Upload app.py

app.py

@@ -77,7 +77,14 @@ def get_conn():
 
 def init_db():
     with get_conn() as conn:
-        conn.execute("PRAGMA journal_mode = WAL;")
+        # WAL gives better concurrency on a real local disk, but it relies on
+        # shared-memory/mmap that does NOT work on FUSE/object-store mounts
+        # (e.g. a Hugging Face Storage Bucket). Default to DELETE for safety;
+        # set MOS_JOURNAL_MODE=WAL when running on a genuine local disk.
+        journal = os.environ.get("MOS_JOURNAL_MODE", "DELETE").upper()
+        if journal not in ("DELETE", "WAL", "TRUNCATE", "PERSIST", "MEMORY"):
+            journal = "DELETE"
+        conn.execute(f"PRAGMA journal_mode = {journal};")
         conn.execute("""
             CREATE TABLE IF NOT EXISTS users (
                 id            INTEGER PRIMARY KEY AUTOINCREMENT,
@@ -418,110 +425,141 @@ def reviewer_lang_choices(session):
     return [(l["name"], l["id"]) for l in session["languages"]]
 
 
-with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Soft()) as demo:
+CSS = """
+.gradio-container { max-width: 1080px !important; margin: auto !important; }
+#app-title { text-align: center; margin-bottom: 0; }
+#app-title h1 { font-size: 1.7rem; margin: 6px 0 0; }
+#app-sub { text-align: center; color: var(--body-text-color-subdued); margin-top: 4px; font-size: 0.95rem; }
+#auth-wrap { max-width: 460px; margin: 18px auto; }
+.soft-card { border: 1px solid var(--block-border-color); border-radius: 16px;
+             padding: 18px; background: var(--block-background-fill); }
+#userbar { display: flex; align-items: center; justify-content: space-between;
+           padding: 4px 2px 10px; }
+#scale-hint { text-align: center; font-size: 0.9rem; color: var(--body-text-color-subdued);
+              margin: 4px 0 12px; }
+#submit-row button { font-size: 1.05rem; padding: 12px; border-radius: 12px; }
+.rating-grid .gr-radio { margin-bottom: 6px; }
+footer { display: none !important; }
+"""
+
+with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation",
+               theme=gr.themes.Soft(primary_hue="indigo", secondary_hue="indigo"),
+               css=CSS) as demo:
     session = gr.State(None)          # logged-in user session dict
     current_sample = gr.State(None)   # sample id currently being rated
 
-    gr.Markdown("# 🎧 Plotweaver AI — TTS MOS Evaluation Platform")
+    gr.Markdown("# 🎧 Plotweaver AI — TTS MOS Evaluation", elem_id="app-title")
+    gr.Markdown("Rate synthesised speech on 7 quality criteria, by language.", elem_id="app-sub")
 
     # ----------------------------- AUTH ------------------------------------ #
-    with gr.Column(visible=True) as auth_col:
-        gr.Markdown("Sign in or create a reviewer account to begin.")
-        with gr.Tabs():
-            with gr.Tab("Sign in"):
-                li_user = gr.Textbox(label="Username")
-                li_pw = gr.Textbox(label="Password", type="password")
-                li_btn = gr.Button("Sign in", variant="primary")
-                li_msg = gr.Markdown()
-            with gr.Tab("Create account"):
-                su_user = gr.Textbox(label="Username", info="3-32 chars: letters, numbers, _ . -")
-                su_email = gr.Textbox(label="Email (optional)")
-                su_pw = gr.Textbox(label="Password", type="password", info="At least 6 characters")
-                su_langs = gr.CheckboxGroup(label="Languages you can evaluate", choices=lang_choices())
-                su_code = gr.Textbox(label="Admin code (optional)", type="password",
-                                     info="Leave blank for a normal reviewer account.")
-                su_btn = gr.Button("Create account", variant="primary")
-                su_msg = gr.Markdown()
+    with gr.Column(visible=True, elem_id="auth-wrap") as auth_col:
+        with gr.Column(elem_classes="soft-card"):
+            with gr.Tabs():
+                with gr.Tab("Sign in"):
+                    li_user = gr.Textbox(label="Username", autofocus=True)
+                    li_pw = gr.Textbox(label="Password", type="password")
+                    li_btn = gr.Button("Sign in", variant="primary")
+                    li_msg = gr.Markdown()
+                with gr.Tab("Create account"):
+                    su_user = gr.Textbox(label="Username", info="3–32 chars: letters, numbers, _ . -")
+                    su_email = gr.Textbox(label="Email (optional)")
+                    su_pw = gr.Textbox(label="Password", type="password", info="At least 6 characters")
+                    su_langs = gr.CheckboxGroup(label="Languages you can evaluate", choices=lang_choices())
+                    su_code = gr.Textbox(label="Admin code (optional)", type="password",
+                                         info="Leave blank for a normal reviewer account.")
+                    su_btn = gr.Button("Create account", variant="primary")
+                    su_msg = gr.Markdown()
 
     # ----------------------------- APP ------------------------------------- #
     with gr.Column(visible=False) as app_col:
-        with gr.Row():
+        with gr.Row(elem_id="userbar"):
             greeting = gr.Markdown()
-            logout_btn = gr.Button("Log out", scale=0)
+            logout_btn = gr.Button("Log out", scale=0, size="sm")
 
-        with gr.Tabs() as app_tabs:
+        with gr.Tabs():
             # ---------- Rate tab ----------
             with gr.Tab("Rate samples"):
+                with gr.Row():
+                    rate_lang = gr.Dropdown(label="Language", choices=[], interactive=True,
+                                            allow_custom_value=True, scale=2)
+                    rate_sample = gr.Dropdown(label="Sample  (✓ = already rated)", choices=[],
+                                              interactive=True, allow_custom_value=True, scale=3)
+                    next_btn = gr.Button("Next unrated ▶", scale=1, size="sm")
+
+                rate_audio = gr.Audio(label="▶  Listen to the full sample",
+                                      type="filepath", interactive=False)
                 gr.Markdown(
-                    "Please listen to **the whole clip** with headphones in a quiet room before rating. "
-                    f"Scale: {SCALE_HINT}"
+                    "Use headphones in a quiet room.    "
+                    "**1** Very Poor · **2** Poor · **3** Fair · **4** Good · **5** Excellent",
+                    elem_id="scale-hint",
                 )
-                with gr.Row():
-                    rate_lang = gr.Dropdown(label="Language", choices=[], interactive=True)
-                    rate_sample = gr.Dropdown(label="Sample (✓ = already rated)", choices=[], interactive=True)
-                    next_btn = gr.Button("Next unrated ▶", scale=0)
-                rate_audio = gr.Audio(label="Audio sample", type="filepath", interactive=False)
 
                 criterion_inputs = {}
-                with gr.Row():
-                    for key, label, definition in CRITERIA[:4]:
-                        criterion_inputs[key] = gr.Radio(
-                            choices=[1, 2, 3, 4, 5], label=label, info=definition, value=None
-                        )
-                with gr.Row():
-                    for key, label, definition in CRITERIA[4:]:
-                        criterion_inputs[key] = gr.Radio(
-                            choices=[1, 2, 3, 4, 5], label=label, info=definition, value=None
-                        )
-                rate_comments = gr.Textbox(label="Comments (pronunciation errors, artifacts, etc.)", lines=2)
-                with gr.Row():
-                    submit_btn = gr.Button("Submit / update rating", variant="primary")
+                with gr.Column(elem_classes="rating-grid"):
+                    with gr.Row():
+                        for key, label, definition in CRITERIA[:4]:
+                            criterion_inputs[key] = gr.Radio(
+                                choices=[1, 2, 3, 4, 5], label=label, info=definition, value=None)
+                    with gr.Row():
+                        for key, label, definition in CRITERIA[4:]:
+                            criterion_inputs[key] = gr.Radio(
+                                choices=[1, 2, 3, 4, 5], label=label, info=definition, value=None)
+
+                rate_comments = gr.Textbox(
+                    label="Comments (optional)",
+                    placeholder="Pronunciation errors, unnatural prosody, noise, artifacts…", lines=2)
+                with gr.Row(elem_id="submit-row"):
+                    submit_btn = gr.Button("✓  Submit / update rating", variant="primary")
                 rate_msg = gr.Markdown()
 
             # ---------- Progress tab ----------
             with gr.Tab("My progress"):
-                refresh_prog_btn = gr.Button("Refresh")
+                refresh_prog_btn = gr.Button("Refresh", size="sm")
                 progress_md = gr.Markdown()
-                progress_tbl = gr.Dataframe(headers=["Language", "Rated", "Total", "Remaining"], interactive=False)
+                progress_tbl = gr.Dataframe(
+                    headers=["Language", "Rated", "Total", "Remaining"], interactive=False)
 
             # ---------- Profile tab ----------
             with gr.Tab("My languages"):
-                gr.Markdown("Update the set of languages you are eligible to evaluate.")
+                gr.Markdown("Choose which languages you are eligible to evaluate.")
                 prof_langs = gr.CheckboxGroup(label="Languages", choices=lang_choices())
-                prof_save = gr.Button("Save", variant="primary")
+                prof_save = gr.Button("Save", variant="primary", size="sm")
                 prof_msg = gr.Markdown()
 
             # ---------- Admin tab ----------
             with gr.Tab("Admin", visible=False) as admin_tab:
                 gr.Markdown("### Languages")
                 with gr.Row():
-                    al_code = gr.Textbox(label="Code", info="e.g. yo, ha, ig, pcm, en-NG")
-                    al_name = gr.Textbox(label="Name", info="e.g. Yoruba")
-                    al_btn = gr.Button("Add language", scale=0)
+                    al_code = gr.Textbox(label="Code", info="e.g. yo, ha, ig, pcm, en-NG", scale=1)
+                    al_name = gr.Textbox(label="Name", info="e.g. Yoruba", scale=2)
+                    al_btn = gr.Button("Add language", scale=0, size="sm")
                 al_msg = gr.Markdown()
-                langs_tbl = gr.Dataframe(headers=["id", "code", "name"], interactive=False, label="Existing languages")
+                langs_tbl = gr.Dataframe(headers=["id", "code", "name"], interactive=False,
+                                         label="Existing languages")
 
                 gr.Markdown("### Upload audio samples")
                 with gr.Row():
-                    up_lang = gr.Dropdown(label="Language", choices=lang_choices())
+                    up_lang = gr.Dropdown(label="Language", choices=lang_choices(),
+                                          allow_custom_value=True, scale=1)
                     up_model = gr.Textbox(label="Model / system name", value="",
-                                          info="e.g. F5-TTS, XTTS-v2, MMS-TTS, human. Hidden from reviewers.")
+                                          info="e.g. F5-TTS, XTTS-v2, MMS-TTS, human. Hidden from reviewers.",
+                                          scale=2)
                 up_files = gr.File(label="Audio files (wav/mp3/flac/ogg)", file_count="multiple",
                                    file_types=["audio"])
                 with gr.Row():
                     up_isref = gr.Checkbox(label="These are reference / human anchor samples", value=False)
                     up_transcript = gr.Textbox(label="Transcript (optional, applies to all uploaded)", scale=2)
-                up_btn = gr.Button("Upload", variant="primary")
+                up_btn = gr.Button("Upload", variant="primary", size="sm")
                 up_msg = gr.Markdown()
                 samples_tbl = gr.Dataframe(
                     headers=["id", "language", "sample_name", "model", "reference"],
                     interactive=False, label="Samples")
                 with gr.Row():
                     del_sample_id = gr.Number(label="Delete sample by id", precision=0)
-                    del_btn = gr.Button("Delete", variant="stop", scale=0)
+                    del_btn = gr.Button("Delete", variant="stop", scale=0, size="sm")
 
                 gr.Markdown("### Users")
-                refresh_users_btn = gr.Button("Refresh users")
+                refresh_users_btn = gr.Button("Refresh users", size="sm")
                 users_tbl = gr.Dataframe(
                     headers=["id", "username", "role", "active", "languages", "ratings"],
                     interactive=False)
@@ -529,14 +567,15 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
                     promote_id = gr.Number(label="User id", precision=0)
                     role_choice = gr.Dropdown(label="Set role", choices=["reviewer", "admin"], value="reviewer")
                     active_choice = gr.Dropdown(label="Set active", choices=["yes", "no"], value="yes")
-                    update_user_btn = gr.Button("Apply", scale=0)
+                    update_user_btn = gr.Button("Apply", scale=0, size="sm")
                 user_admin_msg = gr.Markdown()
 
                 gr.Markdown("### Results")
                 with gr.Row():
-                    res_lang = gr.Dropdown(label="Language", choices=lang_choices())
-                    res_btn = gr.Button("Compute MOS", variant="primary")
-                    export_btn = gr.Button("Export XLSX")
+                    res_lang = gr.Dropdown(label="Language", choices=lang_choices(),
+                                           allow_custom_value=True, scale=2)
+                    res_btn = gr.Button("Compute MOS", variant="primary", scale=0, size="sm")
+                    export_btn = gr.Button("Export XLSX", scale=0, size="sm")
                 res_summary = gr.Markdown()
                 res_model_tbl = gr.Dataframe(label="MOS by model", interactive=False)
                 res_sample_tbl = gr.Dataframe(label="MOS by sample", interactive=False)
@@ -550,26 +589,36 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
     def do_login(username, password):
         user = authenticate(username, password)
         if not user:
+            # keep typed credentials so the user can correct them
             return (gr.update(), gr.update(), None, "❌ Invalid username or password.",
-                    gr.update(), gr.update(), gr.update(), gr.update())
+                    gr.update(), gr.update(), gr.update(), gr.update(),
+                    gr.update(), gr.update())
         sess = user_session(user["id"])
         is_admin = sess["role"] == "admin"
         rl = reviewer_lang_choices(sess)
         return (
             gr.update(visible=False),                       # auth_col
             gr.update(visible=True),                        # app_col
-            sess,                                           # session state
+            sess,                                           # session
             "",                                             # li_msg
-            gr.update(value=f"Signed in as **{sess['username']}** ({sess['role']})"),  # greeting
+            gr.update(value=f"Signed in as **{sess['username']}**  ·  {sess['role']}"),  # greeting
             gr.update(visible=is_admin),                    # admin_tab
-            gr.update(choices=rl, value=(rl[0][1] if rl else None)),  # rate_lang
+            gr.update(choices=rl, value=None),              # rate_lang
             gr.update(choices=lang_choices(),
-                      value=[l["id"] for l in sess["languages"]]),    # prof_langs
+                      value=[l["id"] for l in sess["languages"]]),  # prof_langs
+            gr.update(value=""),                            # li_user  (clear)
+            gr.update(value=""),                            # li_pw    (clear)
         )
 
     li_btn.click(
         do_login, [li_user, li_pw],
-        [auth_col, app_col, session, li_msg, greeting, admin_tab, rate_lang, prof_langs],
+        [auth_col, app_col, session, li_msg, greeting, admin_tab, rate_lang, prof_langs,
+         li_user, li_pw],
+    )
+    li_pw.submit(  # allow Enter-to-login
+        do_login, [li_user, li_pw],
+        [auth_col, app_col, session, li_msg, greeting, admin_tab, rate_lang, prof_langs,
+         li_user, li_pw],
     )
 
     def do_signup(username, email, password, lang_ids, code):
@@ -577,10 +626,14 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
         try:
             create_user(username, email, password, role=role, language_ids=lang_ids or [])
         except ValueError as e:
-            return f"❌ {e}", gr.update()
-        note = " (admin)" if role == "admin" else ""
-        return f"✅ Account created{note}. Switch to **Sign in** to continue.", gr.update(value="")
-    su_btn.click(do_signup, [su_user, su_email, su_pw, su_langs, su_code], [su_msg, su_pw])
+            # keep fields so the user can fix the problem
+            return (f"❌ {e}", gr.update(), gr.update(), gr.update(), gr.update(), gr.update())
+        note = " (admin account)" if role == "admin" else ""
+        return ("✅ Account created" + note + ". Switch to the **Sign in** tab to continue.",
+                gr.update(value=""), gr.update(value=""), gr.update(value=""),
+                gr.update(value=[]), gr.update(value=""))
+    su_btn.click(do_signup, [su_user, su_email, su_pw, su_langs, su_code],
+                 [su_msg, su_user, su_email, su_pw, su_langs, su_code])
 
     def do_logout():
         return (gr.update(visible=True), gr.update(visible=False), None, "")
@@ -596,7 +649,6 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
     rate_lang.change(load_samples_for_lang, [session, rate_lang], [rate_sample])
 
     def load_sample(sess, sample_id):
-        """Load audio + any existing rating into the form."""
         if not sample_id:
             return (None, None, *[None] * len(CRITERIA_KEYS), "")
         with get_conn() as conn:
@@ -622,30 +674,28 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
         return gr.update(value=nxt)
     next_btn.click(go_next_unrated, [session, rate_lang], [rate_sample])
 
+    def score_lang(sess, sample_id):
+        with get_conn() as conn:
+            row = conn.execute("SELECT language_id FROM samples WHERE id=?", (sample_id,)).fetchone()
+        return row["language_id"] if row else None
+
     def submit_rating(sess, sample_id, comments, *scores):
         if not sess:
-            return "❌ Not signed in.", gr.update()
+            return "❌ Not signed in."
         if not sample_id:
-            return "❌ No sample selected.", gr.update()
+            return "❌ No sample selected."
         score_map = dict(zip(CRITERIA_KEYS, scores))
         missing = [lbl for (k, lbl, _) in CRITERIA if score_map.get(k) in (None, "")]
         if missing:
-            return f"❌ Please rate every criterion. Missing: {', '.join(missing)}", gr.update()
+            return "❌ Please rate every criterion. Missing: " + ", ".join(missing)
         upsert_rating(sess["id"], sample_id, score_map, comments)
-        # refresh sample dropdown to show the ✓ and move on
-        items = samples_for_reviewer(sess["id"], score_lang(sess, sample_id))
+        lid = score_lang(sess, sample_id)
+        items = samples_for_reviewer(sess["id"], lid)
         rated = sum(1 for s in items if s["rated"])
-        return (f"✅ Saved. You have rated {rated}/{len(items)} samples in this language.", gr.update())
-
-    def score_lang(sess, sample_id):
-        with get_conn() as conn:
-            row = conn.execute("SELECT language_id FROM samples WHERE id=?", (sample_id,)).fetchone()
-        return row["language_id"] if row else None
+        return f"✅ Saved — {rated}/{len(items)} samples rated in this language. Click **Next unrated ▶** to continue."
 
     submit_btn.click(
-        submit_rating,
-        [session, current_sample, rate_comments, *rate_outputs],
-        [rate_msg, rate_sample],
+        submit_rating, [session, current_sample, rate_comments, *rate_outputs], [rate_msg],
     ).then(
         load_samples_for_lang, [session, rate_lang], [rate_sample]
     )
@@ -667,24 +717,14 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
     # ---- Profile ----
     def save_profile(sess, lang_ids):
         if not sess:
-            return "❌ Not signed in.", gr.update(), gr.update()
+            return "❌ Not signed in.", sess, gr.update()
         set_user_languages(sess["id"], lang_ids or [])
         new_sess = user_session(sess["id"])
         rl = reviewer_lang_choices(new_sess)
-        return ("✅ Languages updated.", new_sess,
-                gr.update(choices=rl, value=(rl[0][1] if rl else None)))
+        return "✅ Languages updated.", new_sess, gr.update(choices=rl, value=None)
     prof_save.click(save_profile, [session, prof_langs], [prof_msg, session, rate_lang])
 
     # ---- Admin: languages ----
-    def admin_add_language(sess, code, name):
-        if not sess or sess["role"] != "admin":
-            return "❌ Admin only.", _languages_table(), *_lang_dropdown_updates()
-        try:
-            add_language(code, name)
-        except ValueError as e:
-            return f"❌ {e}", _languages_table(), *_lang_dropdown_updates()
-        return f"✅ Added {name} ({code}).", _languages_table(), *_lang_dropdown_updates()
-
     def _languages_table():
         return [[l["id"], l["code"], l["name"]] for l in list_languages()]
 
@@ -692,12 +732,24 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
         ch = lang_choices()
         return (gr.update(choices=ch), gr.update(choices=ch), gr.update(choices=ch), gr.update(choices=ch))
 
+    def admin_add_language(sess, code, name):
+        if not sess or sess["role"] != "admin":
+            return ("❌ Admin only.", _languages_table(), *_lang_dropdown_updates())
+        try:
+            add_language(code, name)
+        except ValueError as e:
+            return (f"❌ {e}", _languages_table(), *_lang_dropdown_updates())
+        return (f"✅ Added {name} ({code}).", _languages_table(), *_lang_dropdown_updates())
     al_btn.click(
         admin_add_language, [session, al_code, al_name],
         [al_msg, langs_tbl, up_lang, res_lang, su_langs, prof_langs],
     )
 
     # ---- Admin: samples ----
+    def _samples_table():
+        return [[s["id"], f"{s['language_name']} ({s['language_code']})", s["sample_name"],
+                 s["model_name"], "yes" if s["is_reference"] else "no"] for s in list_samples()]
+
     def admin_upload(sess, language_id, files, model, is_ref, transcript):
         if not sess or sess["role"] != "admin":
             return "❌ Admin only.", _samples_table()
@@ -714,11 +766,6 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
             except Exception as e:  # noqa
                 return f"❌ Error on a file: {e}", _samples_table()
         return f"✅ Uploaded {count} sample(s).", _samples_table()
-
-    def _samples_table():
-        return [[s["id"], f"{s['language_name']} ({s['language_code']})", s["sample_name"],
-                 s["model_name"], "yes" if s["is_reference"] else "no"] for s in list_samples()]
-
     up_btn.click(admin_upload, [session, up_lang, up_files, up_model, up_isref, up_transcript],
                  [up_msg, samples_tbl])
 
@@ -739,11 +786,13 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
                 langs = conn.execute(
                     "SELECT l.name FROM user_languages ul JOIN languages l ON l.id=ul.language_id "
                     "WHERE ul.user_id=?", (u["id"],)).fetchall()
-                nratings = conn.execute("SELECT COUNT(*) c FROM ratings WHERE user_id=?", (u["id"],)).fetchone()["c"]
+                nratings = conn.execute("SELECT COUNT(*) c FROM ratings WHERE user_id=?",
+                                        (u["id"],)).fetchone()["c"]
                 rows.append([u["id"], u["username"], u["role"], "yes" if u["is_active"] else "no",
                              ", ".join(l["name"] for l in langs), nratings])
         return rows
-    refresh_users_btn.click(lambda s: _users_table() if s and s["role"] == "admin" else [], [session], [users_tbl])
+    refresh_users_btn.click(lambda s: _users_table() if s and s["role"] == "admin" else [],
+                            [session], [users_tbl])
 
     def admin_update_user(sess, uid, role, active):
         if not sess or sess["role"] != "admin":
@@ -760,9 +809,9 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
     # ---- Admin: results ----
     def admin_results(sess, language_id):
         if not sess or sess["role"] != "admin":
-            return "❌ Admin only.", pd.DataFrame(), pd.DataFrame()
+            return "❌ Admin only.", None, None
         if not language_id:
-            return "Choose a language.", pd.DataFrame(), pd.DataFrame()
+            return "Choose a language.", None, None
         per_model, per_sample, summary = compute_results(language_id)
         return summary, per_model, per_sample
     res_btn.click(admin_results, [session, res_lang], [res_summary, res_model_tbl, res_sample_tbl])
@@ -773,11 +822,15 @@ with gr.Blocks(title="Plotweaver AI — TTS MOS Evaluation", theme=gr.themes.Sof
         return export_results(language_id)
     export_btn.click(admin_export, [session, res_lang], [res_file])
 
-    # Populate admin tables when the app loads for an admin (via login .then chain)
+    # Populate admin tables right after an admin logs in.
     li_btn.click(lambda s: (_languages_table(), _samples_table(), _users_table())
                  if s and s["role"] == "admin" else ([], [], []),
                  [session], [langs_tbl, samples_tbl, users_tbl])
 
 
 if __name__ == "__main__":
-    demo.queue().launch(server_name="0.0.0.0", server_port=int(os.environ.get("PORT", 7860)))
+    demo.queue().launch(
+        server_name="0.0.0.0",
+        server_port=int(os.environ.get("PORT", 7860)),
+        allowed_paths=[DATA_DIR],  # let Gradio serve audio stored under MOS_DATA_DIR (e.g. /data)
+    )