feat(sub): Add XHTTP session field compatibility in share links and subscriptions (#5929)

* ✨ Add sessionKey and sessionPlacement compatability for previous clients

* ✨ Add sessionKey and sessionPlacement compatability for previous clients on backend

frontend/src/lib/xray/inbound-link.ts

@@ -42,8 +42,7 @@ function xhttpHostFallback(xhttp: XHttpStreamSettings | undefined): string {
 // Pull the bidirectional SplitHTTPConfig fields out of xhttp into a
 // compact extra payload. Server-only fields (noSSEHeader, scMaxBufferedPosts,
 // scStreamUpServerSecs, serverMaxHeaderBytes) are excluded — the client
-// reading the share link wouldn't honor them. Mirrors the legacy
-// Inbound.buildXhttpExtra exactly so the shadow link snapshots line up.
+// reading the share link wouldn't honor them.
 function buildXhttpExtra(xhttp: XHttpStreamSettings | undefined): Record<string, unknown> | null {
   if (!xhttp) return null;
   const extra: Record<string, unknown> = {};
@@ -85,6 +84,15 @@ function buildXhttpExtra(xhttp: XHttpStreamSettings | undefined): Record<string,
     const v = xhttp[k];
     if (typeof v === 'string' && v.length > 0 && v !== coreDefaults[k]) extra[k] = v;
   }
+  // xray-core #6258 renamed these fields, but older clients still read the
+  // legacy names from share-link extra. Emit both names so one link works
+  // across old and new clients while the stored panel config stays canonical.
+  if (typeof extra.sessionIDPlacement === 'string') {
+    extra.sessionPlacement = extra.sessionIDPlacement;
+  }
+  if (typeof extra.sessionIDKey === 'string') {
+    extra.sessionKey = extra.sessionIDKey;
+  }
 
   // Headers on the wire are a record; emit them as a map upstream's
   // SplitHTTPConfig.headers expects, dropping Host (already on the URL).

frontend/src/test/inbound-link.test.ts

@@ -745,3 +745,73 @@ describe('genVlessLink flow gating (#5322)', () => {
     expect(new URL(link).searchParams.get('flow')).toBe('xtls-rprx-vision');
   });
 });
+
+describe('genVlessLink XHTTP extra compatibility', () => {
+  it('emits both sessionID and legacy session keys in XHTTP extra', () => {
+    const typed = InboundSchema.parse({
+      id: 1,
+      up: 0,
+      down: 0,
+      total: 0,
+      remark: 'xhttp-session',
+      enable: true,
+      expiryTime: 0,
+      listen: '',
+      port: 443,
+      tag: 'inbound-vless-xhttp',
+      sniffing: {
+        enabled: false,
+        destOverride: [],
+        metadataOnly: false,
+        routeOnly: false,
+        ipsExcluded: [],
+        domainsExcluded: [],
+      },
+      protocol: 'vless',
+      settings: {
+        clients: [
+          {
+            id: '11111111-2222-3333-4444-555555555555',
+            email: 'a@example.test',
+            flow: '',
+            limitIp: 0,
+            totalGB: 0,
+            expiryTime: 0,
+            enable: true,
+            tgId: 0,
+            subId: 's1',
+            comment: '',
+            reset: 0,
+          },
+        ],
+        decryption: 'none',
+        encryption: 'none',
+        fallbacks: [],
+      },
+      streamSettings: {
+        network: 'xhttp',
+        security: 'none',
+        xhttpSettings: {
+          path: '/sp',
+          host: 'edge.example.test',
+          mode: 'auto',
+          sessionIDPlacement: 'header',
+          sessionIDKey: 'X-Session',
+        },
+      },
+    });
+
+    const link = genVlessLink({
+      inbound: typed,
+      address: 'example.test',
+      port: 443,
+      clientId: '11111111-2222-3333-4444-555555555555',
+    });
+    const extra = JSON.parse(new URL(link).searchParams.get('extra') ?? '{}') as Record<string, unknown>;
+
+    expect(extra.sessionIDPlacement).toBe('header');
+    expect(extra.sessionIDKey).toBe('X-Session');
+    expect(extra.sessionPlacement).toBe('header');
+    expect(extra.sessionKey).toBe('X-Session');
+  });
+});