Django reCAPTCHA

Django reCAPTCHA form field/widget integration app.

Contents

• Requirements
• Installation
• Usage
  • Fields
  • Widgets
  • reCAPTCHA v3 Score
  • reCAPTCHA V3 Action
  • Local Development and Functional Testing
• Credits

Note

django-recaptcha supports Google reCAPTCHA V2 - Checkbox (Default), Google reCAPTCHA V2 - Invisible and Google reCAPTCHA V3 please look at the widgets section for more information.

Django reCAPTCHA uses a modified version of the Python reCAPTCHA client which is included in the package as client.py.

Requirements

Tested with:

• Python: 3.8, 3.9, 3.10, 3.11
• Django: 3.2, 4.1, 4.2
• You can view the Python-Django support matrix here

This package only supports modern, “evergreen” desktop and mobile browsers. For IE11 support, make sure to add a polyfill for Element.closest.

Installation

1. Sign up for reCAPTCHA.

2. Install with pip install django-recaptcha.

3. Add 'captcha' to your INSTALLED_APPS setting.

   INSTALLED_APPS = [
       ...,
       'captcha',
       ...
   ]

4. Add the Google reCAPTCHA keys generated in step 1 to your Django production settings with RECAPTCHA_PUBLIC_KEY and RECAPTCHA_PRIVATE_KEY. Note that omitting these settings will default to a set of test keys refer to Local Development and Functional Testing for more information.

   For example:

   RECAPTCHA_PUBLIC_KEY = 'MyRecaptchaKey123'
   RECAPTCHA_PRIVATE_KEY = 'MyRecaptchaPrivateKey456'

   These can also be specified per field by passing the public_key or private_key parameters to ReCaptchaField - see field usage below.

5. (OPTIONAL) If you require a proxy, add a RECAPTCHA_PROXY setting (dictionary of proxies), for example:

   RECAPTCHA_PROXY = {'http': 'http://127.0.0.1:8000', 'https': 'https://127.0.0.1:8000'}

6. (OPTIONAL) In the event www.google.com is not accessible the RECAPTCHA_DOMAIN setting can be changed to www.recaptcha.net as per the reCAPTCHA FAQ:

   RECAPTCHA_DOMAIN = 'www.recaptcha.net'

This will change the Google JavaScript api domain as well as the client side field verification domain.

Usage

Fields

The quickest way to add reCAPTCHA to a form is to use the included ReCaptchaField field class. A ReCaptchaV2Checkbox will be rendered by default. For example:

from django import forms
from captcha.fields import ReCaptchaField

class FormWithCaptcha(forms.Form):
    captcha = ReCaptchaField()

Be sure to include the captcha field in your forms. There are many ways to add fields to forms in Django. We recommend you refer to the form rendering options and rendering fields manually sections of the official Django documentation for forms.

To allow for runtime specification of keys you can optionally pass the private_key or public_key parameters to the constructor. For example:

captcha = ReCaptchaField(
    public_key='76wtgdfsjhsydt7r5FFGFhgsdfytd656sad75fgh',
    private_key='98dfg6df7g56df6gdfgdfg65JHJH656565GFGFGs',
)

If specified, these parameters will be used instead of your reCAPTCHA project settings.

Widgets

There are three widgets that can be used with the ReCaptchaField class:

ReCaptchaV2Checkbox for Google reCAPTCHA V2 - Checkbox

ReCaptchaV2Invisible for Google reCAPTCHA V2 - Invisible

ReCaptchaV3 for Google reCAPTCHA V3

To make use of widgets other than the default Google reCAPTCHA V2 - Checkbox widget, simply replace the ReCaptchaField widget. For example:

from django import forms
from captcha.fields import ReCaptchaField
from captcha.widgets import ReCaptchaV2Invisible

class FormWithCaptcha(forms.Form):
    captcha = ReCaptchaField(widget=ReCaptchaV2Invisible)

The reCAPTCHA widget supports several data attributes that customize the behaviour of the widget, such as data-theme, data-size, etc. You can forward these options to the widget by passing an attrs parameter to the widget, containing a dictionary of options. For example:

captcha = fields.ReCaptchaField(
    widget=widgets.ReCaptchaV2Checkbox(
        attrs={
            'data-theme': 'dark',
            'data-size': 'compact',
        }
    )
)
# The ReCaptchaV2Invisible widget
# ignores the "data-size" attribute in favor of 'data-size="invisible"'

The reCAPTCHA api supports several parameters. To customise the parameters that get sent along pass an api_params parameter to the widget, containing a dictionary of options. For example:

captcha = fields.ReCaptchaField(
    widget=widgets.ReCaptchaV2Checkbox(
        api_params={'hl': 'cl', 'onload': 'onLoadFunc'}
    )
)
# The dictionary is urlencoded and appended to the reCAPTCHA api url.

By default, the widgets provided only supports a single form with a single widget on each page.

The language can be set with the 'h1' parameter, look at language codes for the language code options. Note that translations need to be added to this package for the errors to be shown correctly. Currently the package has error translations for the following language codes: es, fr, nl, pl, pt_BR, ru, zh_CN, zh_TW

However, the JavaScript used by the widgets can easily be overridden in the templates.

The templates are located in:

captcha/includes/js_v2_checkbox.html for overriding the reCAPTCHA V2 - Checkbox template

captcha/includes/js_v2_invisible.html for overriding the reCAPTCHA V2 - Invisible template

captcha/includes/js_v3.html for overriding the reCAPTCHA V3 template

For more information about overriding templates look at Django's template override

reCAPTCHA v3 Score

As of version 3, reCAPTCHA also returns a score value. This can be used to determine the likelihood of the page interaction being a bot. See the Google documentation for more details.

To set a project wide score limit use the RECAPTCHA_REQUIRED_SCORE setting.

For example:

RECAPTCHA_REQUIRED_SCORE = 0.85

For per field, runtime, specification the attribute can also be passed to the widget:

captcha = fields.ReCaptchaField(
    widget=ReCaptchaV3(
        attrs={
            'required_score':0.85,
            ...
        }
    )
)

In the event the score does not meet the requirements, the field validation will fail as expected and an error message will be logged.

reCAPTCHA V3 Action

The V3 reCAPTCHA supports an [action](https://developers.google.com/recaptcha/docs/v3#actions) value that provides break-downs of actions and adaptive risk analysis.

To set the action value, pass it when instantiating the ReCaptcha widget. By default it is set to form.

captcha = fields.ReCaptchaField(
    widget=widgets.ReCaptchaV3(
        action='signup'
    )
)

Local Development and Functional Testing

If RECAPTCHA_PUBLIC_KEY and RECAPTCHA_PRIVATE_KEY are not set, django-recaptcha will use Google's test keys instead. These cannot be used in production since they always validate to true and a warning will be shown on the reCAPTCHA. Google's test keys only work for reCAPTCHA version 2.

To bypass the security check that prevents the test keys from being used unknowingly add SILENCED_SYSTEM_CHECKS = [..., 'captcha.recaptcha_test_key_error', ...] to your settings, here is an example:

SILENCED_SYSTEM_CHECKS = ['captcha.recaptcha_test_key_error']

If you want to mock the call to Google's servers altogether, have a look at test_fields.py:

from unittest.mock import patch
from django.test import TestCase
from captcha.client import RecaptchaResponse

class TestFields(TestCase):
    @patch("captcha.fields.client.submit")
    def test_client_success_response(self, mocked_submit):
        mocked_submit.return_value = RecaptchaResponse(is_valid=True)
        ...

Credits

Originally developed by Praekelt Consulting

Inspired Marco Fucci's blogpost titled Integrating reCAPTCHA with Django

client.py taken from recaptcha-client licenced MIT/X11 by Mike Crawford.

reCAPTCHA copyright 2012 Google.