django-rest-framework/rest_framework/compat.py
2016-02-04 13:49:55 -05:00

271 lines
8.5 KiB
Python

"""
The `compat` module provides support for backwards compatibility with older
versions of Django/Python, and compatibility wrappers around optional packages.
"""
# flake8: noqa
from __future__ import unicode_literals
import django
from django.conf import settings
from django.db import connection, transaction
from django.template import Context, RequestContext, Template
from django.utils import six
from django.views.generic import View
try:
import importlib # Available in Python 3.1+
except ImportError:
from django.utils import importlib # Will be removed in Django 1.9
def unicode_repr(instance):
# Get the repr of an instance, but ensure it is a unicode string
# on both python 3 (already the case) and 2 (not the case).
if six.PY2:
return repr(instance).decode('utf-8')
return repr(instance)
def unicode_to_repr(value):
# Coerce a unicode string to the correct repr return type, depending on
# the Python version. We wrap all our `__repr__` implementations with
# this and then use unicode throughout internally.
if six.PY2:
return value.encode('utf-8')
return value
def unicode_http_header(value):
# Coerce HTTP header value to unicode.
if isinstance(value, six.binary_type):
return value.decode('iso-8859-1')
return value
def total_seconds(timedelta):
# TimeDelta.total_seconds() is only available in Python 2.7
if hasattr(timedelta, 'total_seconds'):
return timedelta.total_seconds()
else:
return (timedelta.days * 86400.0) + float(timedelta.seconds) + (timedelta.microseconds / 1000000.0)
def distinct(queryset, base):
if settings.DATABASES[queryset.db]["ENGINE"] == "django.db.backends.oracle":
# distinct analogue for Oracle users
return base.filter(pk__in=set(queryset.values_list('pk', flat=True)))
return queryset.distinct()
# contrib.postgres only supported from 1.8 onwards.
try:
from django.contrib.postgres import fields as postgres_fields
except ImportError:
postgres_fields = None
# JSONField is only supported from 1.9 onwards
try:
from django.contrib.postgres.fields import JSONField
except ImportError:
JSONField = None
# django-filter is optional
try:
import django_filters
except ImportError:
django_filters = None
# django-crispy-forms is optional
try:
import crispy_forms
except ImportError:
crispy_forms = None
if django.VERSION >= (1, 6):
def clean_manytomany_helptext(text):
return text
else:
# Up to version 1.5 many to many fields automatically suffix
# the `help_text` attribute with hardcoded text.
def clean_manytomany_helptext(text):
if text.endswith(' Hold down "Control", or "Command" on a Mac, to select more than one.'):
text = text[:-69]
return text
# Django-guardian is optional. Import only if guardian is in INSTALLED_APPS
# Fixes (#1712). We keep the try/except for the test suite.
guardian = None
try:
if 'guardian' in settings.INSTALLED_APPS:
import guardian
import guardian.shortcuts # Fixes #1624
except ImportError:
pass
# MinValueValidator, MaxValueValidator et al. only accept `message` in 1.8+
if django.VERSION >= (1, 8):
from django.core.validators import MinValueValidator, MaxValueValidator
from django.core.validators import MinLengthValidator, MaxLengthValidator
else:
from django.core.validators import MinValueValidator as DjangoMinValueValidator
from django.core.validators import MaxValueValidator as DjangoMaxValueValidator
from django.core.validators import MinLengthValidator as DjangoMinLengthValidator
from django.core.validators import MaxLengthValidator as DjangoMaxLengthValidator
class MinValueValidator(DjangoMinValueValidator):
def __init__(self, *args, **kwargs):
self.message = kwargs.pop('message', self.message)
super(MinValueValidator, self).__init__(*args, **kwargs)
class MaxValueValidator(DjangoMaxValueValidator):
def __init__(self, *args, **kwargs):
self.message = kwargs.pop('message', self.message)
super(MaxValueValidator, self).__init__(*args, **kwargs)
class MinLengthValidator(DjangoMinLengthValidator):
def __init__(self, *args, **kwargs):
self.message = kwargs.pop('message', self.message)
super(MinLengthValidator, self).__init__(*args, **kwargs)
class MaxLengthValidator(DjangoMaxLengthValidator):
def __init__(self, *args, **kwargs):
self.message = kwargs.pop('message', self.message)
super(MaxLengthValidator, self).__init__(*args, **kwargs)
# PATCH method is not implemented by Django
if 'patch' not in View.http_method_names:
View.http_method_names = View.http_method_names + ['patch']
# Markdown is optional
try:
import markdown
if markdown.version <= '2.2':
HEADERID_EXT_PATH = 'headerid'
else:
HEADERID_EXT_PATH = 'markdown.extensions.headerid'
def apply_markdown(text):
"""
Simple wrapper around :func:`markdown.markdown` to set the base level
of '#' style headers to <h2>.
"""
extensions = [HEADERID_EXT_PATH]
extension_configs = {
HEADERID_EXT_PATH: {
'level': '2'
}
}
md = markdown.Markdown(
extensions=extensions, extension_configs=extension_configs
)
return md.convert(text)
except ImportError:
apply_markdown = None
# `separators` argument to `json.dumps()` differs between 2.x and 3.x
# See: http://bugs.python.org/issue22767
if six.PY3:
SHORT_SEPARATORS = (',', ':')
LONG_SEPARATORS = (', ', ': ')
INDENT_SEPARATORS = (',', ': ')
else:
SHORT_SEPARATORS = (b',', b':')
LONG_SEPARATORS = (b', ', b': ')
INDENT_SEPARATORS = (b',', b': ')
if django.VERSION >= (1, 8):
from django.db.models import DurationField
from django.utils.dateparse import parse_duration
from django.utils.duration import duration_string
else:
DurationField = duration_string = parse_duration = None
try:
# DecimalValidator is unavailable in Django < 1.9
from django.core.validators import DecimalValidator
except ImportError:
DecimalValidator = None
def set_rollback():
if hasattr(transaction, 'set_rollback'):
if connection.settings_dict.get('ATOMIC_REQUESTS', False):
# If running in >=1.6 then mark a rollback as required,
# and allow it to be handled by Django.
if connection.in_atomic_block:
transaction.set_rollback(True)
elif transaction.is_managed():
# Otherwise handle it explicitly if in managed mode.
if transaction.is_dirty():
transaction.rollback()
transaction.leave_transaction_management()
else:
# transaction not managed
pass
def template_render(template, context=None, request=None):
"""
Passing Context or RequestContext to Template.render is deprecated in 1.9+,
see https://github.com/django/django/pull/3883 and
https://github.com/django/django/blob/1.9rc1/django/template/backends/django.py#L82-L84
:param template: Template instance
:param context: dict
:param request: Request instance
:return: rendered template as SafeText instance
"""
if django.VERSION < (1, 8) or isinstance(template, Template):
if request:
context = RequestContext(request, context)
else:
context = Context(context)
return template.render(context)
# backends template, e.g. django.template.backends.django.Template
else:
return template.render(context, request=request)
def get_all_related_objects(opts):
"""
Django 1.8 changed meta api, see
https://docs.djangoproject.com/en/1.8/ref/models/meta/#migrating-old-meta-api
https://code.djangoproject.com/ticket/12663
https://github.com/django/django/pull/3848
:param opts: Options instance
:return: list of relations except many-to-many ones
"""
if django.VERSION < (1, 8):
return opts.get_all_related_objects()
else:
return [r for r in opts.related_objects if not r.field.many_to_many]
def get_all_related_many_to_many_objects(opts):
"""
Django 1.8 changed meta api, see docstr in compat.get_all_related_objects()
:param opts: Options instance
:return: list of many-to-many relations
"""
if django.VERSION < (1, 8):
return opts.get_all_related_many_to_many_objects()
else:
return [r for r in opts.related_objects if r.field.many_to_many]