Re #2408 - Correctly let the watch headers override global, use a case-insensitive dictionary

changedetectionio/processors/__init__.py

@@ -6,6 +6,8 @@ from copy import deepcopy
 from changedetectionio.strtobool import strtobool
 from loguru import logger
 
+from requests.structures import CaseInsensitiveDict
+
 class difference_detection_processor():
 
     browser_steps = None
@@ -93,14 +95,16 @@ class difference_detection_processor():
             self.fetcher.browser_steps_screenshot_path = os.path.join(self.datastore.datastore_path, self.watch.get('uuid'))
 
         # Tweak the base config with the per-watch ones
-        request_headers = self.watch.get('headers', [])
+        request_headers = CaseInsensitiveDict()
-        request_headers.update(self.datastore.get_all_base_headers())
-        request_headers.update(self.datastore.get_all_headers_in_textfile_for_watch(uuid=self.watch.get('uuid')))
 
         ua = self.datastore.data['settings']['requests'].get('default_ua')
         if ua and ua.get(prefer_fetch_backend):
             request_headers.update({'User-Agent': ua.get(prefer_fetch_backend)})
 
+        request_headers.update(self.watch.get('headers', {}))
+        request_headers.update(self.datastore.get_all_base_headers())
+        request_headers.update(self.datastore.get_all_headers_in_textfile_for_watch(uuid=self.watch.get('uuid')))
+
         # https://github.com/psf/requests/issues/4525
         # Requests doesnt yet support brotli encoding, so don't put 'br' here, be totally sure that the user cannot
         # do this by accident.