django-markdownfield

django-markdownfield

A simple custom field for Django that can safely render Markdown and store it in the database.

Your text is stored in a MarkdownField. When the model is saved, django-markdownfield will parse the Markdown, render it, sanitise it with bleach, and store the result in a RenderedMarkdownField for display to end users.

django-markdownfield also bundles a minified version of the EasyMDE editor (v2.14.0) in admin views to make working with Markdown easier.

Installation

django-markdownfield can be installed from PyPi:

# Install directly or add to your requirements.txt
pip install django-markdownfield

After installation, you need to add markdownfield to INSTALLED_APPS of your Django project's settings.

INSTALLED_APPS = [
    "markdownfield",
    ...
    "django.contrib.staticfiles",
]

Usage

Implementing django-markdownfield is simple. See the below example.

from django.db import models

from markdownfield.models import MarkdownField, RenderedMarkdownField
from markdownfield.validators import VALIDATOR_STANDARD

class Page(models.Model):
    text = MarkdownField(rendered_field='text_rendered', validator=VALIDATOR_STANDARD)
    text_rendered = RenderedMarkdownField()

Please also set SITE_URL in your Django configuration - it will be needed for detecting external links.

SITE_URL = "https://example.com"

To disable the EasyMDE editor, see the amended line below.

text = MarkdownField(rendered_field='text_rendered', use_editor=False, use_admin_editor=True)

Use in templates

To use the rendered markdown in templates, just use the RenderedMarkdownField() you created on your model, like below. This field should be marked as safe with the safe filter to ensure it displays correctly.

{{ post.text_rendered | safe }}

Validators

django-markdownfield comes with a number of validators, which are used to process and clean the output of the markdown engine

VALIDATOR_STANDARD

from markdownfield.validators import VALIDATOR_STANDARD

This validator strips any tags that are not used by standard Markdown. It also automatically links any URLs in the output, adding class="external", rel="nofollow noopener noreferrer", and target="_blank" to any URLs which it determines to be external.

VALIDATOR_CLASSY

from markdownfield.validators import VALIDATOR_CLASSY

This validator does much the same as VALIDATOR_STANDARD, but it allows you to set the class on links and images. This is useful to create buttons and other enhanced links.

VALIDATOR_NULL

from markdownfield.validators import VALIDATOR_NULL

This validator does not call bleach to sanitize the output at all. This is not safe for user input. It allows arbitrary (unsafe) HTML in your markdown input.

Creating Custom Validators

To create a custom validator, just create an instance of the markdownfield.validators.Validator dataclass. An example of this is shown below.

from markdownfield.validators import Validator

# allows only bold and italic text
VALIDATOR_COMMENTS = Validator(
    allowed_tags=["b", "i", "strong", "em"],
    allowed_attrs={},
    linkify=False
)

You can also find a standard set of markdown-safe tags and attrs in markdownfield.validators, and extend that.

from markdownfield.validators import Validator, MARKDOWN_TAGS, MARKDOWN_ATTRS

# allows all standard markdown features,
# but also allows the class to be set on images and links
VALIDATOR_CLASSY = Validator(
    allowed_tags=MARKDOWN_TAGS,
    allowed_attrs={
        **MARKDOWN_ATTRS,
        'img': ['src', 'alt', 'title', 'class'],
        'a': ['href', 'alt', 'title', 'name', 'class']
    }
)

Migrations

If you need to migrate from TextField or CharField to the MarkdownField you need to migrate the stored text also in the rendered_text field. Update your auto-created migration fiele and add the method below. Use a method to save() every instance of your model once after the migrations, so the text will be copied into the text_rendered field correctly.

from django.db import migrations
import markdownfield.models


def save_text_rendered(apps, schema_editor):
    ExampleModel = apps.get_model('yourapp', 'ExampleModel')
    for examplemodel in ExampleModel.objects.all():
        examplemodel.save()


class Migration(migrations.Migration):

    dependencies = [
        ('yourapp', '000X_migrate_to_markdownfield'),
    ]

    operations = [
        migrations.AddField(
            model_name='yourapp',
            name='text_rendered',
            field=markdownfield.models.RenderedMarkdownField(default=''),
            preserve_default=False,
        ),
        migrations.AlterField(
            model_name='ExampleModel',
            name='text',
            field=markdownfield.models.MarkdownField(rendered_field='text_rendered'),
        ),
        migrations.RunPython(save_text_rendered),
    ]

License

This software is released under the MIT license.

Copyright (c) 2019-2021 Luke Rogers

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.