[patreon] use '"browser": "firefox"' by default (#1117)

docs/configuration.rst

@@ -392,8 +392,9 @@ extractor.*.browser
 -------------------
 Type
     ``string``
+Default
+    ``"firefox"`` for ``patreon``, ``null`` everywhere else
 Example
-    * ``"firefox"``
     * ``"chrome:macos"``
 Description
     Try to emulate a real browser (``firefox`` or ``chrome``)

gallery_dl/extractor/common.py

@@ -32,6 +32,7 @@ class Extractor():
     filename_fmt = "{filename}.{extension}"
     archive_fmt = ""
     cookiedomain = ""
+    browser = None
     root = ""
     test = None
     request_interval = 0.0
@@ -65,7 +66,7 @@ class Extractor():
             self.config = self._config_shared
             self.config_accumulate = self._config_shared_accumulate
 
-        browser = self.config("browser")
+        browser = self.config("browser", self.browser)
         if browser:
             self._emulate_browser(browser)
         else:

gallery_dl/extractor/patreon.py

@@ -23,6 +23,7 @@ class PatreonExtractor(Extractor):
     directory_fmt = ("{category}", "{creator[full_name]}")
     filename_fmt = "{id}_{title}_{num:>02}.{extension}"
     archive_fmt = "{id}_{num}"
+    browser = "firefox"
     _warning = True
 
     def items(self):