26bac9f611
Pagination should be standard and easy to adopt so moved the paginators into the edx_rest_framework_extensions package so they can be easily installed into other app/projects
86 lines
2.7 KiB
Python
86 lines
2.7 KiB
Python
"""
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Discussion API pagination support
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"""
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from rest_framework.utils.urls import replace_query_param
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from edx_rest_framework_extensions.paginators import NamespacedPageNumberPagination
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class _Page(object):
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"""
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Implements just enough of the django.core.paginator.Page interface to allow
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PaginationSerializer to work.
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"""
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def __init__(self, page_num, num_pages):
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"""
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Create a new page containing the given objects, with the given page
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number and number of pages
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"""
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self.page_num = page_num
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self.num_pages = num_pages
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def has_next(self):
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"""Returns True if there is a page after this one, otherwise False"""
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return self.page_num < self.num_pages
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def has_previous(self):
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"""Returns True if there is a page before this one, otherwise False"""
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return self.page_num > 1
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def next_page_number(self):
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"""Returns the number of the next page"""
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return self.page_num + 1
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def previous_page_number(self):
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"""Returns the number of the previous page"""
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return self.page_num - 1
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class DiscussionAPIPagination(NamespacedPageNumberPagination):
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"""
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Subclasses NamespacedPageNumberPagination to provide custom implementation of pagination metadata
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by overriding it's methods
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"""
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def __init__(self, request, page_num, num_pages, result_count=0):
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"""
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Overrides parent constructor to take information from discussion api
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essential for the parent method
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"""
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self.page = _Page(page_num, num_pages)
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self.base_url = request.build_absolute_uri()
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self.count = result_count
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super(DiscussionAPIPagination, self).__init__()
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def get_result_count(self):
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"""
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Returns total number of results
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"""
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return self.count
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def get_num_pages(self):
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"""
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Returns total number of pages the response is divided into
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"""
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return self.page.num_pages
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def get_next_link(self):
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"""
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Returns absolute url of the next page if there's a next page available
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otherwise returns None
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"""
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next_url = None
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if self.page.has_next():
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next_url = replace_query_param(self.base_url, "page", self.page.next_page_number())
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return next_url
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def get_previous_link(self):
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"""
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Returns absolute url of the previous page if there's a previous page available
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otherwise returns None
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"""
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previous_url = None
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if self.page.has_previous():
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previous_url = replace_query_param(self.base_url, "page", self.page.previous_page_number())
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return previous_url
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