[Danbooru] add 'random' extractor

Adds a new `DanbooruRandomExtractor` to support downloading from `danbooru.donmai.us/posts/random?tags=` URLs.

docs/supportedsites.md

@@ -1252,25 +1252,25 @@ Consider all listed sites to potentially be NSFW.
 <tr id="danbooru" title="danbooru">
     <td>Danbooru</td>
     <td>https://danbooru.donmai.us/</td>
-    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Tag Searches</td>
+    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Random Posts, Tag Searches</td>
     <td>Supported</td>
 </tr>
 <tr id="atfbooru" title="atfbooru">
     <td>ATFBooru</td>
     <td>https://booru.allthefallen.moe/</td>
-    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Tag Searches</td>
+    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Random Posts, Tag Searches</td>
     <td>Supported</td>
 </tr>
 <tr id="aibooru" title="aibooru">
     <td>AIBooru</td>
     <td>https://aibooru.online/</td>
-    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Tag Searches</td>
+    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Random Posts, Tag Searches</td>
     <td>Supported</td>
 </tr>
 <tr id="booruvar" title="booruvar">
     <td>Booruvar</td>
     <td>https://booru.borvar.art/</td>
-    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Tag Searches</td>
+    <td>Artists, Artist Searches, Favorite Groups, Pools, Popular Images, Posts, Random Posts, Tag Searches</td>
     <td>Supported</td>
 </tr>
 

gallery_dl/extractor/danbooru.py

@@ -278,6 +278,23 @@ class DanbooruTagExtractor(DanbooruExtractor):
         return self._pagination("/posts.json", {"tags": self.tags}, prefix)
 
 
+class DanbooruRandomExtractor(DanbooruTagExtractor):
+    """Extractor for a random danbooru post"""
+    subcategory = "random"
+    pattern = BASE_PATTERN + r"/posts/random(?:\?(?:[^&#]*&)*tags=([^&#]*))?"
+    example = "https://danbooru.donmai.us/posts/random?tags=TAG"
+
+    def metadata(self):
+        tags = self.groups[-1] or ""
+        self.tags = text.unquote(tags.replace("+", " "))
+        return {"search_tags": self.tags}
+
+    def posts(self):
+        posts = self.request_json(self.root + "/posts/random.json",
+                                  params={"tags": self.tags or None})
+        return (posts,) if isinstance(posts, dict) else posts
+
+
 class DanbooruPoolExtractor(DanbooruExtractor):
     """Extractor for Danbooru pools"""
     subcategory = "pool"

scripts/supportedsites.py

@@ -264,6 +264,7 @@ SUBCATEGORY_MAP = {
     },
     "Danbooru": {
         "favgroup": "Favorite Groups",
+        "random"  : "Random Posts",
     },
     "desktopography": {
         "site": "",

test/results/aibooru.py

@@ -80,4 +80,24 @@ __tests__ = (
     "#class"   : danbooru.DanbooruPopularExtractor,
 },
 
+{
+    "#url"     : "https://aibooru.online/posts/random?tags=center_frills&z=1",
+    "#category": ("Danbooru", "aibooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+    "#pattern" : "https://cdn.aibooru.download/original/.+",
+    "#count"   : 1,
+
+    "search_tags": "center_frills",
+},
+
+{
+    "#url"     : "https://aibooru.online/posts/random",
+    "#category": ("Danbooru", "aibooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+    "#pattern" : "https://cdn.aibooru.download/original/.+",
+    "#count"   : 1,
+
+    "search_tags": "",
+},
+
 )

test/results/atfbooru.py

@@ -36,4 +36,16 @@ __tests__ = (
     "#class"   : danbooru.DanbooruPopularExtractor,
 },
 
+{
+    "#url"     : "https://booru.allthefallen.moe/posts/random?tags=yume_shokunin",
+    "#category": ("Danbooru", "atfbooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+},
+
+{
+    "#url"     : "https://booru.allthefallen.moe/posts/random",
+    "#category": ("Danbooru", "atfbooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+},
+
 )

test/results/booruvar.py

@@ -37,4 +37,16 @@ __tests__ = (
     "#class"   : danbooru.DanbooruPopularExtractor,
 },
 
+{
+    "#url"     : "https://booru.borvar.art/posts/random?tags=chibi&z=1",
+    "#category": ("Danbooru", "booruvar", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+},
+
+{
+    "#url"     : "https://booru.borvar.art/posts/random",
+    "#category": ("Danbooru", "booruvar", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+},
+
 )

test/results/danbooru.py

@@ -382,4 +382,24 @@ __tests__ = (
     "other_names": list,
 },
 
+{
+    "#url"     : "https://danbooru.donmai.us/posts/random?tags=bonocho",
+    "#category": ("Danbooru", "danbooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+    "#pattern" : "https://cdn.donmai.us/original/.+",
+    "#count"   : 1,
+
+    "search_tags": "bonocho",
+},
+
+{
+    "#url"     : "https://danbooru.donmai.us/posts/random",
+    "#category": ("Danbooru", "danbooru", "random"),
+    "#class"   : danbooru.DanbooruRandomExtractor,
+    "#pattern" : "https://cdn.donmai.us/original/.+",
+    "#count"   : 1,
+
+    "search_tags": "",
+},
+
 )