djc · pirr · Sep 27, 2017 · Oct 3, 2017 · Oct 5, 2017 · Oct 5, 2017
diff --git a/couchdb/client.py b/couchdb/client.py
@@ -34,6 +34,7 @@
 import socket
 
 from couchdb import http, json, util
+from couchdb.query_utils import Q
 
 __all__ = ['Server', 'Database', 'Document', 'ViewResults', 'Row']
 __docformat__ = 'restructuredtext en'
@@ -811,6 +812,58 @@ def find(self, mango_query, wrapper=None):
         status, headers, data = self.resource.post_json('_find', mango_query)
         return map(wrapper or Document, data.get('docs', []))
 
+    def filter(self, *args, **kwargs):
+        """Execute a mango find-query against the database.
+
+        Note: only available for CouchDB version >= 2.0.0
+
+        More information on the `mango_query` structure can be found here:
+          http://docs.couchdb.org/en/master/api/database/find.html#find-selectors
+
+        >>> server = Server()
+        >>> db = server.create('python-tests')
+        >>> db['johndoe'] = dict(type='Person', name='John Doe', hobby=dict(main='read', second='game'), feats=[dict(feat1=1, feat2=2), dict(feat1=10, feat2=20)])
+        >>> db['maryjane'] = dict(type='Person', name='Mary Jane', hobby=dict(main='read'), feats=[dict(feat1=3, feat2=4), dict(feat1=30, feat2=40)])
+        >>> db['sillybilly'] = dict(type='Person', name='Silly Billy', hobby=dict(main='read', second='game'), feats=[dict(feat1=5, feat2=6), dict(feat1=50, feat2=60)])
+        >>> db['billysilly'] = dict(type='Person', name='Billy Silly', hobby=dict(main='swim', second='horse riding'), feats=[dict(feat1=1, feat2=2), dict(feat1=30, feat2=60)])
+        >>> for row in db.filter(name__eq='John Doe'):  # doctest: +SKIP
+        ...    print(row['name'])                       # doctest: +SKIP
+        John Doe
+        >>> for row in db.filter(name__regex='(*UTF)(?i)illy'):  # doctest: +SKIP
+        ...    print(row['name'])                                # doctest: +SKIP
+        Billy Silly
+        Silly Billy
+        >>> from couchdb.query_utils import Q
+        >>> for row in db.filter(Q(name__regex='(*UTF)(?i)silly') & Q(hobby__main__eq='read')):  # doctest: +SKIP
+        ...    print(row['name'])                                                                # doctest: +SKIP
+        Silly Billy
+        >>> for row in db.filter(feats_L_elemMatch__feat2__in = [20, 4]):                        # doctest: +SKIP
+        ...    print(row['name'])                                                                # doctest: +SKIP
+        John Doe
+        Mary Jane
+        >>> del server['python-tests']
+
+        :param args: Q objects, parse into a query - Request JSON Object selector:
+                     http://docs.couchdb.org/en/master/api/database/find.html#post--db-_find
+        :param kwargs: Request JSON Object:
+                     http://docs.couchdb.org/en/master/api/database/find.html#post--db-_find
+        :return: the query results as a list of `Document`
+        """
+        limit = kwargs.pop('limit', 30)
+        fields = kwargs.pop('fields', [])
+        sort = kwargs.pop('sort', [])
+        if args:
+            selector = args[0].P
+        elif kwargs:
+            selector = Q(**kwargs).P
+        else:
+            raise Exception('Need query, for example: name__eq = "Name" or used Q for complex conditions')
+        query = dict(selector=selector, limit=limit, fields=fields, sort=sort)
+        data = self.find(mango_query=query)
+        return data
+
+
+
     def explain(self, mango_query):
         """Explain a mango find-query.
 

diff --git a/couchdb/query_utils.py b/couchdb/query_utils.py
@@ -0,0 +1,70 @@
+try:
+    from functools import reduce
+except ImportError:
+    pass
+
+'''
+maybe overwrite
+'''
+
+class Q:
+    """
+        Q-object need for creating mango_query in filter function
+    """
+    OR = '$or'
+    AND = '$and'
+
+    def __init__(self, **kwarg):
+        """
+        :param kwarg: field__subfield1__...__mango_operator = value
+                      separate by double underscore - '__'
+        """
+        self.field_cond = list(kwarg.keys())[0]
+        self.val = list(kwarg.values())[0]
+
+    @property
+    def P(self):
+        """
+        P - parser
+        :return: dict for query
+        """
+        field_cond_list = self.field_cond.split('__')
+        field = field_cond_list[:-1]
+        for i, subf in enumerate(field):
+            if '_L_' in subf:
+                subf_list = subf.split('_L_')
+                field.insert(i + 1, '$' + subf_list[1])
+                field[i] = subf_list[0]
+
+        cond = '$' + field_cond_list[-1]
+        parsed_field_cond = reduce(lambda x, y: {y: x},
+                                   reversed(field + [cond, self.val]))
+        return parsed_field_cond
+
+    def _combine(self, other, cond):
+        """
+        :param other: Q or _FQ objects
+        :param cond: or, and
+        :return:  _FQ object
+        """
+        query = dict()
+        query[cond] = [self.P, other.P]
+        return _FQ(query)
+
+    def __or__(self, other):
+        return self._combine(other, self.OR)
+
+    def __and__(self, other):
+        return self._combine(other, self.AND)
+
+
+class _FQ(Q):
+    '''
+        subobject need for _combine method in Q
+    '''
+    def __init__(self, val):
+        self.val = val
+
+    @property
+    def P(self):
+        return self.val