fix: relay x-ip-token from HF proxy to JS for ZeroGPU Pro quota attribution

ZeroGPU identifies the user via the x-ip-token header injected by HF's
proxy on browser requests, but NOT on raw JS fetch() calls.

Solution:
- Add get_ip_token Gradio endpoint that reads x-ip-token from gr.Request
- On page load, JS calls this endpoint to retrieve the token and stores
it in window.__hf_ip_token
- All regen fetch() calls now include x-ip-token as a request header,
so ZeroGPU correctly attributes quota to the logged-in Pro account

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -1970,6 +1970,52 @@ _GLOBAL_JS = """
   if (window._wf_global_listener) return;  // already registered
   window._wf_global_listener = true;
 
+  // Fetch the x-ip-token via a Gradio endpoint where HF's proxy injects it.
+  // Store in window.__hf_ip_token so all regen fetch() calls can include it,
+  // ensuring ZeroGPU attributes quota to the logged-in user's Pro account.
+  window.__hf_ip_token = '';
+  function _fetchIpToken() {
+    fetch('/gradio_api/queue/join', {
+      method: 'POST',
+      credentials: 'include',
+      headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({
+        data: [], fn_index: null, session_hash: window.__gradio_session_hash__,
+        event_data: null, trigger_id: null
+      })
+    }).catch(function() {});
+    // Use the dedicated get_ip_token endpoint
+    var ipFnIndex = null;
+    var deps = window.gradio_config && window.gradio_config.dependencies;
+    if (deps) deps.forEach(function(d, i) { if (d.api_name === 'get_ip_token') ipFnIndex = i; });
+    if (ipFnIndex === null) return;
+    fetch('/gradio_api/queue/join', {
+      method: 'POST',
+      credentials: 'include',
+      headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({
+        data: [], fn_index: ipFnIndex,
+        session_hash: window.__gradio_session_hash__,
+        event_data: null, trigger_id: null
+      })
+    }).then(function(r) { return r.json(); }).then(function(j) {
+      if (!j.event_id) return;
+      var es = new EventSource('/gradio_api/queue/data?session_hash=' + window.__gradio_session_hash__);
+      es.onmessage = function(e) {
+        var msg; try { msg = JSON.parse(e.data); } catch(_) { return; }
+        if (msg.event_id !== j.event_id) return;
+        if (msg.msg === 'process_completed') {
+          es.close();
+          var token = msg.output && msg.output.data && msg.output.data[0];
+          if (token) { window.__hf_ip_token = token; console.log('[zerogpu] x-ip-token acquired, length:', token.length); }
+        }
+        if (msg.msg === 'close_stream') es.close();
+      };
+      es.onerror = function() { es.close(); };
+    }).catch(function() {});
+  }
+  // Run after Gradio config is ready
+  setTimeout(_fetchIpToken, 1500);
 
   // Cache: api_name -> fn_index, built once from gradio_config.dependencies
   let _fnIndexCache = null;
@@ -2093,10 +2139,12 @@ _GLOBAL_JS = """
       console.warn('[fireRegen] fn_index not found for api_name:', apiName);
       return;
     }
+    var regenHeaders = {'Content-Type': 'application/json'};
+    if (window.__hf_ip_token) regenHeaders['x-ip-token'] = window.__hf_ip_token;
     fetch('/gradio_api/queue/join', {
       method: 'POST',
       credentials: 'include',
-      headers: {'Content-Type': 'application/json'},
+      headers: regenHeaders,
       body: JSON.stringify({
         data: data,
         fn_index: fnIndex,
@@ -2554,5 +2602,20 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
         api_name="xregen_hunyuan",
     )
 
+    # ---- x-ip-token relay ----
+    # ZeroGPU uses the x-ip-token header to attribute quota to the logged-in user.
+    # HF's proxy injects it on browser requests but NOT on raw JS fetch() calls.
+    # Solution: expose a lightweight Gradio endpoint that reads the token from the
+    # incoming request (where HF DOES inject it) and returns it. The JS _GLOBAL_JS
+    # calls this on page load, stores the result in window.__hf_ip_token, and
+    # includes it as a header on all subsequent queue/join fetch calls.
+    _ip_token_tb = gr.Textbox(render=False)
+    def _get_ip_token(request: gr.Request):
+        return request.headers.get("x-ip-token", "")
+    gr.Button(render=False).click(
+        fn=_get_ip_token, inputs=[], outputs=[_ip_token_tb],
+        api_name="get_ip_token",
+    )
+
 print("[startup] app.py fully loaded — regen handlers registered, SSR disabled")
 demo.queue(max_size=10).launch(ssr_mode=False, height=900, allowed_paths=["/tmp"])