36.6 kB

	"""
	Pagination serializers determine the structure of the output that should
	be used for paginated responses.
	"""

	import contextlib
	import warnings
	from base64 import b64decode, b64encode
	from collections import namedtuple
	from urllib import parse

	from django.core.paginator import InvalidPage
	from django.core.paginator import Paginator as DjangoPaginator
	from django.template import loader
	from django.utils.encoding import force_str
	from django.utils.translation import gettext_lazy as _

	from rest_framework import RemovedInDRF317Warning
	from rest_framework.compat import coreapi, coreschema
	from rest_framework.exceptions import NotFound
	from rest_framework.response import Response
	from rest_framework.settings import api_settings
	from rest_framework.utils.urls import remove_query_param, replace_query_param


	def _positive_int(integer_string, strict=False, cutoff=None):
	"""
	Cast a string to a strictly positive integer.
	"""
	ret = int(integer_string)
	if ret < 0 or (ret == 0 and strict):
	raise ValueError()
	if cutoff:
	return min(ret, cutoff)
	return ret


	def _divide_with_ceil(a, b):
	"""
	Returns 'a' divided by 'b', with any remainder rounded up.
	"""
	if a % b:
	return (a // b) + 1

	return a // b


	def _get_displayed_page_numbers(current, final):
	"""
	This utility function determines a list of page numbers to display.
	This gives us a nice contextually relevant set of page numbers.

	For example:
	current=14, final=16 -> [1, None, 13, 14, 15, 16]

	This implementation gives one page to each side of the cursor,
	or two pages to the side when the cursor is at the edge, then
	ensures that any breaks between non-continuous page numbers never
	remove only a single page.

	For an alternative implementation which gives two pages to each side of
	the cursor, eg. as in GitHub issue list pagination, see:

	https://gist.github.com/tomchristie/321140cebb1c4a558b15
	"""
	assert current >= 1
	assert final >= current

	if final <= 5:
	return list(range(1, final + 1))

	# We always include the first two pages, last two pages, and
	# two pages either side of the current page.
	included = {1, current - 1, current, current + 1, final}

	# If the break would only exclude a single page number then we
	# may as well include the page number instead of the break.
	if current <= 4:
	included.add(2)
	included.add(3)
	if current >= final - 3:
	included.add(final - 1)
	included.add(final - 2)

	# Now sort the page numbers and drop anything outside the limits.
	included = [
	idx for idx in sorted(included)
	if 0 < idx <= final
	]

	# Finally insert any `...` breaks
	if current > 4:
	included.insert(1, None)
	if current < final - 3:
	included.insert(len(included) - 1, None)
	return included


	def _get_page_links(page_numbers, current, url_func):
	"""
	Given a list of page numbers and `None` page breaks,
	return a list of `PageLink` objects.
	"""
	page_links = []
	for page_number in page_numbers:
	if page_number is None:
	page_link = PAGE_BREAK
	else:
	page_link = PageLink(
	url=url_func(page_number),
	number=page_number,
	is_active=(page_number == current),
	is_break=False
	)
	page_links.append(page_link)
	return page_links


	def _reverse_ordering(ordering_tuple):
	"""
	Given an order_by tuple such as `('-created', 'uuid')` reverse the
	ordering and return a new tuple, eg. `('created', '-uuid')`.
	"""
	def invert(x):
	return x[1:] if x.startswith('-') else '-' + x

	return tuple([invert(item) for item in ordering_tuple])


	Cursor = namedtuple('Cursor', ['offset', 'reverse', 'position'])
	PageLink = namedtuple('PageLink', ['url', 'number', 'is_active', 'is_break'])

	PAGE_BREAK = PageLink(url=None, number=None, is_active=False, is_break=True)


	class BasePagination:
	display_page_controls = False

	def paginate_queryset(self, queryset, request, view=None): # pragma: no cover
	raise NotImplementedError('paginate_queryset() must be implemented.')

	def get_paginated_response(self, data): # pragma: no cover
	raise NotImplementedError('get_paginated_response() must be implemented.')

	def get_paginated_response_schema(self, schema):
	return schema

	def to_html(self): # pragma: no cover
	raise NotImplementedError('to_html() must be implemented to display page controls.')

	def get_results(self, data):
	return data['results']

	def get_schema_fields(self, view):
	assert coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
	if coreapi is not None:
	warnings.warn('CoreAPI compatibility is deprecated and will be removed in DRF 3.17', RemovedInDRF317Warning)
	return []

	def get_schema_operation_parameters(self, view):
	return []


	class PageNumberPagination(BasePagination):
	"""
	A simple page number based style that supports page numbers as
	query parameters. For example:

	http://api.example.org/accounts/?page=4
	http://api.example.org/accounts/?page=4&page_size=100
	"""
	# The default page size.
	# Defaults to `None`, meaning pagination is disabled.
	page_size = api_settings.PAGE_SIZE

	django_paginator_class = DjangoPaginator

	# Client can control the page using this query parameter.
	page_query_param = 'page'
	page_query_description = _('A page number within the paginated result set.')

	# Client can control the page size using this query parameter.
	# Default is 'None'. Set to eg 'page_size' to enable usage.
	page_size_query_param = None
	page_size_query_description = _('Number of results to return per page.')

	# Set to an integer to limit the maximum page size the client may request.
	# Only relevant if 'page_size_query_param' has also been set.
	max_page_size = None

	last_page_strings = ('last',)

	template = 'rest_framework/pagination/numbers.html'

	invalid_page_message = _('Invalid page.')

	def paginate_queryset(self, queryset, request, view=None):
	"""
	Paginate a queryset if required, either returning a
	page object, or `None` if pagination is not configured for this view.
	"""
	self.request = request
	page_size = self.get_page_size(request)
	if not page_size:
	return None

	paginator = self.django_paginator_class(queryset, page_size)
	page_number = self.get_page_number(request, paginator)

	try:
	self.page = paginator.page(page_number)
	except InvalidPage as exc:
	msg = self.invalid_page_message.format(
	page_number=page_number, message=str(exc)
	)
	raise NotFound(msg)

	if paginator.num_pages > 1 and self.template is not None:
	# The browsable API should display pagination controls.
	self.display_page_controls = True

	return list(self.page)

	def get_page_number(self, request, paginator):
	page_number = request.query_params.get(self.page_query_param) or 1
	if page_number in self.last_page_strings:
	page_number = paginator.num_pages
	return page_number

	def get_paginated_response(self, data):
	return Response({
	'count': self.page.paginator.count,
	'next': self.get_next_link(),
	'previous': self.get_previous_link(),
	'results': data,
	})

	def get_paginated_response_schema(self, schema):
	return {
	'type': 'object',
	'required': ['count', 'results'],
	'properties': {
	'count': {
	'type': 'integer',
	'example': 123,
	},
	'next': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{page_query_param}=4'.format(
	page_query_param=self.page_query_param)
	},
	'previous': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{page_query_param}=2'.format(
	page_query_param=self.page_query_param)
	},
	'results': schema,
	},
	}

	def get_page_size(self, request):
	if self.page_size_query_param:
	with contextlib.suppress(KeyError, ValueError):
	return _positive_int(
	request.query_params[self.page_size_query_param],
	strict=True,
	cutoff=self.max_page_size
	)
	return self.page_size

	def get_next_link(self):
	if not self.page.has_next():
	return None
	url = self.request.build_absolute_uri()
	page_number = self.page.next_page_number()
	return replace_query_param(url, self.page_query_param, page_number)

	def get_previous_link(self):
	if not self.page.has_previous():
	return None
	url = self.request.build_absolute_uri()
	page_number = self.page.previous_page_number()
	if page_number == 1:
	return remove_query_param(url, self.page_query_param)
	return replace_query_param(url, self.page_query_param, page_number)

	def get_html_context(self):
	base_url = self.request.build_absolute_uri()

	def page_number_to_url(page_number):
	if page_number == 1:
	return remove_query_param(base_url, self.page_query_param)
	else:
	return replace_query_param(base_url, self.page_query_param, page_number)

	current = self.page.number
	final = self.page.paginator.num_pages
	page_numbers = _get_displayed_page_numbers(current, final)
	page_links = _get_page_links(page_numbers, current, page_number_to_url)

	return {
	'previous_url': self.get_previous_link(),
	'next_url': self.get_next_link(),
	'page_links': page_links
	}

	def to_html(self):
	template = loader.get_template(self.template)
	context = self.get_html_context()
	return template.render(context)

	def get_schema_fields(self, view):
	assert coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
	if coreapi is not None:
	warnings.warn('CoreAPI compatibility is deprecated and will be removed in DRF 3.17', RemovedInDRF317Warning)
	assert coreschema is not None, 'coreschema must be installed to use `get_schema_fields()`'
	fields = [
	coreapi.Field(
	name=self.page_query_param,
	required=False,
	location='query',
	schema=coreschema.Integer(
	title='Page',
	description=force_str(self.page_query_description)
	)
	)
	]
	if self.page_size_query_param is not None:
	fields.append(
	coreapi.Field(
	name=self.page_size_query_param,
	required=False,
	location='query',
	schema=coreschema.Integer(
	title='Page size',
	description=force_str(self.page_size_query_description)
	)
	)
	)
	return fields

	def get_schema_operation_parameters(self, view):
	parameters = [
	{
	'name': self.page_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.page_query_description),
	'schema': {
	'type': 'integer',
	},
	},
	]
	if self.page_size_query_param is not None:
	parameters.append(
	{
	'name': self.page_size_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.page_size_query_description),
	'schema': {
	'type': 'integer',
	},
	},
	)
	return parameters


	class LimitOffsetPagination(BasePagination):
	"""
	A limit/offset based style. For example:

	http://api.example.org/accounts/?limit=100
	http://api.example.org/accounts/?offset=400&limit=100
	"""
	default_limit = api_settings.PAGE_SIZE
	limit_query_param = 'limit'
	limit_query_description = _('Number of results to return per page.')
	offset_query_param = 'offset'
	offset_query_description = _('The initial index from which to return the results.')
	max_limit = None
	template = 'rest_framework/pagination/numbers.html'

	def paginate_queryset(self, queryset, request, view=None):
	self.request = request
	self.limit = self.get_limit(request)
	if self.limit is None:
	return None

	self.count = self.get_count(queryset)
	self.offset = self.get_offset(request)
	if self.count > self.limit and self.template is not None:
	self.display_page_controls = True

	if self.count == 0 or self.offset > self.count:
	return []
	return list(queryset[self.offset:self.offset + self.limit])

	def get_paginated_response(self, data):
	return Response({
	'count': self.count,
	'next': self.get_next_link(),
	'previous': self.get_previous_link(),
	'results': data
	})

	def get_paginated_response_schema(self, schema):
	return {
	'type': 'object',
	'required': ['count', 'results'],
	'properties': {
	'count': {
	'type': 'integer',
	'example': 123,
	},
	'next': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{offset_param}=400&{limit_param}=100'.format(
	offset_param=self.offset_query_param, limit_param=self.limit_query_param),
	},
	'previous': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{offset_param}=200&{limit_param}=100'.format(
	offset_param=self.offset_query_param, limit_param=self.limit_query_param),
	},
	'results': schema,
	},
	}

	def get_limit(self, request):
	if self.limit_query_param:
	with contextlib.suppress(KeyError, ValueError):
	return _positive_int(
	request.query_params[self.limit_query_param],
	strict=True,
	cutoff=self.max_limit
	)
	return self.default_limit

	def get_offset(self, request):
	try:
	return _positive_int(
	request.query_params[self.offset_query_param],
	)
	except (KeyError, ValueError):
	return 0

	def get_next_link(self):
	if self.offset + self.limit >= self.count:
	return None

	url = self.request.build_absolute_uri()
	url = replace_query_param(url, self.limit_query_param, self.limit)

	offset = self.offset + self.limit
	return replace_query_param(url, self.offset_query_param, offset)

	def get_previous_link(self):
	if self.offset <= 0:
	return None

	url = self.request.build_absolute_uri()
	url = replace_query_param(url, self.limit_query_param, self.limit)

	if self.offset - self.limit <= 0:
	return remove_query_param(url, self.offset_query_param)

	offset = self.offset - self.limit
	return replace_query_param(url, self.offset_query_param, offset)

	def get_html_context(self):
	base_url = self.request.build_absolute_uri()

	if self.limit:
	current = _divide_with_ceil(self.offset, self.limit) + 1

	# The number of pages is a little bit fiddly.
	# We need to sum both the number of pages from current offset to end
	# plus the number of pages up to the current offset.
	# When offset is not strictly divisible by the limit then we may
	# end up introducing an extra page as an artifact.
	final = (
	_divide_with_ceil(self.count - self.offset, self.limit) +
	_divide_with_ceil(self.offset, self.limit)
	)

	final = max(final, 1)
	else:
	current = 1
	final = 1

	if current > final:
	current = final

	def page_number_to_url(page_number):
	if page_number == 1:
	return remove_query_param(base_url, self.offset_query_param)
	else:
	offset = self.offset + ((page_number - current) * self.limit)
	return replace_query_param(base_url, self.offset_query_param, offset)

	page_numbers = _get_displayed_page_numbers(current, final)
	page_links = _get_page_links(page_numbers, current, page_number_to_url)

	return {
	'previous_url': self.get_previous_link(),
	'next_url': self.get_next_link(),
	'page_links': page_links
	}

	def to_html(self):
	template = loader.get_template(self.template)
	context = self.get_html_context()
	return template.render(context)

	def get_count(self, queryset):
	"""
	Determine an object count, supporting either querysets or regular lists.
	"""
	try:
	return queryset.count()
	except (AttributeError, TypeError):
	return len(queryset)

	def get_schema_fields(self, view):
	assert coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
	if coreapi is not None:
	warnings.warn('CoreAPI compatibility is deprecated and will be removed in DRF 3.17', RemovedInDRF317Warning)
	assert coreschema is not None, 'coreschema must be installed to use `get_schema_fields()`'
	return [
	coreapi.Field(
	name=self.limit_query_param,
	required=False,
	location='query',
	schema=coreschema.Integer(
	title='Limit',
	description=force_str(self.limit_query_description)
	)
	),
	coreapi.Field(
	name=self.offset_query_param,
	required=False,
	location='query',
	schema=coreschema.Integer(
	title='Offset',
	description=force_str(self.offset_query_description)
	)
	)
	]

	def get_schema_operation_parameters(self, view):
	parameters = [
	{
	'name': self.limit_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.limit_query_description),
	'schema': {
	'type': 'integer',
	},
	},
	{
	'name': self.offset_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.offset_query_description),
	'schema': {
	'type': 'integer',
	},
	},
	]
	return parameters


	class CursorPagination(BasePagination):
	"""
	The cursor pagination implementation is necessarily complex.
	For an overview of the position/offset style we use, see this post:
	https://cra.mr/2011/03/08/building-cursors-for-the-disqus-api
	"""
	cursor_query_param = 'cursor'
	cursor_query_description = _('The pagination cursor value.')
	page_size = api_settings.PAGE_SIZE
	invalid_cursor_message = _('Invalid cursor')
	ordering = '-created'
	template = 'rest_framework/pagination/previous_and_next.html'

	# Client can control the page size using this query parameter.
	# Default is 'None'. Set to eg 'page_size' to enable usage.
	page_size_query_param = None
	page_size_query_description = _('Number of results to return per page.')

	# Set to an integer to limit the maximum page size the client may request.
	# Only relevant if 'page_size_query_param' has also been set.
	max_page_size = None

	# The offset in the cursor is used in situations where we have a
	# nearly-unique index. (Eg millisecond precision creation timestamps)
	# We guard against malicious users attempting to cause expensive database
	# queries, by having a hard cap on the maximum possible size of the offset.
	offset_cutoff = 1000

	def paginate_queryset(self, queryset, request, view=None):
	self.request = request
	self.page_size = self.get_page_size(request)
	if not self.page_size:
	return None

	self.base_url = request.build_absolute_uri()
	self.ordering = self.get_ordering(request, queryset, view)

	self.cursor = self.decode_cursor(request)
	if self.cursor is None:
	(offset, reverse, current_position) = (0, False, None)
	else:
	(offset, reverse, current_position) = self.cursor

	# Cursor pagination always enforces an ordering.
	if reverse:
	queryset = queryset.order_by(*_reverse_ordering(self.ordering))
	else:
	queryset = queryset.order_by(*self.ordering)

	# If we have a cursor with a fixed position then filter by that.
	if current_position is not None:
	order = self.ordering[0]
	is_reversed = order.startswith('-')
	order_attr = order.lstrip('-')

	# Test for: (cursor reversed) XOR (queryset reversed)
	if self.cursor.reverse != is_reversed:
	kwargs = {order_attr + '__lt': current_position}
	else:
	kwargs = {order_attr + '__gt': current_position}

	queryset = queryset.filter(**kwargs)

	# If we have an offset cursor then offset the entire page by that amount.
	# We also always fetch an extra item in order to determine if there is a
	# page following on from this one.
	results = list(queryset[offset:offset + self.page_size + 1])
	self.page = list(results[:self.page_size])

	# Determine the position of the final item following the page.
	if len(results) > len(self.page):
	has_following_position = True
	following_position = self._get_position_from_instance(results[-1], self.ordering)
	else:
	has_following_position = False
	following_position = None

	if reverse:
	# If we have a reverse queryset, then the query ordering was in reverse
	# so we need to reverse the items again before returning them to the user.
	self.page = list(reversed(self.page))

	# Determine next and previous positions for reverse cursors.
	self.has_next = (current_position is not None) or (offset > 0)
	self.has_previous = has_following_position
	if self.has_next:
	self.next_position = current_position
	if self.has_previous:
	self.previous_position = following_position
	else:
	# Determine next and previous positions for forward cursors.
	self.has_next = has_following_position
	self.has_previous = (current_position is not None) or (offset > 0)
	if self.has_next:
	self.next_position = following_position
	if self.has_previous:
	self.previous_position = current_position

	# Display page controls in the browsable API if there is more
	# than one page.
	if (self.has_previous or self.has_next) and self.template is not None:
	self.display_page_controls = True

	return self.page

	def get_page_size(self, request):
	if self.page_size_query_param:
	with contextlib.suppress(KeyError, ValueError):
	return _positive_int(
	request.query_params[self.page_size_query_param],
	strict=True,
	cutoff=self.max_page_size
	)
	return self.page_size

	def get_next_link(self):
	if not self.has_next:
	return None

	if self.page and self.cursor and self.cursor.reverse and self.cursor.offset != 0:
	# If we're reversing direction and we have an offset cursor
	# then we cannot use the first position we find as a marker.
	compare = self._get_position_from_instance(self.page[-1], self.ordering)
	else:
	compare = self.next_position
	offset = 0

	has_item_with_unique_position = False
	for item in reversed(self.page):
	position = self._get_position_from_instance(item, self.ordering)
	if position != compare:
	# The item in this position and the item following it
	# have different positions. We can use this position as
	# our marker.
	has_item_with_unique_position = True
	break

	# The item in this position has the same position as the item
	# following it, we can't use it as a marker position, so increment
	# the offset and keep seeking to the previous item.
	compare = position
	offset += 1

	if self.page and not has_item_with_unique_position:
	# There were no unique positions in the page.
	if not self.has_previous:
	# We are on the first page.
	# Our cursor will have an offset equal to the page size,
	# but no position to filter against yet.
	offset = self.page_size
	position = None
	elif self.cursor.reverse:
	# The change in direction will introduce a paging artifact,
	# where we end up skipping forward a few extra items.
	offset = 0
	position = self.previous_position
	else:
	# Use the position from the existing cursor and increment
	# it's offset by the page size.
	offset = self.cursor.offset + self.page_size
	position = self.previous_position

	if not self.page:
	position = self.next_position

	cursor = Cursor(offset=offset, reverse=False, position=position)
	return self.encode_cursor(cursor)

	def get_previous_link(self):
	if not self.has_previous:
	return None

	if self.page and self.cursor and not self.cursor.reverse and self.cursor.offset != 0:
	# If we're reversing direction and we have an offset cursor
	# then we cannot use the first position we find as a marker.
	compare = self._get_position_from_instance(self.page[0], self.ordering)
	else:
	compare = self.previous_position
	offset = 0

	has_item_with_unique_position = False
	for item in self.page:
	position = self._get_position_from_instance(item, self.ordering)
	if position != compare:
	# The item in this position and the item following it
	# have different positions. We can use this position as
	# our marker.
	has_item_with_unique_position = True
	break

	# The item in this position has the same position as the item
	# following it, we can't use it as a marker position, so increment
	# the offset and keep seeking to the previous item.
	compare = position
	offset += 1

	if self.page and not has_item_with_unique_position:
	# There were no unique positions in the page.
	if not self.has_next:
	# We are on the final page.
	# Our cursor will have an offset equal to the page size,
	# but no position to filter against yet.
	offset = self.page_size
	position = None
	elif self.cursor.reverse:
	# Use the position from the existing cursor and increment
	# it's offset by the page size.
	offset = self.cursor.offset + self.page_size
	position = self.next_position
	else:
	# The change in direction will introduce a paging artifact,
	# where we end up skipping back a few extra items.
	offset = 0
	position = self.next_position

	if not self.page:
	position = self.previous_position

	cursor = Cursor(offset=offset, reverse=True, position=position)
	return self.encode_cursor(cursor)

	def get_ordering(self, request, queryset, view):
	"""
	Return a tuple of strings, that may be used in an `order_by` method.
	"""
	# The default case is to check for an `ordering` attribute
	# on this pagination instance.
	ordering = self.ordering

	ordering_filters = [
	filter_cls for filter_cls in getattr(view, 'filter_backends', [])
	if hasattr(filter_cls, 'get_ordering')
	]

	if ordering_filters:
	# If a filter exists on the view that implements `get_ordering`
	# then we defer to that filter to determine the ordering.
	filter_cls = ordering_filters[0]
	filter_instance = filter_cls()
	ordering_from_filter = filter_instance.get_ordering(request, queryset, view)
	if ordering_from_filter:
	ordering = ordering_from_filter

	assert ordering is not None, (
	'Using cursor pagination, but no ordering attribute was declared '
	'on the pagination class.'
	)
	assert '__' not in ordering, (
	'Cursor pagination does not support double underscore lookups '
	'for orderings. Orderings should be an unchanging, unique or '
	'nearly-unique field on the model, such as "-created" or "pk".'
	)

	assert isinstance(ordering, (str, list, tuple)), (
	'Invalid ordering. Expected string or tuple, but got {type}'.format(
	type=type(ordering).__name__
	)
	)

	if isinstance(ordering, str):
	return (ordering,)
	return tuple(ordering)

	def decode_cursor(self, request):
	"""
	Given a request with a cursor, return a `Cursor` instance.
	"""
	# Determine if we have a cursor, and if so then decode it.
	encoded = request.query_params.get(self.cursor_query_param)
	if encoded is None:
	return None

	try:
	querystring = b64decode(encoded.encode('ascii')).decode('ascii')
	tokens = parse.parse_qs(querystring, keep_blank_values=True)

	offset = tokens.get('o', ['0'])[0]
	offset = _positive_int(offset, cutoff=self.offset_cutoff)

	reverse = tokens.get('r', ['0'])[0]
	reverse = bool(int(reverse))

	position = tokens.get('p', [None])[0]
	except (TypeError, ValueError):
	raise NotFound(self.invalid_cursor_message)

	return Cursor(offset=offset, reverse=reverse, position=position)

	def encode_cursor(self, cursor):
	"""
	Given a Cursor instance, return an url with encoded cursor.
	"""
	tokens = {}
	if cursor.offset != 0:
	tokens['o'] = str(cursor.offset)
	if cursor.reverse:
	tokens['r'] = '1'
	if cursor.position is not None:
	tokens['p'] = cursor.position

	querystring = parse.urlencode(tokens, doseq=True)
	encoded = b64encode(querystring.encode('ascii')).decode('ascii')
	return replace_query_param(self.base_url, self.cursor_query_param, encoded)

	def _get_position_from_instance(self, instance, ordering):
	field_name = ordering[0].lstrip('-')
	if isinstance(instance, dict):
	attr = instance[field_name]
	else:
	attr = getattr(instance, field_name)
	return str(attr)

	def get_paginated_response(self, data):
	return Response({
	'next': self.get_next_link(),
	'previous': self.get_previous_link(),
	'results': data,
	})

	def get_paginated_response_schema(self, schema):
	return {
	'type': 'object',
	'required': ['results'],
	'properties': {
	'next': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{cursor_query_param}=cD00ODY%3D"'.format(
	cursor_query_param=self.cursor_query_param)
	},
	'previous': {
	'type': 'string',
	'nullable': True,
	'format': 'uri',
	'example': 'http://api.example.org/accounts/?{cursor_query_param}=cj0xJnA9NDg3'.format(
	cursor_query_param=self.cursor_query_param)
	},
	'results': schema,
	},
	}

	def get_html_context(self):
	return {
	'previous_url': self.get_previous_link(),
	'next_url': self.get_next_link()
	}

	def to_html(self):
	template = loader.get_template(self.template)
	context = self.get_html_context()
	return template.render(context)

	def get_schema_fields(self, view):
	assert coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
	if coreapi is not None:
	warnings.warn('CoreAPI compatibility is deprecated and will be removed in DRF 3.17', RemovedInDRF317Warning)
	assert coreschema is not None, 'coreschema must be installed to use `get_schema_fields()`'
	fields = [
	coreapi.Field(
	name=self.cursor_query_param,
	required=False,
	location='query',
	schema=coreschema.String(
	title='Cursor',
	description=force_str(self.cursor_query_description)
	)
	)
	]
	if self.page_size_query_param is not None:
	fields.append(
	coreapi.Field(
	name=self.page_size_query_param,
	required=False,
	location='query',
	schema=coreschema.Integer(
	title='Page size',
	description=force_str(self.page_size_query_description)
	)
	)
	)
	return fields

	def get_schema_operation_parameters(self, view):
	parameters = [
	{
	'name': self.cursor_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.cursor_query_description),
	'schema': {
	'type': 'string',
	},
	}
	]
	if self.page_size_query_param is not None:
	parameters.append(
	{
	'name': self.page_size_query_param,
	'required': False,
	'in': 'query',
	'description': force_str(self.page_size_query_description),
	'schema': {
	'type': 'integer',
	},
	}
	)
	return parameters

Xet Storage Details

Size:: 36.6 kB
Xet hash:: 4c365ee942e3ece07cc84d1d011eb92ee755ab761bcc17452110a77926ddd84d

Xet efficiently stores files, intelligently splitting them into unique chunks and accelerating uploads and downloads. More info.