WTFormsValidator

A python library for generating client side validation functions from WTForms for various validator libraries.

Developed and tested with Python 3.8 and WTForms 2.3.1 Compatible with Python 3.6 and Python 3.7

Table of Contents

• Supported validators
• Setup
• Running the sample application
• Usage
  • Integrating with YairEO
  • Integrating with ParsleyJS
  • Integrating with Bouncer.js
  • Implementing custom behaviour

Supported validators

Here you can see which libraries are currently supported or planned to be added, and which WTForms validators are supported by them.
Validators marked with an R are supported via regexes. Using multiple regex-backed validators concurrently will disable all but the last one.

WTForms validator	YairEO	ParsleyJS	Bouncer.js	just-validate	Pristine	jQuery validation
DataRequired	✔️	✔️	✔️	TODO	TODO	TODO
Email	✔️|R¹	✔️|R¹	✔️|R¹
EqualTo	✔️	✔️	❌
InputRequired	✔️²	✔️²	✔️²
IPAddress	R	R	R
Length	✔️	✔️	✔️
MacAddress	R	R	R
NumberRange	✔️	✔️	✔️
Optional	✔️³	✔️	✔️
Regexp	✔️	✔️	✔️
URL	✔️|R¹	✔️|R¹	✔️|R¹
UUID	R	R	R
AnyOf	R	R	R
NoneOf	R	R	R
Custom validators	❌	❌	❌
Custom errors	❌⁴	✔️	✔️

¹ These libraries have built-in support for e-mail and URL validation, but you can choose to use the WTFormsValidation's regex validators instead. Defaults to built-in, unless that requires WTFormsValidation to change the field's type (in the case of YairEO and Bouncer.js)
² Same behaviour as DataRequired
³ Due to a bug in YairEO, only fields marked as required are validated, so currently this should have no effect
⁴ With YairEO currently you can only override the default messages

Setup

Install it with pip, in your preferred virtual environment:

pip install WTFormsValidation

Running the sample application

• Create a virtualenv virtualenv -p python3.8 venv
• Activate it . venv/bin/activate
• Install the sample's requirements pip install -r sample/requirements.txt
• Run python -m sample.sample_app
• Use the navbar to select which validator's demo you wish to examine.

Usage

Adding the validator library's boilerplate code should be done according to their documentation. Integrate WTFormsValidator as described below.

Integrating with YairEO

Using the default settings for the tagger class:

from WTFormsValidation import yairify
...
render_template('your_template.html', form=yairify(form))

or by instantiating the tagger class yourself:

from WTFormsValidation.tagging.yaireo import YairEOtagger
yaireo_tagger = YairEOtagger(email_builtin=True, url_builtin=True)  # defaults negated
...
render_template('your_template.html', form=yaireo_tagger.extend(form))

Integrating with ParsleyJS

Using the default settings for the tagger class:

from WTFormsValidation import parslify
...
render_template('your_template.html', form=parslify(form))

or by instantiating the tagger class yourself:

from WTFormsValidation.tagging.parsley import ParsleyTagger
parsley_tagger = ParsleyTagger(email_builtin=False, url_builtin=False)  # defaults negated
...
render_template('your_template.html', form=parsley_tagger.extend(form))

Integrating with Bouncer.js

Using the default settings for the tagger class:

from WTFormsValidation import bouncify
...
render_template('your_template.html', form=bouncify(form))

or by instantiating the tagger class yourself:

from WTFormsValidation.tagging.bouncer import BouncerTagger
bouncer_tagger = BouncerTagger(email_builtin=True, url_builtin=True)  # defaults negated
...
render_template('your_template.html', form=bouncer_tagger.extend(form))

Implementing custom behaviour

You can inherit from the default tagger classes (YairEOtagger, ParsleyTagger, BouncerTagger) and override any handler functions to suit your use case.