Documentation below is related to project version 2.0.0 or higher, old versions has
completely different approach for forms generation.
And despite the fact that the old code is included in version 2.0.0 to keep correct
deprecation workflow (where possible), it is not documented (and was not) and not
maintained.
If you faced any forms problems, consider migration to new methods and approach.
Flask-Mongoengine and Flask-WTF/WTForms are heavily integrated, to reduce amount of boilerplate code, required to make database model and online form. In the same time a lot of options was created to keep extreme flexibility.
After database model definition user does not require to repeat same code in form definition, instead it is possible to use integrated converter, that will do most of the work.
Flask-Mongoengine will transform some model's properties to Flask-WTF/WTForms validators, so user does not need to care about standards. For full list of transformations, please review global transforms and specific field documentation below.
In the same time, user is able to adjust database fields definition with specific settings as on stage of Document model definition, as on form generation stage. This allows to create several forms for same model, for different circumstances.
For correct integration behavior several requirements should be met:
- Document classes should be used from Flask-Mongoengine
{class}
flask_mongoengine.MongoEngineclass, or from {mod}flask_mongoengine.documentsmodule. - Document classes should be used from Flask-Mongoengine
{class}
flask_mongoengine.MongoEngineclass, or from {mod}flask_mongoengine.db_fieldsmodule.
For all fields, processed by Flask-Mongoengine integration:
- If model field definition have {attr}
wtf_validatorsdefined, they will be forwarded to WTForm as {attr}validators. This is not protection from {attr}validatorsextension by Flask-Mongoengine. - If model field definition have {attr}
wtf_filtersdefined, they will be forwarded to WTForm as {attr}filters. - If model field definition have {attr}
required, then {class}~wtforms.validators.InputRequiredwill be added to form {attr}validators, otherwise {class}~wtforms.validators.Optionaladded. - If model field definition have {attr}
verbose_nameit will be used as form field {attr}label, otherwise pure field name used. - If model field definition have {attr}
help_textit will be used as form field {attr}description, otherwise empty string used. - Field's {attr}
defaultused as form {attr}default, that's why special WTForms fields implementations was created. Details can be found in {mod}flask_mongoengine.wtf.fieldsmodule. In new form generator only 'Mongo' prefixed classes are used for fields, other classes are deprecated and will be removed in version 3.0.0. If you have own nesting classes, you should check inheritance and make an update. - Field's {attr}
choices, if exist, used as form {attr}choices.
As at version **2.0.0** there is no {attr}`wtf_validators` duplicates/conflicts check.
User should be careful with manual {attr}`wtf_validators` setup. And in case of forms
problems this is first place to look on.
{attr}`wtf_validators` and {attr}`wtf_filters` duplication check expected in future
versions; PRs are welcome.
Some additional transformations are made by specific field, check exact field documentation below for more info.
Not yet documented. Please help us with new pull request.
- API: {class}
.db_fields.BooleanField - Default form field class: {class}
~.MongoBooleanField
BooleanField is very complicated in terms of Mongo database support. In
Flask-Mongoengine before version 2.0.0+ database BooleanField used
{class}wtforms.fields.BooleanField as form representation, this raised several not
clear problems, that was related to how {class}wtforms.fields.BooleanField parse
and work with form values. Known problems in version, before 2.0.0+:
- Default value of field, specified in database definition was ignored, if default
is
Noneand nulls allowed, i.e. {attr}null=True(Value was alwaysFalse). - Field was always created in database document, even if not checked, as there is
impossible to split
NoneandFalsevalues, when only checkbox available.
To fix all these issues, and do not create database field by default, Flask-Mongoengine 2.0.0+ uses dropdown field by default.
By default, database BooleanField not allowing None value, meaning that field can
be True, False or not created in database at all. If database field configuration
allowing None values, i.e. {attr}null=True, then, when nothing selected in
dropdown, the field will be created with None value.
It is responsobility of developer, to correctly setup database field definition and
make proper tests before own application release. BooleanField can create unexpected
application behavior in if checks. Developer, should recheck all if checks like:
- `if filed_value:` this will match `True` database value
- `if not filed_value:` this will match `False` or `None` database value or not existing
document key
- `if field_value is None:` this will match `None` database value or not existing
document key
- `if field_value is True:` this will match `True` database value
- `if field_value is False:` this will match `False` database value
- `if field_value is not None:` this will match `True`, `False` database value
- `if field_value is not True:` this will match `False`, `None` database value or not
existing document key
- `if filed_value is not False:` this will match `True`, `None` database value or not
existing document key
Such definition will not create any field in document, if dropdown not selected.
"""boolean_demo.py"""
from example_app.models import db
class BooleanDemoModel(db.Document):
"""Documentation example model."""
boolean_field = db.BooleanField()Such definition will create document field, even if nothing selected. The value will
be None. If, during edit, yes or no dropdown values replaced to ---, then
saved value in document will be also changed to None.
By default, None value represented as --- text in dropdown.
"""boolean_demo.py"""
from example_app.models import db
class BooleanDemoModel(db.Document):
"""Documentation example model."""
boolean_field_with_null = db.BooleanField(null=True)Dropdown text can be easily replaced, there is only one requirement: New choices,
should be correctly coerced by {func}~.coerce_boolean, or function should be
replaced too.
"""boolean_demo.py"""
from example_app.models import db
class BooleanDemoModel(db.Document):
"""Documentation example model."""
boolean_field_with_as_choices_replace = db.BooleanField(
wtf_options={
"choices": [("", "Not selected"), ("yes", "Positive"), ("no", "Negative")]
}
)"""boolean_demo.py"""
from example_app.models import db
class BooleanDemoModel(db.Document):
"""Documentation example model."""
true_boolean_field_with_allowed_null = db.BooleanField(default=True, null=True)- API: {class}
.db_fields.ComplexDateTimeField - Default form field class: {class}
wtforms.fields.DateTimeLocalField
ComplexDateTimeField stores date and time information in database string format. This
format allow precision up to microseconds dimension.
Unfortunately, there is no HTML5 field, that allow so high precision. That's why, by
default the generated field will use HTML5 <input type="datetime-local"> with
precision set to milliseconds.
If you require concrete microseconds for edit purposes, please use
{class}wtforms.fields.DateTimeField with correct format (see examples below).
Field is easy adjustable, to use any other precision. Check examples and example app for more details.
dates_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
complex_datetime = db.ComplexDateTimeField()"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
complex_datetime_sec = db.ComplexDateTimeField(
wtf_options={"render_kw": {"step": "1"}}
)"""dates_demo.py"""
from wtforms.fields import DateTimeField
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
complex_datetime_microseconds = db.ComplexDateTimeField(
wtf_field_class=DateTimeField, wtf_options={"format": "%Y-%m-%d %H:%M:%S.%f"}
)- API: {class}
.db_fields.DateField - Default form field class: {class}
wtforms.fields.DateField
DateField is one of the simplest fields in the forms generation process. By default,
the field use {class}wtforms.fields.DateField WTForms class, representing a form
input with standard HTML5 <input type="date">. No custom additional transformation
done, during field generation. Field is fully controllable by global transforms.
dates_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
date = db.DateField()- API: {class}
.db_fields.DateTimeField - Default form field class: {class}
wtforms.fields.DateTimeLocalField
DateTimeField stores date and time information in database date format. This
format allow precision up to milliseconds dimension. By default, generated form will
use HTML5 <input type="datetime-local"> with precision set to seconds.
Field is easy adjustable, to use any other precision. Check examples and example app for more details.
It is possible to use {class}wtforms.fields.DateTimeField for text input behaviour.
dates_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
datetime = db.DateTimeField()"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
datetime_no_sec = db.DateTimeField(wtf_options={"render_kw": {"step": "60"}})"""dates_demo.py"""
from example_app.models import db
class DateTimeModel(db.Document):
"""Documentation example model."""
datetime_ms = db.DateTimeField(wtf_options={"render_kw": {"step": "0.001"}})- API: {class}
.db_fields.DecimalField - Default form field class: {class}
wtforms.fields.DecimalField
From form generation side this field is pretty standard and do not use any form generation adjustments.
If database field definition has any of {attr}min_value or {attr}max_value, then
{class}~wtforms.validators.NumberRange validator will be added to form field.
numbers_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""numbers_demo.py"""
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
decimal_field_unlimited = db.DecimalField()"""numbers_demo.py"""
from decimal import Decimal
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
decimal_field_limited = db.DecimalField(
min_value=Decimal("1"), max_value=Decimal("200.455")
)- API: {class}
.db_fields.DictField - Default form field class: {class}
~.MongoDictField
DictField has Object type in terms of Mongo database itself, so basically it defines
document inside document, but without pre-defined structure. That's why this is one
of fields, that has default value specified inside Mongoengine itself, and that's
why is always (almost) created.
The developer should understand that database keyword argument {attr}default is
forwarded to form by default, but can be separately overwritten in form. This brings
a lot of options for form field configuration.
Also, should be additionally noted that database Null value in form is represented as
empty string. Non-existing field is represented with form {attr}default for new
forms (without instance inside) or with empty string for non-empty forms.
Complicated? Probably. That's why this field was completely rewritten in version 2.0.0. Check examples, and everything will be clear.
Our default form generation follow Mongoengine internals and will use database field default (empty dict) to populate to new form or to not filled field in existing form.
In the same time, we are allowing extending of this behaviour, and not creating
field in database, if default value provided as None. In this case, generated
field for new form will be empty, without any pre-filled value.
Same empty field will be displayed in case, when both {attr}default=None and
{attr}null=True selected, during database form initialization. In this case form
field will be empty, without any placeholder, but on save null object will be
created in document.
Also, we even support separated defaults for form field and database field, allowing any form+database behaviour.
Will place {} to form for existing/new fields. This value is hardcodded in parent
MongoEngine project.
"""dict_demo.py"""
from example_app.models import db
class DictDemoModel(db.Document):
"""Documentation example model."""
dict_field = db.DictField()Reminder: Such field is empty in form, and will not create anything in database if not filled.
"""dict_demo.py"""
from example_app.models import db
class DictDemoModel(db.Document):
"""Documentation example model."""
no_dict_field = db.DictField(default=None)Reminder: Such field is empty in form, and will create null object in database if
not filled.
"""dict_demo.py"""
from example_app.models import db
class DictDemoModel(db.Document):
"""Documentation example model."""
null_dict_field = db.DictField(default=None, null=True)This value is pre-defined on database level. So behaviour of form and in-code creation of such objects will be the same - default dict will be saved to database, if nothing provided to form/instance. Form will be pre-filled with default dict.
"""dict_demo.py"""
from example_app.models import db
def get_default_dict():
"""Example of default dict specification."""
return {"alpha": 1, "text": "text", "float": 1.2}
class DictDemoModel(db.Document):
"""Documentation example model."""
dict_default = db.DictField(default=get_default_dict)This is a case when you do not want to create any record in database document, if
user completely delete pre-filled value in new document form. Here we use different
null and default values in form field generation and during database object
generation.
"""dict_demo.py"""
from example_app.models import db
def get_default_dict():
"""Example of default dict specification."""
return {"alpha": 1, "text": "text", "float": 1.2}
class DictDemoModel(db.Document):
"""Documentation example model."""
no_dict_prefilled = db.DictField(
default=None,
null=False,
wtf_options={"default": get_default_dict, "null": True},
)This is very rare case, when some default value is given, meaning that this
value will be populated to the field, but if completely deleted, than Null will be
saved in database.
"""dict_demo.py"""
from example_app.models import db
def get_default_dict():
"""Example of default dict specification."""
return {"alpha": 1, "text": "text", "float": 1.2}
class DictDemoModel(db.Document):
"""Documentation example model."""
null_dict_default = db.DictField(default=get_default_dict, null=True)- API: {class}
.db_fields.EmailField - Default form field class: {class}
~.MongoEmailField
Unlike StringField WTForm class of the field is not adjusted by normal form
generation sequence and always match {class}~.MongoEmailField. All other
adjustments, related to validators insert are work with EmailField in the same way,
as in StringField.
Additional {class}~wtforms.validators.Email validator is also inserted to form
field, to exclude unnecessary database request, if form data incorrect.
Field respect user's adjustments in {attr}wtf_field_class option of
{class}.db_fields.EmailField. This will change form field display, but will not
change inserted validators.
strings_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
url_field = db.EmailField()"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
required_url_field = db.EmailField(required=True)Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Default form field class changed from: {class}`wtforms.fields.FloatField` to
{class}`~.fields.MongoFloatField`.
- API: {class}
.db_fields.FloatField - Default form field class: {class}
~.fields.MongoFloatField
For Mongo database {class}~.db_fields.FloatField special WTForm field was created.
This field's behaviour is the same, as for {class}wtforms.fields.FloatField,
but the widget is replaced to {class}~wtforms.widgets.NumberInput, this should make a
look of generated form better. It is possible, that in some cases usage of base,
{class}wtforms.fields.FloatField can be required by form design. Both fields are
completely compatible, and replace can be done with {attr}wtf_field_class db form
parameter.
If database field definition has any of {attr}min_value or {attr}max_value, then
{class}~wtforms.validators.NumberRange validator will be added to form field.
numbers_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""numbers_demo.py"""
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
float_field_unlimited = db.FloatField()"""numbers_demo.py"""
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
float_field_limited = db.FloatField(min_value=float(1), max_value=200.455)- API: {class}
.db_fields.IntField - Default form field class: {class}
wtforms.fields.IntegerField
From form generation side this field is pretty standard and do not use any form generation adjustments.
If database field definition has any of {attr}min_value or {attr}max_value, then
{class}~wtforms.validators.NumberRange validator will be added to form field.
numbers_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""numbers_demo.py"""
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
integer_field_unlimited = db.IntField()"""numbers_demo.py"""
from example_app.models import db
class NumbersDemoModel(db.Document):
"""Documentation example model."""
integer_field_limited = db.IntField(min_value=1, max_value=200)Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
- API: {class}
.db_fields.StringField - Default form field class: Selected by field settings combination
By default, during WTForm generation for fields without specified size (
{attr}min_length or {attr}max_length) class {class}.MongoTextAreaField is used,
in case when {attr}min_length or {attr}max_length set, then
{class}.MongoStringField used and {class}~wtforms.validators.Length will be added
to form field validators. This allows to keep documents of any size in mongodb.
In some cases class {class}~.MongoStringField is not the best choice for field, even
with limited size. In this case user can easily overwrite generated field class by
providing {attr}wtf_field_class on {class}.db_fields.StringField field declaration,
as on document, as well as on form generation steps.
If database field definition has {attr}regex parameter set, then
{class}~wtforms.validators.Regexp validator will be added to the form field.
Field declaration step keyword arguments {attr}password and {attr}textarea are
deprecated in Flask-Mongoengine version 2.0.0 and exist only to make migration
steps easy.
To implement same behaviour, user should use {attr}wtf_field_class setting on
{class}.db_fields.StringField init.
Several special WTForms field implementation was created to support mongodb database
behaviour and do not create any values in database, in case of empty fields. They
can be used as {attr}wtf_field_class setting or independently. Some of them used
in another database fields too, but all of them based on
{class}wtforms.fields.StringField and {class}~.EmptyStringIsNoneMixin. You can use
{class}~.EmptyStringIsNoneMixin for own field types.
- {class}
~.MongoEmailField - {class}
~.MongoHiddenField - {class}
~.MongoPasswordField - {class}
~.MongoSearchField - {class}
~.MongoStringField - {class}
~.MongoTelField - {class}
~.MongoTextAreaField - {class}
~.MongoURLField
strings_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
string_field = db.StringField()"""strings_demo.py"""
from example_app.models import db
from flask_mongoengine.wtf import fields as mongo_fields
class StringsDemoModel(db.Document):
"""Documentation example model."""
tel_field = db.StringField(wtf_field_class=mongo_fields.MongoTelField)mongoengine and wtforms projects are not consistent in how they work with regex.
You will be safe, if you use {func}re.compile each time, when you work with regex
settings, before parent projects itself.
"""strings_demo.py"""
import re
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
regexp_string_field = db.StringField(regex=re.compile(
r"^(https:\/\/)[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~:/?#[\]@!\$&'\(\)\*\+,;=]+$"
))"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
sized_string_field = db.StringField(min_length=5)"""strings_demo.py"""
from example_app.models import db
from flask_mongoengine.wtf import fields as mongo_fields
class StringsDemoModel(db.Document):
"""Documentation example model."""
password_field = db.StringField(
wtf_field_class=mongo_fields.MongoPasswordField,
required=True,
min_length=5,
)- API: {class}
.db_fields.URLField - Default form field class: {class}
~.MongoURLField
Unlike StringField WTForm class of the field is not adjusted by normal form
generation sequence and always match {class}~.MongoURLField. All other
adjustments, related to validators insert are work with EmailField in the same way,
as in StringField.
Additional {class}~wtforms.validators.Regexp validator is also inserted to form
field, to exclude unnecessary database request, if form data incorrect. This
validator use regexp, provided in {attr}url_regex of {class}.db_fields.URLField,
or default URL regexp from mongoengine project. This is different from
Flask-Mongoengine version 1.0.0 or earlier, where {class}~wtforms.validators.URL
was inserted. This was changed, to exclude validators conflicts.
{func}`~.model_form` is still use {class}`~wtforms.validators.URL` for
compatibility with old setups.
Field respect user's adjustments in {attr}wtf_field_class option of
{class}.db_fields.URLField. This will change form field display, but will not
change inserted validators.
strings_demo.py in example app contain basic non-requirement example. You can adjust it to any provided example for test purposes.
"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
url_field = db.URLField()"""strings_demo.py"""
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
required_url_field = db.URLField(required=True, min_length=25)Regexp for {attr}url_regex should be prepared by {mod}re.
"""strings_demo.py"""
import re
from example_app.models import db
class StringsDemoModel(db.Document):
"""Documentation example model."""
https_url_field = db.URLField(
url_regex=re.compile(
r"^(https:\/\/)[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~:/?#[\]@!\$&'\(\)\*\+,;=]+$"
),
)Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
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Not yet documented. Please help us with new pull request.
Not yet documented. Please help us with new pull request.
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