Download HTML only as a link, not as a file

boards/models/attachment/downloaders.py

@@ -19,6 +19,11 b' FILE_DOWNLOAD_CHUNK_BYTES = 200000'
 
 YOUTUBE_URL = re.compile(r'https?://((www\.)?youtube\.com/watch\?v=|youtu.be/)[-\w]+')
 
+TYPE_URL_ONLY = (
+    'application/xhtml+xml',
+    'text/html',
+)
+
 
 class Downloader:
     @staticmethod
@@ -77,3 +82,14 b' class YouTubeDownloader(Downloader):'
     def handles(url: str) -> bool:
         return YOUTUBE_URL.match(url)
 
+
+class NothingDownloader(Downloader):
+    @staticmethod
+    def handles(url: str) -> bool:
+        response_head = requests.head(url, verify=False)
+        content_type = response_head.headers[HEADER_CONTENT_TYPE].split(';')[0]
+        return content_type in TYPE_URL_ONLY
+
+    @staticmethod
+    def download(url: str):
+        return None