Server-side rendering of React components with data from your Python system
from react.render import render_component
rendered = render_component(
'/path/to/component.jsx',
{
'foo': 'bar',
'woz': [1,2,3],
}
)
print(rendered)For client-side integrations, refer to the docs.
- Installation
- Basic usage
- Using React on the front-end
- render_component
- Render server
- Settings
- Frequently Asked Questions
- Running the tests
pip install reactpython-react provides an interface to a render server which is capable of rendering React components with data from your python process.
Render requests should provide a path to a JS file that exports a React component. If you want to pass
data to the component, you can optionally provide a second argument that will be used as the component's
props property.
from react.render import render_component
rendered = render_component('path/to/component.jsx', {'foo': 'bar'})
print(rendered)The object returned has three properties:
markup- the rendered markupprops- the JSON-serialized propsdata- the data returned by the render server
If the object is coerced to a string, it will emit the value of the markup attribute.
Render servers are typically Node.js processes which sit alongside the python process and respond to network requests.
To add a render server to your project, you can refer to the basic rendering example for a simple server that will cover most cases. The key files for the render server are:
- render_server.js - the server's source code
- package.json - the server's dependencies, installable with npm
There are a number of ways in which you can integrate React into the frontend of a Python system. The typical setup involves a build tool and a python package that can integrate it.
The two most popular build tools are:
- Webpack - compiles your files into browser-executable code and provides a variety of tools and processes which can simplify complicated workflows.
- Browserify - has a lot of cross-over with webpack. Is argurably the easiest of the two to use, but it tends to lag behind webpack in functionality.
For React projects, you'll find that webpack is the usual recommendation. Webpack's hot module replacement, code-splitting, and a wealth of loaders are the features typically cited as being irreplaceable. react-hot-loader is a particularly useful tool, as it allows changes to your components to be streamed live into your browser.
If you want to integrate webpack's output into your python system, you can either hard-code the paths or you can use a manifest plugin that provides a way for your python system to introspect the compiler's state.
The most popular manifest tool is owais/django-webpack-loader. Owais has provided a great set of docs and examples, so it's your best bet for integrating webpack into your project.
If you aren't running a Django system, or you need portable manifests that can be decoupled and deployed, markfinger/python-webpack-manifest might suit your needs.
There's also markfinger/python-webpack, but it's a bit more heavy handed, abstract, and is only of use if you need a really tight coupling between your python and javascript worlds.
Renders a component to its initial HTML. You can use this method to generate HTML on the server and send the markup down on the initial request for faster page loads and to allow search engines to crawl your pages for SEO purposes.
from react.render import render_component
render_component(
# A path to a file which exports your React component
path='...',
# An optional dictionary of data that will be passed to the renderer
# and can be reused on the client-side.
props={
'foo': 'bar'
},
# An optional boolean indicating that React's `renderToStaticMarkup` method
# should be used, rather than `renderToString`
to_static_markup=False,
# An optional object which will be used instead of the default renderer
renderer=None,
# An optional dictionary of request header information (such as `Accept-Language`)
# to pass along with the request to the render server
request_headers={
'Accept-Language': 'da, en-gb;q=0.8, en;q=0.7'
},
# An optional timeout that is used when handling communications with the render server.
# Can be an integer, a float, or a tuple containing two numeric values (the two values
# represent the individual timeouts on the send & receive phases of the request).
# Note that if not defined, this value will default to (5, 5)
timeout=None
)If you are using python-react in a Django project, relative paths to components will be resolved via Django's static file finders.
By default, render_component relies on access to a render server that exposes an endpoint compatible
with react-render's API. If you want to use a different
renderer, pass in an object as the renderer arg. The object should expose a render method which
accepts the path, data, to_static_markup, and request_headers arguments.
Earlier versions of this library would run the render server as a subprocess, this tended to make development easier, but introduced instabilities and opaque behaviour. To avoid these issues python-react now relies on externally managed process. While managing extra processes can add more overhead initially, it avoids pain down the track.
If you only want to run the render server in particular environments, change the RENDER setting to
False. When RENDER is False, the render server is not used directly, but it's wrapper will return similar
objects with the markup attribute as an empty string.
In development environments, it can be easiest to set the RENDER setting to False. This ensures that the
render server will not be used, hence you only need to manage your python process.
Be aware that the render servers provided in the examples and elsewhere rely on Node.js's module system which - similarly to Python - caches all modules as soon as they are imported. If you use the render server in a development environment, your code is cached and your changes will not effect the rendered markup until you reset the render server.
In production environments, you should ensure that RENDER is set to True.
You will want to run the render server under whatever supervisor process suits your need. Depending on
your setup, you may need to change the RENDER_URL setting to reflect your environment.
The render server should be run with the NODE_ENV environment variable set to production,
eg: NODE_ENV=production node render_server.js. React defaults to development mode and relies on the
NODE_ENV variable to deactivate dev-oriented code (types and constraint checking) that slows down renders.
Defining this variable will ensure that your code is rendered much faster.
Depending on your load, you may want to use a worker farm to handle rendering. Node's cluster module provides an easy way to fork a process and serve multiple instances from a single network address.
An alternative to worker farms is to put a cache in front of the render server. Be aware that render server requests are sent as POST requests and most reverse proxies have issues with caching POST requests.
When the render server wrapper connects to the JS process, it adds a ?hash=... parameter to the url. The
hash parameter is a SHA-1 hash of the serialized data that is sent in the request's body and is intended
for consumption by caching layers.
Another alternative is to wire the calls to the render server into your caching system. If you override the
renderer kwarg, you could wrap the call to the server to first check if the data is available locally and
fallback to populating the cache with the rendered markup.
If you want to override the default renderer, one approach is to create a wrapper function so that
you can consistently define the renderer argument to render_component. For example:
from react.render import render_component
class MyRenderer(object):
def render(self, path, props=None, to_static_markup=False, request_headers=None, timeout=None):
# ...
def my_render_function(*args, **kwargs):
kwargs['renderer'] = MyRenderer()
return render_component(*args, **kwargs)If you are using python-react in a non-django project, settings can be defined by calling
react.conf.settings.configure with keyword arguments matching the setting that you want to define.
For example:
from react.conf import settings
DEBUG = True
settings.configure(
RENDER=not DEBUG,
RENDER_URL='http://127.0.0.1:9009/render',
)If you are using python-react in a Django project, add 'react' to your INSTALLED_APPS and define
settings in a REACT dictionary.
INSTALLED_APPS = (
# ...
'react',
)
REACT = {
'RENDER': not DEBUG,
'RENDER_URL': 'http://127.0.0.1:8001/render',
}A flag denoting that the render server should be used. If set to False, the renderer will return
objects with an empty string as the markup attribute.
Pre-rendering your components is only intended for environments where serving markup quickly is a must.
In a live development environment, running multiple processes overly complicates your setup and can lead
to inexplicable behaviour due to the render server's file caches. Setting this to False will remove the
need to run a render server next to your python server.
Default: True
A complete url to an endpoint which accepts POST requests conforming to react-render's API.
Default: 'http://127.0.0.1:9009/render'
You can edit the render server's code and annotate the returned payload with whatever data
that you like. The payload provided by the render server is available under the data attribute
of the response object.
For example:
from react.render import render_component
rendered = render_component('path/to/component.js')
print(rendered.data)python-react can integrate with Django's settings and the renderer integration can resolve relative paths to components via django's static file finders.
sillygod sparked a discussion of this at issue #69.
Anima-t3d has a write-up of their experience in #70.
Anima-t3d sparked a discussion of this at issue #71.
pip install -r requirements.txt
npm install
python runtests.py
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