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#The MIT License (MIT)
#Copyright (c) 2014 Microsoft Corporation
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#The above copyright notice and this permission notice shall be included in all
#copies or substantial portions of the Software.
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#SOFTWARE.
"""Iterable query results in the Azure Cosmos database service.
"""
from azure.cosmos.execution_context import execution_dispatcher
from azure.cosmos.execution_context import base_execution_context
class QueryIterable(object):
"""Represents an iterable object of the query results.
QueryIterable is a wrapper for query execution context.
"""
def __init__(self, client, query, options, fetch_function, collection_link = None):
"""
Instantiates a QueryIterable for non-client side partitioning queries.
_ProxyQueryExecutionContext will be used as the internal query execution context
:param CosmosClient client:
Instance of document client.
:param (str or dict) query:
:param dict options:
The request options for the request.
:param method fetch_function:
:param str collection_link:
If this is a Document query/feed collection_link is required.
Example of `fetch_function`:
>>> def result_fn(result):
>>> return result['Databases']
"""
self._client = client
self.retry_options = client.connection_policy.RetryOptions
self._query = query
self._options = options
self._fetch_function = fetch_function
self._collection_link = collection_link
self._ex_context = None
@classmethod
def PartitioningQueryIterable(cls, client, query, options, database_link, partition_key):
"""
Represents a client side partitioning query iterable.
This constructor instantiates a QueryIterable for
client side partitioning queries, and sets _MultiCollectionQueryExecutionContext
as the internal execution context.
:param CosmosClient client:
Instance of document client
:param (str or dict) options:
:param dict options:
The request options for the request.
:param str database_link:
Database self link or ID based link
:param str partition_key:
Partition key for the query
"""
# This will call the base constructor(__init__ method above)
self = cls(client, query, options, None, None)
self._database_link = database_link
self._partition_key = partition_key
return self
def _create_execution_context(self):
"""instantiates the internal query execution context based.
"""
if hasattr(self, '_database_link'):
# client side partitioning query
return base_execution_context._MultiCollectionQueryExecutionContext(self._client, self._options, self._database_link, self._query, self._partition_key)
else:
#
return execution_dispatcher._ProxyQueryExecutionContext(self._client, self._collection_link, self._query, self._options, self._fetch_function)
def __iter__(self):
"""Makes this class iterable.
"""
return self.Iterator(self)
class Iterator(object):
def __init__(self, iterable):
self._iterable = iterable
self._finished = False
self._ex_context = iterable._create_execution_context()
def __iter__(self):
# Always returns self
return self
def __next__(self):
return next(self._ex_context)
# Also support Python 3.x iteration
def next(self):
return self.__next__()
def fetch_next_block(self):
"""Returns a block of results with respecting retry policy.
This method only exists for backward compatibility reasons. (Because QueryIterable
has exposed fetch_next_block api).
:return:
List of results.
:rtype:
list
"""
if self._ex_context is None:
# initiates execution context for the first time
self._ex_context = self._create_execution_context()
return self._ex_context.fetch_next_block()
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