@swell/cli/dist/lib/theme-sync.js

Swell's command line interface/utility

import http from 'http';
import getPort, { portNumbers } from 'get-port';
import util from 'node:util';
import zlib from 'node:zlib';
// @ts-ignore
import httpProxy from 'http-proxy';
// @ts-ignore
import WebSocket, { WebSocketServer } from 'ws';
const gunzipAsync = util.promisify(zlib.gunzip);
const inflateAsync = util.promisify(zlib.inflate);
const brotliDecompressAsync = util.promisify(zlib.brotliDecompress);
const FALLBACK_PORT = 3000;
export class ThemeSync {
    server;
    proxy;
    wss;
    options;
    async selectPort() {
        return (await getPort({ port: portNumbers(3000, 3100) })) || FALLBACK_PORT;
    }
    constructor(options) {
        this.options = options;
        this.server = http.createServer();
        this.proxy = httpProxy.createProxyServer({});
        this.wss = new WebSocketServer({ server: this.server });
    }
    async start() {
        // Select port if not specified
        if (!this.options.port) {
            this.options.port = await this.selectPort();
        }
        return new Promise((resolve, reject) => {
            // Create proxy server
            this.server.on('request', (req, res) => {
                this.proxy.web(req, res, {
                    target: this.options.targetUrl,
                    changeOrigin: true,
                    selfHandleResponse: true,
                }, (err) => {
                    if (err) {
                        console.error('Proxy error:', err);
                        if (res instanceof http.ServerResponse) {
                            res.writeHead(500, { 'Content-Type': 'text/plain' });
                            res.end('Proxy error');
                        }
                    }
                });
            });
            this.proxy.on('proxyReq', (proxyReq) => {
                proxyReq.setHeader('swell-request-id', `${Date.now()}`);
            });
            this.proxy.on('proxyRes', (proxyRes, req, res) => {
                let body = Buffer.from('');
                proxyRes.on('data', (chunk) => {
                    body = Buffer.concat([body, chunk]);
                });
                // Preserve headers
                for (let i = 0; i < proxyRes.rawHeaders.length; i += 2) {
                    const header = proxyRes.rawHeaders[i];
                    res.setHeader(header, proxyRes.rawHeaders[i + 1]);
                }
                // Use utf8 encoding for the response
                res.setHeader('Content-Encoding', 'utf8');
                proxyRes.on('end', async () => {
                    const html = await this.parseRequestBody(proxyRes, body);
                    if (this.shouldInjectScript(proxyRes, html)) {
                        const modifiedHtml = this.injectScript(html, `localhost:${this.options.port}`);
                        res.end(modifiedHtml);
                    }
                    else {
                        res.end(html);
                    }
                });
            });
            // Handle proxy errors
            this.proxy.on('error', (err) => {
                console.error('Proxy error:', err);
            });
            // Start server
            this.server.listen(this.options.port, () => {
                resolve(this.options.port);
            });
            this.server.on('error', (err) => {
                reject(err);
            });
        });
    }
    reload() {
        // Get all connected WebSocket clients
        const clients = Array.from(this.wss.clients).filter((client) => client.readyState === WebSocket.OPEN);
        // Notify clients to reload
        clients.forEach((client) => {
            client.send('reload');
        });
    }
    async parseRequestBody(proxyRes, body) {
        // May contain multiple encodings
        const contentEncoding = String(proxyRes.headers['content-encoding'] ?? '')
            .split(',')
            .reverse();
        for (const value of contentEncoding) {
            const encoding = value.trim().toLowerCase();
            if (encoding) {
                body = await this.decodeRequestBody(body, encoding);
            }
        }
        return body.toString('utf8');
    }
    decodeRequestBody(body, encoding) {
        switch (encoding) {
            case 'gzip':
                return gunzipAsync(body);
            case 'deflate':
                return inflateAsync(body);
            case 'br':
                return brotliDecompressAsync(body);
            default:
                return Promise.reject(new Error(`Unsupported content encoding: ${encoding}`));
        }
    }
    shouldInjectScript(proxyRes, html) {
        // Check if this is an HTML response
        const contentType = proxyRes.headers['content-type'];
        if (!contentType?.includes('text/html')) {
            return false;
        }
        if (!html.includes('</body>')) {
            return false;
        }
        return true;
    }
    // Inject WebSocket client script into proxied HTML
    injectScript(html, host) {
        const script = `
      <script>
        const ws = new WebSocket('ws://${host}/ws');
        ws.onmessage = () => {
          window.location.reload();
        };
      </script>
    `;
        return html.replace('</body>', `${script}</body>`);
    }
}