Django/Webpack – How to serve generated webpack bundles with webpack dev server

Django’s ‘static’ tag generates urls using STATIC_URL, which results in something like ‘/static/myapp/js/bundle.js’ Mean while, webpack-dev-server is serving bundles from the url ‘localhost:3000’

My question is how do I get Django ‘static’ template tag to generate a different url ( which points to webpack dev server) for js bundles. Of course I can hardcode it in the template, but that would not be a good solution.

Below is my project configuration

webpack.config.js

const path = require('path')
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const BundleTracker = require('webpack-bundle-tracker')


module.exports = {
    mode: 'development',
    context: path.dirname(path.resolve(__dirname)),
    entry: {
        index: './typescript_src/index.ts',
    },
    output: {
        path: path.resolve('./myproject/assets/myapp/bundles/'),
        filename: "[name]-[hash].js"
    },
    resolve: {
        extensions: ['.ts', '.js' ]
    },
    module: {
        rules: [
            {
                test: /.css$/,
                use: ['style-loader', 'css-loader']
            },
            {
                test: /.ts$/,
                use: 'ts-loader',
                exclude: /node_modules/
            }
        ]
    },
    plugins: [
        new CleanWebpackPlugin(),
        new BundleTracker({filename: './myproject/webpack-stats.json'})
    ],
    devServer: {
        port: 3000,
        publicPath: '/myapp/bundles/',
        // hot: true,
        headers: {
            "Access-Control-Allow-Origin": "http://127.0.0.1:8000", /**Django dev server */
        }
    }
}

settings.py

WEBPACK_LOADER = {
    'DEFAULT': {
        'CACHE': not DEBUG,
        'BUNDLE_DIR_NAME': 'myapp/bundles/', # must end with slash
        'STATS_FILE': os.path.join(BASE_DIR, 'webpack-stats.json'),
        'POLL_INTERVAL': 0.1,
        'TIMEOUT': None,
        'IGNORE': [r'.+.hot-update.js', r'.+.map']
    }
}

STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'assets'),
)

Initially I decided webpack should serve other static files as well during development

webpack.config.js

devServer: {
        port: 3000,
        publicPath: '/myapp/bundles/',
        contentBase: path.resolve('./myproject/assets')
        // hot: true,
        headers: {
            "Access-Control-Allow-Origin": "http://127.0.0.1:8000", /**Django dev server */
        }

settings.py

# in development mode serve from wepack dev server
if DEBUG:
    STATIC_URL = 'http://localhost:3000/'
else:
    STATIC_URL = '/static/'

But I later realized I have to serve static files of other apps (admin, tinymce, …), which is impossible for webpack Dev server to reach

The problem here is that the url generated by ‘render_bundle’ tag of django-webpack-loader (/static/myapp/bundles/bundle-name.js) will result in a Http 404 because webpack-dev-server keeps the generated bundle in memory and not on disk

Also if I set

STATIC_URL = localhost:3000

and configure webpack-dev-server to serve other static files of my app, static files of other apps won’t be served

Answer

Let’s analyze the issue:

We have 2 servers and we want to route requests to one or the other based on the path requested:

"/static/webpackbundles/** ==> webpack dev server

other paths ==> django dev server

This is exactly the job of a proxy server, it can be achieved with a third server (haproxy, nginx …), but that might seem like an overkill, especially if we know that webpack dev server can be used as a proxy! (https://webpack.js.org/configuration/dev-server/#devserverproxy)

webpack.config.js

const path = require('path');

module.exports = {
  mode: 'development',
  entry: './src/index.js',
  output: {
    filename: 'main.js',
    path: '/path/to/django_project/django_project/static/webpackbundles',
    publicPath: '/static/webpackbundles/',
  },
  devServer: {
    contentBase: '/path/to/django_project/django_project/static/webpackbundles',
    hot: true,
    proxy: {
      '!/static/webpackbundles/**': {
        target: 'http://localhost:8000', // points to django dev server
        changeOrigin: true,
      },
    },
  },
};

In your django template:

<script type="text/javascript" src="{% static 'webpackbundles/main.js' %}"></script>

Now access your django app/site using webpack dev server address: ex: http://localhost:8081

With this simple config you’ll have browser auto refresh and hot module replacement. You will not need to change anything in django, also no need for django-webpack-loader