django/forms/utils.py
import json
from collections import UserList
from django.conf import settings
from django.core.exceptions import ValidationError
from django.forms.renderers import get_default_renderer
from django.utils import timezone
from django.utils.html import escape, format_html_join
from django.utils.safestring import mark_safe
from django.utils.translation import gettext_lazy as _
def pretty_name(name):
"""Convert 'first_name' to 'First name'."""
if not name:
return ""
return name.replace("_", " ").capitalize()
def flatatt(attrs):
"""
Convert a dictionary of attributes to a single string.
The returned string will contain a leading space followed by key="value",
XML-style pairs. In the case of a boolean value, the key will appear
without a value. It is assumed that the keys do not need to be
XML-escaped. If the passed dictionary is empty, then return an empty
string.
The result is passed through 'mark_safe' (by way of 'format_html_join').
"""
key_value_attrs = []
boolean_attrs = []
for attr, value in attrs.items():
if isinstance(value, bool):
if value:
boolean_attrs.append((attr,))
elif value is not None:
key_value_attrs.append((attr, value))
return format_html_join("", ' {}="{}"', sorted(key_value_attrs)) + format_html_join(
"", " {}", sorted(boolean_attrs)
)
class RenderableMixin:
def get_context(self):
raise NotImplementedError(
"Subclasses of RenderableMixin must provide a get_context() method."
)
def render(self, template_name=None, context=None, renderer=None):
renderer = renderer or self.renderer
template = template_name or self.template_name
context = context or self.get_context()
return mark_safe(renderer.render(template, context))
__str__ = render
__html__ = render
class RenderableFieldMixin(RenderableMixin):
def as_field_group(self):
return self.render()
def as_hidden(self):
raise NotImplementedError(
"Subclasses of RenderableFieldMixin must provide an as_hidden() method."
)
def as_widget(self):
raise NotImplementedError(
"Subclasses of RenderableFieldMixin must provide an as_widget() method."
)
def __str__(self):
"""Render this field as an HTML widget."""
if self.field.show_hidden_initial:
return self.as_widget() + self.as_hidden(only_initial=True)
return self.as_widget()
__html__ = __str__
class RenderableFormMixin(RenderableMixin):
def as_p(self):
"""Render as <p> elements."""
return self.render(self.template_name_p)
def as_table(self):
"""Render as <tr> elements excluding the surrounding <table> tag."""
return self.render(self.template_name_table)
def as_ul(self):
"""Render as <li> elements excluding the surrounding <ul> tag."""
return self.render(self.template_name_ul)
def as_div(self):
"""Render as <div> elements."""
return self.render(self.template_name_div)
class RenderableErrorMixin(RenderableMixin):
def as_json(self, escape_html=False):
return json.dumps(self.get_json_data(escape_html))
def as_text(self):
return self.render(self.template_name_text)
def as_ul(self):
return self.render(self.template_name_ul)
class ErrorDict(dict, RenderableErrorMixin):
"""
A collection of errors that knows how to display itself in various formats.
The dictionary keys are the field names, and the values are the errors.
"""
template_name = "django/forms/errors/dict/default.html"
template_name_text = "django/forms/errors/dict/text.txt"
template_name_ul = "django/forms/errors/dict/ul.html"
def __init__(self, *args, renderer=None, **kwargs):
super().__init__(*args, **kwargs)
self.renderer = renderer or get_default_renderer()
def as_data(self):
return {f: e.as_data() for f, e in self.items()}
def get_json_data(self, escape_html=False):
return {f: e.get_json_data(escape_html) for f, e in self.items()}
def get_context(self):
return {
"errors": self.items(),
"error_class": "errorlist",
}
class ErrorList(UserList, list, RenderableErrorMixin):
"""
A collection of errors that knows how to display itself in various formats.
"""
template_name = "django/forms/errors/list/default.html"
template_name_text = "django/forms/errors/list/text.txt"
template_name_ul = "django/forms/errors/list/ul.html"
def __init__(self, initlist=None, error_class=None, renderer=None):
super().__init__(initlist)
if error_class is None:
self.error_class = "errorlist"
else:
self.error_class = "errorlist {}".format(error_class)
self.renderer = renderer or get_default_renderer()
def as_data(self):
return ValidationError(self.data).error_list
def copy(self):
copy = super().copy()
copy.error_class = self.error_class
return copy
def get_json_data(self, escape_html=False):
errors = []
for error in self.as_data():
message = next(iter(error))
errors.append(
{
"message": escape(message) if escape_html else message,
"code": error.code or "",
}
)
return errors
def get_context(self):
return {
"errors": self,
"error_class": self.error_class,
}
def __repr__(self):
return repr(list(self))
def __contains__(self, item):
return item in list(self)
def __eq__(self, other):
return list(self) == other
def __getitem__(self, i):
error = self.data[i]
if isinstance(error, ValidationError):
return next(iter(error))
return error
def __reduce_ex__(self, *args, **kwargs):
# The `list` reduce function returns an iterator as the fourth element
# that is normally used for repopulating. Since we only inherit from
# `list` for `isinstance` backward compatibility (Refs #17413) we
# nullify this iterator as it would otherwise result in duplicate
# entries. (Refs #23594)
info = super(UserList, self).__reduce_ex__(*args, **kwargs)
return info[:3] + (None, None)
# Utilities for time zone support in DateTimeField et al.
def from_current_timezone(value):
"""
When time zone support is enabled, convert naive datetimes
entered in the current time zone to aware datetimes.
"""
if settings.USE_TZ and value is not None and timezone.is_naive(value):
current_timezone = timezone.get_current_timezone()
try:
if timezone._datetime_ambiguous_or_imaginary(value, current_timezone):
raise ValueError("Ambiguous or non-existent time.")
return timezone.make_aware(value, current_timezone)
except Exception as exc:
raise ValidationError(
_(
"%(datetime)s couldn’t be interpreted "
"in time zone %(current_timezone)s; it "
"may be ambiguous or it may not exist."
),
code="ambiguous_timezone",
params={"datetime": value, "current_timezone": current_timezone},
) from exc
return value
def to_current_timezone(value):
"""
When time zone support is enabled, convert aware datetimes
to naive datetimes in the current time zone for display.
"""
if settings.USE_TZ and value is not None and timezone.is_aware(value):
return timezone.make_naive(value)
return value