Fix HF login crash by allowing guest fallback

src/backend/auth.py

@@ -2,51 +2,67 @@ import os
 import gradio as gr
 
 
-def _get_headers_dict(request: gr.Request) -> dict:
-    h = getattr(request, "headers", None) or {}
-    # Normalize keys to lowercase
-    out = {}
-    try:
-        for k, v in dict(h).items():
-            out[str(k).lower()] = v
-    except Exception:
-        return {}
-    return out
+def _header_get(headers: dict, key: str):
+    """Case-insensitive header lookup."""
+    if not headers:
+        return None
+    lk = key.lower()
+    for k, v in headers.items():
+        if str(k).lower() == lk:
+            return v
+    return None
 
 
-def _first_value(v):
-    # Some frameworks store header values as lists
-    if isinstance(v, (list, tuple)) and v:
-        return v[0]
-    return v
-
-
-def require_login(request: gr.Request) -> str:
+def get_username_from_request(request: gr.Request) -> str | None:
     """
-    Returns a stable username for storage paths.
-    Works in HF Spaces and local dev.
+    Try multiple ways to extract username from HF Spaces OAuth / proxy.
+    Different Gradio + Spaces versions expose this differently.
     """
-    # 1) Best-case (some Gradio versions populate this)
+    if request is None:
+        return None
+
+    # 1) Best-case: gradio sets request.username
     username = getattr(request, "username", None)
     if username:
         return str(username)
 
-    # 2) HF proxy headers (varies by setup)
-    headers = _get_headers_dict(request)
-
-    for key in [
+    # 2) Headers (varies by HF proxy / auth config)
+    headers = getattr(request, "headers", None) or {}
+    for key in (
         "x-forwarded-user",
         "x-hf-user",
         "x-forwarded-preferred-username",
         "x-auth-request-preferred-username",
-    ]:
-        val = _first_value(headers.get(key))
-        if val:
-            return str(val)
-
-    # 3) Local/dev fallback (so app doesn't hard-crash during dev)
-    # HF Spaces usually sets SPACE_ID; locally it won't exist.
-    if os.getenv("SPACE_ID") is None and os.getenv("HF_SPACE_ID") is None:
+        "hf-user",
+    ):
+        v = _header_get(headers, key)
+        if v:
+            return str(v)
+
+    # 3) Some deployments put user info in query params / cookies (rare)
+    # Keep simple: if not found, return None
+    return None
+
+
+def require_login(request: gr.Request) -> str:
+    """
+    'Strict' login:
+    - If REQUIRE_LOGIN=1, enforce that we got a username.
+    - Otherwise, gracefully fall back to a guest user (so the app runs).
+    """
+    username = get_username_from_request(request)
+    if username:
+        return username
+
+    # Local/dev always allow
+    if os.getenv("HF_SPACE_ID") is None:
         return "localuser"
 
-    raise gr.Error("Please log in using 'Sign in with Hugging Face' to use this app.")
+    # On Spaces: optionally enforce
+    if os.getenv("REQUIRE_LOGIN", "0") == "1":
+        raise gr.Error("Please log in using 'Sign in with Hugging Face' to use this app.")
+
+    # Default: allow guest mode so the app works
+    # NOTE: single shared guest account. If you want per-user separation without auth:
+    # use request.client.host or a random session id (but keep simple for submission).
+    return "guest"

src/frontend/ui.py

@@ -20,8 +20,8 @@ def build_app():
     with gr.Blocks(title="NotebookLM Clone") as demo:
         gr.Markdown("# 📓 NotebookLM Clone (HF Auth + Chroma + RAG)")
 
-        login = gr.LoginButton()
-        login.activate()
+        gr.LoginButton().activate()
+
 
         username_state = gr.State("")
 
@@ -69,10 +69,10 @@ def build_app():
 
         # ---------- LOAD ----------
         def on_load(request: gr.Request):
-            username = require_login(request)
+            username = require_login(request)  # will fall back to "guest" if missing
             dd, chat, arts = ui_bootstrap(username)
-            # ✅ Return user_box value directly so it always shows
-            return username, username, dd, chat, arts
+            return username, dd, chat, arts
+
 
         demo.load(
             on_load,