podcast: duration is lazy-loaded

larigira/audiogen_podcast.py

@@ -6,11 +6,11 @@ import sys
 from subprocess import CalledProcessError, check_output
 
 import requests
-
-from larigira.fsutils import download_http
 from lxml import html
 from pytimeparse.timeparse import timeparse
 
+from larigira.fsutils import download_http
+
 
 def delta_humanreadable(tdelta):
     if tdelta is None:
@@ -35,8 +35,9 @@ def get_duration(url):
                 url,
             ]
         ).split(b"\n")
-    except CalledProcessError as exc:
-        raise ValueError("error probing `%s`" % url) from exc
+    except CalledProcessError:
+        logging.exception("error probing `%s`", url)
+        return 0
     duration = next(l for l in lineout if l.startswith(b"duration="))
     value = duration.split(b"=")[1]
     return int(float(value))
@@ -45,9 +46,7 @@ def get_duration(url):
 class Audio(object):
     def __init__(self, url, duration=None, date=None):
         self.url = url
-        if duration is None:
-            duration = get_duration(url.encode("utf-8"))
-        self.duration = duration
+        self._duration = duration
         self.date = date
         self.end_date = datetime.datetime(
             9999, 12, 31, tzinfo=datetime.timezone.utc
@@ -58,10 +57,17 @@ class Audio(object):
 
     def __repr__(self):
         return "<Audio {} ({} {})>".format(
-            self.url, self.duration, delta_humanreadable(self.age)
+            self.url, self._duration, delta_humanreadable(self.age)
         )
 
     @property
+    def duration(self):
+        """lazy-calculation"""
+        if self._duration is None:
+            self._duration = get_duration(self.url.encode("utf-8"))
+        return self._duration
+
+    @property
     def urls(self):
         return [self.url]