[discord] add 'server-assets' extractor (#8589)

docs/supportedsites.md

@@ -268,7 +268,7 @@ Consider all listed sites to potentially be NSFW.
 <tr id="discord" title="discord">
     <td>Discord</td>
     <td>https://discord.com/</td>
-    <td>Channels, DMs, Messages, Servers</td>
+    <td>Channels, DMs, Messages, Servers, Server Assets</td>
     <td></td>
 </tr>
 <tr id="dynastyscans" title="dynastyscans">

gallery_dl/extractor/discord.py

@@ -9,7 +9,6 @@
 from .common import Extractor, Message
 from .. import text, exception
 
-
 BASE_PATTERN = r"(?:https?://)?discord\.com"
 
 
@@ -203,29 +202,47 @@ class DiscordExtractor(Extractor):
 
     def parse_server(self, server):
         self.server_metadata = {
-            "server": server["name"],
+            "server"   : server["name"],
             "server_id": server["id"],
-            "server_files": [],
-            "owner_id": server["owner_id"]
+            "owner_id" : server["owner_id"],
+            "server_files": self.collect_server_assets_general(server),
         }
 
-        for icon_type, icon_path in (
-            ("icon", "icons"),
-            ("banner", "banners"),
-            ("splash", "splashes"),
-            ("discovery_splash", "discovery-splashes")
-        ):
-            if server.get(icon_type):
-                self.server_metadata["server_files"].append({
-                    "url": (f"https://cdn.discordapp.com/{icon_path}/"
-                            f"{self.server_metadata['server_id']}/"
-                            f"{server[icon_type]}.png?size=4096"),
-                    "filename": icon_type,
-                    "extension": "png",
-                })
-
         return self.server_metadata
 
+    def collect_server_assets_general(self, server):
+        return [
+            {
+                "url": (f"https://cdn.discordapp.com/{asset_path}/"
+                        f"{server['id']}/{asset_id}.png?size=4096"),
+                "id"       : f"{server['id']}/{asset_id}",
+                "label"    : "general",
+                "name"     : asset_type,
+                "filename" : asset_type,
+                "extension": "png",
+            }
+            for asset_type, asset_path in (
+                ("icon"  , "icons"),
+                ("banner", "banners"),
+                ("splash", "splashes"),
+                ("discovery_splash", "discovery-splashes")
+            )
+            if (asset_id := server.get(asset_type))
+        ]
+
+    def collect_server_assets_type(self, server, asset_type):
+        return [
+            {
+                **asset,
+                "url": (f"https://cdn.discordapp.com/{asset_type}/"
+                        f"{asset['id']}.png?size=4096"),
+                "label"    : asset_type,
+                "filename" : f"{asset['name']} ({asset['id']})",
+                "extension": "png",
+            }
+            for asset in assets
+        ] if (assets := server.get(asset_type)) else ()
+
     def build_server_and_channels(self, server_id):
         self.parse_server(self.api.get_server(server_id))
 
@@ -266,6 +283,38 @@ class DiscordMessageExtractor(DiscordExtractor):
             self.api.get_message(channel_id, message_id))
 
 
+class DiscordServerAssetsExtractor(DiscordExtractor):
+    subcategory = "server-assets"
+    filename_fmt = "{name} ({id}).{extension}"
+    directory_fmt = ["{category}", "{server_id}_{server}", "Assets"]
+    archive_fmt = "asset_{server_id}_{id}"
+    pattern = (BASE_PATTERN +
+               r"/channels/(\d+)/(?:assets?|files)(?:/([\w-]+))?/?$")
+    example = "https://discord.com/channels/1234567890/assets"
+
+    def items(self):
+        server_id, asset_type = self.groups
+        server = self.api.get_server(server_id)
+        parsed = self.parse_server(server)
+
+        if asset_type is None:
+            assets = [
+                *self.collect_server_assets_general(server),
+                *self.collect_server_assets_type(server, "emojis"),
+                *self.collect_server_assets_type(server, "stickers"),
+            ]
+        elif asset_type == "general":
+            assets = self.collect_server_assets_general(server)
+        else:
+            assets = self.collect_server_assets_type(server, asset_type)
+
+        parsed["count"] = len(assets)
+        yield Message.Directory, "", parsed
+        for asset in assets:
+            asset.update(parsed)
+            yield Message.Url, asset["url"], asset
+
+
 class DiscordServerExtractor(DiscordExtractor):
     subcategory = "server"
     pattern = BASE_PATTERN + r"/channels/(\d+)/?$"

test/results/discord.py

@@ -73,4 +73,38 @@ __tests__ = (
     "#class"   : discord.DiscordDirectMessagesExtractor,
 },
 
+{
+    "#url"     : "https://discord.com/channels/403905762268545024/assets",
+    "#class"   : discord.DiscordServerAssetsExtractor,
+    "#auth"    : "token",
+    "#count"   : range(380, 450),
+
+    "name"     : str,
+    "filename" : str,
+    "extension": "png",
+    "id"       : str,
+    "label"    : {"general", "emojis", "stickers"},
+    "owner_id" : "699203962691256400",
+    "server"   : "MangaDex",
+    "server_id": "403905762268545024",
+    "url"      : str,
+},
+
+{
+    "#url"     : "https://discord.com/channels/403905762268545024/assets/general",
+    "#class"   : discord.DiscordServerAssetsExtractor,
+    "#auth"    : "token",
+    "#count"   : 3,
+
+    "name"     : {"icon", "banner", "splash"},
+    "filename" : {"icon", "banner", "splash"},
+    "extension": "png",
+    "id"       : str,
+    "label"    : "general",
+    "owner_id" : "699203962691256400",
+    "server"   : "MangaDex",
+    "server_id": "403905762268545024",
+    "url"      : str,
+},
+
 )