Source code for azure.core.paging

# --------------------------------------------------------------------------
#
# Copyright (c) Microsoft Corporation. All rights reserved.
#
# The MIT License (MIT)
#
# 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.
#
# --------------------------------------------------------------------------
import itertools
from typing import (  # pylint: disable=unused-import
    Callable,
    Optional,
    TypeVar,
    Iterator,
    Iterable,
    Tuple,
)
import logging

from .exceptions import AzureError


_LOGGER = logging.getLogger(__name__)

ReturnType = TypeVar("ReturnType")
ResponseType = TypeVar("ResponseType")


[docs]class PageIterator(Iterator[Iterator[ReturnType]]): def __init__( self, get_next, # type: Callable[[Optional[str]], ResponseType] extract_data, # type: Callable[[ResponseType], Tuple[str, Iterable[ReturnType]]] continuation_token=None, # type: Optional[str] ): """Return an iterator of pages. :param get_next: Callable that take the continuation token and return a HTTP response :param extract_data: Callable that take an HTTP response and return a tuple continuation token, list of ReturnType :param str continuation_token: The continuation token needed by get_next """ self._get_next = get_next self._extract_data = extract_data self.continuation_token = continuation_token self._did_a_call_already = False self._response = None # type: Optional[ResponseType] self._current_page = None # type: Optional[Iterable[ReturnType]] def __iter__(self): """Return 'self'.""" return self def __next__(self): # type: () -> Iterator[ReturnType] if self.continuation_token is None and self._did_a_call_already: raise StopIteration("End of paging") try: self._response = self._get_next(self.continuation_token) except AzureError as error: if not error.continuation_token: error.continuation_token = self.continuation_token raise self._did_a_call_already = True self.continuation_token, self._current_page = self._extract_data(self._response) return iter(self._current_page) next = __next__ # Python 2 compatibility.
[docs]class ItemPaged(Iterator[ReturnType]): def __init__(self, *args, **kwargs): """Return an iterator of items. args and kwargs will be passed to the PageIterator constructor directly, except page_iterator_class """ self._args = args self._kwargs = kwargs self._page_iterator = None self._page_iterator_class = self._kwargs.pop( "page_iterator_class", PageIterator )
[docs] def by_page(self, continuation_token=None): # type: (Optional[str]) -> Iterator[Iterator[ReturnType]] """Get an iterator of pages of objects, instead of an iterator of objects. :param str continuation_token: An opaque continuation token. This value can be retrieved from the continuation_token field of a previous generator object. If specified, this generator will begin returning results from this point. :returns: An iterator of pages (themselves iterator of objects) """ return self._page_iterator_class( continuation_token=continuation_token, *self._args, **self._kwargs )
def __repr__(self): return "<iterator object azure.core.paging.ItemPaged at {}>".format(hex(id(self))) def __iter__(self): """Return 'self'.""" return self def __next__(self): if self._page_iterator is None: self._page_iterator = itertools.chain.from_iterable(self.by_page()) return next(self._page_iterator) next = __next__ # Python 2 compatibility.