[tumblr] improve inline extraction (#137)

gallery_dl/extractor/tumblr.py

@@ -104,16 +104,16 @@ class TumblrExtractor(Extractor):
             if "video_url" in post:  # type: "video"
                 yield self._prepare(_original_video(post["video_url"]), post)
 
-            if self.inline:  # inline media
-                for key in ("body", "description", "source"):
-                    if key not in post:
-                        continue
-                    for url in re.findall('<img src="([^"]+)"', post[key]):
-                        url = _original_inline_image(url)
-                        yield self._prepare_image(url, post)
-                    for url in re.findall('<source src="([^"]+)"', post[key]):
-                        url = _original_video(url)
-                        yield self._prepare(url, post)
+            if self.inline and "reblog" in post:  # inline media
+                # only "chat" posts are missing a "reblog" key in their
+                # API response, but they can't contain images/videos anyway
+                body = post["reblog"]["comment"]
+                for url in re.findall('<img src="([^"]+)"', body):
+                    url = _original_inline_image(url)
+                    yield self._prepare_image(url, post)
+                for url in re.findall('<source src="([^"]+)"', body):
+                    url = _original_video(url)
+                    yield self._prepare(url, post)
 
             if self.external:  # external links
                 post["extension"] = None