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Template Tag

Overview

Django template tags can be used within your HTML templates to provide ReactPy features.

Component

This template tag can be used to insert any number of ReactPy components onto your page.

Each component loaded via this template tag will receive a dedicated WebSocket connection to the server.

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{% load reactpy %}
<!DOCTYPE html>
<html>
  <body>
    {% component "example_project.my_app.components.hello_world" recipient="World" %}
  </body>
</html>
See Interface

Parameters

Name Type Description Default
dotted_path str The dotted path to the component to render. N/A
*args Any The positional arguments to provide to the component. N/A
class str | None The HTML class to apply to the top-level component div. None
key Any Force the component's root node to use a specific key value. Using key within a template tag is effectively useless. None
host str | None The host to use for the ReactPy connections. If unset, the host will be automatically configured.
Example values include: localhost:8000, example.com, example.com/subdir		 None
prerender str If "true" the component will pre-rendered, which enables SEO compatibility and reduces perceived latency. "false"
offline str The dotted path to a component that will be displayed if your root component loses connection to the server. Keep in mind, this offline component will be non-interactive (hooks won't operate). ""
**kwargs Any The keyword arguments to provide to the component. N/A

Returns

Type Description
Component A ReactPy component.
Do not use context variables for the component path

The ReactPy component finder requires that your component path is a string.

Do not use Django template/context variables for the component path. Failure to follow this warning can result in unexpected behavior, such as components that will not render.

For example, do not do the following:

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<!-- This is good -->
{% component "example_project.my_app.components.hello_world" recipient="World" %}

<!-- This is bad -->
{% component my_variable recipient="World" %}

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from django.shortcuts import render


def example_view(request):
    context_vars = {"my_variable": "example_project.my_app.components.hello_world"}
    return render(request, "my-template.html", context_vars)

Note: If you decide to not follow this warning, you will need to use the register_component function to manually register your components.

Can I use multiple components on one page?

You can add as many components to a webpage as needed by using the template tag multiple times. Retrofitting legacy sites to use ReactPy will typically involve many components on one page.

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{% load reactpy %}
<!DOCTYPE html>
<html>
    <body>
        <h1>{% component "example_project.my_app.components.my_title" %}</h1>
        <p>{% component "example_project.my_app_2.components.goodbye_world" class="bold small-font" %}</p>
        {% component "example_project.my_app_3.components.simple_button" %}
    </body>
</html>

Please note that components separated like this will not be able to interact with each other, except through database queries.

Additionally, in scenarios where you are trying to create a Single Page Application (SPA) within Django, you will only have one component within your <body> tag.

Can I use positional arguments instead of keyword arguments?

You can use any combination of *args/**kwargs in your template tag.

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{% component "example_project.my_app.components.frog_greeter" 123 "Mr. Froggles" species="Grey Treefrog" %}

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from reactpy import component


@component
def frog_greeter(number, name, species=""):
    return f"Hello #{number}, {name} the {species}!"
Can I render components on a different server (distributed computing)?

Yes! This is most commonly done through settings.py:REACTPY_HOSTS. However, you can use the host keyword to render components on a specific ASGI server.

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...
{% component "example_project.my_app.components.do_something" host="127.0.0.1:8001" %}
...

This configuration most commonly involves you deploying multiple instances of your project. But, you can also create dedicated Django project(s) that only render specific ReactPy components if you wish.

Here's a couple of things to keep in mind:

  1. If your host address are completely separate ( origin1.com != origin2.com ) you will need to configure CORS headers on your main application during deployment.
  2. You will not need to register ReactPy WebSocket or HTTP paths on any applications that do not perform any component rendering.
  3. Your component will only be able to access your template tag's *args/**kwargs if your applications share a common database.
How do I pre-render components for SEO compatibility?

This is most commonly done through settings.py:REACTPY_PRERENDER. However, you can use the prerender keyword to pre-render a specific component.

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{% component "example_project.my_app.components.do_something" prerender="true" %}
...
How do I show something when the client disconnects?

You can use the offline keyword to display a specific component when the client disconnects from the server.

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{% component "example_project.my_app.components.do_something" offline="example_project.my_app.components.offline" %}
...

Note: The offline component will be non-interactive (hooks won't operate).

Last update: February 21, 2024
Authors: Mark Bakhit