InfinitePaginator (from Pownce) with tests! The InfinitePaginator does not count...

diff --git a/pagination/paginator.py b/pagination/paginator.py
new file mode 100644 (file)
index 0000000..9a6ec83
--- /dev/null
+++ b/pagination/paginator.py
@@ -0,0 +1,95 @@
+from django.core.paginator import Paginator, Page, PageNotAnInteger, EmptyPage
+
+class InfinitePaginator(Paginator):
+    '''
+        Paginator designed for cases when it's not important to know how many total pages.
+        This is useful for any object_list that has no count() method or can be used to
+        improve performance for MySQL by removing counts.
+        
+        The orphans parameter has been removed for simplicity and there's a link template string
+        for creating the links to the next and previous pages.
+        
+        Class name is pronounced verbally in a deep tone.
+    '''
+
+    def __init__(self, object_list, per_page, allow_empty_first_page=True, link_template='/page/%d/'):
+        orphans = 0 # no orphans
+        super(InfinitePaginator, self).__init__(object_list, per_page, orphans, allow_empty_first_page)
+        # no count or num pages
+        del self._num_pages, self._count
+        # bonus links
+        self.link_template = link_template
+
+    def validate_number(self, number):
+        "Validates the given 1-based page number."
+        try:
+            number = int(number)
+        except ValueError:
+            raise PageNotAnInteger('That page number is not an integer')
+        if number < 1:
+            raise EmptyPage('That page number is less than 1')
+        return number
+
+    def page(self, number):
+        "Returns a Page object for the given 1-based page number."
+        number = self.validate_number(number)
+        bottom = (number - 1) * self.per_page
+        top = bottom + self.per_page
+        page_items = self.object_list[bottom:top]
+        # check moved from validate_number
+        if not page_items:
+            if number == 1 and self.allow_empty_first_page:
+                pass
+            else:
+                raise EmptyPage('That page contains no results')
+        return InfinitePage(page_items, number, self)
+
+    def _get_count(self):
+        "Returns the total number of objects, across all pages."
+        raise NotImplementedError
+    count = property(_get_count)
+
+    def _get_num_pages(self):
+        "Returns the total number of pages."
+        raise NotImplementedError
+    num_pages = property(_get_num_pages)
+
+    def _get_page_range(self):
+        """
+        Returns a 1-based range of pages for iterating through within
+        a template for loop.
+        """
+        raise NotImplementedError
+    page_range = property(_get_page_range)
+
+class InfinitePage(Page):
+
+    def __repr__(self):
+        return '<Page %s>' % self.number
+
+    def has_next(self):
+        "Checks for one more item than last on this page."
+        try:
+            next_item = self.paginator.object_list[self.number * self.paginator.per_page]
+        except IndexError:
+            return False
+        return True
+
+    def end_index(self):
+        """
+        Returns the 1-based index of the last object on this page,
+        relative to total objects found (hits).
+        """
+        return (self.number - 1) * self.paginator.per_page + len(self.object_list)
+    
+    '''Bonus methods for creating links'''
+
+    def next_link(self):
+        if self.has_next():
+            return self.paginator.link_template % (self.number + 1)
+        return None
+
+    def previous_link(self):
+        if self.has_previous():
+            return self.paginator.link_template % (self.number - 1)
+        return None
\ No newline at end of file

diff --git a/pagination/tests.py b/pagination/tests.py
index 647bbfd..c0a4a6c 100644 (file)
--- a/pagination/tests.py
+++ b/pagination/tests.py
@@ -58,4 +58,32 @@ u'\\n\\n<div class="pagination">...
 >>> t.render(Context({'var': range(21), 'by': 20, 'request': RequestProxy()}))
 u'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]'
 >>>
+
+# Testing InfinitePaginator
+
+>>> from paginator import InfinitePaginator
+>>> InfinitePaginator
+<class 'pagination.paginator.InfinitePaginator'>
+>>> p = InfinitePaginator(range(20), 2, link_template='/bacon/page/%d')
+>>> p.validate_number(2)
+2
+>>> p.orphans
+0
+>>> p3 = p.page(3)
+>>> p3
+<Page 3>
+>>> p3.end_index()
+6
+>>> p3.has_next()
+True
+>>> p3.has_previous()
+True
+>>> p.page(10).has_next()
+False
+>>> p.page(1).has_previous()
+False
+>>> p3.next_link()
+'/bacon/page/4'
+>>> p3.previous_link()
+'/bacon/page/2'
 """
\ No newline at end of file