|
| 1 | +import logging |
| 2 | +import re |
| 3 | + |
| 4 | +from django.core.paginator import Paginator |
| 5 | +from django.db.models.query import QuerySet |
1 | 6 | from rest_framework.pagination import PageNumberPagination |
2 | 7 |
|
| 8 | +logger = logging.getLogger(__name__) |
| 9 | + |
3 | 10 |
|
4 | 11 | class SmallResultSetPagination(PageNumberPagination): |
5 | 12 | page_size_query_param = "page_size" |
6 | 13 | max_page_size = 100 |
| 14 | + |
| 15 | + |
| 16 | +class PaginatedListViewMixin: |
| 17 | + """ |
| 18 | + A mixin that adds pagination functionality to ListView-based views. |
| 19 | + """ |
| 20 | + |
| 21 | + paginate_by = 20 |
| 22 | + max_page_size = 100 |
| 23 | + PAGE_SIZE_CHOICES = [ |
| 24 | + {"value": 20, "label": "20 per page"}, |
| 25 | + {"value": 50, "label": "50 per page"}, |
| 26 | + {"value": 100, "label": "100 per page"}, |
| 27 | + ] |
| 28 | + |
| 29 | + def get_queryset(self): |
| 30 | + """ |
| 31 | + Ensure a queryset is always available |
| 32 | + """ |
| 33 | + try: |
| 34 | + queryset = super().get_queryset() |
| 35 | + if not queryset: |
| 36 | + queryset = self.model.objects.all() |
| 37 | + if not isinstance(queryset, QuerySet): |
| 38 | + queryset = self.model.objects.all() |
| 39 | + return queryset |
| 40 | + except Exception as e: |
| 41 | + logger.error(f"Error in get_queryset: {e}") |
| 42 | + return self.model.objects.all() |
| 43 | + |
| 44 | + def sanitize_page_size(self, raw_page_size): |
| 45 | + """ |
| 46 | + Sanitize page size input to prevent XSS and injection attempts. |
| 47 | + """ |
| 48 | + if not raw_page_size: |
| 49 | + return self.paginate_by |
| 50 | + clean_page_size = re.sub(r"\D", "", str(raw_page_size)) |
| 51 | + try: |
| 52 | + page_size = int(clean_page_size) if clean_page_size else self.paginate_by |
| 53 | + valid_sizes = {choice["value"] for choice in self.PAGE_SIZE_CHOICES} |
| 54 | + if page_size not in valid_sizes: |
| 55 | + logger.warning(f"Attempted to use unauthorized page size: {page_size}") |
| 56 | + return self.paginate_by |
| 57 | + return page_size |
| 58 | + except (ValueError, TypeError): |
| 59 | + logger.info("Empty or invalid page_size input attempted") |
| 60 | + return self.paginate_by |
| 61 | + |
| 62 | + def get_paginate_by(self, queryset=None): |
| 63 | + """ |
| 64 | + Get the number of items to paginate by from the request. |
| 65 | + """ |
| 66 | + raw_page_size = self.request.GET.get("page_size") |
| 67 | + return self.sanitize_page_size(raw_page_size) |
| 68 | + |
| 69 | + def get_page_range(self, paginator, page_obj): |
| 70 | + """ |
| 71 | + Generate a list of page numbers for navigation |
| 72 | + """ |
| 73 | + num_pages = paginator.num_pages |
| 74 | + current_page = page_obj.number |
| 75 | + if num_pages <= 7: |
| 76 | + return list(range(1, num_pages + 1)) |
| 77 | + pages = [] |
| 78 | + pages.append(1) |
| 79 | + if current_page > 4: |
| 80 | + pages.append("...") |
| 81 | + start = max(2, current_page - 2) |
| 82 | + end = min(num_pages - 1, current_page + 2) |
| 83 | + pages.extend(range(start, end + 1)) |
| 84 | + if current_page < num_pages - 3: |
| 85 | + pages.append("...") |
| 86 | + if num_pages > 1: |
| 87 | + pages.append(num_pages) |
| 88 | + return [str(p) for p in pages] |
| 89 | + |
| 90 | + def paginate_queryset(self, queryset, page_size): |
| 91 | + try: |
| 92 | + if not queryset or queryset.count() == 0: |
| 93 | + queryset = self.model.objects.all() |
| 94 | + paginator = Paginator(queryset, page_size) |
| 95 | + page_params = self.request.GET.getlist("page") |
| 96 | + page_number = page_params[-1] if page_params else "1" |
| 97 | + try: |
| 98 | + page_number = int(re.sub(r"\D", "", str(page_number))) |
| 99 | + if not page_number: |
| 100 | + page_number = 1 |
| 101 | + except (ValueError, TypeError): |
| 102 | + page_number = 1 |
| 103 | + page_number = max(1, min(page_number, paginator.num_pages)) |
| 104 | + page = paginator.page(page_number) |
| 105 | + return (paginator, page, page.object_list, page.has_other_pages()) |
| 106 | + except Exception as e: |
| 107 | + logger.error(f"Pagination error: {e}") |
| 108 | + queryset = self.model.objects.all() |
| 109 | + paginator = Paginator(queryset, page_size) |
| 110 | + page = paginator.page(1) |
| 111 | + return (paginator, page, page.object_list, page.has_other_pages()) |
| 112 | + |
| 113 | + def get_context_data(self, **kwargs): |
| 114 | + """ |
| 115 | + Return a mapping of pagination-related context data, preserving filters. |
| 116 | + """ |
| 117 | + queryset = self.get_queryset() |
| 118 | + page_size = self.get_paginate_by() |
| 119 | + paginator, page, object_list, is_paginated = self.paginate_queryset(queryset, page_size) |
| 120 | + page_range = self.get_page_range(paginator, page) |
| 121 | + |
| 122 | + search = self.request.GET.get("search", "") |
| 123 | + |
| 124 | + context = super().get_context_data( |
| 125 | + object_list=object_list, |
| 126 | + page_obj=page, |
| 127 | + paginator=paginator, |
| 128 | + is_paginated=is_paginated, |
| 129 | + **kwargs, |
| 130 | + ) |
| 131 | + |
| 132 | + context.update( |
| 133 | + { |
| 134 | + "current_page_size": page_size, |
| 135 | + "page_size_choices": self.PAGE_SIZE_CHOICES, |
| 136 | + "total_count": paginator.count, |
| 137 | + "page_range": page_range, |
| 138 | + "search": search, |
| 139 | + "previous_page_url": page.previous_page_number() if page.has_previous() else None, |
| 140 | + "next_page_url": page.next_page_number() if page.has_next() else None, |
| 141 | + } |
| 142 | + ) |
| 143 | + return context |
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