fix: add CM3000 auth diagnostics

Author: itsDNNS

app/drivers/cm3000.py

@@ -39,6 +39,8 @@
     "sessionstorage.getitem('privatekey')",
     "sessionstorage.getitem(\"privatekey\")",
 )
+_RE_TITLE = re.compile(r"<title[^>]*>(.*?)</title>", re.IGNORECASE | re.DOTALL)
+_RE_FORM_ACTION = re.compile(r"<form[^>]+action=['\"]([^'\"]+)['\"]", re.IGNORECASE)
 
 # Fields per channel for each section (after the leading count value).
 _DS_QAM_FIELDS = 9   # num|lock|mod|chID|freq|power|snr|corrErr|uncorrErr
@@ -86,6 +88,9 @@ def login(self) -> None:
                 raise RuntimeError("CM3000 authentication failed: connection refused after retry")
             except requests.RequestException as e:
                 raise RuntimeError(f"CM3000 authentication failed: {e}")
+            except RuntimeError as e:
+                self._log_status_page_diagnostics(r.text, "login")
+                raise e
 
     def get_docsis_data(self) -> dict:
         """Retrieve DOCSIS channel data from JavaScript on status page.
@@ -166,7 +171,11 @@ def _fetch_status_page(self) -> str:
             r.raise_for_status()
         except requests.RequestException as e:
             raise RuntimeError(f"CM3000 status page retrieval failed: {e}")
-        self._ensure_status_page(r.text)
+        try:
+            self._ensure_status_page(r.text)
+        except RuntimeError:
+            self._log_status_page_diagnostics(r.text, "fetch")
+            raise
         return r.text
 
     @staticmethod
@@ -200,6 +209,59 @@ def _ensure_status_page(html: str) -> None:
                 "CM3000 status page did not contain the expected DOCSIS data blocks"
             )
 
+    @staticmethod
+    def _status_page_diagnostics(html: str) -> dict:
+        """Summarize the response shape for debugging failed CM3000 auth."""
+        if not html:
+            return {
+                "length": 0,
+                "title": "",
+                "form_action": "",
+                "login_markers": [],
+                "has_sys_info": False,
+                "has_channel_data": False,
+            }
+
+        lower_html = html.lower()
+        title_match = _RE_TITLE.search(html)
+        form_match = _RE_FORM_ACTION.search(html)
+        login_markers = [marker for marker in _LOGIN_MARKERS if marker in lower_html]
+        has_sys_info = bool(CM3000Driver._extract_tag_value_list(html, "InitTagValue"))
+        has_channel_data = any(
+            CM3000Driver._extract_tag_value_list(html, function_name)
+            for function_name in (
+                "InitDsTableTagValue",
+                "InitUsTableTagValue",
+                "InitDsOfdmTableTagValue",
+                "InitUsOfdmaTableTagValue",
+            )
+        )
+
+        return {
+            "length": len(html),
+            "title": (title_match.group(1).strip() if title_match else ""),
+            "form_action": (form_match.group(1).strip() if form_match else ""),
+            "login_markers": login_markers,
+            "has_sys_info": has_sys_info,
+            "has_channel_data": has_channel_data,
+        }
+
+    @staticmethod
+    def _log_status_page_diagnostics(html: str, context: str) -> None:
+        """Emit a compact debug summary of the CM3000 response page."""
+        diag = CM3000Driver._status_page_diagnostics(html)
+        log.debug(
+            "CM3000 %s diagnostics: len=%s title=%r form_action=%r login_markers=%s "
+            "has_sys_info=%s has_channel_data=%s",
+            context,
+            diag["length"],
+            diag["title"],
+            diag["form_action"],
+            ",".join(diag["login_markers"]) or "(none)",
+            diag["has_sys_info"],
+            diag["has_channel_data"],
+        )
+
     # -- Channel parsers --
 
     def _parse_ds_qam(self, html: str) -> list:

tests/test_cm3000_driver.py

@@ -551,6 +551,37 @@ def test_extracts_double_quoted_concatenated_assignment(self):
         )
 
 
+class TestDiagnostics:
+    def test_status_page_diagnostics_for_valid_page(self):
+        diag = CM3000Driver._status_page_diagnostics(STATUS_HTML)
+        assert diag["title"] == "NETGEAR - Cable Modem CM3000"
+        assert diag["form_action"] == ""
+        assert diag["login_markers"] == []
+        assert diag["has_sys_info"] is True
+        assert diag["has_channel_data"] is True
+
+    def test_status_page_diagnostics_for_login_page(self):
+        html = """
+            <html><head><title>Login</title></head>
+            <body>
+              <script>
+                if (sessionStorage.getItem('PrivateKey') === null) {
+                    window.location.replace('../Login.htm');
+                }
+              </script>
+              <form action='/goform/Login'></form>
+            </body></html>
+        """
+        diag = CM3000Driver._status_page_diagnostics(html)
+        assert diag["title"] == "Login"
+        assert diag["form_action"] == "/goform/Login"
+        assert "login.htm" in diag["login_markers"]
+        assert "window.location.replace" in diag["login_markers"]
+        assert "sessionstorage.getitem('privatekey')" in diag["login_markers"]
+        assert diag["has_sys_info"] is False
+        assert diag["has_channel_data"] is False
+
+
 # -- Collect cycle (cache reuse) --
 
 class TestCollectCycle: