[4chan] simplify

- remove 'chan.py'
- slight adjustments to directory and filenames

gallery_dl/extractor/4chan.py

@@ -6,15 +6,19 @@
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
 
-"""Extract images and videos from https://www.4chan.org/"""
+"""Extractors for https://www.4chan.org/"""
 
-from . import chan
+from .common import Extractor, Message
 from .. import text
 
 
-class FourchanThreadExtractor(chan.ChanThreadExtractor):
-    """Extractor for images from threads from 4chan.org"""
+class _4chanThreadExtractor(Extractor):
+    """Extractor for 4chan threads"""
     category = "4chan"
+    subcategory = "thread"
+    directory_fmt = ("{category}", "{board}", "{thread} {title}")
+    filename_fmt = "{tim} {filename}.{extension}"
+    archive_fmt = "{board}_{thread}_{tim}"
     pattern = (r"(?:https?://)?boards\.4chan(?:nel)?\.org"
                r"/([^/]+)/thread/(\d+)")
     test = (
@@ -28,9 +32,30 @@ class FourchanThreadExtractor(chan.ChanThreadExtractor):
             "keyword": "7ae2f4049adf0d2f835eb91b6b26b7f4ec882e0a",
         }),
     )
-    api_url = "https://a.4cdn.org/{board}/thread/{thread}.json"
-    file_url = "https://i.4cdn.org/{board}/{tim}{ext}"
 
-    def update(self, post, data=None):
-        chan.ChanThreadExtractor.update(self, post, data)
-        post["filename"] = text.unescape(post["filename"])
+    def __init__(self, match):
+        Extractor.__init__(self, match)
+        self.board, self.thread = match.groups()
+
+    def items(self):
+        url = "https://a.4cdn.org/{}/thread/{}.json".format(
+            self.board, self.thread)
+        posts = self.request(url).json()["posts"]
+        title = posts[0].get("sub") or text.remove_html(posts[0]["com"])
+
+        data = {
+            "board" : self.board,
+            "thread": self.thread,
+            "title" : text.unescape(title)[:50],
+        }
+
+        yield Message.Version, 1
+        yield Message.Directory, data
+        for post in posts:
+            if "filename" in post:
+                post.update(data)
+                post["extension"] = post["ext"][1:]
+                post["filename"] = text.unescape(post["filename"])
+                url = "https://i.4cdn.org/{}/{}{}".format(
+                    post["board"], post["tim"], post["ext"])
+                yield Message.Url, url, post