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)