Restock detection - Better reporting when it fails (#1584)

changedetectionio/processors/restock_diff.py

@@ -12,6 +12,12 @@ urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
 name = 'Re-stock detection for single product pages'
 description = 'Detects if the product goes back to in-stock'
 
+class UnableToExtractRestockData(Exception):
+    def __init__(self, status_code):
+        # Set this so we can use it in other parts of the app
+        self.status_code = status_code
+        return
+
 class perform_site_check(difference_detection_processor):
     screenshot = None
     xpath_data = None
@@ -105,7 +111,8 @@ class perform_site_check(difference_detection_processor):
             fetched_md5 = hashlib.md5(fetcher.instock_data.encode('utf-8')).hexdigest()
             # 'Possibly in stock' comes from stock-not-in-stock.js when no string found above the fold.
             update_obj["in_stock"] = True if fetcher.instock_data == 'Possibly in stock' else False
-
+        else:
+            raise UnableToExtractRestockData(status_code=fetcher.status_code)
 
         # The main thing that all this at the moment comes down to :)
         changed_detected = False

changedetectionio/update_worker.py

@@ -5,7 +5,7 @@ import time
 
 from changedetectionio import content_fetcher
 from .processors.text_json_diff import FilterNotFoundInResponse
-
+from .processors.restock_diff import UnableToExtractRestockData
 
 # A single update worker
 #
@@ -319,6 +319,11 @@ class update_worker(threading.Thread):
                                                                            'last_check_status': e.status_code,
                                                                            'has_ldjson_price_data': None})
                         process_changedetection_results = False
+                    except UnableToExtractRestockData as e:
+                        # Usually when fetcher.instock_data returns empty
+                        self.app.logger.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
+                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': f"Unable to extract restock data for this page unfortunately. (Got code {e.status_code} from server)"})
+                        process_changedetection_results = False
                     except Exception as e:
                         self.app.logger.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
                         self.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})