download_media: Add function for checking if a URL has been downloaded before

common/common/media.py

@@ -14,7 +14,7 @@ import prometheus_client as prom
 import urllib3.connection
 from ipaddress import ip_address
 
-from . import atomic_write, ensure_directory, jitter
+from . import atomic_write, ensure_directory, jitter, listdir
 from .stats import timed
 
 
@@ -52,6 +52,12 @@ class WrongContent(Rejected):
 	"""Response was not a video or image"""
 
 
+def check_for_media(output_dir, url):
+	"""Returns True if we have at least one version of content for the given url already."""
+	url_dir = get_url_dir(output_dir, url)
+	return any(filename.endswith(".metadata.json") for filename in listdir(url_dir))
+
+
 @timed()
 def download_media(
 	url,