feincms3-forms 0.4.0

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This is an extremely flexible forms builder for the Django admin interface. It allows using django-content-editor for your form which enables:

• Build your own form in the CMS and not have to ask programmers to change anything.

• Reorder, add and remove pre-existing fields.

• Add content (text, images, anything) between form fields.

• Use regions to add additional structure to a form, e.g. to build configurable multi-step forms (wizards).

• Add your own form field plugins with all the flexibility and configurability you desire.

If you only want to integrate short and simple forms (e.g. a contact form) you’re probably better off using form_designer. The feincms3 documentation contains a guide showing how to integrate it.

High level overview

The documentation is very sparse, sorry for that.

Models

FormFieldBase

Form fields have to inherit FormFieldBase. FormFieldBase only has a name field. This field can be checked for clashes etc. The base class is used instead of duck typing in various places where the code may encounter not only form field plugins but also other django-content-editor plugins. The latter are useful e.g. to add blocks of text or other content between form fields.

The FormFieldBase model defines the basic API of form fields:

• get_fields(): Return a dictionary of form fields.

• get_initial(): Return initial values of said fields.

• get_cleaners(): Return a list of callables which receive the form instance, return the cleaned data and may raise ValidationError exceptions.

• get_loaders(): Return a list of loaders. The purpose of loaders is to load form submissions, e.g. for reporting purposes. Loaders are callables which receive the serialized form data and return a dictionary of the following shape: {"name": ..., "label": ..., "value": ...}.

FormField

The FormField offers a basic set of attributes for standard fields such as a label, a help text and whether the field should be required or not. You do not have to use this model if you want to define your own. It’s purpose is just to offer a few good defaults.

SimpleFieldBase

The SimpleFieldBase should be instantiated in your project and can be used to cheaply add support for many basic field types such as text fields, email fields, checkboxes, choice fields and more with a single backing database table and model.

The SimpleFieldBase has a corresponding SimpleFieldInline in the feincms3_forms.admin module which shows and hides fields depending on the field type. For example, it makes no sense to define placeholders for checkboxes (browsers do not support them) therefore the field is omitted in the CMS.

Renderer

The renderer functions are responsible for creating and instantiating the form class. Form class creation and instantiation happens at once.

Validation

The validation module offers utilities to validate a form when it it defined in the CMS. For example, the backend code may require that an email field always exists and always has a certain predefined name (for example email 😏). These rules are not enforced at the moment but the user is always notified and can therefore choose to head them. Or bad things may happen depending on the code you write.

Reporting

The reporting functions are mostly useful if you want to do something with submitted data.

Installation and usage

Create a module containing the models for the form builder (app.forms.models):

from content_editor.models import Region, create_plugin_base
from django.db import models
from feincms3 import plugins
from feincms3_forms import models as forms_models

class ConfiguredForm(forms_models.ConfiguredForm):
    FORMS = [
        forms_models.FormType(
            key="contact",
            label="contact form",
            regions=[Region(key="form", title="form")],

            # Base class for the dynamically created form:
            # form_class="...",

            # Validation hook for configured form (the bundled ModelAdmin
            # class calls this):
            # validate="...",

            # Processing function which you can call after submission
            # (feincms3-forms never calls this function itself, but it
            # may be a nice convention):
            process="app.forms.forms.process_contact_form",
        ),
    ]

ConfiguredFormPlugin = create_plugin_base(ConfiguredForm)

class SimpleField(forms_models.SimpleFieldBase, ConfiguredFormPlugin):
    pass

Text = SimpleField.proxy(SimpleField.Type.TEXT)
Email = SimpleField.proxy(SimpleField.Type.EMAIL)
URL = SimpleField.proxy(SimpleField.Type.URL)
Date = SimpleField.proxy(SimpleField.Type.DATE)
Integer = SimpleField.proxy(SimpleField.Type.INTEGER)
Textarea = SimpleField.proxy(SimpleField.Type.TEXTAREA)
Checkbox = SimpleField.proxy(SimpleField.Type.CHECKBOX)
Select = SimpleField.proxy(SimpleField.Type.SELECT)
Radio = SimpleField.proxy(SimpleField.Type.RADIO)
SelectMultiple = SimpleField.proxy(SimpleField.Type.SELECT_MULTIPLE)
CheckboxSelectMultiple = SimpleField.proxy(SimpleField.Type.CHECKBOX_SELECT_MULTIPLE)

class RichText(plugins.richtext.RichText, ConfiguredFormPlugin):
    pass

Add the processing function referenced above (app.forms.forms):

from django.core.mail import mail_managers
from django.http import HttpResponse

def process_contact_form(request, form, *, configured_form):
    mail_managers("Contact form", repr(form.cleaned_data))
    return HttpResponseRedirect(".")

Add the renderer and the view (app.forms.views):

from content_editor.contents import contents_for_item
from django.shortcuts import render
from feincms3.renderer import RegionRenderer, render_in_context, template_renderer
from feincms3_forms.renderer import create_form, short_prefix
from app.forms import models

renderer = RegionRenderer()
renderer.register(models.RichText, template_renderer("plugins/richtext.html"))
renderer.register(
    models.SimpleField,
    lambda plugin, context: render_in_context(
        context,
        "forms/simple-field.html",
        {"plugin": plugin, "fields": context["form"].get_form_fields(plugin)},
    ),
)

def form(request):
    context = {}
    cf = models.ConfiguredForm.objects.first()

    contents = contents_for_item(cf, plugins=renderer.plugins())

    # Add a prefix in case more than one form exists on the same page:
    form_kwargs = {"prefix": short_prefix(cf, "form")}

    if request.method == "POST":
        form_kwargs |= {"data": request.POST, "files": request.FILES}

    form = create_form(
        contents["form"],
        form_class=cf.type.form_class,
        form_kwargs=form_kwargs,
    )

    if form.is_valid():
        return cf.type.process(request, form, configured_form=cf)

    context["form"] = form
    context["form_other_fields"] = form.get_form_fields(None)
    context["form_regions"] = renderer.regions_from_contents(contents)

    return render(request, "forms/form.html", context)

The forms/simple-field.html template referenced above might look as follows:

{% for field in fields.values %}{{ field }}{% endfor %}

An example forms/form.html:

{% extends "base.html" %}

{% load feincms3 i18n %}

{% block content %}
<div class="content">
  <form class="form" method="post">
    {% csrf_token %}
    {{ form.errors }}
    {% render_region form_regions 'form' %}
    {% for field in form_other_fields.values %}{{ field }}{% endfor %}
    <button type="submit">Submit</button>
  </form>
</div>
{% endblock content %}

Finally, the form would have to be added to the admin site (app.forms.admin):

from content_editor.admin import ContentEditorInline
from django.contrib import admin
from feincms3 import plugins
from feincms3_forms.admin import ConfiguredFormAdmin, SimpleFieldInline

from app.forms import models


@admin.register(models.ConfiguredForm)
class ConfiguredFormAdmin(ConfiguredFormAdmin):
    inlines = [
        plugins.richtext.RichTextInline.create(model=models.RichText),
        SimpleFieldInline.create(
            model=models.Text,
            button='<i class="material-icons">short_text</i>',
        ),
        SimpleFieldInline.create(
            model=models.Email,
            button='<i class="material-icons">alternate_email</i>',
        ),
        SimpleFieldInline.create(
            model=models.URL,
            button='<i class="material-icons">link</i>',
        ),
        SimpleFieldInline.create(
            model=models.Date,
            button='<i class="material-icons">event</i>',
        ),
        SimpleFieldInline.create(
            model=models.Integer,
            button='<i class="material-icons">looks_one</i>',
        ),
        SimpleFieldInline.create(
            model=models.Textarea,
            button='<i class="material-icons">notes</i>',
        ),
        SimpleFieldInline.create(
            model=models.Checkbox,
            button='<i class="material-icons">check_box</i>',
        ),
        SimpleFieldInline.create(
            model=models.Select,
            button='<i class="material-icons">arrow_drop_down_circle</i>',
        ),
        SimpleFieldInline.create(
            model=models.Radio,
            button='<i class="material-icons">radio_button_checked</i>',
        ),
    ]

And last but not least, create and apply migrations. That should be basically it. We haven’t touched validating the configured form, reporting utilities or creating your own (compound) field types yet, for now you have to check the testsuite.