Tweaks, and add pagination controls for offset/limit.

1 files changed, 96 insertions, 30 deletions

diff --git a/rest_framework/pagination.py b/rest_framework/pagination.py
index 69d0f77d..2b78f1f7 100644
--- a/rest_framework/pagination.py
+++ b/rest_framework/pagination.py
@@ -29,6 +29,15 @@ def _strict_positive_int(integer_string, cutoff=None):
     return ret
 
 
+def _divide_with_ceil(a, b):
+    """
+    Returns 'a' divded by 'b', with any remainder rounded up.
+    """
+    if a % b:
+        return (a / b) + 1
+    return a / b
+
+
 def _get_count(queryset):
     """
     Determine an object count, supporting either querysets or regular lists.
@@ -48,14 +57,21 @@ def _get_displayed_page_numbers(current, final):
     current=14, final=16 -> [1, None, 13, 14, 15, 16]
 
     This implementation gives one page to each side of the cursor,
-    for an implementation which gives two pages to each side of the cursor,
-    which is a copy of how GitHub treat pagination in their issue lists, see:
+    or two pages to the side when the cursor is at the edge, then
+    ensures that any breaks between non-continous page numbers never
+    remove only a single page.
+
+    For an alernativative implementation which gives two pages to each side of
+    the cursor, eg. as in GitHub issue list pagination, see:
 
     https://gist.github.com/tomchristie/321140cebb1c4a558b15
     """
     assert current >= 1
     assert final >= current
 
+    if final <= 5:
+        return range(1, final + 1)
+
     # We always include the first two pages, last two pages, and
     # two pages either side of the current page.
     included = set((
@@ -87,16 +103,46 @@ def _get_displayed_page_numbers(current, final):
     return included
 
 
+def _get_page_links(page_numbers, current, url_func):
+    """
+    Given a list of page numbers and `None` page breaks,
+    return a list of `PageLink` objects.
+    """
+    page_links = []
+    for page_number in page_numbers:
+        if page_number is None:
+            page_link = PageLink(
+                url=None,
+                number=None,
+                is_active=False,
+                is_break=True
+            )
+        else:
+            page_link = PageLink(
+                url=url_func(page_number),
+                number=page_number,
+                is_active=(page_number == current),
+                is_break=False
+            )
+        page_links.append(page_link)
+    return page_links
+
+
 PageLink = namedtuple('PageLink', ['url', 'number', 'is_active', 'is_break'])
 
 
 class BasePagination(object):
+    display_page_controls = False
+
     def paginate_queryset(self, queryset, request, view):
         raise NotImplemented('paginate_queryset() must be implemented.')
 
     def get_paginated_response(self, data):
         raise NotImplemented('get_paginated_response() must be implemented.')
 
+    def to_html(self):
+        raise NotImplemented('to_html() must be implemented to display page controls.')
+
 
 class PageNumberPagination(BasePagination):
     """
@@ -161,8 +207,9 @@ class PageNumberPagination(BasePagination):
             )
             raise NotFound(msg)
 
-        # Indicate that the browsable API should display pagination controls.
-        self.mark_as_used = True
+        if paginator.count > 1:
+            # The browsable API should display pagination controls.
+            self.display_page_controls = True
         self.request = request
         return self.page
 
@@ -203,31 +250,17 @@ class PageNumberPagination(BasePagination):
         return replace_query_param(url, self.page_query_param, page_number)
 
     def to_html(self):
-        current = self.page.number
-        final = self.page.paginator.num_pages
-
-        page_links = []
         base_url = self.request.build_absolute_uri()
-        for page_number in _get_displayed_page_numbers(current, final):
-            if page_number is None:
-                page_link = PageLink(
-                    url=None,
-                    number=None,
-                    is_active=False,
-                    is_break=True
-                )
+        def page_number_to_url(page_number):
+            if page_number == 1:
+                return remove_query_param(base_url, self.page_query_param)
             else:
-                if page_number == 1:
-                    url = remove_query_param(base_url, self.page_query_param)
-                else:
-                    url = replace_query_param(url, self.page_query_param, page_number)
-                page_link = PageLink(
-                    url=url,
-                    number=page_number,
-                    is_active=(page_number == current),
-                    is_break=False
-                )
-            page_links.append(page_link)
+                return replace_query_param(base_url, self.page_query_param, page_number)
+
+        current = self.page.number
+        final = self.page.paginator.num_pages
+        page_numbers = _get_displayed_page_numbers(current, final)
+        page_links = _get_page_links(page_numbers, current, page_number_to_url)
 
         template = loader.get_template(self.template)
         context = Context({
@@ -250,11 +283,15 @@ class LimitOffsetPagination(BasePagination):
     offset_query_param = 'offset'
     max_limit = None
 
+    template = 'rest_framework/pagination/numbers.html'
+
     def paginate_queryset(self, queryset, request, view):
         self.limit = self.get_limit(request)
         self.offset = self.get_offset(request)
         self.count = _get_count(queryset)
         self.request = request
+        if self.count > self.limit:
+            self.display_page_controls = True
         return queryset[self.offset:self.offset + self.limit]
 
     def get_paginated_response(self, data):
@@ -285,16 +322,45 @@ class LimitOffsetPagination(BasePagination):
         except (KeyError, ValueError):
             return 0
 
-    def get_next_link(self, page):
+    def get_next_link(self):
         if self.offset + self.limit >= self.count:
             return None
+
         url = self.request.build_absolute_uri()
         offset = self.offset + self.limit
         return replace_query_param(url, self.offset_query_param, offset)
 
-    def get_previous_link(self, page):
-        if self.offset - self.limit < 0:
+    def get_previous_link(self):
+        if self.offset <= 0:
             return None
+
         url = self.request.build_absolute_uri()
+
+        if self.offset - self.limit <= 0:
+            return remove_query_param(url, self.offset_query_param)
+
         offset = self.offset - self.limit
         return replace_query_param(url, self.offset_query_param, offset)
+
+    def to_html(self):
+        base_url = self.request.build_absolute_uri()
+        current = _divide_with_ceil(self.offset, self.limit) + 1
+        final = _divide_with_ceil(self.count, self.limit)
+
+        def page_number_to_url(page_number):
+            if page_number == 1:
+                return remove_query_param(base_url, self.offset_query_param)
+            else:
+                offset = self.offset + ((page_number - current) * self.limit)
+                return replace_query_param(base_url, self.offset_query_param, offset)
+
+        page_numbers = _get_displayed_page_numbers(current, final)
+        page_links = _get_page_links(page_numbers, current, page_number_to_url)
+
+        template = loader.get_template(self.template)
+        context = Context({
+            'previous_url': self.get_previous_link(),
+            'next_url': self.get_next_link(),
+            'page_links': page_links
+        })
+        return template.render(context)
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