8555630df7
* Upgrade edx-submissions * Upgrade edx-ora2 * Upgrade edx-val * Upgrade edx-proctoring * Update all edx-platform code that depends on DRF, including: - auth_exchange - cors_csrf - embargo - enrollment - util - commerce - course_structure - discussion_api - mobile_api - notifier_api - teams - credit - profile_images - user_api - lib/api (OAuth2 and pagination)
68 lines
2.3 KiB
Python
68 lines
2.3 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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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, object_list, 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.object_list = object_list
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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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def get_paginated_data(request, results, page_num, per_page):
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"""
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Return a dict with the following values:
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next: The URL for the next page
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previous: The URL for the previous page
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results: The results on this page
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"""
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# Note: Previous versions of this function used Django Rest Framework's
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# paginated serializer. With the upgrade to DRF 3.1, paginated serializers
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# have been removed. We *could* use DRF's paginator classes, but there are
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# some slight differences between how DRF does pagination and how we're doing
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# pagination here. (For example, we respond with a next_url param even if
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# there is only one result on the current page.) To maintain backwards
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# compatability, we simulate the behavior that DRF used to provide.
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page = _Page(results, page_num, per_page)
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next_url, previous_url = None, None
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base_url = request.build_absolute_uri()
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if page.has_next():
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next_url = replace_query_param(base_url, "page", page.next_page_number())
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if page.has_previous():
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previous_url = replace_query_param(base_url, "page", page.previous_page_number())
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return {
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"next": next_url,
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"previous": previous_url,
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"results": results,
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}
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