Django form error list - Исправление ошибок и поиск оптимальных решений проблем

The Forms API¶

Bound and unbound forms¶

A Form instance is either bound to a set of data, or unbound.

If it’s bound to a set of data, it’s capable of validating that data
and rendering the form as HTML with the data displayed in the HTML.
If it’s unbound, it cannot do validation (because there’s no data to
validate!), but it can still render the blank form as HTML.

class Form¶

To create an unbound Form instance, instantiate the class:

To bind data to a form, pass the data as a dictionary as the first parameter to
your Form class constructor:

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> f = ContactForm(data)

In this dictionary, the keys are the field names, which correspond to the
attributes in your Form class. The values are the data you’re trying to
validate. These will usually be strings, but there’s no requirement that they be
strings; the type of data you pass depends on the Field, as we’ll see
in a moment.

Form.is_bound¶

If you need to distinguish between bound and unbound form instances at runtime,
check the value of the form’s is_bound attribute:

>>> f = ContactForm()
>>> f.is_bound
False
>>> f = ContactForm({'subject': 'hello'})
>>> f.is_bound
True

Note that passing an empty dictionary creates a bound form with empty data:

>>> f = ContactForm({})
>>> f.is_bound
True

If you have a bound Form instance and want to change the data somehow,
or if you want to bind an unbound Form instance to some data, create
another Form instance. There is no way to change data in a
Form instance. Once a Form instance has been created, you
should consider its data immutable, whether it has data or not.

Using forms to validate data¶

Form.clean()¶

Implement a clean() method on your Form when you must add custom
validation for fields that are interdependent. See
Cleaning and validating fields that depend on each other for example usage.

Form.is_valid()¶

The primary task of a Form object is to validate data. With a bound
Form instance, call the is_valid() method to run validation
and return a boolean designating whether the data was valid:

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> f = ContactForm(data)
>>> f.is_valid()
True

Let’s try with some invalid data. In this case, subject is blank (an error,
because all fields are required by default) and sender is not a valid
email address:

>>> data = {'subject': '',
...         'message': 'Hi there',
...         'sender': 'invalid email address',
...         'cc_myself': True}
>>> f = ContactForm(data)
>>> f.is_valid()
False

Form.errors¶

Access the errors attribute to get a dictionary of error
messages:

>>> f.errors
{'sender': ['Enter a valid email address.'], 'subject': ['This field is required.']}

In this dictionary, the keys are the field names, and the values are lists of
strings representing the error messages. The error messages are stored
in lists because a field can have multiple error messages.

You can access errors without having to call
is_valid() first. The form’s data will be validated the first time
either you call is_valid() or access errors.

The validation routines will only get called once, regardless of how many times
you access errors or call is_valid(). This means that
if validation has side effects, those side effects will only be triggered once.

Form.errors.as_data()¶

Returns a dict that maps fields to their original ValidationError
instances.

>>> f.errors.as_data()
{'sender': [ValidationError(['Enter a valid email address.'])],
'subject': [ValidationError(['This field is required.'])]}

Use this method anytime you need to identify an error by its code. This
enables things like rewriting the error’s message or writing custom logic in a
view when a given error is present. It can also be used to serialize the errors
in a custom format (e.g. XML); for instance, as_json()
relies on as_data().

The need for the as_data() method is due to backwards compatibility.
Previously ValidationError instances were lost as soon as their
rendered error messages were added to the Form.errors dictionary.
Ideally Form.errors would have stored ValidationError instances
and methods with an as_ prefix could render them, but it had to be done
the other way around in order not to break code that expects rendered error
messages in Form.errors.

Form.errors.as_json(escape_html=False)¶

Returns the errors serialized as JSON.

>>> f.errors.as_json()
{"sender": [{"message": "Enter a valid email address.", "code": "invalid"}],
"subject": [{"message": "This field is required.", "code": "required"}]}

By default, as_json() does not escape its output. If you are using it for
something like AJAX requests to a form view where the client interprets the
response and inserts errors into the page, you’ll want to be sure to escape the
results on the client-side to avoid the possibility of a cross-site scripting
attack. You can do this in JavaScript with element.textContent = errorText
or with jQuery’s $(el).text(errorText) (rather than its .html()
function).

If for some reason you don’t want to use client-side escaping, you can also
set escape_html=True and error messages will be escaped so you can use them
directly in HTML.

Form.errors.get_json_data(escape_html=False)¶

Returns the errors as a dictionary suitable for serializing to JSON.
Form.errors.as_json() returns serialized JSON, while this returns the
error data before it’s serialized.

The escape_html parameter behaves as described in
Form.errors.as_json().

Form.add_error(field, error)¶

This method allows adding errors to specific fields from within the
Form.clean() method, or from outside the form altogether; for instance
from a view.

The field argument is the name of the field to which the errors
should be added. If its value is None the error will be treated as
a non-field error as returned by Form.non_field_errors().

The error argument can be a string, or preferably an instance of
ValidationError. See Raising ValidationError for best practices
when defining form errors.

Note that Form.add_error() automatically removes the relevant field from
cleaned_data.

Form.has_error(field, code=None)¶

This method returns a boolean designating whether a field has an error with
a specific error code. If code is None, it will return True
if the field contains any errors at all.

To check for non-field errors use
NON_FIELD_ERRORS as the field parameter.

Form.non_field_errors()¶

This method returns the list of errors from Form.errors that aren’t associated with a particular field.
This includes ValidationErrors that are raised in Form.clean() and errors added using Form.add_error(None, "...").

Behavior of unbound forms¶

It’s meaningless to validate a form with no data, but, for the record, here’s
what happens with unbound forms:

>>> f = ContactForm()
>>> f.is_valid()
False
>>> f.errors
{}

Initial form values¶

Form.initial¶

Use initial to declare the initial value of form fields at
runtime. For example, you might want to fill in a username field with the
username of the current session.

To accomplish this, use the initial argument to a Form.
This argument, if given, should be a dictionary mapping field names to initial
values. Only include the fields for which you’re specifying an initial value;
it’s not necessary to include every field in your form. For example:

>>> f = ContactForm(initial={'subject': 'Hi there!'})

These values are only displayed for unbound forms, and they’re not used as
fallback values if a particular value isn’t provided.

If a Field defines initial and you
include initial when instantiating the Form, then the latter
initial will have precedence. In this example, initial is provided both
at the field level and at the form instance level, and the latter gets
precedence:

>>> from django import forms
>>> class CommentForm(forms.Form):
...     name = forms.CharField(initial='class')
...     url = forms.URLField()
...     comment = forms.CharField()
>>> f = CommentForm(initial={'name': 'instance'}, auto_id=False)
>>> print(f)
<tr><th>Name:</th><td><input type="text" name="name" value="instance" required></td></tr>
<tr><th>Url:</th><td><input type="url" name="url" required></td></tr>
<tr><th>Comment:</th><td><input type="text" name="comment" required></td></tr>

Form.get_initial_for_field(field, field_name)¶

Returns the initial data for a form field. It retrieves the data from
Form.initial if present, otherwise trying Field.initial.
Callable values are evaluated.

It is recommended to use BoundField.initial over
get_initial_for_field() because BoundField.initial has a
simpler interface. Also, unlike get_initial_for_field(),
BoundField.initial caches its values. This is useful especially when
dealing with callables whose return values can change (e.g. datetime.now or
uuid.uuid4):

>>> import uuid
>>> class UUIDCommentForm(CommentForm):
...     identifier = forms.UUIDField(initial=uuid.uuid4)
>>> f = UUIDCommentForm()
>>> f.get_initial_for_field(f.fields['identifier'], 'identifier')
UUID('972ca9e4-7bfe-4f5b-af7d-07b3aa306334')
>>> f.get_initial_for_field(f.fields['identifier'], 'identifier')
UUID('1b411fab-844e-4dec-bd4f-e9b0495f04d0')
>>> # Using BoundField.initial, for comparison
>>> f['identifier'].initial
UUID('28a09c59-5f00-4ed9-9179-a3b074fa9c30')
>>> f['identifier'].initial
UUID('28a09c59-5f00-4ed9-9179-a3b074fa9c30')

Checking which form data has changed¶

Form.has_changed()¶

Use the has_changed() method on your Form when you need to check if the
form data has been changed from the initial data.

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> f = ContactForm(data, initial=data)
>>> f.has_changed()
False

When the form is submitted, we reconstruct it and provide the original data
so that the comparison can be done:

>>> f = ContactForm(request.POST, initial=data)
>>> f.has_changed()

has_changed() will be True if the data from request.POST differs
from what was provided in initial or False otherwise. The
result is computed by calling Field.has_changed() for each field in the
form.

Form.changed_data¶

The changed_data attribute returns a list of the names of the fields whose
values in the form’s bound data (usually request.POST) differ from what was
provided in initial. It returns an empty list if no data differs.

>>> f = ContactForm(request.POST, initial=data)
>>> if f.has_changed():
...     print("The following fields changed: %s" % ", ".join(f.changed_data))
>>> f.changed_data
['subject', 'message']

Accessing the fields from the form¶

Form.fields¶

You can access the fields of Form instance from its fields
attribute:

>>> for row in f.fields.values(): print(row)
...
<django.forms.fields.CharField object at 0x7ffaac632510>
<django.forms.fields.URLField object at 0x7ffaac632f90>
<django.forms.fields.CharField object at 0x7ffaac3aa050>
>>> f.fields['name']
<django.forms.fields.CharField object at 0x7ffaac6324d0>

You can alter the field and BoundField of Form instance to
change the way it is presented in the form:

>>> f.as_div().split("</div>")[0]
'<div><label for="id_subject">Subject:</label><input type="text" name="subject" maxlength="100" required id="id_subject">'
>>> f["subject"].label = "Topic"
>>> f.as_div().split("</div>")[0]
'<div><label for="id_subject">Topic:</label><input type="text" name="subject" maxlength="100" required id="id_subject">'

Beware not to alter the base_fields attribute because this modification
will influence all subsequent ContactForm instances within the same Python
process:

>>> f.base_fields["subject"].label_suffix = "?"
>>> another_f = CommentForm(auto_id=False)
>>> f.as_div().split("</div>")[0]
'<div><label for="id_subject">Subject?</label><input type="text" name="subject" maxlength="100" required id="id_subject">'

Accessing “clean” data¶

Form.cleaned_data¶

Each field in a Form class is responsible not only for validating
data, but also for “cleaning” it – normalizing it to a consistent format. This
is a nice feature, because it allows data for a particular field to be input in
a variety of ways, always resulting in consistent output.

For example, DateField normalizes input into a
Python datetime.date object. Regardless of whether you pass it a string in
the format '1994-07-15', a datetime.date object, or a number of other
formats, DateField will always normalize it to a datetime.date object
as long as it’s valid.

Once you’ve created a Form instance with a set of data and validated
it, you can access the clean data via its cleaned_data attribute:

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> f = ContactForm(data)
>>> f.is_valid()
True
>>> f.cleaned_data
{'cc_myself': True, 'message': 'Hi there', 'sender': 'foo@example.com', 'subject': 'hello'}

Note that any text-based field – such as CharField or EmailField –
always cleans the input into a string. We’ll cover the encoding implications
later in this document.

If your data does not validate, the cleaned_data dictionary contains
only the valid fields:

>>> data = {'subject': '',
...         'message': 'Hi there',
...         'sender': 'invalid email address',
...         'cc_myself': True}
>>> f = ContactForm(data)
>>> f.is_valid()
False
>>> f.cleaned_data
{'cc_myself': True, 'message': 'Hi there'}

cleaned_data will always only contain a key for fields defined in the
Form, even if you pass extra data when you define the Form. In this
example, we pass a bunch of extra fields to the ContactForm constructor,
but cleaned_data contains only the form’s fields:

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True,
...         'extra_field_1': 'foo',
...         'extra_field_2': 'bar',
...         'extra_field_3': 'baz'}
>>> f = ContactForm(data)
>>> f.is_valid()
True
>>> f.cleaned_data # Doesn't contain extra_field_1, etc.
{'cc_myself': True, 'message': 'Hi there', 'sender': 'foo@example.com', 'subject': 'hello'}

When the Form is valid, cleaned_data will include a key and value for
all its fields, even if the data didn’t include a value for some optional
fields. In this example, the data dictionary doesn’t include a value for the
nick_name field, but cleaned_data includes it, with an empty value:

>>> from django import forms
>>> class OptionalPersonForm(forms.Form):
...     first_name = forms.CharField()
...     last_name = forms.CharField()
...     nick_name = forms.CharField(required=False)
>>> data = {'first_name': 'John', 'last_name': 'Lennon'}
>>> f = OptionalPersonForm(data)
>>> f.is_valid()
True
>>> f.cleaned_data
{'nick_name': '', 'first_name': 'John', 'last_name': 'Lennon'}

In this above example, the cleaned_data value for nick_name is set to an
empty string, because nick_name is CharField, and CharFields treat
empty values as an empty string. Each field type knows what its “blank” value
is – e.g., for DateField, it’s None instead of the empty string. For
full details on each field’s behavior in this case, see the “Empty value” note
for each field in the “Built-in Field classes” section below.

You can write code to perform validation for particular form fields (based on
their name) or for the form as a whole (considering combinations of various
fields). More information about this is in Form and field validation.

Outputting forms as HTML¶

The second task of a Form object is to render itself as HTML. To do so,
print it:

>>> f = ContactForm()
>>> print(f)
<tr><th><label for="id_subject">Subject:</label></th><td><input id="id_subject" type="text" name="subject" maxlength="100" required></td></tr>
<tr><th><label for="id_message">Message:</label></th><td><input type="text" name="message" id="id_message" required></td></tr>
<tr><th><label for="id_sender">Sender:</label></th><td><input type="email" name="sender" id="id_sender" required></td></tr>
<tr><th><label for="id_cc_myself">Cc myself:</label></th><td><input type="checkbox" name="cc_myself" id="id_cc_myself"></td></tr>

If the form is bound to data, the HTML output will include that data
appropriately. For example, if a field is represented by an
<input type="text">, the data will be in the value attribute. If a
field is represented by an <input type="checkbox">, then that HTML will
include checked if appropriate:

>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> f = ContactForm(data)
>>> print(f)
<tr><th><label for="id_subject">Subject:</label></th><td><input id="id_subject" type="text" name="subject" maxlength="100" value="hello" required></td></tr>
<tr><th><label for="id_message">Message:</label></th><td><input type="text" name="message" id="id_message" value="Hi there" required></td></tr>
<tr><th><label for="id_sender">Sender:</label></th><td><input type="email" name="sender" id="id_sender" value="foo@example.com" required></td></tr>
<tr><th><label for="id_cc_myself">Cc myself:</label></th><td><input type="checkbox" name="cc_myself" id="id_cc_myself" checked></td></tr>

This default output is a two-column HTML table, with a <tr> for each field.
Notice the following:

For flexibility, the output does not include the <table> and
</table> tags, nor does it include the <form> and </form>
tags or an <input type="submit"> tag. It’s your job to do that.
Each field type has a default HTML representation. CharField is
represented by an <input type="text"> and EmailField by an
<input type="email">. BooleanField(null=False) is represented by an
<input type="checkbox">. Note these are merely sensible defaults; you can
specify which HTML to use for a given field by using widgets, which we’ll
explain shortly.
The HTML name for each tag is taken directly from its attribute name
in the ContactForm class.
The text label for each field – e.g. 'Subject:', 'Message:' and
'Cc myself:' is generated from the field name by converting all
underscores to spaces and upper-casing the first letter. Again, note
these are merely sensible defaults; you can also specify labels manually.
Each text label is surrounded in an HTML <label> tag, which points
to the appropriate form field via its id. Its id, in turn, is
generated by prepending 'id_' to the field name. The id
attributes and <label> tags are included in the output by default, to
follow best practices, but you can change that behavior.
The output uses HTML5 syntax, targeting <!DOCTYPE html>. For example,
it uses boolean attributes such as checked rather than the XHTML style
of checked='checked'.

Although <table> output is the default output style when you print a
form, other output styles are available. Each style is available as a method on
a form object, and each rendering method returns a string.

Default rendering¶

The default rendering when you print a form uses the following methods and
attributes.

`template_name`¶

New in Django 4.0.

Form.template_name¶

The name of the template rendered if the form is cast into a string, e.g. via
print(form) or in a template via {{ form }}.

By default, a property returning the value of the renderer’s
form_template_name. You may set it
as a string template name in order to override that for a particular form
class.

Changed in Django 4.1:

In older versions template_name defaulted to the string value
'django/forms/default.html'.

`render()`¶

New in Django 4.0.

Form.render(template_name=None, context=None, renderer=None)¶

The render method is called by __str__ as well as the
Form.as_table(), Form.as_p(), and Form.as_ul() methods.
All arguments are optional and default to:

template_name: Form.template_name
context: Value returned by Form.get_context()
renderer: Value returned by Form.default_renderer

By passing template_name you can customize the template used for just a
single call.

`get_context()`¶

New in Django 4.0.

Form.get_context()¶

Return the template context for rendering the form.

The available context is:

form: The bound form.
fields: All bound fields, except the hidden fields.
hidden_fields: All hidden bound fields.
errors: All non field related or hidden field related form errors.

`template_name_label`¶

New in Django 4.0.

Form.template_name_label¶

The template used to render a field’s <label>, used when calling
BoundField.label_tag()/legend_tag(). Can be changed per
form by overriding this attribute or more generally by overriding the default
template, see also Overriding built-in form templates.

Output styles¶

As well as rendering the form directly, such as in a template with
{{ form }}, the following helper functions serve as a proxy to
Form.render() passing a particular template_name value.

These helpers are most useful in a template, where you need to override the
form renderer or form provided value but cannot pass the additional parameter
to render(). For example, you can render a form as an unordered
list using {{ form.as_ul }}.

Each helper pairs a form method with an attribute giving the appropriate
template name.

`as_div()`¶

Form.template_name_div¶

New in Django 4.1.

The template used by as_div(). Default: 'django/forms/div.html'.

Form.as_div()¶

New in Django 4.1.

as_div() renders the form as a series of <div> elements, with each
<div> containing one field, such as:

>>> f = ContactForm()
>>> f.as_div()

… gives HTML like:

<div>
<label for="id_subject">Subject:</label>
<input type="text" name="subject" maxlength="100" required id="id_subject">
</div>
<div>
<label for="id_message">Message:</label>
<input type="text" name="message" required id="id_message">
</div>
<div>
<label for="id_sender">Sender:</label>
<input type="email" name="sender" required id="id_sender">
</div>
<div>
<label for="id_cc_myself">Cc myself:</label>
<input type="checkbox" name="cc_myself" id="id_cc_myself">
</div>

Note

Of the framework provided templates and output styles, as_div() is
recommended over the as_p(), as_table(), and as_ul() versions
as the template implements <fieldset> and <legend> to group related
inputs and is easier for screen reader users to navigate.

`as_p()`¶

Form.template_name_p¶

The template used by as_p(). Default: 'django/forms/p.html'.

Form.as_p()¶

as_p() renders the form as a series of <p> tags, with each <p>
containing one field:

>>> f = ContactForm()
>>> f.as_p()
'<p><label for="id_subject">Subject:</label> <input id="id_subject" type="text" name="subject" maxlength="100" required></p>n<p><label for="id_message">Message:</label> <input type="text" name="message" id="id_message" required></p>n<p><label for="id_sender">Sender:</label> <input type="text" name="sender" id="id_sender" required></p>n<p><label for="id_cc_myself">Cc myself:</label> <input type="checkbox" name="cc_myself" id="id_cc_myself"></p>'
>>> print(f.as_p())
<p><label for="id_subject">Subject:</label> <input id="id_subject" type="text" name="subject" maxlength="100" required></p>
<p><label for="id_message">Message:</label> <input type="text" name="message" id="id_message" required></p>
<p><label for="id_sender">Sender:</label> <input type="email" name="sender" id="id_sender" required></p>
<p><label for="id_cc_myself">Cc myself:</label> <input type="checkbox" name="cc_myself" id="id_cc_myself"></p>

`as_ul()`¶

Form.template_name_ul¶

The template used by as_ul(). Default: 'django/forms/ul.html'.

Form.as_ul()¶

as_ul() renders the form as a series of <li> tags, with each <li>
containing one field. It does not include the <ul> or </ul>, so that
you can specify any HTML attributes on the <ul> for flexibility:

>>> f = ContactForm()
>>> f.as_ul()
'<li><label for="id_subject">Subject:</label> <input id="id_subject" type="text" name="subject" maxlength="100" required></li>n<li><label for="id_message">Message:</label> <input type="text" name="message" id="id_message" required></li>n<li><label for="id_sender">Sender:</label> <input type="email" name="sender" id="id_sender" required></li>n<li><label for="id_cc_myself">Cc myself:</label> <input type="checkbox" name="cc_myself" id="id_cc_myself"></li>'
>>> print(f.as_ul())
<li><label for="id_subject">Subject:</label> <input id="id_subject" type="text" name="subject" maxlength="100" required></li>
<li><label for="id_message">Message:</label> <input type="text" name="message" id="id_message" required></li>
<li><label for="id_sender">Sender:</label> <input type="email" name="sender" id="id_sender" required></li>
<li><label for="id_cc_myself">Cc myself:</label> <input type="checkbox" name="cc_myself" id="id_cc_myself"></li>

`as_table()`¶

Form.template_name_table¶

The template used by as_table(). Default: 'django/forms/table.html'.

Form.as_table()¶

as_table() renders the form as an HTML <table>:

>>> f = ContactForm()
>>> f.as_table()
'<tr><th><label for="id_subject">Subject:</label></th><td><input id="id_subject" type="text" name="subject" maxlength="100" required></td></tr>n<tr><th><label for="id_message">Message:</label></th><td><input type="text" name="message" id="id_message" required></td></tr>n<tr><th><label for="id_sender">Sender:</label></th><td><input type="email" name="sender" id="id_sender" required></td></tr>n<tr><th><label for="id_cc_myself">Cc myself:</label></th><td><input type="checkbox" name="cc_myself" id="id_cc_myself"></td></tr>'
>>> print(f)
<tr><th><label for="id_subject">Subject:</label></th><td><input id="id_subject" type="text" name="subject" maxlength="100" required></td></tr>
<tr><th><label for="id_message">Message:</label></th><td><input type="text" name="message" id="id_message" required></td></tr>
<tr><th><label for="id_sender">Sender:</label></th><td><input type="email" name="sender" id="id_sender" required></td></tr>
<tr><th><label for="id_cc_myself">Cc myself:</label></th><td><input type="checkbox" name="cc_myself" id="id_cc_myself"></td></tr>

Styling required or erroneous form rows¶

Form.error_css_class¶

Form.required_css_class¶

It’s pretty common to style form rows and fields that are required or have
errors. For example, you might want to present required form rows in bold and
highlight errors in red.

The Form class has a couple of hooks you can use to add class
attributes to required rows or to rows with errors: set the
Form.error_css_class and/or Form.required_css_class
attributes:

from django import forms

class ContactForm(forms.Form):
    error_css_class = 'error'
    required_css_class = 'required'

    # ... and the rest of your fields here

Once you’ve done that, rows will be given "error" and/or "required"
classes, as needed. The HTML will look something like:

>>> f = ContactForm(data)
>>> print(f.as_table())
<tr class="required"><th><label class="required" for="id_subject">Subject:</label>    ...
<tr class="required"><th><label class="required" for="id_message">Message:</label>    ...
<tr class="required error"><th><label class="required" for="id_sender">Sender:</label>      ...
<tr><th><label for="id_cc_myself">Cc myself:<label> ...
>>> f['subject'].label_tag()
<label class="required" for="id_subject">Subject:</label>
>>> f['subject'].legend_tag()
<legend class="required" for="id_subject">Subject:</legend>
>>> f['subject'].label_tag(attrs={'class': 'foo'})
<label for="id_subject" class="foo required">Subject:</label>
>>> f['subject'].legend_tag(attrs={'class': 'foo'})
<legend for="id_subject" class="foo required">Subject:</legend>

Notes on field ordering¶

In the as_p(), as_ul() and as_table() shortcuts, the fields are
displayed in the order in which you define them in your form class. For
example, in the ContactForm example, the fields are defined in the order
subject, message, sender, cc_myself. To reorder the HTML
output, change the order in which those fields are listed in the class.

There are several other ways to customize the order:

Form.field_order¶

By default Form.field_order=None, which retains the order in which you
define the fields in your form class. If field_order is a list of field
names, the fields are ordered as specified by the list and remaining fields are
appended according to the default order. Unknown field names in the list are
ignored. This makes it possible to disable a field in a subclass by setting it
to None without having to redefine ordering.

You can also use the Form.field_order argument to a Form to
override the field order. If a Form defines
field_order and you include field_order when instantiating
the Form, then the latter field_order will have precedence.

Form.order_fields(field_order)¶

You may rearrange the fields any time using order_fields() with a list of
field names as in field_order.

How errors are displayed¶

If you render a bound Form object, the act of rendering will automatically
run the form’s validation if it hasn’t already happened, and the HTML output
will include the validation errors as a <ul class="errorlist"> near the
field. The particular positioning of the error messages depends on the output
method you’re using:

>>> data = {'subject': '',
...         'message': 'Hi there',
...         'sender': 'invalid email address',
...         'cc_myself': True}
>>> f = ContactForm(data, auto_id=False)
>>> print(f.as_div())
<div>Subject:<ul class="errorlist"><li>This field is required.</li></ul><input type="text" name="subject" maxlength="100" required></div>
<div>Message:<textarea name="message" cols="40" rows="10" required>Hi there</textarea></div>
<div>Sender:<ul class="errorlist"><li>Enter a valid email address.</li></ul><input type="email" name="sender" value="invalid email address" required></div>
<div>Cc myself:<input type="checkbox" name="cc_myself" checked></div>
>>> print(f.as_table())
<tr><th>Subject:</th><td><ul class="errorlist"><li>This field is required.</li></ul><input type="text" name="subject" maxlength="100" required></td></tr>
<tr><th>Message:</th><td><textarea name="message" cols="40" rows="10" required></textarea></td></tr>
<tr><th>Sender:</th><td><ul class="errorlist"><li>Enter a valid email address.</li></ul><input type="email" name="sender" value="invalid email address" required></td></tr>
<tr><th>Cc myself:</th><td><input checked type="checkbox" name="cc_myself"></td></tr>
>>> print(f.as_ul())
<li><ul class="errorlist"><li>This field is required.</li></ul>Subject: <input type="text" name="subject" maxlength="100" required></li>
<li>Message: <textarea name="message" cols="40" rows="10" required></textarea></li>
<li><ul class="errorlist"><li>Enter a valid email address.</li></ul>Sender: <input type="email" name="sender" value="invalid email address" required></li>
<li>Cc myself: <input checked type="checkbox" name="cc_myself"></li>
>>> print(f.as_p())
<p><ul class="errorlist"><li>This field is required.</li></ul></p>
<p>Subject: <input type="text" name="subject" maxlength="100" required></p>
<p>Message: <textarea name="message" cols="40" rows="10" required></textarea></p>
<p><ul class="errorlist"><li>Enter a valid email address.</li></ul></p>
<p>Sender: <input type="email" name="sender" value="invalid email address" required></p>
<p>Cc myself: <input checked type="checkbox" name="cc_myself"></p>

Customizing the error list format¶

class ErrorList(initlist=None, error_class=None, renderer=None)¶

By default, forms use django.forms.utils.ErrorList to format validation
errors. ErrorList is a list like object where initlist is the
list of errors. In addition this class has the following attributes and
methods.

error_class¶: The CSS classes to be used when rendering the error list. Any provided
classes are added to the default errorlist class.

renderer¶

New in Django 4.0.

Specifies the renderer to use for ErrorList.
Defaults to None which means to use the default renderer
specified by the FORM_RENDERER setting.

template_name¶

New in Django 4.0.

The name of the template used when calling __str__ or
render(). By default this is
'django/forms/errors/list/default.html' which is a proxy for the
'ul.html' template.

template_name_text¶

New in Django 4.0.

The name of the template used when calling as_text(). By default
this is 'django/forms/errors/list/text.html'. This template renders
the errors as a list of bullet points.

template_name_ul¶

New in Django 4.0.

The name of the template used when calling as_ul(). By default
this is 'django/forms/errors/list/ul.html'. This template renders
the errors in <li> tags with a wrapping <ul> with the CSS
classes as defined by error_class.

get_context()¶

New in Django 4.0.

Return context for rendering of errors in a template.

The available context is:

errors : A list of the errors.
error_class : A string of CSS classes.

render(template_name=None, context=None, renderer=None)¶

New in Django 4.0.

The render method is called by __str__ as well as by the
as_ul() method.

All arguments are optional and will default to:

template_name: Value returned by template_name
context: Value returned by get_context()
renderer: Value returned by renderer

as_text()¶: Renders the error list using the template defined by
template_name_text.

as_ul()¶: Renders the error list using the template defined by
template_name_ul.

If you’d like to customize the rendering of errors this can be achieved by
overriding the template_name attribute or more generally by
overriding the default template, see also
Overriding built-in form templates.

Changed in Django 4.0:

Rendering of ErrorList was moved to the template engine.

Deprecated since version 4.0: The ability to return a str when calling the __str__ method is
deprecated. Use the template engine instead which returns a SafeString.

More granular output¶

The as_p(), as_ul(), and as_table() methods are shortcuts –
they’re not the only way a form object can be displayed.

class BoundField¶

Used to display HTML or access attributes for a single field of a
Form instance.

The __str__() method of this object displays the HTML for this field.

To retrieve a single BoundField, use dictionary lookup syntax on your form
using the field’s name as the key:

>>> form = ContactForm()
>>> print(form['subject'])
<input id="id_subject" type="text" name="subject" maxlength="100" required>

To retrieve all BoundField objects, iterate the form:

>>> form = ContactForm()
>>> for boundfield in form: print(boundfield)
<input id="id_subject" type="text" name="subject" maxlength="100" required>
<input type="text" name="message" id="id_message" required>
<input type="email" name="sender" id="id_sender" required>
<input type="checkbox" name="cc_myself" id="id_cc_myself">

The field-specific output honors the form object’s auto_id setting:

>>> f = ContactForm(auto_id=False)
>>> print(f['message'])
<input type="text" name="message" required>
>>> f = ContactForm(auto_id='id_%s')
>>> print(f['message'])
<input type="text" name="message" id="id_message" required>

Attributes of `BoundField`¶

BoundField.auto_id¶: The HTML ID attribute for this BoundField. Returns an empty string
if Form.auto_id is False.

BoundField.data¶

This property returns the data for this BoundField
extracted by the widget’s value_from_datadict()
method, or None if it wasn’t given:

>>> unbound_form = ContactForm()
>>> print(unbound_form['subject'].data)
None
>>> bound_form = ContactForm(data={'subject': 'My Subject'})
>>> print(bound_form['subject'].data)
My Subject

BoundField.errors¶

A list-like object that is displayed
as an HTML <ul class="errorlist"> when printed:

>>> data = {'subject': 'hi', 'message': '', 'sender': '', 'cc_myself': ''}
>>> f = ContactForm(data, auto_id=False)
>>> print(f['message'])
<input type="text" name="message" required>
>>> f['message'].errors
['This field is required.']
>>> print(f['message'].errors)
<ul class="errorlist"><li>This field is required.</li></ul>
>>> f['subject'].errors
[]
>>> print(f['subject'].errors)

>>> str(f['subject'].errors)
''

BoundField.field¶: The form Field instance from the form class that
this BoundField wraps.

BoundField.form¶: The Form instance this BoundField
is bound to.

BoundField.help_text¶: The help_text of the field.

BoundField.html_name¶: The name that will be used in the widget’s HTML name attribute. It takes
the form prefix into account.

BoundField.id_for_label¶

Use this property to render the ID of this field. For example, if you are
manually constructing a <label> in your template (despite the fact that
label_tag()/legend_tag() will do this
for you):

<label for="{{ form.my_field.id_for_label }}">...</label>{{ my_field }}

By default, this will be the field’s name prefixed by id_
(”id_my_field” for the example above). You may modify the ID by setting
attrs on the field’s widget. For example,
declaring a field like this:

my_field = forms.CharField(widget=forms.TextInput(attrs={'id': 'myFIELD'}))

and using the template above, would render something like:

<label for="myFIELD">...</label><input id="myFIELD" type="text" name="my_field" required>

BoundField.initial¶

Use BoundField.initial to retrieve initial data for a form field.
It retrieves the data from Form.initial if present, otherwise
trying Field.initial. Callable values are evaluated. See
Initial form values for more examples.

BoundField.initial caches its return value, which is useful
especially when dealing with callables whose return values can change (e.g.
datetime.now or uuid.uuid4):

>>> from datetime import datetime
>>> class DatedCommentForm(CommentForm):
...     created = forms.DateTimeField(initial=datetime.now)
>>> f = DatedCommentForm()
>>> f['created'].initial
datetime.datetime(2021, 7, 27, 9, 5, 54)
>>> f['created'].initial
datetime.datetime(2021, 7, 27, 9, 5, 54)

Using BoundField.initial is recommended over
get_initial_for_field().

BoundField.is_hidden¶: Returns True if this BoundField’s widget is
hidden.

BoundField.label¶: The label of the field. This is used in
label_tag()/legend_tag().

BoundField.name¶

The name of this field in the form:

>>> f = ContactForm()
>>> print(f['subject'].name)
subject
>>> print(f['message'].name)
message

BoundField.use_fieldset¶

New in Django 4.1.

Returns the value of this BoundField widget’s use_fieldset attribute.

BoundField.widget_type¶

Returns the lowercased class name of the wrapped field’s widget, with any
trailing input or widget removed. This may be used when building
forms where the layout is dependent upon the widget type. For example:

{% for field in form %}
    {% if field.widget_type == 'checkbox' %}
        # render one way
    {% else %}
        # render another way
    {% endif %}
{% endfor %}

Methods of `BoundField`¶

BoundField.as_hidden(attrs=None, **kwargs)¶

Returns a string of HTML for representing this as an <input type="hidden">.

**kwargs are passed to as_widget().

This method is primarily used internally. You should use a widget instead.

BoundField.as_widget(widget=None, attrs=None, only_initial=False)¶

Renders the field by rendering the passed widget, adding any HTML
attributes passed as attrs. If no widget is specified, then the
field’s default widget will be used.

only_initial is used by Django internals and should not be set
explicitly.

BoundField.css_classes(extra_classes=None)¶

When you use Django’s rendering shortcuts, CSS classes are used to
indicate required form fields or fields that contain errors. If you’re
manually rendering a form, you can access these CSS classes using the
css_classes method:

>>> f = ContactForm(data={'message': ''})
>>> f['message'].css_classes()
'required'

If you want to provide some additional classes in addition to the
error and required classes that may be required, you can provide
those classes as an argument:

>>> f = ContactForm(data={'message': ''})
>>> f['message'].css_classes('foo bar')
'foo bar required'

BoundField.label_tag(contents=None, attrs=None, label_suffix=None, tag=None)¶

Renders a label tag for the form field using the template specified by
Form.template_name_label.

The available context is:

field: This instance of the BoundField.
contents: By default a concatenated string of
BoundField.label and Form.label_suffix (or
Field.label_suffix, if set). This can be overridden by the
contents and label_suffix arguments.
attrs: A dict containing for,
Form.required_css_class, and id. id is generated by the
field’s widget attrs or BoundField.auto_id. Additional
attributes can be provided by the attrs argument.
use_tag: A boolean which is True if the label has an id.
If False the default template omits the tag.
tag: An optional string to customize the tag, defaults to label.

Tip

In your template field is the instance of the BoundField.
Therefore field.field accesses BoundField.field being
the field you declare, e.g. forms.CharField.

To separately render the label tag of a form field, you can call its
label_tag() method:

>>> f = ContactForm(data={'message': ''})
>>> print(f['message'].label_tag())
<label for="id_message">Message:</label>

If you’d like to customize the rendering this can be achieved by overriding
the Form.template_name_label attribute or more generally by
overriding the default template, see also
Overriding built-in form templates.

Changed in Django 4.0:

The label is now rendered using the template engine.

Changed in Django 4.1:

The tag argument was added.

BoundField.legend_tag(contents=None, attrs=None, label_suffix=None)¶

New in Django 4.1.

Calls label_tag() with tag='legend' to render the label with
<legend> tags. This is useful when rendering radio and multiple
checkbox widgets where <legend> may be more appropriate than a
<label>.

BoundField.value()¶

Use this method to render the raw value of this field as it would be rendered
by a Widget:

>>> initial = {'subject': 'welcome'}
>>> unbound_form = ContactForm(initial=initial)
>>> bound_form = ContactForm(data={'subject': 'hi'}, initial=initial)
>>> print(unbound_form['subject'].value())
welcome
>>> print(bound_form['subject'].value())
hi

Customizing `BoundField`¶

If you need to access some additional information about a form field in a
template and using a subclass of Field isn’t
sufficient, consider also customizing BoundField.

A custom form field can override get_bound_field():

Field.get_bound_field(form, field_name)¶: Takes an instance of Form and the name of the field.
The return value will be used when accessing the field in a template. Most
likely it will be an instance of a subclass of
BoundField.

If you have a GPSCoordinatesField, for example, and want to be able to
access additional information about the coordinates in a template, this could
be implemented as follows:

class GPSCoordinatesBoundField(BoundField):
    @property
    def country(self):
        """
        Return the country the coordinates lie in or None if it can't be
        determined.
        """
        value = self.value()
        if value:
            return get_country_from_coordinates(value)
        else:
            return None

class GPSCoordinatesField(Field):
    def get_bound_field(self, form, field_name):
        return GPSCoordinatesBoundField(form, self, field_name)

Now you can access the country in a template with
{{ form.coordinates.country }}.

Binding uploaded files to a form¶

Dealing with forms that have FileField and ImageField fields
is a little more complicated than a normal form.

Firstly, in order to upload files, you’ll need to make sure that your
<form> element correctly defines the enctype as
"multipart/form-data":

<form enctype="multipart/form-data" method="post" action="/foo/">

Secondly, when you use the form, you need to bind the file data. File
data is handled separately to normal form data, so when your form
contains a FileField and ImageField, you will need to specify
a second argument when you bind your form. So if we extend our
ContactForm to include an ImageField called mugshot, we
need to bind the file data containing the mugshot image:

# Bound form with an image field
>>> from django.core.files.uploadedfile import SimpleUploadedFile
>>> data = {'subject': 'hello',
...         'message': 'Hi there',
...         'sender': 'foo@example.com',
...         'cc_myself': True}
>>> file_data = {'mugshot': SimpleUploadedFile('face.jpg', <file data>)}
>>> f = ContactFormWithMugshot(data, file_data)

In practice, you will usually specify request.FILES as the source
of file data (just like you use request.POST as the source of
form data):

# Bound form with an image field, data from the request
>>> f = ContactFormWithMugshot(request.POST, request.FILES)

Constructing an unbound form is the same as always – omit both form data and
file data:

# Unbound form with an image field
>>> f = ContactFormWithMugshot()

Testing for multipart forms¶

Form.is_multipart()¶

If you’re writing reusable views or templates, you may not know ahead of time
whether your form is a multipart form or not. The is_multipart() method
tells you whether the form requires multipart encoding for submission:

>>> f = ContactFormWithMugshot()
>>> f.is_multipart()
True

Here’s an example of how you might use this in a template:

{% if form.is_multipart %}
    <form enctype="multipart/form-data" method="post" action="/foo/">
{% else %}
    <form method="post" action="/foo/">
{% endif %}
{{ form }}
</form>

Subclassing forms¶

If you have multiple Form classes that share fields, you can use
subclassing to remove redundancy.

When you subclass a custom Form class, the resulting subclass will
include all fields of the parent class(es), followed by the fields you define
in the subclass.

In this example, ContactFormWithPriority contains all the fields from
ContactForm, plus an additional field, priority. The ContactForm
fields are ordered first:

>>> class ContactFormWithPriority(ContactForm):
...     priority = forms.CharField()
>>> f = ContactFormWithPriority(auto_id=False)
>>> print(f.as_div())
<div>Subject:<input type="text" name="subject" maxlength="100" required></div>
<div>Message:<textarea name="message" cols="40" rows="10" required></textarea></div>
<div>Sender:<input type="email" name="sender" required></div>
<div>Cc myself:<input type="checkbox" name="cc_myself"></div>
<div>Priority:<input type="text" name="priority" required></div>

It’s possible to subclass multiple forms, treating forms as mixins. In this
example, BeatleForm subclasses both PersonForm and InstrumentForm
(in that order), and its field list includes the fields from the parent
classes:

>>> from django import forms
>>> class PersonForm(forms.Form):
...     first_name = forms.CharField()
...     last_name = forms.CharField()
>>> class InstrumentForm(forms.Form):
...     instrument = forms.CharField()
>>> class BeatleForm(InstrumentForm, PersonForm):
...     haircut_type = forms.CharField()
>>> b = BeatleForm(auto_id=False)
>>> print(b.as_div())
<div>First name:<input type="text" name="first_name" required></div>
<div>Last name:<input type="text" name="last_name" required></div>
<div>Instrument:<input type="text" name="instrument" required></div>
<div>Haircut type:<input type="text" name="haircut_type" required></div>

It’s possible to declaratively remove a Field inherited from a parent class
by setting the name of the field to None on the subclass. For example:

>>> from django import forms

>>> class ParentForm(forms.Form):
...     name = forms.CharField()
...     age = forms.IntegerField()

>>> class ChildForm(ParentForm):
...     name = None

>>> list(ChildForm().fields)
['age']

Prefixes for forms¶

Form.prefix¶

You can put several Django forms inside one <form> tag. To give each
Form its own namespace, use the prefix keyword argument:

>>> mother = PersonForm(prefix="mother")
>>> father = PersonForm(prefix="father")
>>> print(mother.as_div())
<div><label for="id_mother-first_name">First name:</label><input type="text" name="mother-first_name" required id="id_mother-first_name"></div>
<div><label for="id_mother-last_name">Last name:</label><input type="text" name="mother-last_name" required id="id_mother-last_name"></div>
>>> print(father.as_div())
<div><label for="id_father-first_name">First name:</label><input type="text" name="father-first_name" required id="id_father-first_name"></div>
<div><label for="id_father-last_name">Last name:</label><input type="text" name="father-last_name" required id="id_father-last_name"></div>

The prefix can also be specified on the form class:

>>> class PersonForm(forms.Form):
...     ...
...     prefix = 'person'

Источник

I’m trying to create a form in Django. That works and all, but I want all the errors to be at the top of the form, not next to each field that has the error. I tried looping over form.errors, but it only showed the name of the field that had an error, not an error message such as «Name is required.»

This is pretty much what I’d like to be able to use at the top of the form:

{% if form.??? %}
    <ul class="errorlist">
    {% for error in form.??? %}
        <li>{{ error }}</li>
    {% endfor %}
    </ul>
{% endif %}

What would I use for ??? there? It’s not errors; that just outputs the names of the fields.

asked Jan 9, 2010 at 22:53

icktoofayicktoofay

125k21 gold badges246 silver badges230 bronze badges

form.errors is a dictionary. When you do {% for error in form.errors %} error corresponds to the key.

Instead try

{% for field, errors in form.errors.items %}
    {% for error in errors %}
...

Etc.

alecxe

455k116 gold badges1061 silver badges1180 bronze badges

answered Jan 9, 2010 at 23:05

Dannys’s answer is not a good idea. You could get a ValueError.

{% if form.errors %}
      {% for field in form %}

           {% for error in field.errors %}
                {{field.label}}: {{ error|escape }}
           {% endfor %}

      {% endfor %}
{% endif %}

answered Jul 24, 2019 at 19:29

sandessandes

1,73816 silver badges28 bronze badges

If you want something simple with a condition take this way :

{% if form.errors %}
  <ul>
    {% for error in form.errors %} 
      <li>{{ error }}</li>
    {% endfor %}
  </ul>
{% endif %}

If you want more info and see the name and the error of the field, do this:

{% if form.errors %}
  <ul>
    {% for key,value in form.errors.items %} 
      <li>{{ key|escape }} : {{ value|escape }}</li>
    {% endfor %}
  </ul>
{% endif %}

If you want to understant form.errors is a big dictionary.

answered Jan 11, 2017 at 19:14

BukyBuky

7379 silver badges21 bronze badges

You can use this code:

{% if form.errors %}
    {% for field in form %}
        {% for error in field.errors %}
            <div class="alert alert-danger">
                <strong>{{ error|escape }}</strong>
            </div>
        {% endfor %}
    {% endfor %}

    {% for error in form.non_field_errors %}
        <div class="alert alert-danger">
            <strong>{{ error|escape }}</strong>
        </div>
    {% endfor %}

{% endif %}

this add https://docs.djangoproject.com/en/3.0/ref/forms/api/#django.forms.Form.non_field_error

answered Jul 23, 2020 at 21:49

NEFEGAGONEFEGAGO

2511 silver badge10 bronze badges

Источник

Built-in Form Field Validations in Django Forms are the default validations that come predefined to all fields. Every field comes in with some built-in validations from Django validators. Each Field class constructor takes some fixed arguments.

The error_messages argument lets you specify manual error messages for attributes of the field. The error_messages argument lets you override the default messages that the field will raise. Pass in a dictionary with keys matching the error messages you want to override. For example, here is the default error message:

>>> from django import forms
>>> generic = forms.CharField()
>>> generic.clean('')
Traceback (most recent call last):
  ...
ValidationError: ['This field is required.']

And here is a custom error message:

>>> name = forms.CharField(
                error_messages={
               'required': 'Please enter your name'
                })
>>> name.clean('')
Traceback (most recent call last):
  ...
ValidationError: ['Please enter your name']

Syntax

field_name = models.Field(option = value)

Django Form Field Validation `error_messages` Explanation

Illustration of error_messages using an Example. Consider a project named geeksforgeeks having an app named geeks.

Refer to the following articles to check how to create a project and an app in Django.

How to Create a Basic Project using MVT in Django?

How to Create an App in Django ?

Enter the following code into forms.py file of geeks app. We will be using CharField for experimenting for all field options.

from django import forms

class GeeksForm(forms.Form):

geeks_field = forms.CharField(

error_messages = {

'required':"Please Enter your Name"

})

Add the geeks app to INSTALLED_APPS

INSTALLED_APPS = [

'django.contrib.admin',

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.messages',

'django.contrib.staticfiles',

'geeks',

]

Now to render this form into a view we need a view and a URL mapped to that view. Let’s create a view first in views.py of geeks app,

from django.shortcuts import render

from .forms import GeeksForm

def home_view(request):

context = {}

form = GeeksForm(request.POST or None)

context['form'] = form

if request.POST:

if form.is_valid():

temp = form.cleaned_data.get("geeks_field")

print(temp)

return render(request, "home.html", context)

Here we are importing that particular form from forms.py and creating an object of it in the view so that it can be rendered in a template.
Now, to initiate a Django form you need to create home.html where one would be designing the stuff as they like. Let’s create a form in home.html.

<form method = "POST">

{% csrf_token %}

{{ form }}

<input type = "submit" value = "Submit">

</form>

Finally, a URL to map to this view in urls.py

from django.urls import path

from .views import home_view

URLpatterns = [

path('', home_view ),

]

Let’s run the server and check what has actually happened, Run

Python manage.py runserver

Now let’s try to submit it empty and check if required error_message has been overridden.

Thus the field is displaying a custom error message for required attribute of Charfield.

More Built-in Form Validations

Field Options	Description
required	By default, each Field class assumes the value is required, so to make it not required you need to set `required=False`
label	The label argument lets you specify the “human-friendly” label for this field. This is used when the Field is displayed in a Form.
label_suffix	The label_suffix argument lets you override the form’s label_suffix on a per-field basis.
widget	The widget argument lets you specify a Widget class to use when rendering this Field. See Widgets for more information.
help_text	The help_text argument lets you specify descriptive text for this Field. If you provide help_text, it will be displayed next to the Field when the Field is rendered by one of the convenience Form methods.
error_messages	The error_messages argument lets you override the default messages that the field will raise. Pass in a dictionary with keys matching the error messages you want to override.
validators	The validators argument lets you provide a list of validation functions for this field.
localize	The localize argument enables the localization of form data input, as well as the rendered output.
disabled.	The disabled boolean argument, when set to True, disables a form field using the disabled HTML attribute so that it won’t be editable by users.

Источник

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 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

Источник

14.03.2012

Думаю, вы хотите, чтобы ваши сообщения об ошибках в заполняемых формах были на том же языке, что и сам сайт. Один из простых способов — это добавить следующий код в соответствующий forms.py. Затем формы надо будет наследовать не от forms.Form, а от MyForm (обратите внимание, ExampleForm, в примере ниже, наследуется от него).

class MyForm(forms.Form):
    def __init__(self, *args, **kwargs):
        super(MyForm, self).__init__(*args, **kwargs)
        for k, field in self.fields.items():
            if 'required' in field.error_messages:
                field.error_messages['required'] = u'Это поле обязательно!'

class ExampleForm(MyForm):
    title = forms.CharField(max_length=100, required=True, label=u'Название')

Полный список error_messages для различных типов полей можно увидеть, если просмотреть этот раздел: https://docs.djangoproject.com/en/1.3/ref/forms/fields/#built-in-field-classes

Вот что есть на данный момент:

required — показывается, если данное поле обязательно;
max_length — если превышено максимальное количество символов в символьном поле / в случае с файлами — длина имени файла;
min_length — если символов меньше, чем должно быть, в символьном поле;
invalid_choice — если выбран невозможный choice;
invalid — при неправильном email’е и прочем неправильном вводе данных;
max_value — если превышено числовое значение;
min_value — если значение меньше минимального числового ограничения;
max_digits — если превышено количество цифр в числе;
max_decimal_places — если превышено количество цифр после запятой;
max_whole_digits — если превышено количество цифр до запятой;
missing — если файл не найден;
empty — если файл пустой;
invalid_image — если изображение повреждено;
invalid_list — если неправильный список choice’ов;
invalid_link — для URLField — вызывается, если данного url не существует.

Основано на примере с http://stackoverflow.com/questions/1481771/django-override-default-form-error-messages

django

Источник

The Forms API¶

Bound and unbound forms¶

Using forms to validate data¶

Behavior of unbound forms¶

Initial form values¶

Checking which form data has changed¶

Accessing the fields from the form¶

Accessing “clean” data¶

Outputting forms as HTML¶

Default rendering¶

template_name¶

render()¶

get_context()¶

template_name_label¶

Output styles¶

as_div()¶

as_p()¶

as_ul()¶

as_table()¶

Styling required or erroneous form rows¶

Notes on field ordering¶

How errors are displayed¶

Customizing the error list format¶

More granular output¶

Attributes of BoundField¶

Methods of BoundField¶

Customizing BoundField¶

Binding uploaded files to a form¶

Testing for multipart forms¶

Subclassing forms¶

Prefixes for forms¶

Django Form Field Validation error_messages Explanation

More Built-in Form Validations

`template_name`¶

`render()`¶

`get_context()`¶

`template_name_label`¶

`as_div()`¶

`as_p()`¶

`as_ul()`¶

`as_table()`¶

Attributes of `BoundField`¶

Methods of `BoundField`¶

Customizing `BoundField`¶

Django Form Field Validation `error_messages` Explanation