mongoql-conv 0.1.1

Library to convert those MongoDB queries to something else, like a python expresion, a function or a Django Q object tree to be used with a ORM query.

Library to convert those MongoDB queries to something else, like a python expresion, a function or a Django Q object tree to be used with a ORM query.

For now, only supports flat operations. No subdocuments. It might work but results are undefined/buggy. Could be fixed though …

Installation

pip install mongoql-conv

Or:

pip install mongoql-conv[django]

API

• mongoql_conv.to_string: to_string

• mongoql_conv.to_func: to_func

• mongoql_conv.django.to_Q: to_Q

to_string

>>> from mongoql_conv import to_string

>>> to_string({"myfield": 1})
"row['myfield'] == 1"

>>> to_string({"field1": 1, "field2": 2})
"(row['field2'] == 2) and (row['field1'] == 1)"

>>> to_string({"myfield": 1}, object_name='item')
"item['myfield'] == 1"

>>> to_string({"myfield": {"$in": [1, 2]}})
"row['myfield'] in {1, 2}"

>>> to_string({"myfield": {"$in": {1: 2}}})
Traceback (most recent call last):
...
InvalidQuery: Invalid query part {1: 2}. Expected one of: set, list, tuple, frozenset.

Supported operators

Arithmetic

• $gt:

  >>> to_string({"myfield": {"$gt": 1}})
  "row['myfield'] > 1"
  >>> to_string({"myfield": {"$gt": [1]}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part [1]. Expected value of type int, float, str, unicode, bool or None.

• $gte:

  >>> to_string({"myfield": {"$gte": 1}})
  "row['myfield'] >= 1"

• $lt:

  >>> to_string({"myfield": {"$lt": 1}})
  "row['myfield'] < 1"

• $lte:

  >>> to_string({"myfield": {"$lte": 1}})
  "row['myfield'] <= 1"

• $eq:

  >>> to_string({"myfield": {"$eq": 1}})
  "row['myfield'] == 1"
  >>> to_string({"myfield": 1})
  "row['myfield'] == 1"

• $ne:

  >>> to_string({"myfield": {"$ne": 1}})
  "row['myfield'] != 1"

• $mod:

  >>> to_string({"myfield": {"$mod": [2, 1]}})
  "row['myfield'] % 2 == 1"
  >>> to_string({"myfield": {"$mod": [2, 1, 3]}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part [2, 1, 3]. You must have two items: divisor and remainder.
  >>> to_string({"myfield": {"$mod": 2}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 2. Expected one of: list, tuple.
  >>> to_string({"myfield": {"$mod": (2, 1)}})
  "row['myfield'] % 2 == 1"

Containers

• $in:

  >>> to_string({"myfield": {"$in": (1, 2, 3)}})
  "row['myfield'] in {1, 2, 3}"

• $nin:

  >>> to_string({"myfield": {"$nin": [1, 2, 3]}})
  "row['myfield'] not in {1, 2, 3}"
  >>> to_string({"myfield": {"$nin": {1: 2}}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part {1: 2}. Expected one of: set, list, tuple, frozenset.

• $size:

  >>> to_string({"myfield": {"$size": 3}})
  "len(row['myfield']) == 3"
  >>> to_string({"myfield": {"$size": "3"}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part '3'. Expected one of: int, long.

• $all:

  >>> to_string({"myfield": {"$all": [1, 2, 3]}})
  "set(row['myfield']) >= {1, 2, 3}"
  >>> to_string({"myfield": {"$all": 1}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 1. Expected one of: set, list, tuple, frozenset.

• $exists:

  >>> to_string({"myfield": {"$exists": True}})
  "'myfield' in row"
  >>> to_string({"myfield": {"$exists": False}})
  "'myfield' not in row"

Boolean operators

• $or:

  >>> to_string({'$or':  [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]})
  "(row['bubu'] > 1) or (row['bubu'] < 2)"
  >>> to_string({'$or': "invalid value"})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'invalid value'. Expected one of: list, tuple.

• $and:

  >>> to_string({'$and':  [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]})
  "(row['bubu'] > 1) and (row['bubu'] < 2)"
  >>> to_string({'$or': "invalid value"})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'invalid value'. Expected one of: list, tuple.

• $*nesting*:

  >>> to_string({'$and': [
  ...     {"bubu": {"$gt": 1}},
  ...     {'$or': [
  ...         {'bubu': {'$lt': 2}},
  ...         {'$and': [
  ...             {'bubu': {'$lt': 3}},
  ...             {'bubu': {'$lt': 4}},
  ...         ]}
  ...     ]}
  ... ]})
  "(row['bubu'] > 1) and ((row['bubu'] < 2) or ((row['bubu'] < 3) and (row['bubu'] < 4)))"

Regular expressions

• $regex:

  >>> to_string({"myfield": {"$regex": 'a'}})
  "re.match('a', row['myfield'], 0)"
  
  >>> to_string({"bubu": {"$regex": ".*x"}}, object_name='X')
  "re.match('.*x', X['bubu'], 0)"
  
  >>> to_string({"myfield": {"$regex": 'a', "$options": 'i'}})
  "re.match('a', row['myfield'], 2)"
  
  >>> closure = {}
  >>> to_string({"bubu": {"$regex": ".*x"}}, closure=closure), closure
  ("var0.match(row['bubu'])", {'var0': "re.compile('.*x', 0)"})
  
  >>> to_string({"myfield": {"$regex": 'junk('}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid regular expression 'junk(': unbalanced parenthesis
  
  >>> to_string({"myfield": {"$regex": 'a', 'junk': 'junk'}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part "'junk'". You can only have `$options` with `$regex`.
  
  >>> to_string({"bubu": {"$regex": ".*", "$options": "junk"}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'junk'. Unsupported regex option 'j'. Only 's', 'x', 'm', 'i' are supported !
  
  >>> to_string({"bubu": {"$options": "i"}})
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part {'$options': 'i'}. Cannot have $options without $regex.

to_func

>>> from mongoql_conv import to_func

>>> to_func({"myfield": 1}).source
"lambda item: (item['myfield'] == 1) # compiled from {'myfield': 1}"

>>> list(filter(to_func({"myfield": 1}), [{"myfield": 1}, {"myfield": 2}]))
[{'myfield': 1}]

>>> to_func({"myfield": {"$in": [1, 2]}}).source
"lambda item, var0={1, 2}: (item['myfield'] in var0) # compiled from {'myfield': {'$in': [1, 2]}}"

>>> list(filter(to_func({"myfield": {"$in": [1, 2]}}), [{"myfield": 1}, {"myfield": 2}]))
[{'myfield': 1}, {'myfield': 2}]

>>> to_func({"myfield": {"$in": {1: 2}}}).source
Traceback (most recent call last):
...
InvalidQuery: Invalid query part {1: 2}. Expected one of: set, list, tuple, frozenset.

Supported operators

Arithmetic

• $gt:

  >>> to_func({"myfield": {"$gt": 1}}).source
  "lambda item: (item['myfield'] > 1) # compiled from {'myfield': {'$gt': 1}}"
  >>> to_func({"myfield": {"$gt": [1]}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part [1]. Expected value of type int, float, str, unicode, bool or None.
  
  >>> list(filter(to_func({"myfield": {"$gt": 1}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 2}, {'myfield': 3}, {'myfield': 4}]

• $gte:

  >>> to_func({"myfield": {"$gte": 1}}).source
  "lambda item: (item['myfield'] >= 1) # compiled from {'myfield': {'$gte': 1}}"
  
  >>> list(filter(to_func({"myfield": {"$gte": 2}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 2}, {'myfield': 3}, {'myfield': 4}]

• $lt:

  >>> to_func({"myfield": {"$lt": 1}}).source
  "lambda item: (item['myfield'] < 1) # compiled from {'myfield': {'$lt': 1}}"
  
  >>> list(filter(to_func({"myfield": {"$lt": 1}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 0}]

• $lte:

  >>> to_func({"myfield": {"$lte": 1}}).source
  "lambda item: (item['myfield'] <= 1) # compiled from {'myfield': {'$lte': 1}}"
  
  >>> list(filter(to_func({"myfield": {"$lte": 1}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 0}, {'myfield': 1}]

• $eq:

  >>> to_func({"myfield": {"$eq": 1}}).source
  "lambda item: (item['myfield'] == 1) # compiled from {'myfield': {'$eq': 1}}"
  >>> to_func({"myfield": 1}).source
  "lambda item: (item['myfield'] == 1) # compiled from {'myfield': 1}"
  
  >>> list(filter(to_func({"myfield": {"$eq": 2}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 2}]

• $ne:

  >>> to_func({"myfield": {"$ne": 1}}).source
  "lambda item: (item['myfield'] != 1) # compiled from {'myfield': {'$ne': 1}}"
  
  >>> list(filter(to_func({"myfield": {"$ne": 2}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 0}, {'myfield': 1}, {'myfield': 3}, {'myfield': 4}]

• $mod:

  >>> to_func({"myfield": {"$mod": [2, 1]}}).source
  "lambda item: (item['myfield'] % 2 == 1) # compiled from {'myfield': {'$mod': [2, 1]}}"
  >>> to_func({"myfield": {"$mod": [2, 1, 3]}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part [2, 1, 3]. You must have two items: divisor and remainder.
  
  >>> to_func({"myfield": {"$mod": 2}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 2. Expected one of: list, tuple.
  
  >>> to_func({"myfield": {"$mod": (2, 1)}}).source
  "lambda item: (item['myfield'] % 2 == 1) # compiled from {'myfield': {'$mod': (2, 1)}}"
  
  >>> list(filter(to_func({"myfield": {"$mod": (2, 1)}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 1}, {'myfield': 3}]

Containers

• $in:

  >>> to_func({"myfield": {"$in": (1, 2, 3)}}).source
  "lambda item, var0={1, 2, 3}: (item['myfield'] in var0) # compiled from {'myfield': {'$in': (1, 2, 3)}}"
  
  >>> list(filter(to_func({"myfield": {"$in": (1, 2, 3)}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 1}, {'myfield': 2}, {'myfield': 3}]

• $nin:

  >>> to_func({"myfield": {"$nin": [1, 2, 3]}}).source
  "lambda item, var0={1, 2, 3}: (item['myfield'] not in var0) # compiled from {'myfield': {'$nin': [1, 2, 3]}}"
  
  >>> to_func({"myfield": {"$nin": {1: 2}}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part {1: 2}. Expected one of: set, list, tuple, frozenset.
  
  >>> list(filter(to_func({"myfield": {"$nin": (1, 2, 3)}}), [{"myfield": i} for i in range(5)]))
  [{'myfield': 0}, {'myfield': 4}]

• $size:

  >>> to_func({"myfield": {"$size": 3}}).source
  "lambda item: (len(item['myfield']) == 3) # compiled from {'myfield': {'$size': 3}}"
  
  >>> to_func({"myfield": {"$size": "3"}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part '3'. Expected one of: int, long.
  
  >>> list(filter(to_func({"myfield": {"$size": 3}}), [{"myfield": 'x'*i} for i in range(5)]))
  [{'myfield': 'xxx'}]
  
  >>> list(filter(to_func({"myfield": {"$size": 3}}), [{"myfield": list(range(i))} for i in range(5)]))
  [{'myfield': [0, 1, 2]}]

• $all:

  >>> to_func({"myfield": {"$all": [1, 2, 3]}}).source
  "lambda item, var0={1, 2, 3}: (set(item['myfield']) >= var0) # compiled from {'myfield': {'$all': [1, 2, 3]}}"
  
  >>> to_func({"myfield": {"$all": 1}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 1. Expected one of: set, list, tuple, frozenset.
  
  >>> list(filter(to_func({"myfield": {"$all": [3, 4]}}), [{"myfield": list(range(i))} for i in range(7)]))
  [{'myfield': [0, 1, 2, 3, 4]}, {'myfield': [0, 1, 2, 3, 4, 5]}]

• $exists:

  >>> to_func({"myfield": {"$exists": True}}).source
  "lambda item: ('myfield' in item) # compiled from {'myfield': {'$exists': True}}"
  
  >>> to_func({"myfield": {"$exists": False}}).source
  "lambda item: ('myfield' not in item) # compiled from {'myfield': {'$exists': False}}"
  
  >>> list(filter(to_func({"$or": [{"field1": {"$exists": True}}, {"field2": {"$exists": False}}]}), [{"field%s" % i: i} for i in range(5)]))
  [{'field0': 0}, {'field1': 1}, {'field3': 3}, {'field4': 4}]

Boolean operators

• $or:

  >>> to_func({'$or':  [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]}).source
  "lambda item: ((item['bubu'] > 1) or (item['bubu'] < 2)) # compiled from {'$or': [{'bubu': {'$gt': 1}}, {'bubu': {'$lt': 2}}]}"
  
  >>> to_func({'$or': "invalid value"}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'invalid value'. Expected one of: list, tuple.
  
  >>> list(filter(to_func({'$or': [{"bubu": {"$gt": 3}}, {'bubu': {'$lt': 2}}]}), [{"bubu": i} for i in range(5)]))
  [{'bubu': 0}, {'bubu': 1}, {'bubu': 4}]

• $and:

  >>> to_func({'$and': [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]}).source
  "lambda item: ((item['bubu'] > 1) and (item['bubu'] < 2)) # compiled from {'$and': [{'bubu': {'$gt': 1}}, {'bubu': {'$lt': 2}}]}"
  >>> to_func({'$or': "invalid value"}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'invalid value'. Expected one of: list, tuple.
  >>> list(filter(to_func({'$and': [{"bubu": {"$lt": 3}}, {'bubu': {'$gt': 1}}]}), [{"bubu": i} for i in range(5)]))
  [{'bubu': 2}]

• $*nesting*:

  >>> to_func({'$and': [
  ...     {"bubu": {"$gt": 1}},
  ...     {'$or': [
  ...         {'bubu': {'$lt': 2}},
  ...         {'$and': [
  ...             {'bubu': {'$lt': 3}},
  ...             {'bubu': {'$lt': 4}},
  ...         ]}
  ...     ]}
  ... ]}).source
  "lambda item: ((item['bubu'] > 1) and ((item['bubu'] < 2) or ((item['bubu'] < 3) and (item['bubu'] < 4)))) # compiled from {'$and': [{'bubu': {'$gt': 1}}, {'$or': [{'bubu': {'$lt': 2}}, {'$and': [{'bubu': {'$lt': 3}}, {'bubu': {'$lt': 4}}]}]}]}"

Regular expressions

• $regex:

  >>> to_func({"myfield": {"$regex": 'a'}}).source
  "lambda item, var0=re.compile('a', 0): (var0.match(item['myfield'])) # compiled from {'myfield': {'$regex': 'a'}}"
  
  >>> to_func({"myfield": {"$regex": 'a', "$options": 'i'}}).source
  "lambda item, var0=re.compile('a', 2): (var0.match(item['myfield'])) # compiled from {'myfield': {'$options': 'i', '$regex': 'a'}}"
  
  >>> to_func({"myfield": {"$regex": 'junk('}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid regular expression 'junk(': unbalanced parenthesis
  
  >>> to_func({"myfield": {"$regex": 'a', 'junk': 'junk'}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part "'junk'". You can only have `$options` with `$regex`.
  
  >>> to_func({"bubu": {"$regex": ".*", "$options": "junk"}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'junk'. Unsupported regex option 'j'. Only 's', 'x', 'm', 'i' are supported !
  
  >>> to_func({"bubu": {"$options": "i"}}).source
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part {'$options': 'i'}. Cannot have $options without $regex.
  
  >>> import string
  >>> list(filter(to_func({"myfield": {"$regex": '[a-c]', "$options": 'i'}}), [{"myfield": i} for i in string.ascii_letters]))
  [{'myfield': 'a'}, {'myfield': 'b'}, {'myfield': 'c'}, {'myfield': 'A'}, {'myfield': 'B'}, {'myfield': 'C'}]

to_Q

Compiles down to a Django Q object tree:

>>> from mongoql_conv.django import to_Q
>>> print(to_Q({"myfield": 1}))
(AND: ('myfield', 1))

>>> from test_app.models import MyModel
>>> MyModel.objects.clean_and_create([(i, i) for i in range(5)])
>>> MyModel.objects.filter(to_Q({"field1": 1}))
[<MyModel: field1=1, field2='1'>]

>>> print(to_Q({"field1": 1, "field2": 2}))
(AND: ('field2', 2), ('field1', 1))

>>> MyModel.objects.filter(to_Q({"field1": 1, "field2": 1}))
[<MyModel: field1=1, field2='1'>]

>>> print(to_Q({"myfield": {"$in": [1, 2]}}))
(AND: ('myfield__in', [1, 2]))

>>> MyModel.objects.filter(to_Q({"field1": {"$in": [1, 2]}}))
[<MyModel: field1=1, field2='1'>, <MyModel: field1=2, field2='2'>]

>>> print(to_Q({"myfield": {"$in": {1: 2}}}))
Traceback (most recent call last):
...
InvalidQuery: Invalid query part {1: 2}. Expected one of: set, list, tuple, frozenset.

Supported operators

Arithmetic

• $gt:

  >>> print(to_Q({"myfield": {"$gt": 1}}))
  (AND: ('myfield__gt', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$gt": 2}}))
  [<MyModel: field1=3, field2='3'>, <MyModel: field1=4, field2='4'>]

• $gte:

  >>> print(to_Q({"myfield": {"$gte": 1}}))
  (AND: ('myfield__gte', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$gte": 2}}))
  [<MyModel: field1=2, field2='2'>, <MyModel: field1=3, field2='3'>, <MyModel: field1=4, field2='4'>]

• $lt:

  >>> print(to_Q({"myfield": {"$lt": 1}}))
  (AND: ('myfield__lt', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$lt": 1}}))
  [<MyModel: field1=0, field2='0'>]

• $lte:

  >>> print(to_Q({"myfield": {"$lte": 1}}))
  (AND: ('myfield__lte', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$lte": 1}}))
  [<MyModel: field1=0, field2='0'>, <MyModel: field1=1, field2='1'>]

• $eq:

  >>> print(to_Q({"myfield": {"$eq": 1}}))
  (AND: ('myfield', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": 1}))
  [<MyModel: field1=1, field2='1'>]
  
  >>> print(to_Q({"myfield": 1}))
  (AND: ('myfield', 1))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$eq": 1}}))
  [<MyModel: field1=1, field2='1'>]

• $ne:

  >>> print(to_Q({"myfield": {"$ne": 1}}))
  (NOT (AND: ('myfield', 1)))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$ne": 1}}))
  [<MyModel: field1=0, field2='0'>, <MyModel: field1=2, field2='2'>, <MyModel: field1=3, field2='3'>, <MyModel: field1=4, field2='4'>]

• $mod:

  >>> print(to_Q({"myfield": {"$mod": [2, 1]}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: DjangoVisitor doesn't support operator '$mod'

Containers

• $in:

  >>> print(to_Q({"myfield": {"$in": (1, 2, 3)}}))
  (AND: ('myfield__in', (1, 2, 3)))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$in": (1, 2)}}))
  [<MyModel: field1=1, field2='1'>, <MyModel: field1=2, field2='2'>]

• $nin:

  >>> print(to_Q({"myfield": {"$nin": [1, 2, 3]}}))
  (NOT (AND: ('myfield__in', [1, 2, 3])))
  
  >>> MyModel.objects.filter(to_Q({"field1": {"$nin": (1, 2)}}))
  [<MyModel: field1=0, field2='0'>, <MyModel: field1=3, field2='3'>, <MyModel: field1=4, field2='4'>]

• $size:

  >>> print(to_Q({"myfield": {"$size": 3}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: DjangoVisitor doesn't support operator '$size'

• $all:

  >>> print(to_Q({"myfield": {"$all": [1, 2, 3]}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: DjangoVisitor doesn't support operator '$all'

• $exists:

  >>> print(to_Q({"myfield": {"$exists": True}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: DjangoVisitor doesn't support operator '$exists'

Boolean operators

• $or:

  >>> print(to_Q({'$or':  [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]}))
  (OR: ('bubu__gt', 1), ('bubu__lt', 2))
  
  >>> MyModel.objects.filter(to_Q({'$or': [{"field1": {"$gt": 3}}, {'field1': {'$lt': 2}}]}))
  [<MyModel: field1=0, field2='0'>, <MyModel: field1=1, field2='1'>, <MyModel: field1=4, field2='4'>]

• $and:

  >>> print(to_Q({'$and':  [{"bubu": {"$gt": 1}}, {'bubu': {'$lt': 2}}]}))
  (AND: ('bubu__gt', 1), ('bubu__lt', 2))
  
  >>> MyModel.objects.filter(to_Q({'$and': [{"field1": {"$gt": 1}}, {'field1': {'$lt': 3}}]}))
  [<MyModel: field1=2, field2='2'>]

• $*nesting*:

  >>> print(to_Q({'$and': [
  ...     {"bubu": {"$gt": 1}},
  ...     {'$or': [
  ...         {'bubu': {'$lt': 2}},
  ...         {'$and': [
  ...             {'bubu': {'$lt': 3}},
  ...             {'bubu': {'$lt': 4}},
  ...         ]}
  ...     ]}
  ... ]}))
  (AND: ('bubu__gt', 1), (OR: ('bubu__lt', 2), (AND: ('bubu__lt', 3), ('bubu__lt', 4))))
  
  >>> MyModel.objects.filter(to_Q({'$and': [
  ...     {"field1": {"$gt": 1}},
  ...     {'$or': [
  ...         {'field2': {'$lt': 2}},
  ...         {'$and': [
  ...             {'field2': {'$lt': 5}},
  ...             {'field2': {'$gt': 2}},
  ...         ]}
  ...     ]}
  ... ]}))
  [<MyModel: field1=3, field2='3'>, <MyModel: field1=4, field2='4'>]

Regular expressions

• $regex:

  >>> print(to_Q({"myfield": {"$regex": 'a'}}))
  (AND: ('myfield__regex', 'a'))
  
  >>> print(to_Q({"myfield": {"$regex": 'a', "$options": 'i'}}))
  (AND: ('myfield__iregex', 'a'))
  
  >>> print(to_Q({"myfield": {"$regex": 'junk('}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid regular expression 'junk(': unbalanced parenthesis
  
  >>> print(to_Q({"myfield": {"$regex": 'a', 'junk': 'junk'}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part "'junk'". You can only have `$options` with `$regex`.
  
  >>> print(to_Q({"bubu": {"$regex": ".*", "$options": "mxs"}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part 'mxs'. Unsupported regex option 'm'. Only i are supported !
  
  >>> print(to_Q({"bubu": {"$options": "i"}}))
  Traceback (most recent call last):
  ...
  InvalidQuery: Invalid query part {'$options': 'i'}. Cannot have $options without $regex.
  
  >>> MyModel.objects.clean_and_create([(None, i) for i in string.ascii_letters])
  >>> MyModel.objects.filter(to_Q({"field2": {"$regex": '[a-b]', "$options": 'i'}}))
  [<MyModel: field1=None, field2='a'>, <MyModel: field1=None, field2='b'>, <MyModel: field1=None, field2='A'>, <MyModel: field1=None, field2='B'>]

Extending (implementing a custom visitor)

There are few requirements for a visitor. Fist, you need to be able to render boolean $and:

>>> from mongoql_conv import BaseVisitor
>>> class MyVisitor(BaseVisitor):
...     def __init__(self, object_name):
...         self.object_name = object_name
...     def visit_foobar(self, value, field_name, context):
...         return "foobar(%s[%r], %r)" % (self.object_name, field_name, value)
>>> MyVisitor('obj').visit({'field': {'$foobar': 'test'}})
Traceback (most recent call last):
...
TypeError: Can't instantiate abstract class MyVisitor with abstract methods render_and

This is the minimal code to have a custom generator:

>>> class MyVisitor(BaseVisitor):
...     def __init__(self, object_name):
...         self.object_name = object_name
...     def visit_foobar(self, value, field_name, context):
...         return "foobar(%s[%r], %r)" % (self.object_name, field_name, value)
...     def render_and(self, parts, field_name, context):
...         return ' & '.join(parts)
>>> MyVisitor('obj').visit({'field': {'$foobar': 'test'}})
"foobar(obj['field'], 'test')"

Ofcourse, it won’t do much:

>>> MyVisitor('obj').visit({'field': {'$ne': 'test'}})
Traceback (most recent call last):
...
InvalidQuery: MyVisitor doesn't support operator '$ne'

Take a look at ExprVisitor too see all the methods you should implement.