Add content-type check for HLS responses

src/delarte/hls.py

@@ -29,11 +29,19 @@ from .model import Rendition, RenditionAudio, RenditionSubtitles, Source, Varian
 #   the same file
 # - Subtitles indexes have only one segment
 
+MIME_TYPE = "application/x-mpegURL"
+
 
 def _fetch_index(http_session, url):
     # Fetch a M3U8 playlist
     r = http_session.get(url)
     r.raise_for_status()
+
+    if (_ := r.headers["content-type"]) != MIME_TYPE:
+        raise UnexpectedHLSResponse("MIME_TYPE", url, MIME_TYPE, _)
+
+    r.encoding = "utf-8"
+
     return m3u8.loads(r.text, url)