Update app.py

app.py

@@ -35,7 +35,7 @@ def get_current_time_in_timezone(timezone: str) -> str:
 
 @tool
 def subfinder_tool(domain: str, subdomains: str) -> str:
-    """A tool that checks which subdomains of a given domain exist by performing DNS lookups.
+    """A tool that checks which subdomains of a given domain exist by querying a public DNS API.
     Args:
         domain: The main domain (e.g., 'example.com').
         subdomains: A comma-separated list of subdomains to check (e.g., 'www,mail,blog').
@@ -49,11 +49,13 @@ def subfinder_tool(domain: str, subdomains: str) -> str:
             continue
         full_domain = f"{sub}.{domain}"
         try:
-            # Perform DNS lookup
-            socket.gethostbyname(full_domain)
-            valid_subdomains.append(full_domain)
-        except socket.gaierror:
-            continue  # If domain doesn't resolve
+            # Query Google's DNS-over-HTTPS API
+            response = requests.get(
+                f"https://dns.google/resolve?name={full_domain}&type=A"
+            )
+            data = response.json()
+            if "Answer" in data:
+                valid_subdomains.append(full_domain)
         except Exception as e:
             return f"Error checking {full_domain}: {str(e)}"