Send participants directly to first task via /go/<project> route

ls_proxy_hf.py

@@ -1722,6 +1722,40 @@ def proxy_session_check():
     return Response(json.dumps(result, indent=2), content_type="application/json")
 
 
+@app.route("/go/<int:project_id>/", methods=["GET"])
+@app.route("/go/<int:project_id>", methods=["GET"])
+def go_to_project(project_id):
+    """After autologin, redirect participant straight to their first available task."""
+    uid, _ = get_current_user(request)
+    if not uid:
+        return Response("", status=302, headers={"Location": f"/user/login/?next=/go/{project_id}/"})
+    try:
+        conn = sqlite3.connect(DB_PATH)
+        row = conn.execute(
+            "SELECT at.key FROM authtoken_token at "
+            "JOIN htx_user u ON at.user_id = u.id "
+            "WHERE u.is_superuser=1 ORDER BY u.id LIMIT 1"
+        ).fetchone()
+        conn.close()
+        admin_token = row[0] if row else None
+    except Exception:
+        admin_token = None
+    if admin_token:
+        try:
+            r = requests.get(
+                f"{LS_URL}/api/projects/{project_id}/next/",
+                headers={"Authorization": f"Token {admin_token}", "Host": "localhost:8080"},
+                cookies=_ls_cookies(request), timeout=10,
+            )
+            d = r.json() if r.status_code == 200 else {}
+            if d.get("id"):
+                return Response("", status=302,
+                    headers={"Location": f"/projects/{project_id}/data?task={d['id']}"})
+        except Exception:
+            pass
+    return Response("", status=302, headers={"Location": f"/projects/{project_id}/data"})
+
+
 @app.route("/start", methods=["GET"])
 def prolific_start():
     """Prolific entry point.
@@ -1788,7 +1822,7 @@ def prolific_start():
     <b>Estimated time:</b> approximately {est_min} minutes<br>
     <b>When done:</b> you will be sent back to Prolific automatically
   </div>
-  <a class="task-btn" href="/autologin?pid={pid}&email={cred_email}&password={cred_pw}&next=/projects/{project}/">
+  <a class="task-btn" href="/autologin?pid={pid}&email={cred_email}&password={cred_pw}&next=/go/{project}/">
     {flag} Start &rarr; {task}
   </a>
   <p class="note">Your Prolific ID is recorded automatically. Do not share this link.</p>