mongodol.recipes

Mongodol Recipes

Functions

disallow_sourced_interval_overlaps(store)

Disallow writing to a key that shares the same "source" field value and overlapping ("bt", "tt") interval.

Exceptions

WriteNotAllowedToThatKey

To indicate that once cannot write to some specific key one is trying to write to

exception mongodol.recipes.WriteNotAllowedToThatKey

Bases: KeyError

To indicate that once cannot write to some specific key one is trying to write to

mongodol.recipes.disallow_sourced_interval_overlaps(store)

Disallow writing to a key that shares the same “source” field value and overlapping (“bt”, “tt”) interval.

Parameters:

store – KvPersister (instance or class) s

Returns:

The same store, but where s[dict(source=source, bt=bt, tt=tt)] = v writes are not permitted if there is another doc, with the same source, and an overlapping (bt, tt) interval.

>>> from mongodol.tests import get_test_collection_persister, clear_all_and_populate
>>>
>>> # We're going to take (make really) a store s with the two follwing documents:
>>>
>>> data = [
...     {'source': 'audio', 'bt': 6, 'tt': 9, 'annot': 'dog'},
...     {'source': 'visual', 'bt': 6, 'tt': 15, 'annot': 'dog'}
... ]
>>>
>>> # Then try to do s[k] = v with the following (k, v) pairs.
>>> k1 = {'source': 'audio', 'bt': 12, 'tt': 16}
>>> v1 = {'annot': 'cat'}
>>> # Note here that (7, 10) overlaps with (6, 9) (in source=audio)
>>> k2 = {'source': 'audio', 'bt': 7, 'tt': 10}
>>> v2 = {'annot': 'cat'}
>>>
>>>
>>>
>>> s = get_test_collection_persister()  # Make a persister
>>> clear_all_and_populate(data,s)  # empty it and populate it with the two data docs
>>> assert len(s) == 2  # yep, two docs
>>> assert s.distinct('annot') == ['dog']  # and only has a dog
>>>
>>>
>>> s[k1] = v1
>>> assert len(s) == 3  # Now has three docs
>>> assert 'cat' in s.distinct('annot')  # has a cat now
>>>
>>> s[k2] = v2
>>> assert len(s) == 4  # v2 was written, indeed
>>>
>>>
>>> # Let's start over, usingour disallow_sourced_interval_overlaps decorator this time
>>>
>>> protected_s = disallow_sourced_interval_overlaps(get_test_collection_persister())
>>> clear_all_and_populate(data,protected_s)  # empty it and populate it with the two data docs
>>>
>>> s[k1] = v1
>>> # No problem! And see that you have a cat annot now!
>>> assert 'cat' in s.distinct('annot')
>>> # But this next one will not work since the (7, 10) overlaps with (6, 9) (in source=audio)
>>> try:
...     protected_s[k2] = v2
... except WriteNotAllowedToThatKey:
...     print("WriteNotAllowedToThatKey expected!")
WriteNotAllowedToThatKey expected!