[4chan] use api

gallery_dl/extractor/4chan.py

@@ -8,65 +8,25 @@
 
 """Extract image- and video-urls from threads on https://www.4chan.org/"""
 
-from .common import SequentialExtractor, Message
-from urllib.parse import unquote
-import re
+from .chan import ChanExtractor
 
 info = {
     "category": "4chan",
     "extractor": "FourChanExtractor",
     "directory": ["{category}", "{board}-{thread-id}"],
-    "filename": "{timestamp}-{name}",
+    "filename": "{time}-{filename}{ext}",
     "pattern": [
         r"(?:https?://)?boards\.4chan\.org/([^/]+)/thread/(\d+).*",
     ],
 }
 
-class FourChanExtractor(SequentialExtractor):
+class FourChanExtractor(ChanExtractor):
 
-    url_fmt = "https://boards.4chan.org/{0}/res/{1}.html"
-    regex = (
-        r'<a (?:title="(?P<orig_name>[^"]+)" )?href="'
-        r'(?P<url>//i.4cdn.org/[^/]+/(?P<timestamp>\d+)\.(?P<extension>[^"]+))'
-        r'" target="_blank">(?P<name>[^<]+)</a> '
-        r'\((?P<size>[^,]+), (?P<width>\d+)x(?P<height>\d+)\)'
-    )
+    api_url = "https://a.4cdn.org/{board}/thread/{thread}.json"
+    file_url = "https://i.4cdn.org/{board}/{tim}{ext}"
 
     def __init__(self, match, config):
-        SequentialExtractor.__init__(self, config)
-        self.match = match
-        self.metadata = None
-
-    def items(self):
-        yield Message.Version, 1
-
-        url = self.url_fmt.format(*self.match.groups())
-        text = self.request(url).text
-        self.metadata = self.get_job_metadata(text)
-
-        yield Message.Directory, self.metadata
-        for match in re.finditer(self.regex, text):
-            yield Message.Url, self.get_file_url(match), self.get_file_metadata(match)
-
-    def get_job_metadata(self, text):
-        """Collect metadata for extractor-job"""
-        board, thread_id = self.match.groups()
-        title, _ = self.extract(text, '"description" content="', ' - &quot;/')
-        return {
-            "category": info["category"],
-            "board": board,
-            "thread-id": thread_id,
-            "title": unquote(title),
-        }
-
-    def get_file_metadata(self, match):
-        """Collect metadata for a downloadable file"""
-        data = self.metadata
-        data.update(match.groupdict(default=""))
-        data["name"] = unquote(data["orig_name"] or data["name"])
-        return data
-
-    @staticmethod
-    def get_file_url(match):
-        """Extract download-url from 'match'"""
-        return "https:" + match.group("url")
+        ChanExtractor.__init__(
+            self, config, info["category"],
+            match.group(1), match.group(2)
+        )