Django Block Include 🧱

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An extension of Django's include tag to pass sections of markup to the included template.

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Getting started

Installation

First, install with pip:

$ python -m pip install django-blockinclude

Then, add to your installed apps:

# settings.py

INSTALLED_APPS = [..., "blockinclude", ...]

Basic usage

This is an extension of Django's default include tag and supports all of its features. Additionally, it allows you to pass a section of rendered markup to the included template.

Let's presume we have the following template my-box.html:

{# my-box.html #}

<div class="p-12 border-2 border-black">
    {{ content }}
</div>

Now we want to fill the box with some content. To do that, you use the blockinclude tag and pass it the path to my-box.html, just like you would with the default include tag. Unlike the include tag, blockinclude is a block tag and comes with the endblockinclude end tag. This allows you to pass a section of content from the parent template (my-page.html) to the included template (my-box.html), like so:

{# my-page.html #}

{% load blockinclude %}

{% blockinclude "my-box.html" %}
    The body content of the box.
{% endblockinclude %}

In the above example, the my-box.html template will have a content variable with the value "The body content of the box." in the context. Thus, the result of rendering my-page.html will be:

<div class="p-12 border-2 border-black">
    The body content of the box.
</div>

Of course, passing a single line of text is not very interesting. That would also be possible with a keyword argument to the default include tag.

But, blockinclude is not limited to simple strings. You can wrap any HTML markup or even template logic between the opening and closing tags.

The template logic is evaluated in the context of the parent (my-page.html) and then passed to the included template (my-box.html) as the content variable.

Let's change my-page.html to the following:

{# my-page.html #}

{% load blockinclude %}

{% blockinclude "my-box.html" %}
    <ul>
        {% for item in items %}
            <li>{{ item }}</li>
        {% endfor %}
    </ul>
{% endblockinclude %}

Now, if my-page.html is rendered with items = ["Apple", "Banana"] in the context, then the rendered result will be:

<div class="p-12 border-2 border-black">
    <ul>
        <li>Apple</li>
        <li>Banana</li>
    </ul>
</div>

Passing multiple sections with slot

If you wish to pass more than one section of markup with different names to the included template, you can add slot tags inside the blockinclude.

Let's assume we have the following my-slotted-box.html template. This template does not only use the content variable, but also the header variable.

{# my-slotted-box.html #}

<div class="p-12 border-2 border-black">
    {% if header %}
        <header>
            {{ header }}
        </header>
    {% endif %}

    <div>
        {{ content }}
    </div>
</div>

Now, if we want to fill both of these variables with multiple lines of markup, we can include the template like so:

{# my-page.html #}

{% load blockinclude %}

{% blockinclude "my-slotted-box.html" %}
    {% slot "header" %}
        Header of the box
    {% endslot %}

    The body content of the box.
{% endblockinclude %}

The result of rendering my-page.html will be:

<div class="p-12 border-2 border-black">
    <header>
        Header of the box
    </header>

    <div>
        The body content of the box.
    </div>
</div>

You can use as many slot tags inside a blockinclude as you like.

{# my-slotted-box.html #}

<div class="p-12 border-2 border-black">
    {% if header %}
        <header>
            {{ header }}
        </header>
    {% endif %}

    <div>
        {{ content }}
    </div>

    {% if footer %}
        <footer>
            {{ footer }}
        </footer>
    {% endif %}
</div>

{# my-page.html #}

{% load blockinclude %}

{% blockinclude "my-slotted-box.html" %}
    {% slot "header" %}
        Header of the box
    {% endslot %}

    The body content of the box.

    {% slot "footer" %}
        Footer of the box
    {% endslot %}
{% endblockinclude %}

Just like the blockinclude itself, the content of the slot tag can be markup or even template logic. Template logic in a slot is executed with the context of the parent template, just like logic inside the blockinclude.

Additional notes about tag usage

blockinclude

• blockinclude supports all features of the include tag.
• By default, the included template receives the whole parent context.
• You can pass extra context via keyword arguments, {% blockinclude ... with extra="My value" %}.
• You can prevent passing of the parent context and limit the passed context to only the keyword arguments and the tag content, by appending only to the opening tag, {% blockinclude ... with extra="My value" only %}.
• If you use content=... as a keyword argument, this will be overridden by the content of blockinclude tag.

slot

• The name of the slot needs to be quoted. {% slot "header" %} is ok, while {% slot header %} is not.
• You can not use "content" as a slot name, because that name is reserved for the content of the blockinclude. {% slot "content" %} is not ok.
• The definition order of the slot tags in the parent template does not matter.
• If you reuse the same slot name, then the latter definition overrides a prior one (in source order).
• All content in the blockinclude outside of slot tags is merged into the content variable.
• The slot has to be a direct child of the blockinclude and can not be nested in other template block tags (if or for) inside the blockinclude. The blockinclude itself can be nested inside of other template tag blocks just fine.
• If you use the same name as a keyword argument and as a slot name, then the slot content overrides the value of the keyword argument.
• When you use only on the blockinclude, the slot contents are still passed.

About Django Block Include

Supported versions

• Python >= 3.10
• Django >= 4.2

Contributing

Install

To make changes to this project, first clone this repository:

$ git clone https://github.com/tbrlpld/django-blockinclude.git
$ cd django-blockinclude

With your preferred virtualenv activated, install the development dependencies:

Using pip

$ python -m pip install --upgrade pip>=21.3
$ python -m pip install -e '.[dev]' -U

Using flit

$ python -m pip install flit
$ flit install

pre-commit

Note that this project uses pre-commit. It is included in the project testing requirements. To set up locally:

# initialize pre-commit
$ pre-commit install

# Optional, run all checks once for this, then the checks will run only on the changed files
$ git ls-files --others --cached --exclude-standard | xargs pre-commit run --files

How to run tests

Now you can run all tests like so:

$ tox

Or, you can run them for a specific environment:

$ tox -e python3.13-django5.2

Or, run only a specific test:

$ tox -e python3.13-django5.2 blockinclude.tests.test_file.TestClass.test_method

To run the test app interactively, use:

$ tox -e interactive

You can now visit http://localhost:8020/.

Testing with coverage

tox is configured to run tests with coverage. The coverage report is combined for all environments. This is done by using the --append flag when running coverage in tox. This means it will also include previous results.

You can see the coverage report by running:

$ coverage report

To get a clean report, you can run coverage erase before running tox.

Running tests without tox

If you want to run tests without tox, you can use the testmanage.py script. This script is a wrapper around Django's manage.py and will run tests with the correct settings.

To make this work, you need to have the testing dependencies installed.

$ python -m pip install -e '.[testing]' -U

Then you can run tests with:

$ ./testmanage.py test

To run tests with coverage, use:

$ coverage run ./testmanage.py test

Running the example app

Sometimes you may want to confirm the rendering in the browser with your own eyes instead of test assertions.

You can run the example app with:

$ ./testmanage.py runserver 8000

Now you can visit the app in the browser at http://localhost:8000/.

Python version management

Tox will attempt to find installed Python versions on your machine.

If you use pyenv to manage multiple versions, you can tell tox to use those versions. To ensure that tox will find Python versions installed with pyenv you need virtualenv-pyenv (note: this is not pyenv-virtualenv). virtualenv-pyenv is part of the development dependencies (just like tox itself). Additionally, you have to set the environment variable VIRTUALENV_DISCOVERY=pyenv.

Publishing

This project uses the Trusted Publisher model for PyPI releases. This means that publishing is done through GitHub Actions when a new release is created on GitHub.

Before publishing a new release, make sure to update

• the changelog in CHANGELOG.md, and
• the version number in blockinclude/__init__.py.

To update these files, you will have to create a release-prep branch and PR. Once that PR is merged into main you are ready to create the release.

To manually test publishing the package, you can use flit. Be sure to configure the testpypi repository in your ~/.pypirc file according to the Flit documentation. If your PyPI account is using 2FA, you'll need to create a PyPI API token and use that as your password and __token__ as the username.

When you're ready to test the publishing, run:

$ flit build
$ flit publish --repository testpypi

Once you are ready to actually release the new version, you need to first create a git tag. The tag name should be the version number prefixed with a v (e.g. v0.1.0).

To create the tag on the command line:

$ git switch main
$ git pull
$ git tag v0.1.1
$ git push --tags

Once the tag is on GitHub, you can visit the Tags screen. There you click "create release" in the overflow menu of the tag that you have just created. On the release screen you can click "generate release notes", which will compile release notes based on the merged PRs since the last release. Edit the generated release notes to make them a bit more concise (e.g. remove small fix-up PRs or group related changes).

Once the release notes are ready, click "publish release". This will trigger the release workflow, which you can observe on the "Actions" tab. When the workflow completes, check the new release on PyPI.