
+      qrConnectionUrl,
+      appConfig?.subscriptionUrl,
+    ],
   );
 
   // Check if any platform has configured apps
@@ -217,6 +232,7 @@ export default function Connection() {
       isTelegramWebApp={isTelegramWebApp}
       onGoBack={handleGoBack}
       onOpenQR={handleOpenQR}
+      username={user?.username ?? undefined}
     />
   );
 }

src/utils/templateEngine.ts

@@ -6,6 +6,31 @@ export function hasTemplates(url: string): boolean {
   return TEMPLATE_RE.test(url);
 }
 
+/**
+ * Old bot backends resolve prefix-hardcoded Subpage templates
+ * (happ://crypt4/{{HAPP_CRYPT4_LINK}}) into happ://crypt4/happ://cryptN/... —
+ * strip the outer prefix so the deep link stays openable.
+ */
+export function collapseDoubledCryptPrefix(url: string): string {
+  return url.replace(/^happ:\/\/crypt\d+\/(?=happ:\/\/crypt)/i, '');
+}
+
+// jsencrypt's RSA-4096 takes up to tens of ms on weak devices and its padding is
+// random (a new string every call) — cache per subscription URL so render-time
+// resolution is cheap and stable within a session. Any single ciphertext is valid.
+const cryptLinkCache = new Map<string, string | null>();
+
+function cachedHappCryptoLink(url: string, version: 'v3' | 'v4'): string | null {
+  const key = `${version}|${url}`;
+  let link = cryptLinkCache.get(key);
+  if (link === undefined) {
+    if (cryptLinkCache.size >= 100) cryptLinkCache.clear();
+    link = createHappCryptoLink(url, version, true);
+    cryptLinkCache.set(key, link);
+  }
+  return link;
+}
+
 interface ResolveContext {
   subscriptionUrl: string;
   username?: string;
@@ -14,6 +39,11 @@ interface ResolveContext {
 export function resolveTemplate(template: string, ctx: ResolveContext): string {
   let result = template;
 
+  // {{HAPP_CRYPT*_LINK}} resolves to a FULL happ://crypt.../ deep link; when the
+  // template also hardcodes the prefix (happ://crypt4/{{HAPP_CRYPT4_LINK}}),
+  // collapse it so we don't produce happ://crypt4/happ://crypt5/...
+  result = result.replace(/happ:\/\/crypt\d+\/(?=\{\{HAPP_CRYPT[34]_LINK\}\})/gi, '');
+
   result = result.replace(/\{\{SUBSCRIPTION_LINK\}\}/g, ctx.subscriptionUrl);
 
   if (ctx.username) {
@@ -21,11 +51,11 @@ export function resolveTemplate(template: string, ctx: ResolveContext): string {
   }
 
   result = result.replace(/\{\{HAPP_CRYPT3_LINK\}\}/g, () => {
-    return createHappCryptoLink(ctx.subscriptionUrl, 'v3', true) ?? ctx.subscriptionUrl;
+    return cachedHappCryptoLink(ctx.subscriptionUrl, 'v3') ?? ctx.subscriptionUrl;
   });
 
   result = result.replace(/\{\{HAPP_CRYPT4_LINK\}\}/g, () => {
-    return createHappCryptoLink(ctx.subscriptionUrl, 'v4', true) ?? ctx.subscriptionUrl;
+    return cachedHappCryptoLink(ctx.subscriptionUrl, 'v4') ?? ctx.subscriptionUrl;
   });
 
   return result;