Simplify logic

changedetectionio/processors/restock_diff.py

@@ -1,4 +1,3 @@
-
 import hashlib
 import urllib3
 from . import difference_detection_processor
@@ -9,24 +8,36 @@ 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
 
     def get_itemprop_availability(self):
+        """
+        `itemprop` is a global attribute
+        https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/itemprop
+        https://schema.org/ItemAvailability
+
+        <div class="product-offer" itemprop="offers" itemscope="" itemtype="https://schema.org/Offer">
+          ...
+          <link itemprop="availability" href="https://schema.org/OutOfStock" />
+
+        :return:
+        """
         from ..html_tools import xpath_filter
         import re
-        # <link itemprop="availability" href="https://schema.org/OutOfStock" />
-        # https://schema.org/ItemAvailability
+
         value = None
         try:
-            value = xpath_filter("//link[@itemprop='availability']/@href", self.fetcher.content)
+            value = xpath_filter("//*[@itemtype='https://schema.org/Offer']//*[@itemprop='availability']/@href", self.fetcher.content)
             if value:
                 value = re.sub(r'(?i)^http(s)+://schema.org/', '', value.strip())
 
@@ -35,7 +46,6 @@ class perform_site_check(difference_detection_processor):
 
         return value
 
-
     def run_changedetection(self, uuid, skip_when_checksum_same=True):
 
         # DeepCopy so we can be sure we don't accidently change anything by reference
@@ -61,39 +71,36 @@ class perform_site_check(difference_detection_processor):
         # https://schema.org/ItemAvailability Which strings mean we should consider it in stock?
         availability = self.get_itemprop_availability()
         if availability:
+            self.fetcher.instock_data = availability
             if any(availability in s for s in
                    [
                        'InStock',
                        'InStoreOnly',
                        'LimitedAvailability',
                        'OnlineOnly',
-                       'PreSale' # Debatable?
+                       'PreSale'  # Debatable?
                    ]):
-                self.fetcher.instock_data = 'Possibly in stock'
+                update_obj['in_stock'] = True
             else:
-                self.fetcher.instock_data = availability
+                update_obj['in_stock'] = False
 
         # Fallback to scraping the content for keywords (done in JS)
         if self.fetcher.instock_data:
-            fetched_md5 = hashlib.md5(self.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 self.fetcher.instock_data == 'Possibly in stock' else False
+            update_obj['in_stock'] = True if self.fetcher.instock_data == 'Possibly in stock' else False
         else:
             raise UnableToExtractRestockData(status_code=self.fetcher.status_code)
 
         # The main thing that all this at the moment comes down to :)
         changed_detected = False
 
-        if watch.get('previous_md5') and watch.get('previous_md5') != fetched_md5:
+        if watch.get('in_stock') != update_obj.get('in_stock'):
             # Yes if we only care about it going to instock, AND we are in stock
-            if watch.get('in_stock_only') and update_obj["in_stock"]:
+            if watch.get('in_stock_only') and update_obj['in_stock']:
                 changed_detected = True
 
             if not watch.get('in_stock_only'):
                 # All cases
                 changed_detected = True
 
-        # Always record the new checksum
-        update_obj["previous_md5"] = fetched_md5
-
         return changed_detected, update_obj, self.fetcher.instock_data.encode('utf-8')