commit 871a957f23097807f67e502fd6e2c9a9b9a6c456 Author: Damian Johnson atagar@torproject.org Date: Tue Jul 16 09:28:18 2013 -0700

Rejecting requests for more than 96 descriptors

In our tor-dev@ discussion Karsten mentioned that we could request at most 96 descriptors at a time when polling by their fingerprints...

https://lists.torproject.org/pipermail/tor-dev/2013-June/005005.html

I've emailed him to clarify where this limitation comes from (the url length or something within tor?), but in the meantime adding a check for this to our get_sever_descriptors() method. --- stem/descriptor/remote.py | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/stem/descriptor/remote.py b/stem/descriptor/remote.py index a4b21d4..3021f63 100644 --- a/stem/descriptor/remote.py +++ b/stem/descriptor/remote.py @@ -50,6 +50,11 @@ import stem.descriptor

from stem.util import log

+# Tor has a limit on the number of descriptors we can fetch explicitly by their +# fingerprint. + +MAX_BATCH_SIZE = 96 + # Tor directory authorities as of commit f631b73 (7/4/13). This should only # include authorities with 'v3ident': # @@ -266,6 +271,8 @@ class DescriptorDownloader(object): retrieved, gets all descriptors if **None**

:returns: :class:`~stem.descriptor.remote.Query` for the server descriptors + + :raises: **ValueError** if we request descriptors by fingerprints and there are more than 96 of them (this is a limitation of tor). """

resource = '/tor/server/all' @@ -274,6 +281,9 @@ class DescriptorDownloader(object): if isinstance(fingerprints, str): resource = '/tor/server/fp/%s' % fingerprints else: + if len(fingerprints) > MAX_BATCH_SIZE: + raise ValueError('We can request at most %i descritors at a time when retrieving by fingerprints' % MAX_BATCH_SIZE) + resource = '/tor/server/fp/%s' % '+'.join(fingerprints)

return self._query(resource, 'server-descriptor 1.0')