[exhentai] add 'source' option

setting it to "hitomi" downloads the corresponding gallery from
hitomi.la; might be extended to other sources in the future

docs/configuration.rst

@@ -1081,17 +1081,6 @@ Description
     Minimum wait time in seconds before API requests.
 
 
-extractor.exhentai.limits
--------------------------
-Type
-    ``integer``
-Default
-    ``null``
-Description
-    Sets a custom image download limit and
-    stops extraction when it gets exceeded.
-
-
 extractor.exhentai.domain
 -------------------------
 Type
@@ -1105,6 +1094,17 @@ Description
     * ``"exhentai.org"``: Use ``exhentai.org`` for all URLs
 
 
+extractor.exhentai.limits
+-------------------------
+Type
+    ``integer``
+Default
+    ``null``
+Description
+    Sets a custom image download limit and
+    stops extraction when it gets exceeded.
+
+
 extractor.exhentai.metadata
 ---------------------------
 Type
@@ -1129,6 +1129,18 @@ Description
     Download full-sized original images if available.
 
 
+extractor.exhentai.source
+-------------------------
+Type
+    ``string``
+Default
+    ``"gallery"``
+Description
+    Selects an alternative source to download files from.
+
+    * ``"hitomi"``:  Download the corresponding gallery from ``hitomi.la``
+
+
 extractor.fanbox.embeds
 -----------------------
 Type

gallery_dl/extractor/exhentai.py

@@ -176,6 +176,10 @@ class ExhentaiGalleryExtractor(ExhentaiExtractor):
         self.image_token = match.group(4)
         self.image_num = text.parse_int(match.group(6), 1)
 
+        source = self.config("source")
+        if source == "hitomi":
+            self.items = self._items_hitomi
+
     def items(self):
         self.login()
 
@@ -221,6 +225,18 @@ class ExhentaiGalleryExtractor(ExhentaiExtractor):
                 data["_http_validate"] = None
             yield Message.Url, url, data
 
+    def _items_hitomi(self):
+        if self.config("metadata", False):
+            data = self.metadata_from_api()
+            data["date"] = text.parse_timestamp(data["posted"])
+        else:
+            data = {}
+
+        from .hitomi import HitomiGalleryExtractor
+        url = "https://hitomi.la/galleries/{}.html".format(self.gallery_id)
+        data["_extractor"] = HitomiGalleryExtractor
+        yield Message.Queue, url, data
+
     def get_metadata(self, page):
         """Extract gallery metadata"""
         data = self.metadata_from_page(page)