You have pagination for some blog. At the bottom of the page you have space for seven page links. This module tries to always fill out those slots. It handles the corner cases for first page and last page etc.
The logic for this is complex and sadly the Django pagination module does not deal with this. Also, it's a hell to implement this in Django templates. Believe me.
See pydoc for detailed documentation. Running tests was done with doctest.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | from django.template import Library, Node, TemplateSyntaxError
register = Library()
class _SlicedPaginator:
def __init__(self, curpage, npages, maxpages_items):
"""Contructor.
Example:
>>> _SlicedPaginator(1, 3, 3)
_SlicedPaginator(curpage=1, npages=3, maxpages_items=3)
"""
self.curpage = int(curpage)
self.npages = int(npages)
self.maxpages_items = int(maxpages_items)
assert 1 <= self.curpage <= self.npages, "%s %s" % (self.curpage,
self.npages)
assert self.maxpages_items > 0
assert self.maxpages_items % 2 == 1, "Only uneven maxpages_items supported. Unclear how to be presented otherwise."
self.max_prev_items = (self.maxpages_items - 1) / 2
self.max_next_items = self.max_prev_items
def __repr__(self):
tmpl = "_SlicedPaginator(curpage={0}, npages={1}, maxpages_items={2})"
return tmpl.format(self.curpage, self.npages, self.maxpages_items)
def _build_full_list(self):
"""Build a full list of pages.
Examples:
>>> _SlicedPaginator(1, 7, 5)._build_full_list()
[1, 2, 3, 4, 5]
>>> _SlicedPaginator(6, 7, 5)._build_full_list()
[3, 4, 5, 6, 7]
>>> _SlicedPaginator(6, 7, 5)._build_full_list()
[3, 4, 5, 6, 7]
>>> import itertools
>>> combinations = itertools.combinations(range(100), 2)
>>> combinations = filter(lambda (x,y): x<y, combinations)
>>> for page, maxpages in combinations:
... a = _SlicedPaginator(page + 1, maxpages, 7)
... b = a._build_full_list()
>>> _SlicedPaginator(2, 5, 7)._build_full_list()
[1, 2, 3, 4, 5]
>>> _SlicedPaginator(5, 5, 7)._build_full_list()
[1, 2, 3, 4, 5]
"""
if self.npages <= self.maxpages_items:
return range(1, self.npages + 1)
else:
l = range(self.curpage - self.max_prev_items,
self.curpage + self.max_next_items + 1)
while l and l[0] < 1:
l.append(l[-1] + 1)
del l[0]
while l and l[-1] > self.npages:
l.insert(0, l[0] - 1)
del l[-1]
return l
def prev_pages(self):
"""Get the previous pages.
Example:
>>> map(lambda i: _SlicedPaginator(i, 6, 3).prev_pages(), range(1, 7))
[[], [1], [2], [3], [4], [4, 5]]
>>> map(lambda i: _SlicedPaginator(i, 7, 3).prev_pages(), range(1, 8))
[[], [1], [2], [3], [4], [5], [5, 6]]
>>> map(lambda i: _SlicedPaginator(i, 6, 5).prev_pages(), range(1, 7))
[[], [1], [1, 2], [2, 3], [2, 3, 4], [2, 3, 4, 5]]
>>> map(lambda i: _SlicedPaginator(i, 7, 5).prev_pages(), range(1, 8))
[[], [1], [1, 2], [2, 3], [3, 4], [3, 4, 5], [3, 4, 5, 6]]
"""
return filter(lambda x: x < self.curpage, self._build_full_list())
def hidden_prev_pages(self):
"""Check if the previous pages where sliced.
Example:
>>> map(lambda i: _SlicedPaginator(i, 6, 3).hidden_prev_pages(), range(1, 7))
[False, False, True, True, True, True]
>>> map(lambda i: _SlicedPaginator(i, 7, 3).hidden_prev_pages(), range(1, 8))
[False, False, True, True, True, True, True]
>>> map(lambda i: _SlicedPaginator(i, 6, 5).hidden_prev_pages(), range(1, 7))
[False, False, False, True, True, True]
>>> map(lambda i: _SlicedPaginator(i, 7, 5).hidden_prev_pages(), range(1, 8))
[False, False, False, True, True, True, True]
"""
prev_pages = self.prev_pages()
return len(prev_pages) > 0 and prev_pages[0] > 1
def next_pages(self):
"""Get the next pages.
Example:
>>> map(lambda i: _SlicedPaginator(i, 6, 3).next_pages(), range(1, 7))
[[2, 3], [3], [4], [5], [6], []]
>>> map(lambda i: _SlicedPaginator(i, 7, 3).next_pages(), range(1, 8))
[[2, 3], [3], [4], [5], [6], [7], []]
>>> map(lambda i: _SlicedPaginator(i, 6, 5).next_pages(), range(1, 7))
[[2, 3, 4, 5], [3, 4, 5], [4, 5], [5, 6], [6], []]
>>> map(lambda i: _SlicedPaginator(i, 7, 5).next_pages(), range(1, 8))
[[2, 3, 4, 5], [3, 4, 5], [4, 5], [5, 6], [6, 7], [7], []]
"""
return filter(lambda x: x > self.curpage, self._build_full_list())
def hidden_next_pages(self):
"""Check if the next pages where sliced.
Example:
>>> map(lambda i: _SlicedPaginator(i, 6, 3).hidden_next_pages(), range(1, 7))
[True, True, True, True, False, False]
>>> map(lambda i: _SlicedPaginator(i, 7, 3).hidden_next_pages(), range(1, 8))
[True, True, True, True, True, False, False]
>>> map(lambda i: _SlicedPaginator(i, 6, 5).hidden_next_pages(), range(1, 7))
[True, True, True, False, False, False]
>>> map(lambda i: _SlicedPaginator(i, 7, 5).hidden_next_pages(), range(1, 8))
[True, True, True, True, False, False, False]
"""
next_pages = self.next_pages()
return len(next_pages) > 0 and next_pages[-1] < self.npages
class _PaginatorSliceNode(Node):
def __init__(self, context_name, paginatorname, maxpages_items):
self.context_name = context_name
self.paginatorname = paginatorname
self.maxpages_items = maxpages_items
def render(self, context):
sliced_paginator = _SlicedPaginator(context[self.paginatorname].number,
context[self.paginatorname].paginator.num_pages,
self.maxpages_items)
context[self.context_name] = sliced_paginator
return ""
def _get_errstr(fnctn):
s = "%s takes the syntax %s limited_pagination paginator_page max_items\
as context_variable"
return s % (fnctn, fnctn)
@register.tag
def sliced_pagination(parser, token):
"""
Slices a paginator.
Syntax:
{% sliced_pagination page 5 as sliced_paginator %}
where
- page is an instance of the Django `Page` class.
- max_items are the number of items to be shown in total. Ie., 5 will yield
<< 1 2 3 4 5 ... >>
or
<< ... 4 5 6 7 8 ... >>
or
<< ... 10 11 12 13 15 >>
Currently only uneven numbers are supported for this parameter due to
have even lists of pages on both sides.
Sample syntax to use the sliced paginator:
{% if sliced_paginator.hidden_prev_pages %}
...
{% endif %}
{% for pageno in sliced_paginator.prev_pages %}
<a href="?page={{ pageno }}">{{ pageno}}</a>
{% endfor %}
<a href="#" class="current">{{ page.number }}</a>
{% for pageno in sliced_paginator.next_pages %}
<a href="?page={{ pageno }}">{{ pageno}}</a>
{% endfor %}
{% if sliced_paginator.hidden_next_pages %}
...
{% endif %}
Produces:
... # only shown if needed
<a href="?page=3">3</a>
<a href="?page=4">4</a>
<a href="#" class="current">5</a>
<a href="?page=6">6</a>
<a href="?page=7">7</a>
... # only shown if needed
"""
try:
fnctn, paginatorname, max_items, trash, context_name = token.split_contents()
except ValueError:
raise TemplateSyntaxError, _get_errstr(fnctn)
if not trash == 'as':
raise TemplateSyntaxError, _get_errstr(fnctn)
return _PaginatorSliceNode(context_name, paginatorname, max_items)
|
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Comments
Line 46 throws an error when prelist == []. It needs "if prelist:" clause.
#
@ja_n This is fixed. Also added a test case for it. Thanks.
#
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