fix: try https fallback when http port 80 is closed (fixes HTTPS-only domains marked as dead)

Many modern servers refuse HTTP connections entirely. The validator was
only trying http://, causing HTTPS-only sites to be wrongly marked dead.
Now falls back to https:// on ConnectError. Also increased timeouts slightly.

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

app/validator.py

@@ -85,51 +85,59 @@ async def _check_domain(domain: str) -> dict:
         "load_time_ms":     None,
     }
     t0 = time.monotonic()
-    try:
-        async with httpx.AsyncClient(
-            timeout=httpx.Timeout(connect=5, read=8, write=5, pool=10),
-            follow_redirects=True,
-            headers=_HEADERS,
-            verify=False,
-            max_redirects=5,
-        ) as client:
-            resp = await client.get(f"http://{domain}")
 
-        result["load_time_ms"] = int((time.monotonic() - t0) * 1000)
-        result["status_code"]  = resp.status_code
-        result["server"]       = (resp.headers.get("server") or "")[:100]
+    # Try http first (follows http→https redirects automatically).
+    # Fall back to https directly if port 80 is closed/refused — many modern
+    # servers only listen on 443 and would be wrongly marked dead otherwise.
+    for scheme in ("http", "https"):
+        try:
+            async with httpx.AsyncClient(
+                timeout=httpx.Timeout(connect=7, read=12, write=5, pool=15),
+                follow_redirects=True,
+                headers=_HEADERS,
+                verify=False,
+                max_redirects=5,
+            ) as client:
+                resp = await client.get(f"{scheme}://{domain}")
 
-        # Resolve IP for live-looking domains
-        result["ip"] = await _resolve_ip(domain)
+            result["load_time_ms"] = int((time.monotonic() - t0) * 1000)
+            result["status_code"]  = resp.status_code
+            result["server"]       = (resp.headers.get("server") or "")[:100]
+            result["ip"]           = await _resolve_ip(domain)
 
-        final_url  = str(resp.url)
-        final_host = urlparse(final_url).netloc.lower().lstrip("www.")
+            final_url  = str(resp.url)
+            final_host = urlparse(final_url).netloc.lower().lstrip("www.")
 
-        # Redirected to a different root domain?
-        if not _same_domain(domain, final_url):
-            for ph in PARKING_REDIRECT_HOSTS:
-                if ph in final_host:
-                    result["prescreen_status"] = "parked"
-                    return result
-            result["prescreen_status"] = "redirect"
-            return result
-
-        if resp.status_code not in (200, 203):
-            return result  # dead
-
-        html_lc = resp.text[:20_000].lower()
-        for sig in PARKING_BODY_SIGNALS:
-            if sig in html_lc:
-                result["prescreen_status"] = "parked"
+            if not _same_domain(domain, final_url):
+                for ph in PARKING_REDIRECT_HOSTS:
+                    if ph in final_host:
+                        result["prescreen_status"] = "parked"
+                        return result
+                result["prescreen_status"] = "redirect"
                 return result
 
-        result["prescreen_status"] = "live"
-        return result
+            if resp.status_code not in (200, 203):
+                return result  # dead
 
-    except Exception as e:
-        logger.debug("Validator %s: %s", domain, e)
-        result["load_time_ms"] = int((time.monotonic() - t0) * 1000)
-        return result
+            html_lc = resp.text[:20_000].lower()
+            for sig in PARKING_BODY_SIGNALS:
+                if sig in html_lc:
+                    result["prescreen_status"] = "parked"
+                    return result
+
+            result["prescreen_status"] = "live"
+            return result
+
+        except httpx.ConnectError:
+            # Port closed / connection refused — try the other scheme
+            logger.debug("Validator %s: ConnectError on %s, trying next scheme", domain, scheme)
+            continue
+        except Exception as e:
+            logger.debug("Validator %s (%s): %s", domain, scheme, e)
+            break  # timeout or other error — don't retry
+
+    result["load_time_ms"] = int((time.monotonic() - t0) * 1000)
+    return result
 
 
 def _get_domains_batch(offset: int, limit: int, tld: Optional[str]) -> list[str]: