django-components 0.145.0

A way to create simple reusable template components in Django.

Read the full documentation

See Roadmap for v1

django-components is a modular and extensible UI framework for Django.

It combines Django's templating system with the modularity seen in modern frontend frameworks like Vue or React.

With django-components you can support Django projects small and large without leaving the Django ecosystem.

Sponsors

Quickstart

A component in django-components can be as simple as a Django template and Python code to declare the component:

{# components/calendar/calendar.html #}
<div class="calendar">
  Today's date is <span>{{ date }}</span>
</div>

# components/calendar/calendar.py
from django_components import Component, register

@register("calendar")
class Calendar(Component):
    template_file = "calendar.html"

Or a combination of Django template, Python, CSS, and Javascript:

{# components/calendar/calendar.html #}
<div class="calendar">
  Today's date is <span>{{ date }}</span>
</div>

/* components/calendar/calendar.css */
.calendar {
  width: 200px;
  background: pink;
}

/* components/calendar/calendar.js */
document.querySelector(".calendar").onclick = () => {
  alert("Clicked calendar!");
};

# components/calendar/calendar.py
from django_components import Component, register

@register("calendar")
class Calendar(Component):
    template_file = "calendar.html"
    js_file = "calendar.js"
    css_file = "calendar.css"

    def get_template_data(self, args, kwargs, slots, context):
        return {"date": kwargs["date"]}

Use the component like this:

{% component "calendar" date="2024-11-06" %}{% endcomponent %}

And this is what gets rendered:

<div class="calendar-component">
  Today's date is <span>2024-11-06</span>
</div>

Read on to learn about all the exciting details and configuration possibilities!

(If you instead prefer to jump right into the code, check out the example project)

Features

Modern and modular UI

• Create self-contained, reusable UI elements.
• Each component can include its own HTML, CSS, and JS, or additional third-party JS and CSS.
• HTML, CSS, and JS can be defined on the component class, or loaded from files.

from django_components import Component

@register("calendar")
class Calendar(Component):
    template = """
        <div class="calendar">
            Today's date is
            <span>{{ date }}</span>
        </div>
    """

    css = """
        .calendar {
            width: 200px;
            background: pink;
        }
    """

    js = """
        document.querySelector(".calendar")
            .addEventListener("click", () => {
                alert("Clicked calendar!");
            });
    """

    # Additional JS and CSS
    class Media:
        js = ["https://cdn.jsdelivr.net/npm/htmx.org@2/dist/htmx.min.js"]
        css = ["bootstrap/dist/css/bootstrap.min.css"]

    # Variables available in the template
    def get_template_data(self, args, kwargs, slots, context):
        return {
            "date": kwargs["date"]
        }

Composition with slots

• Render components inside templates with {% component %} tag.
• Compose them with {% slot %} and {% fill %} tags.
• Vue-like slot system, including scoped slots.

{% component "Layout"
    bookmarks=bookmarks
    breadcrumbs=breadcrumbs
%}
    {% fill "header" %}
        <div class="flex justify-between gap-x-12">
            <div class="prose">
                <h3>{{ project.name }}</h3>
            </div>
            <div class="font-semibold text-gray-500">
                {{ project.start_date }} - {{ project.end_date }}
            </div>
        </div>
    {% endfill %}

    {# Access data passed to `{% slot %}` with `data` #}
    {% fill "tabs" data="tabs_data" %}
        {% component "TabItem" header="Project Info" %}
            {% component "ProjectInfo"
                project=project
                project_tags=project_tags
                attrs:class="py-5"
                attrs:width=tabs_data.width
            / %}
        {% endcomponent %}
    {% endfill %}
{% endcomponent %}

Extended template tags

django-components is designed for flexibility, making working with templates a breeze.

It extends Django's template tags syntax with:

• Literal lists and dictionaries in the template
• Self-closing tags {% mytag / %}
• Multi-line template tags
• Spread operator ... to dynamically pass args or kwargs into the template tag
• Template tags inside literal strings like "{{ first_name }} {{ last_name }}"
• Pass dictonaries by their key-value pairs attr:key=val

{% component "table"
    ...default_attrs
    title="Friend list for {{ user.name }}"
    headers=["Name", "Age", "Email"]
    data=[
        {
            "name": "John"|upper,
            "age": 30|add:1,
            "email": "[e-mail]",
            "hobbies": ["reading"],
        },
        {
            "name": "Jane"|upper,
            "age": 25|add:1,
            "email": "[e-mail]",
            "hobbies": ["reading", "coding"],
        },
    ],
    attrs:class="py-4 ma-2 border-2 border-gray-300 rounded-md"
/ %}

You too can define template tags with these features by using @template_tag() or BaseNode.

Read more on Custom template tags.

Full programmatic access

When you render a component, you can access everything about the component:

• Component input: args, kwargs, slots and context
• Component's template, CSS and JS
• Django's context processors
• Unique render ID

class Table(Component):
    js_file = "table.js"
    css_file = "table.css"

    template = """
        <div class="table">
            <span>{{ variable }}</span>
        </div>
    """

    def get_template_data(self, args, kwargs, slots, context):
        # Access component's ID
        assert self.id == "djc1A2b3c"

        # Access component's inputs and slots
        assert self.args == [123, "str"]
        assert self.kwargs == {"variable": "test", "another": 1}
        footer_slot = self.slots["footer"]
        some_var = self.context["some_var"]

        # Access the request object and Django's context processors, if available
        assert self.request.GET == {"query": "something"}
        assert self.context_processors_data['user'].username == "admin"

        return {
            "variable": kwargs["variable"],
        }

# Access component's HTML / JS / CSS
Table.template
Table.js
Table.css

# Render the component
rendered = Table.render(
    kwargs={"variable": "test", "another": 1},
    args=(123, "str"),
    slots={"footer": "MY_FOOTER"},
)

Granular HTML attributes

Use the {% html_attrs %} template tag to render HTML attributes.

It supports:

• Defining attributes as whole dictionaries or keyword arguments
• Merging attributes from multiple sources
• Boolean attributes
• Appending attributes
• Removing attributes
• Defining default attributes

<div
    {% html_attrs
        attrs
        defaults:class="default-class"
        class="extra-class"
    %}
>

{% html_attrs %} offers a Vue-like granular control for class and style HTML attributes, where you can use a dictionary to manage each class name or style property separately.

{% html_attrs
    class="foo bar"
    class={
        "baz": True,
        "foo": False,
    }
    class="extra"
%}

{% html_attrs
    style="text-align: center; background-color: blue;"
    style={
        "background-color": "green",
        "color": None,
        "width": False,
    }
    style="position: absolute; height: 12px;"
%}

Read more about HTML attributes.

HTML fragment support

django-components makes integration with HTMX, AlpineJS or jQuery easy by allowing components to be rendered as HTML fragments:

• Components's JS and CSS files are loaded automatically when the fragment is inserted into the DOM.

• Components can be exposed as Django Views with get(), post(), put(), patch(), delete() methods

• Automatically create an endpoint for a component with Component.View.public

# components/calendar/calendar.py
@register("calendar")
class Calendar(Component):
    template_file = "calendar.html"

    class View:
        # Define handlers
        def get(self, request, *args, **kwargs):
            page = request.GET.get("page", 1)
            return Calendar.render_to_response(
                request=request,
                kwargs={
                    "page": page,
                },
            )

    def get_template_data(self, args, kwargs, slots, context):
        return {
            "page": kwargs["page"],
        }

# Get auto-generated URL for the component
url = get_component_url(Calendar)

# Or define explicit URL in urls.py
path("calendar/", Calendar.as_view())

Provide / Inject

django-components supports the provide / inject pattern, similarly to React's Context Providers or Vue's provide / inject:

• Use the {% provide %} tag to provide data to the component tree
• Use the Component.inject() method to inject data into the component

Read more about Provide / Inject.

<body>
    {% provide "theme" variant="light" %}
        {% component "header" / %}
    {% endprovide %}
</body>

@register("header")
class Header(Component):
    template = "..."

    def get_template_data(self, args, kwargs, slots, context):
        theme = self.inject("theme").variant
        return {
            "theme": theme,
        }

Input validation and static type hints

Avoid needless errors with type hints and runtime input validation.

To opt-in to input validation, define types for component's args, kwargs, slots, and more:

from typing import Optional
from django.template import Context
from django_components import Component, Slot, SlotInput

class Button(Component):
    class Args:
        size: int
        text: str

    class Kwargs:
        variable: str
        another: int
        maybe_var: Optional[int] = None  # May be omitted

    class Slots:
        my_slot: Optional[SlotInput] = None
        another_slot: SlotInput

    def get_template_data(self, args: Args, kwargs: Kwargs, slots: Slots, context: Context):
        args.size  # int
        kwargs.variable  # str
        slots.my_slot  # Slot[MySlotData]

To have type hints when calling Button.render() or Button.render_to_response(), wrap the inputs in their respective Args, Kwargs, and Slots classes:

Button.render(
    # Error: First arg must be `int`, got `float`
    args=Button.Args(
        size=1.25,
        text="abc",
    ),
    # Error: Key "another" is missing
    kwargs=Button.Kwargs(
        variable="text",
    ),
)

Extensions

Django-components functionality can be extended with Extensions. Extensions allow for powerful customization and integrations. They can:

• Tap into lifecycle events, such as when a component is created, deleted, or registered
• Add new attributes and methods to the components
• Add custom CLI commands
• Add custom URLs

Some of the extensions include:

• Component caching
• Django View integration
• Component defaults
• Pydantic integration (input validation)

Some of the planned extensions include:

• AlpineJS integration
• Storybook integration
• Component-level benchmarking with asv

Caching

• Components can be cached using Django's cache framework.
• Caching rules can be configured on a per-component basis.
• Components are cached based on their input. Or you can write custom caching logic.

from django_components import Component

class MyComponent(Component):
    class Cache:
        enabled = True
        ttl = 60 * 60 * 24  # 1 day

        def hash(self, *args, **kwargs):
            return hash(f"{json.dumps(args)}:{json.dumps(kwargs)}")

Simple testing

• Write tests for components with @djc_test decorator.
• The decorator manages global state, ensuring that tests don't leak.
• If using pytest, the decorator allows you to parametrize Django or Components settings.
• The decorator also serves as a stand-in for Django's @override_settings.

from django_components.testing import djc_test

from components.my_table import MyTable

@djc_test
def test_my_table():
    rendered = MyTable.render(
        kwargs={
            "title": "My table",
        },
    )
    assert rendered == "<table>My table</table>"

Debugging features

• Visual component inspection: Highlight components and slots directly in your browser.
• Detailed tracing logs to supply AI-agents with context: The logs include component and slot names and IDs, and their position in the tree.

Sharing components

• Install and use third-party components from PyPI

• Or publish your own "component registry"

• Highly customizable - Choose how the components are called in the template (and more):

  {% component "calendar" date="2024-11-06" %}
  {% endcomponent %}
  
  {% calendar date="2024-11-06" %}
  {% endcalendar %}
  

Documentation

Read the full documentation here.

... or jump right into the code, check out the example project.

Performance

Our aim is to be at least as fast as Django templates.

As of 0.130, django-components is ~4x slower than Django templates.

	Render time
django	68.9±0.6ms
django-components	259±4ms

See the full performance breakdown for more information.

Release notes

Read the Release Notes to see the latest features and fixes.

Community examples

One of our goals with django-components is to make it easy to share components between projects. If you have a set of components that you think would be useful to others, please open a pull request to add them to the list below.

• django-htmx-components: A set of components for use with htmx.

• djc-heroicons: A component that renders icons from Heroicons.com.

Contributing and development

Get involved or sponsor this project - See here

Running django-components locally for development - See here