awx/awx/api/utils/decorators.py
2015-05-29 12:10:39 -04:00

81 lines
2.8 KiB
Python

# Copyright (c) 2015 Ansible, Inc.
# All Rights Reserved.
from ordereddict import OrderedDict
import copy
import functools
from rest_framework.response import Response
from rest_framework.settings import api_settings
from rest_framework import status
def paginated(method):
"""Given an method with a Django REST Framework API method signature
(e.g. `def get(self, request, ...):`), abstract out boilerplate pagination
duties.
This causes the method to receive two additional keyword arguments:
`limit`, and `offset`. The method expects a two-tuple to be
returned, with a result list as the first item, and the total number
of results (across all pages) as the second item.
"""
@functools.wraps(method)
def func(self, request, *args, **kwargs):
# Manually spin up pagination.
# How many results do we show?
limit = api_settings.PAGINATE_BY
if request.QUERY_PARAMS.get(api_settings.PAGINATE_BY_PARAM, False):
limit = request.QUERY_PARAMS[api_settings.PAGINATE_BY_PARAM]
if api_settings.MAX_PAGINATE_BY:
limit = min(api_settings.MAX_PAGINATE_BY, limit)
limit = int(limit)
# Get the order parameter if it's given
if request.QUERY_PARAMS.get("ordering", False):
ordering = request.QUERY_PARAMS["ordering"]
else:
ordering = None
# What page are we on?
page = int(request.QUERY_PARAMS.get('page', 1))
offset = (page - 1) * limit
# Add the limit, offset, page, and order variables to the keyword arguments
# being sent to the underlying method.
kwargs['limit'] = limit
kwargs['offset'] = offset
kwargs['ordering'] = ordering
# Okay, call the underlying method.
results, count, stat = method(self, request, *args, **kwargs)
if stat is None:
stat = status.HTTP_200_OK
if stat == status.HTTP_200_OK:
# Determine the next and previous pages, if any.
prev, next_ = None, None
if page > 1:
get_copy = copy.copy(request.GET)
get_copy['page'] = page - 1
prev = '%s?%s' % (request.path, get_copy.urlencode())
if count > offset + limit:
get_copy = copy.copy(request.GET)
get_copy['page'] = page + 1
next_ = '%s?%s' % (request.path, get_copy.urlencode())
# Compile the results into a dictionary with pagination
# information.
answer = OrderedDict((
('count', count),
('next', next_),
('previous', prev),
('results', results),
))
else:
answer = results
# Okay, we're done; return response data.
return Response(answer, status=stat)
return func