django-components/README.md

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# <img src="https://raw.githubusercontent.com/django-components/django-components/master/logo/logo-black-on-white.svg" alt="django-components" style="max-width: 100%; background: white; color: black;">
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### <table><td>[Read the full documentation](https://django-components.github.io/django-components/latest/)</td></table>
`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.
## Quickstart
A component in django-components can be as simple as a Django template and Python code to declare the component:
```django
{# components/calendar/calendar.html #}
<div class="calendar">
Today's date is <span>{{ date }}</span>
</div>
```
```py
# 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:
```django
{# components/calendar/calendar.html #}
<div class="calendar">
Today's date is <span>{{ date }}</span>
</div>
```
```css
/* components/calendar/calendar.css */
.calendar {
width: 200px;
background: pink;
}
```
```js
/* components/calendar/calendar.js */
document.querySelector(".calendar").onclick = () => {
alert("Clicked calendar!");
};
```
```py
# 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:
```django
{% component "calendar" date="2024-11-06" %}{% endcomponent %}
```
And this is what gets rendered:
```html
<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](https://github.com/django-components/django-components/tree/master/sampleproject))
## 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.
```python
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 %}`](https://django-components.github.io/django-components/latest/reference/template_tags#component) tag.
- Compose them with [`{% slot %}`](https://django-components.github.io/django-components/latest/reference/template_tags#slot)
and [`{% fill %}`](https://django-components.github.io/django-components/latest/reference/template_tags#fill) tags.
- Vue-like slot system, including [scoped slots](https://django-components.github.io/django-components/latest/concepts/fundamentals/slots/#slot-data).
```django
{% 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:
<!-- TODO - Document literal lists and dictionaries -->
- Literal lists and dictionaries in the template
- [Self-closing tags](https://django-components.github.io/django-components/latest/concepts/fundamentals/template_tag_syntax#self-closing-tags) `{% mytag / %}`
- [Multi-line template tags](https://django-components.github.io/django-components/latest/concepts/fundamentals/template_tag_syntax#multiline-tags)
- [Spread operator](https://django-components.github.io/django-components/latest/concepts/fundamentals/template_tag_syntax#spread-operator) `...` to dynamically pass args or kwargs into the template tag
- [Template tags inside literal strings](https://django-components.github.io/django-components/latest/concepts/fundamentals/template_tag_syntax#template-tags-inside-literal-strings) like `"{{ first_name }} {{ last_name }}"`
- [Pass dictonaries by their key-value pairs](https://django-components.github.io/django-components/latest/concepts/fundamentals/template_tag_syntax#pass-dictonary-by-its-key-value-pairs) `attr:key=val`
```django
{% component "table"
...default_attrs
title="Friend list for {{ user.name }}"
headers=["Name", "Age", "Email"]
data=[
{
"name": "John"|upper,
"age": 30|add:1,
"email": "john@example.com",
"hobbies": ["reading"],
},
{
"name": "Jane"|upper,
"age": 25|add:1,
"email": "jane@example.com",
"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()`](https://django-components.github.io/django-components/latest/reference/api/#django_components.template_tag)
or [`BaseNode`](https://django-components.github.io/django-components/latest/reference/api/#django_components.BaseNode).
Read more on [Custom template tags](https://django-components.github.io/django-components/latest/concepts/advanced/template_tags/).
### Full programmatic access
When you render a component, you can access everything about the component:
- Component input: [args, kwargs, slots and context](https://django-components.github.io/django-components/latest/concepts/fundamentals/render_api/#component-inputs)
- Component's template, CSS and JS
- Django's [context processors](https://django-components.github.io/django-components/latest/concepts/fundamentals/render_api/#request-and-context-processors)
- Unique [render ID](https://django-components.github.io/django-components/latest/concepts/fundamentals/render_api/#component-id)
```python
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 %}`](https://django-components.github.io/django-components/latest/concepts/fundamentals/html_attributes/) 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
```django
<div
{% html_attrs
attrs
defaults:class="default-class"
class="extra-class"
%}
>
```
[`{% html_attrs %}`](https://django-components.github.io/django-components/latest/concepts/fundamentals/html_attributes/) offers a Vue-like granular control for
[`class`](https://django-components.github.io/django-components/latest/concepts/fundamentals/html_attributes/#merging-class-attributes)
and [`style`](https://django-components.github.io/django-components/latest/concepts/fundamentals/html_attributes/#merging-style-attributes)
HTML attributes,
where you can use a dictionary to manage each class name or style property separately.
```django
{% html_attrs
class="foo bar"
class={
"baz": True,
"foo": False,
}
class="extra"
%}
```
```django
{% 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](https://django-components.github.io/django-components/latest/concepts/fundamentals/html_attributes/).
### HTML fragment support
`django-components` makes integration with HTMX, AlpineJS or jQuery easy by allowing components to be rendered as [HTML fragments](https://django-components.github.io/django-components/latest/concepts/advanced/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](https://django-components.github.io/django-components/latest/concepts/fundamentals/component_views_urls/) with `get()`, `post()`, `put()`, `patch()`, `delete()` methods
- Automatically create an endpoint for a component with [`Component.View.public`](https://django-components.github.io/django-components/latest/concepts/fundamentals/component_views_urls/#register-urls-automatically)
```py
# components/calendar/calendar.py
@register("calendar")
class Calendar(Component):
template_file = "calendar.html"
class View:
# Register Component with `urlpatterns`
public = True
# Define handlers
def get(self, request, *args, **kwargs):
page = request.GET.get("page", 1)
return self.component.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](https://react.dev/learn/passing-data-deeply-with-context) or Vue's [provide / inject](https://vuejs.org/guide/components/provide-inject):
- Use the [`{% provide %}`](https://django-components.github.io/django-components/latest/reference/template_tags/#provide) tag to provide data to the component tree
- Use the [`Component.inject()`](https://django-components.github.io/django-components/latest/reference/api/#django_components.Component.inject) method to inject data into the component
Read more about [Provide / Inject](https://django-components.github.io/django-components/latest/concepts/advanced/provide_inject).
```django
<body>
{% provide "theme" variant="light" %}
{% component "header" / %}
{% endprovide %}
</body>
```
```djc_py
@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](https://django-components.github.io/django-components/latest/concepts/fundamentals/typing_and_validation/).
To opt-in to input validation, define types for component's args, kwargs, slots, and more:
```py
from typing import NamedTuple, Optional
from django.template import Context
from django_components import Component, Slot, SlotInput
class Button(Component):
class Args(NamedTuple):
size: int
text: str
class Kwargs(NamedTuple):
variable: str
another: int
maybe_var: Optional[int] = None # May be omitted
class Slots(NamedTuple):
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()`](https://django-components.github.io/django-components/latest/reference/api/#django_components.Component.render) or
[`Button.render_to_response()`](https://django-components.github.io/django-components/latest/reference/api/#django_components.Component.render_to_response),
wrap the inputs in their respective `Args`, `Kwargs`, and `Slots` classes:
```py
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](https://django-components.github.io/django-components/latest/concepts/advanced/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](https://github.com/django-components/django-components/blob/master/src/django_components/extensions/cache.py)
- [Django View integration](https://github.com/django-components/django-components/blob/master/src/django_components/extensions/view.py)
- [Component defaults](https://github.com/django-components/django-components/blob/master/src/django_components/extensions/defaults.py)
- [Pydantic integration (input validation)](https://github.com/django-components/djc-ext-pydantic)
Some of the planned extensions include:
- AlpineJS integration
- Storybook integration
- Component-level benchmarking with asv
### Caching
- [Components can be cached](https://django-components.github.io/django-components/latest/concepts/advanced/component_caching/) 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.
```py
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`](https://django-components.github.io/django-components/latest/concepts/advanced/testing/) 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`](https://docs.djangoproject.com/en/5.2/topics/testing/tools/#django.test.override_settings).
```python
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.
<div style="text-align: center;">
<img src="https://github.com/django-components/django-components/blob/master/docs/images/debug-highlight-slots.png?raw=true" alt="Component debugging visualization showing slot highlighting" width="500" style="margin: auto;">
</div>
### 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):
```django
{% component "calendar" date="2024-11-06" %}
{% endcomponent %}
{% calendar date="2024-11-06" %}
{% endcalendar %}
```
## Documentation
[Read the full documentation here](https://django-components.github.io/django-components/latest/).
... or jump right into the code, [check out the example project](https://github.com/django-components/django-components/tree/master/sampleproject).
## 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](https://django-components.github.io/django-components/latest/benchmarks/) for more information.
## Release notes
Read the [Release Notes](https://github.com/django-components/django-components/tree/master/CHANGELOG.md)
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](https://github.com/iwanalabs/django-htmx-components): A set of components for use with [htmx](https://htmx.org/).
- [djc-heroicons](https://pypi.org/project/djc-heroicons/): A component that renders icons from [Heroicons.com](https://heroicons.com/).
## Contributing and development
Get involved or sponsor this project - [See here](https://django-components.github.io/django-components/dev/overview/contributing/)
Running django-components locally for development - [See here](https://django-components.github.io/django-components/dev/overview/development/)