[booru] rewrite using Mixin classes (#59)

- improved code structure
- improved URL patterns
- better pagination to work around page limits on
  - Danbooru
  - e621
  - 3dbooru

gallery_dl/extractor/rule34.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2016-2017 Mike Fährmann
+# Copyright 2016-2018 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -11,31 +11,33 @@
 from . import booru
 
 
-class Rule34Extractor(booru.XMLBooruExtractor):
+class Rule34Extractor(booru.XmlParserMixin,
+                      booru.GelbooruPageMixin,
+                      booru.BooruExtractor):
     """Base class for rule34 extractors"""
     category = "rule34"
     api_url = "https://rule34.xxx/index.php"
-    pagestart = 0
-    pagekey = "pid"
+    page_limit = 4000
 
-    def setup(self):
+    def __init__(self, match):
+        super().__init__(match)
         self.params.update({"page": "dapi", "s": "post", "q": "index"})
 
 
-class Rule34TagExtractor(Rule34Extractor, booru.BooruTagExtractor):
+class Rule34TagExtractor(booru.TagMixin, Rule34Extractor):
     """Extractor for images from rule34.xxx based on search-tags"""
     pattern = [(r"(?:https?://)?(?:www\.)?rule34\.xxx/(?:index\.php)?"
-                r"\?page=post&s=list&tags=([^&]+)")]
+                r"\?page=post&s=list&tags=(?P<tags>[^&#]+)")]
     test = [("http://rule34.xxx/index.php?page=post&s=list&tags=danraku", {
         "url": "104094495973edfe7e764c8f2dd42017163322aa",
         "content": "a01768c6f86f32eb7ebbdeb87c30b0d9968d7f97",
     })]
 
 
-class Rule34PostExtractor(Rule34Extractor, booru.BooruPostExtractor):
+class Rule34PostExtractor(booru.PostMixin, Rule34Extractor):
     """Extractor for single images from rule34.xxx"""
     pattern = [(r"(?:https?://)?(?:www\.)?rule34\.xxx/(?:index\.php)?"
-                r"\?page=post&s=view&id=(\d+)")]
+                r"\?page=post&s=view&id=(?P<post>\d+)")]
     test = [("http://rule34.xxx/index.php?page=post&s=view&id=1974854", {
         "url": "3b1f9817785868d1cd94d5376d20478eed591965",
         "content": "fd2820df78fb937532da0a46f7af6cefc4dc94be",