[keenspot] add comic extractor (#223)

Doesn't work for
- http://brawlinthefamily.keenspot.com/
- http://flipside.keenspot.com/
- http://lastblood.keenspot.com/
- http://mysticrevolution.keenspot.com/
- http://porcelain.keenspot.com/
- http://twokinds.keenspot.com/
yet, because of custom layouts.

docs/supportedsites.rst

@@ -48,6 +48,7 @@ imgur                https://imgur.com/                  Albums, individual Imag
 Instagram            https://www.instagram.com/          Images from Users, individual Images, Tag-Searches
 Jaimini's Box        https://jaiminisbox.com/reader/     Chapters, Manga
 Joyreactor           http://joyreactor.cc/               |joyreactor-C|
+Keenspot             http://www.keenspot.com/            Comics
 Khinsider            https://downloads.khinsider.com/    Soundtracks
 Kirei Cake           https://reader.kireicake.com/       Chapters, Manga
 KissManga            https://kissmanga.com/              Chapters, Manga

gallery_dl/extractor/__init__.py

@@ -44,6 +44,7 @@ modules = [
     "imgth",
     "imgur",
     "instagram",
+    "keenspot",
     "khinsider",
     "kissmanga",
     "komikcast",

gallery_dl/extractor/keenspot.py

@@ -0,0 +1,103 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2019 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
+# published by the Free Software Foundation.
+
+"""Extractors for http://www.keenspot.com/"""
+
+from .common import Extractor, Message
+from .. import text
+
+
+class KeenspotComicExtractor(Extractor):
+    """Extractor for webcomics from keenspot.com"""
+    category = "keenspot"
+    subcategory = "comic"
+    directory_fmt = ("{category}", "{comic}")
+    filename_fmt = "{filename}.{extension}"
+    archive_fmt = "{comic}_{filename}"
+    pattern = r"(?:https?://)?(?!www\.|forums\.)([^.]+)\.keenspot\.com"
+    test = (
+        ("http://marksmen.keenspot.com/", {  # link
+            "range": "1-3",
+            "url": "83bcf029103bf8bc865a1988afa4aaeb23709ba6",
+        }),
+        ("http://barkercomic.keenspot.com/", {  # id
+            "range": "1-3",
+            "url": "c4080926db18d00bac641fdd708393b7d61379e6",
+        }),
+        ("http://crowscare.keenspot.com/", {  # id v2
+            "range": "1-3",
+            "url": "a00e66a133dd39005777317da90cef921466fcaa"
+        }),
+        ("http://supernovas.keenspot.com/", {  # ks
+            "range": "1-3",
+            "url": "de21b12887ef31ff82edccbc09d112e3885c3aab"
+        }),
+    )
+
+    def __init__(self, match):
+        Extractor.__init__(self, match)
+        self._next = None
+        self.comic = match.group(1)
+        self.root = "http://" + self.comic + ".keenspot.com"
+
+    def items(self):
+        data = {"comic": self.comic}
+        yield Message.Version, 1
+        yield Message.Directory, data
+
+        url = self._first(self.request(self.root + "/").text)
+        while url:
+            if url[0] == "/":
+                url = self.root + url
+            page = self.request(url).text
+
+            for img in text.extract_iter(page, 'class="ksc"', '>'):
+                img = text.extract(img, 'src="', '"')[0]
+                if img[0] == "/":
+                    img = self.root + img
+                yield Message.Url, img, text.nameext_from_url(img, data)
+
+            url = self._next(page)
+
+    def _first(self, page):
+        url = text.extract(page, '<link rel="first" href="', '"')[0]
+        if url and not url.startswith("index"):
+            self._next = self._next_link
+            return url
+
+        pos = page.find('id="first_day1"')
+        if pos >= 0:
+            self._next = self._next_id
+            return text.rextract(page, '<a href="', '"', pos)[0]
+
+        pos = page.find('>FIRST PAGE<')
+        if pos >= 0:
+            self._next = self._next_id
+            return text.rextract(page, '<a href="', '"', pos)[0]
+
+        pos = page.find('<div id="kscomicpart"')
+        if pos >= 0:
+            self._next = self._next_ks
+            return text.extract(page, 'href="', '"', pos)[0]
+
+        self.log.error("Unrecognized page layout")
+        return None
+
+    @staticmethod
+    def _next_link(page):
+        return text.extract(page, '<link rel="next" href="', '"')[0]
+
+    @staticmethod
+    def _next_id(page):
+        pos = page.find('id="next_')
+        return text.rextract(page, 'href="', '"', pos)[0] if pos >= 0 else None
+
+    @staticmethod
+    def _next_ks(page):
+        pos = page.index('<a href="/archive.html') + 22
+        return text.extract(page, 'href="', '"', pos)[0]