def exists(cls, path):
"""Returns opened file or None.
`path` is relative to WAITER_ROOT.
Won't open a path leading outside of WAITER_ROOT.
"""
abs_path = check_abspath(path)
# Pre-fetch objects for deletion to avoid minor race condition
relevant = [o.id for o in cls.objects.filter(path=path)]
if isfile(abs_path):
cls.objects.filter(id__in=relevant).delete()
return True
else:
return False
def exists(cls, path):
"""Returns opened file or None.
`path` is relative to WAITER_ROOT.
Won't open a path leading outside of WAITER_ROOT.
"""
abs_path = check_abspath(path)
# Pre-fetch objects for deletion to avoid minor race condition
relevant = [o.id for o in cls.objects.filter(path=path)]
if isfile(abs_path):
cls.objects.filter(id__in=relevant).delete()
return True
else:
return False
def order(cls, path, task_creator, description=None):
"""
Returns an URL for the user to follow.
If the file is ready, returns download URL.
If not, starts preparing it and returns waiting URL.
task_creator: function taking a path and generating the file;
description: a string or string proxy with a description for user;
"""
already = cls.exists(path)
if not already:
waited, created = cls.objects.get_or_create(path=path)
if created or waited.is_stale():
waited.task = task_creator(check_abspath(path))
waited.task_id = waited.task.task_id
waited.description = description
waited.save()
return reverse("waiter", args=[path])
return join(WAITER_URL, path)
def order(cls, path, task_creator, description=None):
"""
Returns an URL for the user to follow.
If the file is ready, returns download URL.
If not, starts preparing it and returns waiting URL.
task_creator: function taking a path and generating the file;
description: a string or string proxy with a description for user;
"""
already = cls.exists(path)
if not already:
waited, created = cls.objects.get_or_create(path=path)
if created:
waited.task = task_creator(check_abspath(path), waited.pk)
waited.task_id = waited.task.task_id
waited.description = description
waited.save()
return reverse("waiter", args=[path])
return join(WAITER_URL, path)