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2020-12-05

Каналы передачи данных | Сетевое программирование | Базы данных | Основы Веб-программирования

Формы

WTForms

См.также

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from jinja2 import Template
from wtforms import BooleanField, Form, StringField, validators


class RegistrationForm(Form):
    username = StringField('Username', [validators.Length(min=4, max=25)])
    email = StringField('Email Address', [validators.Length(min=6, max=35)])
    rules = BooleanField('I accept the site rules',
                         [validators.InputRequired()])

if __name__ == '__main__':
    form = RegistrationForm(username="root")
    template = Template("""
<form method="POST" action="">
    {% for field in form.data %}
        {{ form[field].label }} |
        {{ form[field] }}
        <br />
    {% endfor %}
    <input type="submit" value="Ok">
</form>
    """)
    print(template.render(form=form))
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<form method="POST" action="">
    
        <label for="username">Username</label> |
        <input id="username" name="username" type="text" value="root">
        <br />
    
        <label for="rules">I accept the site rules</label> |
        <input id="rules" name="rules" type="checkbox" value="y">
        <br />
    
        <label for="email">Email Address</label> |
        <input id="email" name="email" type="text" value="">
        <br />
    
    <input type="submit" value="Ok">
</form>
|
|
|

Deform

См.также

Deform — это Python библиотека для генерации форм. Deform использует Colander как генератор схемы, Peppercorn для десериализации данных из формы и шаблонизатор Chameleon.

Основные задачи, которые выполняет Deform:

  • Генерирует форму
  • Имеет набор виджетов для форм
  • Умеет генерировать AJAX формы
  • Использует схемы Colander
  • Использует шаблоны Chameleon (Но можно использовать и другие, например Jinja2 или Mako)

Примеры форм http://deformdemo.repoze.org/

Colander

См.также

Colander - десериализует данные полученные как XML, JSON, HTTP POST запрос и проверяет правильность их заполнения по заранее заданной схеме.

  • Определяет структуру (схему) формы
  • Проверяет содержимое формы

Простая форма

Для создания простой формы нам понадобится:

  • Схема Colander
  • Объект Form из Deform
  • WSGI-приложение, которое получает POST параметры из запроса
  • Шаблон страницы с формой

Схема Colander

0.simple_form.py - Colander схема
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


class Contact(colander.MappingSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def simple_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Contact(), buttons=('submit',))
    template = env.get_template('simple.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render())
    data = {'email': 'jon.staley@fundingoptions.com',
            'name': 'Jon',
            'message': 'Hello World'}
    return template.render(form=form.render(data))


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(simple_form, host='0.0.0.0', port=8000)

Форма deform.Form

0.simple_form.py - Форма от Deform
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


class Contact(colander.MappingSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def simple_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Contact(), buttons=('submit',))
    template = env.get_template('simple.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render())
    data = {'email': 'jon.staley@fundingoptions.com',
            'name': 'Jon',
            'message': 'Hello World'}
    return template.render(form=form.render(data))


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(simple_form, host='0.0.0.0', port=8000)

Шаблон simple.html

templates/simple.html
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<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>simple</title>
    </head>
    <body>
        {{ form }}
    </body>
</html>
../../_images/simple_form.png

Сгенерированная форма

../../_images/simple_form_validation.png

Валидация формы

Добавим стилей:

templates/simple.html с CSS стилями.
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<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>simple</title>
        <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/0.96.1/css/materialize.min.css" />
        <script type="text/javascript" src="https://code.jquery.com/jquery-2.1.3.min.js"></script>
        <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/materialize/0.96.1/js/materialize.min.js"></script>
        <style type="text/css">
            .deformFormFieldset {
                border: none;
                padding: 0;
                margin: 0;
            }
            .control-label {
                left: 0 !important;
            }
            .form-group
            {
                position: relative;
                margin: 1em 0 0 0;
            }
            .alert-danger
            {
                top: -1.5em;
                position: relative;
            }
            p.help-block[id*="error"]
            {
                width: 10em;
                color: red !important;
                font-style: normal;
                padding: 0;
                margin: 0 0 1em 0;
                line-height: 1.5;
                font-family: "Roboto", sans-serif;
                font-weight: normal;
                position: absolute;
                left: -12em;
                text-align: right;
                top: 0.85em;
            }
            .required:after
            {
                content: "*";
                position: relative;
                font-family: "Roboto", sans-serif;
                font-weight: normal;
                color: red;
            }
            .errorMsgLbl
            {
                background: red;
                font-family: "Roboto", sans-serif;
                font-weight: normal;
                padding: 0.5em 1em;
                color: #fff;
                margin: 0 0 1em 0;
            }
            .alert-danger .errorMsg
            {
                display: none;
            }
        </style>
    </head>
    <body>
        <div class="form" style="width: 500px; margin: 0 auto; padding: 50px">
            <h1>Simple Form</h1>
            {{ form }}
        </div>
    </body>
    <script type="text/javascript">
        $(function() {
            $('#item-deformField1').addClass('input-field').addClass('col');
            $('#item-deformField2').addClass('input-field').addClass('col');
            $('#item-deformField3').addClass('input-field').addClass('col');
            $('#deformField3').addClass('materialize-textarea');
        });
    </script>
</html>
../../_images/simple_form_with_css.png

Сгенерированная форма с применением CSS стилей

../../_images/simple_form_validation_with_css.png

Валидация формы с применением CSS стилей

Deform и Colander в реальных проектах

Наследование схем

1.inheritance.py - Наследование Colander схем
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


class AddressSchema(colander.MappingSchema):
    line1 = colander.SchemaNode(colander.String(), title='Address line 1')
    line2 = colander.SchemaNode(colander.String(), title='Address line 2',
                                missing=None)
    line3 = colander.SchemaNode(colander.String(), title='Address line 3',
                                missing=None)
    town = colander.SchemaNode(colander.String(), title='Town')
    postcode = colander.SchemaNode(colander.String(), title='Postcode')


class Business(AddressSchema):
    business_name = colander.SchemaNode(colander.String(),
                                        title='Business Name',
                                        insert_before='line1')


def inheritance_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Business(), buttons=('submit',))
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render())
    return template.render(form=form.render())


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(inheritance_form, host='0.0.0.0', port=8000)
../../_images/inheritance_scheme.png

Наследование Colander схемы

Кастомная валидация

2.custom_validators.py - Кастомная валидация
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


def month_validator(node, month):
    if month.isdigit():
        int_month = int(month)
        if not 0 < int_month < 13:
            raise colander.Invalid(node,
                                   'Please enter a number between 1 and 12')
    else:
        raise colander.Invalid(node, 'Please enter a number')


class AddressSchema(colander.MappingSchema):
    line1 = colander.SchemaNode(colander.String(), title='Address line 1')
    line2 = colander.SchemaNode(colander.String(), title='Address line 2',
                                missing=None)
    line3 = colander.SchemaNode(colander.String(), title='Address line 3',
                                missing=None)
    town = colander.SchemaNode(colander.String(), title='Town')
    postcode = colander.SchemaNode(colander.String(), title='Postcode')


class Business(AddressSchema):
    business_name = colander.SchemaNode(colander.String(),
                                        title='Business Name',
                                        insert_before='line1')
    start_month = colander.SchemaNode(colander.String(), title='Start month',
                                      validator=month_validator)


def custom_validator_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Business(), buttons=('submit',))
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render()).encode("utf-8")
    return template.render(form=form.render()).encode("utf-8")


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(custom_validator_form, host='0.0.0.0', port=8000)
../../_images/custom_validator_form.png

Кастомная валидация поля

Отложенная валидация

См.также

3.defered_validators.py - добавление CSRF токена
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


def get_session(request):
    return request.environ.get('paste.session.factory', lambda: {})()


def get_csrf_token(session):
    if 'csrf' not in session:
        from uuid import uuid4
        session['csrf'] = uuid4().hex
    return session['csrf']


@colander.deferred
def deferred_csrf_default(node, kw):
    request = kw.get('request')
    session = get_session(request)
    csrf_token = get_csrf_token(session)
    return csrf_token


@colander.deferred
def deferred_csrf_validator(node, kw):
    def validate_csrf_token(node, value):
        request = kw.get('request')
        session = get_session(request)
        csrf_token = get_csrf_token(session)
        if value != csrf_token:
            raise colander.Invalid(node, 'Bad CSRF token')

    return validate_csrf_token


class CSRFSchema(colander.Schema):
    csrf = colander.SchemaNode(colander.String(),
                               default=deferred_csrf_default,
                               validator=deferred_csrf_validator,
                               # widget=deform.widget.HiddenWidget(), )
                               )


class Contact(CSRFSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def custom_validator_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)
    session = get_session(request)
    session['csrf'] = get_csrf_token(session)

    schema = Contact().bind(request=request)
    form = deform.Form(schema, buttons=('submit',))
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render()).encode("utf-8")
        session.pop('csrf')
        return template.render(form='OK')
    return template.render(form=form.render()).encode("utf-8")


if __name__ == '__main__':
    from paste.httpserver import serve
    from paste.session import SessionMiddleware

    app = SessionMiddleware(custom_validator_form)

    serve(app, host='0.0.0.0', port=8000)
../../_images/defered_validator_form_csrf_token.png

Ключ CSRF

3.defered_validators.py - отложенная валидация
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import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


def get_session(request):
    return request.environ.get('paste.session.factory', lambda: {})()


def get_csrf_token(session):
    if 'csrf' not in session:
        from uuid import uuid4
        session['csrf'] = uuid4().hex
    return session['csrf']


@colander.deferred
def deferred_csrf_default(node, kw):
    request = kw.get('request')
    session = get_session(request)
    csrf_token = get_csrf_token(session)
    return csrf_token


@colander.deferred
def deferred_csrf_validator(node, kw):
    def validate_csrf_token(node, value):
        request = kw.get('request')
        session = get_session(request)
        csrf_token = get_csrf_token(session)
        if value != csrf_token:
            raise colander.Invalid(node, 'Bad CSRF token')

    return validate_csrf_token


class CSRFSchema(colander.Schema):
    csrf = colander.SchemaNode(colander.String(),
                               default=deferred_csrf_default,
                               validator=deferred_csrf_validator,
                               # widget=deform.widget.HiddenWidget(), )
                               )


class Contact(CSRFSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def custom_validator_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)
    session = get_session(request)
    session['csrf'] = get_csrf_token(session)

    schema = Contact().bind(request=request)
    form = deform.Form(schema, buttons=('submit',))
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render()).encode("utf-8")
        session.pop('csrf')
        return template.render(form='OK')
    return template.render(form=form.render()).encode("utf-8")


if __name__ == '__main__':
    from paste.httpserver import serve
    from paste.session import SessionMiddleware

    app = SessionMiddleware(custom_validator_form)

    serve(app, host='0.0.0.0', port=8000)
../../_images/defered_validator_form_bad_token.png

Ключ CSRF

Переопределение стандартных шаблонов

4.custom_templates.py - переопределение стандартных шаблонов формы
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import os

import colander
import deform
from jinja2 import Environment, FileSystemLoader
from pkg_resources import resource_filename

env = Environment(loader=FileSystemLoader('templates'))


deform_path = os.path.abspath('templates/deform')
deform_templates = resource_filename('deform', 'templates')
print(deform_templates)
print(deform_path)
search_path = (deform_path, deform_templates)
renderer = deform.ZPTRendererFactory(search_path)


class Contact(colander.MappingSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def custom_template_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Contact(), buttons=('submit',), renderer=renderer)
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render()).encode("utf-8")
    data = {'email': 'jon.staley@fundingoptions.com',
            'name': 'Jon',
            'message': 'Hello World'}
    return template.render(form=form.render(data)).encode("utf-8")


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(custom_template_form, host='0.0.0.0', port=8000)
$ tree templates/deform/
templates/deform/
├── form.pt
└── mapping_item.pt

0 directories, 2 files
../../_images/custom_templates.png

Переопределенный шаблон form.pt

Новые шаблоны на Jinja2

См.также

5.custom_jinja2_templates.py - переопределение стандартных шаблонов формы, на свои Jinja2 шаблоны
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import os

import colander
import deform
from jinja2 import Environment, FileSystemLoader

env = Environment(loader=FileSystemLoader('templates'))


def jinja2_renderer(template_name, **kw):
    kw['_'] = str  # Hook for translation string with gettext

    from jinja2 import Template
    deform_jinja_path = os.path.abspath('templates/deform_jinja2')
    jinja2_template = os.path.join(deform_jinja_path,
                                   template_name + '.jinja2')
    template = Template(open(jinja2_template).read())
    return template.render(**kw)


class Contact(colander.MappingSchema):
    email = colander.SchemaNode(colander.String(), validator=colander.Email())
    name = colander.SchemaNode(colander.String())
    message = colander.SchemaNode(colander.String(),
                                  widget=deform.widget.TextAreaWidget())


def custom_template_form(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    from webob import Request
    request = Request(environ)

    form = deform.Form(Contact(), buttons=('submit',),
                       renderer=jinja2_renderer)
    template = env.get_template('simple_with_css.html')
    if request.POST:
        submitted = request.POST.items()
        try:
            form.validate(submitted)
        except deform.ValidationFailure as e:
            return template.render(form=e.render()).encode("utf-8")
    data = {'email': 'jon.staley@fundingoptions.com',
            'name': 'Jon',
            'message': 'Hello World'}
    return template.render(form=form.render(data)).encode("utf-8")


if __name__ == '__main__':
    from paste.httpserver import serve

    serve(custom_template_form, host='0.0.0.0', port=8000)
$ tree templates/deform_jinja2/
templates/deform_jinja2/
├── autocomplete_input.jinja2
├── checkbox_choice.jinja2
├── checkbox.jinja2
├── checked_input.jinja2
├── checked_password.jinja2
├── dateinput.jinja2
├── dateparts.jinja2
├── datetimeinput.jinja2
├── file_upload.jinja2
├── form.jinja2
├── hidden.jinja2
├── mapping_item.jinja2
├── mapping.jinja2
├── moneyinput.jinja2
├── password.jinja2
├── radio_choice.jinja2
├── readonly
│   ├── checkbox_choice.jinja2
│   ├── checkbox.jinja2
│   ├── checked_input.jinja2
│   ├── checked_password.jinja2
│   ├── dateparts.jinja2
│   ├── file_upload.jinja2
│   ├── form.jinja2
│   ├── mapping_item.jinja2
│   ├── mapping.jinja2
│   ├── password.jinja2
│   ├── radio_choice.jinja2
│   ├── richtext.jinja2
│   ├── select.jinja2
│   ├── sequence_item.jinja2
│   ├── sequence.jinja2
│   ├── textarea.jinja2
│   └── textinput.jinja2
├── richtext.jinja2
├── select.jinja2
├── sequence_item.jinja2
├── sequence.jinja2
├── textarea.jinja2
└── textinput.jinja2

1 directory, 39 files
Стандартный шаблон textarea.pt из Deform
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<textarea tal:define="rows rows|field.widget.rows;
                      cols cols|field.widget.cols;
                      css_class css_class|field.widget.css_class;
                      oid oid|field.oid;
                      name name|field.name;
                      style style|field.widget.style"
          tal:attributes="rows rows;
                          cols cols;
                          class string: form-control ${css_class or ''};
                          style style"
          id="${oid}"
          name="${name}">${cstruct}</textarea>
templates/deform_jinja2/textarea.jinja2 - Переопределенный нами шаблон textarea на Jinja2
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<textarea
        style="background: green;color:white;"
        {% if field.widget.rows %}
            rows="{{ field.widget.rows }}"
        {% endif %}
        {% if field.widget.cols %}
            cols="{{ field.widget.cols }}"
        {% endif %}
        {% if field.widget.css_class %}
            class="{{ field.widget.css_class }}"
        {% endif %}
            id="{{ field.oid }}"
            name="{{ field.name }}"
        {% if field.description %}
            placeholder="{{ _(field.description) }}"
        {% endif %}>{{ cstruct }}</textarea>
../../_images/custom_jinja2_templates.png

Переопределенный шаблон textarea.jinja2

Блог

forms.py - Форма для создания статьи
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import deform
import colander

from common import get_csrf_token, get_session


@colander.deferred
def deferred_csrf_default(node, kw):
    request = kw.get('request')
    session = get_session(request)
    csrf_token = get_csrf_token(session)
    return csrf_token


@colander.deferred
def deferred_csrf_validator(node, kw):
    def validate_csrf_token(node, value):
        request = kw.get('request')
        session = get_session(request)
        csrf_token = get_csrf_token(session)
        if value != csrf_token:
            raise colander.Invalid(node, 'Bad CSRF token')

    return validate_csrf_token


class CSRFSchema(colander.Schema):
    csrf = colander.SchemaNode(colander.String(),
                               default=deferred_csrf_default,
                               validator=deferred_csrf_validator,
                               widget=deform.widget.HiddenWidget(), )


class CreateArticle(CSRFSchema):
    title = colander.SchemaNode(colander.String())
    content = colander.SchemaNode(
        colander.String(),
        widget=deform.widget.TextAreaWidget(
            css_class="blog-form-field__textarea")
    )
common.py - Функции get_session и get_csrf_token
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def get_session(request):
    return request.environ.get('paste.session.factory', lambda: {})()


def get_csrf_token(session):
    if 'csrf' not in session:
        from uuid import uuid4
        session['csrf'] = uuid4().hex
    return session['csrf']
__init__.py - Добавляем механизм сессии в наше WSGI-приложение
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#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2015 uralbash <root@uralbash.ru>
#
# Distributed under terms of the MIT license.

"""
Simple blog
"""
from paste.auth.basic import AuthBasicHandler

import selector
from views import BlogCreate, BlogDelete, BlogIndex, BlogRead, BlogUpdate


def authfunc(environ, username, password):
    return username == 'admin' and password == '123'


def make_wsgi_app():
    # BasicAuth applications
    create = AuthBasicHandler(BlogCreate, 'www', authfunc)
    update = AuthBasicHandler(BlogUpdate, 'www', authfunc)
    delete = AuthBasicHandler(BlogDelete, 'www', authfunc)

    # URL dispatching middleware
    dispatch = selector.Selector()
    dispatch.add('/', GET=BlogIndex)
    dispatch.prefix = '/article'
    dispatch.add('/add', GET=create, POST=create)
    dispatch.add('/{id:digits}', GET=BlogRead)
    dispatch.add('/{id:digits}/edit', GET=update, POST=update)
    dispatch.add('/{id:digits}/delete', GET=delete)

    # Static files
    from paste.urlparser import StaticURLParser
    static_app = StaticURLParser("static/")

    from paste import urlmap
    mapping = urlmap.URLMap()
    mapping['/static'] = static_app

    from paste.cascade import Cascade
    app = Cascade([mapping, dispatch])

    return app

if __name__ == '__main__':
    from paste.httpserver import serve
    from paste.session import SessionMiddleware

    app = make_wsgi_app()
    app = SessionMiddleware(app)
    serve(app, host='0.0.0.0', port=8000)
views.py - Генерация форм в представлениях при помощи Deform
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import deform
from jinja2 import Environment, FileSystemLoader
from webob import Request, Response

from common import get_csrf_token, get_session
from models import ARTICLES

env = Environment(loader=FileSystemLoader('templates'))


def wsgify(view):
    def wrapped(environ, start_response):
        request = Request(environ)
        app = view(request).response()
        return app(environ, start_response)
    return wrapped


class BaseArticle(object):

    def __init__(self, request):
        self.request = request
        article_id = self.request.environ['wsgiorg.routing_args'][1]['id']
        (self.index,
         self.article) = next(((i, art) for i, art in enumerate(ARTICLES)
                               if art['id'] == int(article_id)),
                              (None, None))


class BaseArticleForm(object):

    def get_form(self):
        from forms import CreateArticle
        self.session = get_session(self.request)
        self.session['csrf'] = get_csrf_token(self.session)
        schema = CreateArticle().bind(request=self.request)
        submit = deform.Button(name='submit',
                               css_class='blog-form__button')
        self.form = deform.Form(schema, buttons=(submit,))
        return self.form


@wsgify
class BlogIndex(object):

    def __init__(self, request):
        self.page = request.GET.get('page', '1')
        from paginate import Page
        self.paged_articles = Page(
            ARTICLES,
            page=self.page,
            items_per_page=8,
        )

    def response(self):
        return Response(env.get_template('index.html')
                        .render(articles=self.paged_articles))


@wsgify
class BlogCreate(BaseArticleForm):

    def __init__(self, request):
        self.request = request

    def response(self):
        if self.request.method == 'POST':
            submitted = self.request.POST.items()
            try:
                self.get_form().validate(submitted)
            except deform.ValidationFailure as e:
                return Response(
                    env.get_template('create.html').render(form=e.render()))
            max_id = max([art['id'] for art in ARTICLES])
            ARTICLES.append(
                {'id': max_id+1,
                 'title': self.request.POST['title'],
                 'content': self.request.POST['content']
                 }
            )
            self.session = get_session(self.request).pop('csrf')
            return Response(status=302, location='/')
        return Response(env.get_template('create.html')
                        .render(form=self.get_form().render()))


@wsgify
class BlogRead(BaseArticle):

    def response(self):
        if not self.article:
            return Response(status=404)
        return Response(env.get_template('read.html')
                        .render(article=self.article))


@wsgify
class BlogUpdate(BaseArticle, BaseArticleForm):

    def response(self):
        if self.request.method == 'POST':
            submitted = self.request.POST.items()
            try:
                self.get_form().validate(submitted)
            except deform.ValidationFailure as e:
                return Response(
                    env.get_template('create.html').render(form=e.render()))
            self.article['title'] = self.request.POST['title']
            self.article['content'] = self.request.POST['content']
            self.session = get_session(self.request).pop('csrf')
            return Response(status=302, location='/')
        return Response(
            env.get_template('create.html')
            .render(form=self.get_form().render(self.article)))


@wsgify
class BlogDelete(BaseArticle):

    def response(self):
        ARTICLES.pop(self.index)
        return Response(status=302, location='/')
create.html - форма генерируется автоматически
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{% extends "base.html" %}

{% block title %}Create{% endblock %}

{% block content %}
    <div class="blog__title">
        <a href="/" class="blog__title-link">Simple Blog</a>
        <span class="blog__title-text">Edit</span>
    </div>
    <form action="" method="POST" class="blog-form">
        {{ form }}
    </form>
{% endblock %}

Теперь форма имеет валидацию, защиту от CSRF атак и генерируется автоматически при помощи Deform.

../../_images/blog_validation.png

Валидация формы

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