#!/usr/bin/env python3
#
# pagination.py
"""
Class for handling paginated API responses.
"""
#
# Copyright © 2020 Dominic Davis-Foster <dominic@davis-foster.co.uk>
#
# 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.
#
# stdlib
from typing import Any, Dict, Iterable, Iterator, List, MutableMapping, Optional, Type, TypeVar, Union, overload
from urllib.parse import parse_qs, urlparse
# 3rd party
from apeye.slumber_url import SlumberURL
from domdf_python_tools.doctools import prettify_docstrings
from typing_extensions import TypedDict
__all__ = ["OctoResponse", "PaginatedResponse"]
_T = TypeVar("_T")
[docs]class OctoResponse(TypedDict):
"""
:class:`~typing.TypedDict` representing the raw JSON data returned by
the Octopus Energy API.
""" # noqa: D400
#: The total number of responses.
count: int
#: The URL of the next page of results.
next: str # noqa: A003 # pylint: disable=redefined-builtin
#: The URL of the previous page of results.
previous: str
#: The current page of results.
results: List[Dict[str, Any]]
[docs]@prettify_docstrings
class PaginatedResponse(Iterable[_T]):
"""
Represents a multi-page response from a REST API.
The items within the response can be iterated over or accessed by their indices.
The total number of items can be accessed with :func:`len(response) <len>`.
:param query_url: The initial query URL.
:param query_params: The parameters to the query.
:param obj_type: The object to convert the response data to.
.. note::
This class assumes the JSON response is in the format used by
`Django REST framework <https://www.django-rest-framework.org/>`_.
The response should be in the following format:
.. code-block:: json
{
"count": 1023,
"next": "https://api.example.org/accounts/?page=5",
"previous": "https://api.example.org/accounts/?page=3",
"results": []
}
See https://www.django-rest-framework.org/api-guide/pagination/ for more information.
"""
_next_page: Optional[int]
_previous_page: Optional[int]
_results: List[Dict[str, Any]]
def __init__(
self,
query_url: SlumberURL,
query_params: Optional[MutableMapping[str, Any]] = None,
obj_type: Type = dict,
):
response: OctoResponse = query_url.get(**query_params) # type: ignore[assignment,arg-type]
if query_params is None:
query_params = {}
self.query_url: SlumberURL = query_url
self.query_params: Dict[str, Any] = dict(query_params)
self.obj_type = obj_type
self._count: int = response["count"]
self._results = response["results"]
self._next_page = None
self._previous_page = None
self._parse_pages(response)
def _parse_pages(self, response: OctoResponse) -> None:
if response["next"] is not None:
query = parse_qs(urlparse(response["next"]).query)
page = query.get("page", [])
if page:
self._next_page = int(page[0])
else:
self._next_page = None
else:
self._next_page = None
if response["previous"] is not None:
query = parse_qs(urlparse(response["previous"]).query)
page = query.get("page", [])
if page:
self._previous_page = int(page[0])
else:
self._previous_page = None
else:
self._previous_page = None
def _get_next_page(self) -> List[Dict[str, Any]]:
# print(f"Getting {self._next_page}")
response: OctoResponse = self.query_url.get( # type: ignore[assignment]
page=self._next_page,
**self.query_params,
)
self._results.extend(response["results"])
self._parse_pages(response)
return response["results"]
[docs] def __iter__(self) -> Iterator[_T]:
"""
Iterate over items in the :class:`~.PaginatedResponse`.
"""
for res in self._results:
yield self.obj_type(**res)
while self._next_page:
for res in self._get_next_page():
yield self.obj_type(**res)
[docs] def __eq__(self, other) -> bool: # noqa: MAN001
if isinstance(other, Iterable):
for left, right in zip(self, other):
if left != right:
return False
return True
return NotImplemented
[docs] def __len__(self) -> int:
"""
Returns the number of items in the :class:`~.PaginatedResponse`.
"""
return self._count
@overload
def __getitem__(self, item: int) -> _T: ... # pragma: no cover
@overload
def __getitem__(self, item: slice) -> List[_T]: ... # pragma: no cover
[docs] def __getitem__(self, item: Union[int, slice]) -> Union[_T, List[_T]]:
"""
Returns the item or items in the :class:`~.PaginatedResponse`, as given by the index or slice.
:param item:
"""
if isinstance(item, int):
if item >= len(self):
raise IndexError("index out of range")
else:
while item >= len(self._results):
# print(item, len(self._results))
self._get_next_page()
return self.obj_type(**self._results[item])
elif isinstance(item, slice):
max_idx = item.stop + 1
if max_idx >= len(self):
max_idx = len(self)
return [self[idx] for idx in range(item.start or 0, max_idx, item.step or 1)]
else:
return NotImplemented