Initial commit

Author: gregplaysguitar

.gitignore

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+/.tox

LICENSE.txt

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+Copyright (c) 2017 Greg Brown  
+[gregbrown.co.nz](http://gregbrown.co.nz)
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+3. The name of the author may not be used to endorse or promote products
+   derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

MANIFEST.in

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+include LICENSE.txt
+include README.md

README.md

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+Django utility to retrieve the next or previous object, given a current object
+and a queryset.
+
+See <http://gregbrown.co.nz/code/django-next-prev/> for more details.
+
+[![Circle CI](https://circleci.com/gh/gregplaysguitar/django-next-prev.svg?style=svg)](https://circleci.com/gh/gregplaysguitar/django-next-prev)
+[![codecov](https://codecov.io/gh/gregplaysguitar/django-next-prev/branch/master/graph/badge.svg)](https://codecov.io/gh/gregplaysguitar/django-next-prev)
+[![Latest Version](https://img.shields.io/pypi/v/django-next-prev.svg?style=flat)](https://pypi.python.org/pypi/django-next-prev/)
+
+
+## Installation
+
+Download the source from https://pypi.python.org/pypi/django-next-prev/
+and run `python setup.py install`, or:
+
+    > pip install django-next-prev
+
+Django 1.8 or higher is required.
+
+
+## Quick start

circle.yml

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+dependencies:
+  override:
+    - pip install tox tox-pyenv
+    - pyenv local 2.7.12 3.4.4 3.5.2
+  post:
+    - pip install coverage
+    - python ./setup.py install
+test:
+  post:
+    - coverage run --source next_prev ./runtests.py
+    - bash <(curl -s https://codecov.io/bash)

next_prev.py

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+# -*- coding: utf-8 -*-
+
+from functools import partial
+
+from django.db import models
+
+if not locals().get('reduce'):
+    from functools import reduce
+
+__version__ = '1.0.0'
+VERSION = tuple(map(int, __version__.split('.')))
+
+
+def get_model_attr(instance, attr):
+    """Example usage: get_model_attr(instance, 'category__slug')"""
+    for field in attr.split('__'):
+        instance = getattr(instance, field)
+    return instance
+
+
+def next_or_prev_in_order(instance, qs=None, prev=False, loop=False):
+    """Get the next (or previous with prev=True) item for instance, from the
+       given queryset (which is assumed to contain instance) respecting
+       queryset ordering. If loop is True, return the first/last item when the
+       end/start is reached. """
+
+    if not qs:
+        qs = instance.__class__.objects.all()
+
+    if prev:
+        qs = qs.reverse()
+        lookup = 'lt'
+    else:
+        lookup = 'gt'
+
+    q_list = []
+    prev_fields = []
+
+    if qs.query.extra_order_by:
+        ordering = qs.query.extra_order_by
+    elif not qs.query.default_ordering:
+        ordering = qs.query.order_by
+    else:
+        ordering = qs.query.order_by or qs.query.get_meta().ordering
+
+    ordering = list(ordering)
+
+    for field in (ordering + ['pk']):
+        if field[0] == '-':
+            this_lookup = (lookup == 'gt' and 'lt' or 'gt')
+            field = field[1:]
+        else:
+            this_lookup = lookup
+        q_kwargs = dict([(f, get_model_attr(instance, f))
+                         for f in prev_fields])
+        key = "%s__%s" % (field, this_lookup)
+        q_kwargs[key] = get_model_attr(instance, field)
+        q_list.append(models.Q(**q_kwargs))
+        prev_fields.append(field)
+    try:
+        return qs.filter(reduce(models.Q.__or__, q_list))[0]
+    except IndexError:
+        length = qs.count()
+        if loop and length > 1:
+            # queryset is reversed above if prev
+            return qs[0]
+    return None
+
+
+next_in_order = partial(next_or_prev_in_order, prev=False)
+prev_in_order = partial(next_or_prev_in_order, prev=True)

runtests.py

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+#!/usr/bin/env python
+import os
+import sys
+
+import django
+from django.conf import settings
+from django.test.utils import get_runner
+
+
+if __name__ == "__main__":
+    os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_settings'
+    django.setup()
+    TestRunner = get_runner(settings)
+    test_runner = TestRunner()
+    failures = test_runner.run_tests(["tests"])
+
+    # Return failures
+    sys.exit(bool(failures))

setup.py

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+#!/usr/bin/env python
+# coding: utf8
+
+import os
+
+from setuptools import setup
+
+# if there's a converted readme, use it, otherwise fall back to markdown
+if os.path.exists('README.rst'):
+    readme_path = 'README.rst'
+else:
+    readme_path = 'README.md'
+
+setup(
+    name='django-next-prev',
+    version='1.0.0',
+    description='Configurable search for django models',
+    long_description=open(readme_path).read(),
+    author='Greg Brown',
+    author_email='[email protected]',
+    url='https://github.com/gregplaysguitar/django-next-prev',
+    packages=[],
+    license='BSD License',
+    zip_safe=False,
+    platforms='any',
+    install_requires=['Django>=1.8'],
+    include_package_data=True,
+    package_data={},
+    py_modules=['next_prev'],
+    classifiers=[
+        'Development Status :: 5 - Production/Stable',
+        'Environment :: Web Environment',
+        'Intended Audience :: Developers',
+        'Operating System :: OS Independent',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Topic :: Internet :: WWW/HTTP :: Dynamic Content',
+        'Framework :: Django',
+    ],
+)

tests/__init__.py

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+from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
+
+
+@python_2_unicode_compatible
+class Category(models.Model):
+    title = models.CharField(max_length=100)
+
+    def __str__(self):
+        return self.title
+
+
+@python_2_unicode_compatible
+class Post(models.Model):
+    title = models.CharField(max_length=100)
+    category = models.ForeignKey(Category, on_delete=models.CASCADE)
+    created = models.DateField()
+    text = models.TextField()
+
+    def __str__(self):
+        return self.title
+
+    class Meta:
+        ordering = ('created', 'title')