[hitomi] simplify metadata extraction

Use the data from https://ltn.hitomi.la/galleries/<id>.js for both
image URLs and metadata and ignore any gallery or reader pages.

This removes 'artist', 'characters', 'group', and 'parody' metadata
fields since this information is, as for now, only available in
gallery pages.

gallery_dl/extractor/hitomi.py

@@ -10,7 +10,6 @@
 
 from .common import GalleryExtractor
 from .. import text, util
-import string
 import json
 
 
@@ -24,7 +23,7 @@ class HitomiGalleryExtractor(GalleryExtractor):
     test = (
         ("https://hitomi.la/galleries/867789.html", {
             "pattern": r"https://[a-c]a.hitomi.la/images/./../[0-9a-f]+.jpg",
-            "keyword": "6701f8f588f119ef84cd29bdf99a399417b0a6a2",
+            "keyword": "3314105a0b344ea1461c43257b14b0de415b88bb",
             "count": 16,
         }),
         # download test
@@ -55,56 +54,43 @@ class HitomiGalleryExtractor(GalleryExtractor):
     )
 
     def __init__(self, match):
-        self.gallery_id = match.group(1)
-        url = "https://ltn.hitomi.la/galleries/{}.js".format(self.gallery_id)
+        gid = match.group(1)
+        url = "https://ltn.hitomi.la/galleries/{}.js".format(gid)
         GalleryExtractor.__init__(self, match, url)
+        self.data = None
         self.session.headers["Referer"] = "{}/reader/{}.html".format(
-            self.root, self.gallery_id)
-
-    def metadata(self, _):
-        # try galleries page first
-        url = "{}/galleries/{}.html".format(self.root, self.gallery_id)
-        response = self.request(url, fatal=False)
-
-        # follow redirects
-        while b"<title>Redirect</title>" in response.content:
-            url = text.extract(response.text, "href='", "'")[0]
-            if not url.startswith("http"):
-                url = text.urljoin(self.root, url)
-            response = self.request(url, fatal=False)
-
-        # fallback to reader page
-        if response.status_code >= 400:
-            url = "{}/reader/{}.html".format(self.root, self.gallery_id)
-            page = self.request(url).text
-            return {
-                "gallery_id": text.parse_int(self.gallery_id),
-                "title": text.unescape(text.extract(
-                    page, "<title>", "<")[0].rpartition(" | ")[0]),
-            }
-
-        page = response.text
-        extr = text.extract_from(page, page.index('<h1><a href="/reader/'))
-        data = {
-            "gallery_id": text.parse_int(self.gallery_id),
-            "title"     : text.unescape(extr('.html">', '<').strip()),
-            "artist"    : self._prep(extr('<h2>', '</h2>')),
-            "group"     : self._prep(extr('<td>Group</td><td>', '</td>')),
-            "type"      : self._prep_1(extr('<td>Type</td><td>', '</td>')),
-            "language"  : self._prep_1(extr('<td>Language</td><td>', '</td>')),
-            "parody"    : self._prep(extr('<td>Series</td><td>', '</td>')),
-            "characters": self._prep(extr('<td>Characters</td><td>', '</td>')),
-            "tags"      : self._prep(extr('<td>Tags</td><td>', '</td>')),
-            "date"      : self._date(extr('<span class="date">', '</span>')),
+            self.root, gid)
+
+    def metadata(self, page):
+        self.data = data = json.loads(page.partition("=")[2])
+
+        language = data.get("language")
+        if language:
+            language = language.capitalize()
+
+        tags = []
+        for tinfo in data["tags"]:
+            tag = tinfo["tag"]
+            if tinfo.get("female"):
+                tag = "female:" + tag
+            elif tinfo.get("male"):
+                tag = "male:" + tag
+            tags.append(tag)
+
+        return {
+            "gallery_id": text.parse_int(data["id"]),
+            "title"     : data["title"],
+            "type"      : data["type"],
+            "language"  : language,
+            "lang"      : util.language_to_code(language),
+            "tags"      : tags,
+            "date"      : text.parse_datetime(
+                data["date"] + ":00", "%Y-%m-%d %H:%M:%S%z"),
         }
-        if data["language"] == "N/a":
-            data["language"] = None
-        data["lang"] = util.language_to_code(data["language"])
-        return data
 
-    def images(self, page):
+    def images(self, _):
         result = []
-        for image in json.loads(page.partition("=")[2])["files"]:
+        for image in self.data["files"]:
             ihash = image["hash"]
             idata = text.nameext_from_url(image["name"])
 
@@ -120,18 +106,3 @@ class HitomiGalleryExtractor(GalleryExtractor):
             )
             result.append((url, idata))
         return result
-
-    @staticmethod
-    def _prep(value):
-        return [
-            text.unescape(string.capwords(v))
-            for v in text.extract_iter(value or "", '.html">', '<')
-        ]
-
-    @staticmethod
-    def _prep_1(value):
-        return text.remove_html(value).capitalize()
-
-    @staticmethod
-    def _date(value):
-        return text.parse_datetime(value + ":00", "%Y-%m-%d %H:%M:%S%z")