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https://github.com/kubetail-org/starlette-wtf
Simple integration of Starlette and WTForms
https://github.com/kubetail-org/starlette-wtf
Last synced: about 2 months ago
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Simple integration of Starlette and WTForms
- Host: GitHub
- URL: https://github.com/kubetail-org/starlette-wtf
- Owner: kubetail-org
- License: mit
- Created: 2019-12-20T14:23:03.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2024-05-07T07:15:13.000Z (4 months ago)
- Last Synced: 2024-07-28T13:14:03.449Z (about 2 months ago)
- Language: Python
- Size: 54.7 KB
- Stars: 82
- Watchers: 7
- Forks: 9
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
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README
# Starlette-WTF
Starlette-WTF is a simple tool for integrating [Starlette](https://www.starlette.io/) and [WTForms](https://wtforms.readthedocs.io/en/stable/). It is modeled on the excellent [Flask-WTF](https://flask-wtf.readthedocs.io) library.
## Table of Contents
- [Installation](#installation)
- [Quickstart](#quickstart)
- [Creating Forms](#creating-forms)
* [The StarletteForm Class](#the-starletteform-class)
* [Validation](#validation)
* [Async Custom Validators](#async-custom-validators)
- [CSRF Protection](#csrf-protection)
* [Setup](#setup)
* [Protect Views](#protect-views)
* [HTML Forms](#html-forms)
* [JavaScript Requests](#javascript-requests)
* [Disable in Unit Tests](#disable-in-unit-tests)
* [Configuration](#configuration)
- [Development](#development)
* [Get the code](#get-the-code)
* [Run unit tests](#run-unit-tests)
## Installation
Installing Starlette-WTF is simple with [pip](https://pip.pypa.io/en/stable/):
```bash
pip install starlette-wtf
```
## Quickstart
The following code implements a simple form handler with CSRF protection. The form has a required string field and validation errors are handled by the html template. Note that CSRF protection requires `SessionMiddleware`, `CSRFProtectMiddleware`, `@csrf_protect` and the `csrf_token` field to be added to the HTML form.
First, install the dependencies for this quickstart:
```bash
pip install starlette starlette-wtf jinja2 uvicorn
```
Next, create a Python file (app.py) with the following code:
```python
from jinja2 import Template
from starlette.applications import Starlette
from starlette.middleware import Middleware
from starlette.middleware.sessions import SessionMiddleware
from starlette.routing import Route
from starlette.responses import PlainTextResponse, HTMLResponse
from starlette_wtf import StarletteForm, CSRFProtectMiddleware, csrf_protect
from wtforms import StringField
from wtforms.validators import DataRequired
class MyForm(StarletteForm):
name = StringField('name', validators=[DataRequired()])
template = Template('''
{{ form.csrf_token }}
{{ form.name(placeholder='Name') }}
{% if form.name.errors -%}
{{ form.name.errors[0] }}
{%- endif %}
Submit
''')
@csrf_protect
async def index(request):
"""GET|POST /: form handler
"""
form = await MyForm.from_formdata(request)
if await form.validate_on_submit():
return PlainTextResponse('SUCCESS')
html = template.render(form=form)
return HTMLResponse(html)
app = Starlette(
routes=[
Route('/', methods=['GET', 'POST'], endpoint=index),
],
middleware=[
Middleware(SessionMiddleware, secret_key='***REPLACEME1***'),
Middleware(CSRFProtectMiddleware, csrf_secret='***REPLACEME2***'),
],
)
```
Finally, run the app using the following command:
```bash
uvicorn app:app
```
## Creating Forms
### The StarletteForm Class
Starlette-WTF provides a form class that makes it easy to add form validation and CSRF protection to Starlette apps. To make a form, subclass the `StarletteForm` class and use [WTForms](https://wtforms.readthedocs.io/) fields, validators and widgets to define the inputs. The `StarletteForm` class inherits from the WTForms `Form` class so you can use WTForms features and methods to add more advanced functionality to your app:
```python
from starlette_wtf import StarletteForm
from wtforms import StringField, PasswordField
from wtforms.validators import DataRequired, Email, EqualTo
from wtforms.widgets import PasswordInput
class CreateAccountForm(StarletteForm):
email = StringField(
'Email address',
validators=[
DataRequired('Please enter your email address'),
Email()
]
)
password = PasswordField(
'Password',
widget=PasswordInput(hide_value=False),
validators=[
DataRequired('Please enter your password'),
EqualTo('password_confirm', message='Passwords must match')
]
)
password_confirm = PasswordField(
'Confirm Password',
widget=PasswordInput(hide_value=False),
validators=[
DataRequired('Please confirm your password')
]
)
```
Often you will want to initialize form objects using default values on GET requests and from submitted formdata on POST requests. To make this easier you can use the `.from_formdata()` async class method which does this for you automatically:
```python
async def create_account(request):
"""GET|POST /create-account: Create account form handler
"""
form = await CreateAccountForm.from_formdata(request)
return PlainTextResponse()
```
### Validation
The `StarletteForm` class has a useful `.validate_on_submit()` method that performs input validation for POST, PUT, PATCH and DELETE requests and returns a boolean indicating whether or not there were any errors. After validation, errors are available via the `.errors` attribute attached to each input field instance. Note that validation is asynchronous to handle async field validators (see below):
```python
from jinja2 import Template
from starlette.applications import Starlette
from starlette.responses import (PlainTextResponse, RedirectResponse,
HTMLResponse)
from starlette.routing import Route
template = Template('''
Create Account
{{ form.email(placeholder='Email address',
autofocus='true',
type='email',
spellcheck='false') }}
{% if form.email.errors -%}
{{ form.email.errors[0] }}
{%- endif %}
{{ form.password(placeholder="Password") }}
{% if form.password.errors -%}
{{ form.password.errors[0] }}
{%- endif %}
{{ form.password_confirm(placeholder="Confirm password") }}
{% if form.password_confirm.errors -%}
{{ form.password_confirm.errors[0] }}
{%- endif %}
Create account
''')
async def index(request):
"""GET /: Return home page
"""
return PlainTextResponse()
async def create_account(request):
"""GET|POST /create-account: Create account form handler
"""
# initialize form
form = await CreateAccountForm.from_formdata(request)
# validate form
if await form.validate_on_submit():
# TODO: Save account credentials before returning redirect response
return RedirectResponse(url='/', status_code=303)
# generate html
html = template.render(form=form)
# return response
status_code = 422 if form.errors else 200
return HTMLResponse(html, status_code=status_code)
app = Starlette(routes=[
Route('/', methods=['GET'], endpoint=index),
Route('/create-account', methods=['GET', 'POST'], endpoint=create_account),
])
```
### Async Custom Validators
The `StarletteForm` class allows you to implement asynchronous [WTForms-like custom validators](https://wtforms.readthedocs.io/en/stable/validators/#custom-validators) by adding `async_validate_{fieldname}` methods to your form classes:
```python
from starlette_wtf import StarletteForm
from wtforms import TextField, PasswordField, ValidationError
from wtforms.validators import DataRequired, Email, EqualTo
class CreateAccountForm(StarletteForm):
email = TextField(
'Email address',
validators=[
DataRequired('Please enter your email address'),
Email()
]
)
password = PasswordField(
'Password',
widget=PasswordInput(hide_value=False),
validators=[
DataRequired('Please enter your password'),
EqualTo('password_confirm', message='Passwords must match')
]
)
password_confirm = PasswordField(
'Confirm Password',
widget=PasswordInput(hide_value=False),
validators=[
DataRequired('Please confirm your password')
]
)
async def async_validate_email(self, field):
"""Asynchronous validator to check if email is already in-use
"""
# replace this with your own code
if await make_database_request_here():
raise ValidationError('Email is already in use')
```
## CSRF Protection
In order to add CSRF protection to your app, first you must ensure that Starlette's `SessionMiddleware` is enabled, second you must configure Starlette-WTF using `CSRFProtectMiddleware`, third you must use the `@csrf_protect` decorator to protect individual endpoints, and fourth you must add the CSRF token to your HTML forms or JavaScript requests.
### Setup
To enable CSRF protection for your app, first you must ensure that Starlette's `SessionMiddleware` is enabled, and second you must configure Starlette-WTF using `CSRFProtectMiddleware`.
```python
from starlette.applications import Starlette
from starlette.middleware import Middleware
from starlette.middleware.sessions import SessionMiddleware
from starlette_wtf import CSRFProtectMiddleware
app = Starlette(middleware=[
Middleware(SessionMiddleware, secret_key='***REPLACEME1***'),
Middleware(CSRFProtectMiddleware, csrf_secret='***REPLACEME2***')
])
```
### Protect Views
Once Starlette-WTF has been configured using `CSRFProtectMiddleware` you can enable CSRF protection for individual endpoints using the `@csrf_protect` decorator. The `@csrf_protect` decorator will automatically look for `csrf_token` in the form data or in the request headers (`X-CSRFToken`) and it will raise an `HTTPException` if the token is missing or invalid. CSRF token validation will only be performed on submission requests (POST, PUT, PATCH, DELETE):
```python
from starlette.responses import PlainTextResponse
from starlette_wtf import csrf_protect
@csrf_protect
async def form_handler(request):
"""GET|POST /form-handler: Form handler
"""
# this code won't run unless the CSRF token has been validated
return PlainTextResponse()
```
The `@csrf_protect` decorator can also be used with class-based views (e.g. [HTTPEndpoint](https://www.starlette.io/endpoints/)):
```python
from starlette.endpoints import HTTPEndpoint
from starlette.responses import PlainTextResponse
from starlette_wtf import csrf_protect
@csrf_protect
class Endpoint(HTTPEndpoint):
async def get(self, request):
# this code will run without a CSRF check
return PlainTextResponse()
async def post(self, request):
# this code won't run unless the CSRF token has been validated
return PlainTextResponse()
```
The `@csrf_protect` decorator can also be used with bound methods attached to class-based views:
```python
from starlette.endpoints import HTTPEndpoint
from starlette.responses import PlainTextResponse
from starlette_wtf import csrf_protect
class Endpoint(HTTPEndpoint):
async def get(self, request):
# this code will run without a CSRF check
return PlainTextResponse()
@csrf_protect
async def post(self, request):
# this code won't run unless the CSRF token has been validated
return PlainTextResponse()
```
### HTML Forms
When using `StarletteForm` you can render the form's CSRF token field like this:
```html
{{ form.csrf_token }}
```
### JavaScript Requests
When sending an AJAX request, add the `X-CSRFToken` header to allow Starlette-WTF to perform CSRF validation. For example, in jQuery you can configure all requests to send the token:
```html
var csrf_token = "{{ csrf_token(request) }}";
$.ajaxSetup({
beforeSend: function(xhr, settings) {
if (!/^(GET|HEAD|OPTIONS|TRACE)$/i.test(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrf_token);
}
}
});
```
### Disable in Unit Tests
To disable CSRF protection in unit tests you can toggle the `enabled` attribute in `CSRFProtectionMiddleware`:
```python
from starlette.applications import Starlette
from starlette.config import environ
from starlette.middleware import Middleware
from starlette.middleware.sessions import SessionMiddleware
from starlette_wtf import CSRFProtectMiddleware
app = Starlette(middleware=[
Middleware(SessionMiddleware, secret_key='***REPLACEME1***'),
Middleware(CSRFProtectMiddleware,
enabled=not environ.get('TESTING', False),
csrf_secret='***REPLACEME2***')
])
```
### Configuration
`CSRFProtectMiddleware` accepts the following options:
| Argument | Description
| ----------------- | -----------
| enabled | If true, enables CSRF protection. Default to True.
| csrf_secret | The CSRF token signing key.
| csrf_field_name | The CSRF token's field name in the session. Defaults to "csrf_token"
| csrf_time_limit | The time limit for each signed token in seconds. Defaults to 3600.
| csrf_headers | List of CSRF HTTP header field names. Defaults to ["X-CSRFToken", "X-CSRF-Token"]
| csrf_ssl_strict | If enabled, ensures same origin policy on https requests. Defaults to True.
## Development
### Get the code
Starlette-WTF is actively developed on GitHub. You can clone the repository using git:
```bash
git clone [email protected]:muicss/starlette-wtf.git
```
Once you have a copy of the source, you can install it into your site-packages in development mode so you can modify and execute the code:
```bash
pip install -e .
```
### Run unit tests
To install unit test dependencies:
```bash
pip install -e .\[test\]
```
To run unit tests:
```bash
pytest
```