django-rest-framework/rest_framework/compat.py
John Eskew 607e4edca7 Defer translated string evaluation on validators. (#5452)
* Customize validators to defer error string evaluation.

* Add docstring for `CustomValidatorMessage`
2017-09-26 10:02:20 +02:00

377 lines
11 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 inspect
import django
from django.apps import apps
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured, ValidationError
from django.core.validators import \
MaxLengthValidator as DjangoMaxLengthValidator
from django.core.validators import MaxValueValidator as DjangoMaxValueValidator
from django.core.validators import \
MinLengthValidator as DjangoMinLengthValidator
from django.core.validators import MinValueValidator as DjangoMinValueValidator
from django.db import connection, models, transaction
from django.template import Context, RequestContext, Template
from django.utils import six
from django.views.generic import View
try:
from django.urls import (
NoReverseMatch, RegexURLPattern, RegexURLResolver, ResolverMatch, Resolver404, get_script_prefix, reverse, reverse_lazy, resolve
)
except ImportError:
from django.core.urlresolvers import ( # Will be removed in Django 2.0
NoReverseMatch, RegexURLPattern, RegexURLResolver, ResolverMatch, Resolver404, get_script_prefix, reverse, reverse_lazy, resolve
)
try:
import urlparse # Python 2.x
except ImportError:
import urllib.parse as urlparse
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()
# Obtaining manager instances and names from model options differs after 1.10.
def get_names_and_managers(options):
if django.VERSION >= (1, 10):
# Django 1.10 onwards provides a `.managers` property on the Options.
return [
(manager.name, manager)
for manager
in options.managers
]
# For Django 1.8 and 1.9, use the three-tuple information provided
# by .concrete_managers and .abstract_managers
return [
(manager_info[1], manager_info[2])
for manager_info
in (options.concrete_managers + options.abstract_managers)
]
# field.rel is deprecated from 1.9 onwards
def get_remote_field(field, **kwargs):
if 'default' in kwargs:
if django.VERSION < (1, 9):
return getattr(field, 'rel', kwargs['default'])
return getattr(field, 'remote_field', kwargs['default'])
if django.VERSION < (1, 9):
return field.rel
return field.remote_field
def _resolve_model(obj):
"""
Resolve supplied `obj` to a Django model class.
`obj` must be a Django model class itself, or a string
representation of one. Useful in situations like GH #1225 where
Django may not have resolved a string-based reference to a model in
another model's foreign key definition.
String representations should have the format:
'appname.ModelName'
"""
if isinstance(obj, six.string_types) and len(obj.split('.')) == 2:
app_name, model_name = obj.split('.')
resolved_model = apps.get_model(app_name, model_name)
if resolved_model is None:
msg = "Django did not return a model for {0}.{1}"
raise ImproperlyConfigured(msg.format(app_name, model_name))
return resolved_model
elif inspect.isclass(obj) and issubclass(obj, models.Model):
return obj
raise ValueError("{0} is not a Django model".format(obj))
def is_authenticated(user):
if django.VERSION < (1, 10):
return user.is_authenticated()
return user.is_authenticated
def is_anonymous(user):
if django.VERSION < (1, 10):
return user.is_anonymous()
return user.is_anonymous
def get_related_model(field):
if django.VERSION < (1, 9):
return _resolve_model(field.rel.to)
return field.remote_field.model
def value_from_object(field, obj):
if django.VERSION < (1, 9):
return field._get_val_from_obj(obj)
return field.value_from_object(obj)
# 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
# coreapi is optional (Note that uritemplate is a dependency of coreapi)
try:
import coreapi
import uritemplate
except (ImportError, SyntaxError):
# SyntaxError is possible under python 3.2
coreapi = None
uritemplate = None
# coreschema is optional
try:
import coreschema
except ImportError:
coreschema = None
# django-crispy-forms is optional
try:
import crispy_forms
except ImportError:
crispy_forms = None
# requests is optional
try:
import requests
except ImportError:
requests = None
# 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
except ImportError:
pass
# 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'
LEVEL_PARAM = 'level'
elif markdown.version < '2.6':
HEADERID_EXT_PATH = 'markdown.extensions.headerid'
LEVEL_PARAM = 'level'
else:
HEADERID_EXT_PATH = 'markdown.extensions.toc'
LEVEL_PARAM = 'baselevel'
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_PARAM: '2'
}
}
md = markdown.Markdown(
extensions=extensions, extension_configs=extension_configs
)
return md.convert(text)
except ImportError:
apply_markdown = None
markdown = None
try:
import pygments
from pygments.lexers import get_lexer_by_name
from pygments.formatters import HtmlFormatter
def pygments_highlight(text, lang, style):
lexer = get_lexer_by_name(lang, stripall=False)
formatter = HtmlFormatter(nowrap=True, style=style)
return pygments.highlight(text, lexer, formatter)
def pygments_css(style):
formatter = HtmlFormatter(style=style)
return formatter.get_style_defs('.highlight')
except ImportError:
pygments = None
def pygments_highlight(text, lang, style):
return text
def pygments_css(style):
return None
try:
import pytz
from pytz.exceptions import InvalidTimeError
except ImportError:
InvalidTimeError = Exception
# `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': ')
try:
# DecimalValidator is unavailable in Django < 1.9
from django.core.validators import DecimalValidator
except ImportError:
DecimalValidator = None
class CustomValidatorMessage(object):
"""
We need to avoid evaluation of `lazy` translated `message` in `django.core.validators.BaseValidator.__init__`.
https://github.com/django/django/blob/75ed5900321d170debef4ac452b8b3cf8a1c2384/django/core/validators.py#L297
Ref: https://github.com/encode/django-rest-framework/pull/5452
"""
def __init__(self, *args, **kwargs):
self.message = kwargs.pop('message', self.message)
super(CustomValidatorMessage, self).__init__(*args, **kwargs)
class MinValueValidator(CustomValidatorMessage, DjangoMinValueValidator):
pass
class MaxValueValidator(CustomValidatorMessage, DjangoMaxValueValidator):
pass
class MinLengthValidator(CustomValidatorMessage, DjangoMinLengthValidator):
pass
class MaxLengthValidator(CustomValidatorMessage, DjangoMaxLengthValidator):
pass
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/1.9/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 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 set_many(instance, field, value):
if django.VERSION < (1, 10):
setattr(instance, field, value)
else:
field = getattr(instance, field)
field.set(value)
def include(module, namespace=None, app_name=None):
from django.conf.urls import include
if django.VERSION < (1,9):
return include(module, namespace, app_name)
else:
return include((module, app_name), namespace)