Hugo Nijhuis
89efc9b41d
Implement automatic rebuild and browser reload during development:
- File watcher monitors .go files for changes with configurable extensions
- Builder compiles Go source to WASM on file changes
- LiveReload WebSocket server notifies connected browsers to reload
- DevServer combines all components for easy development setup
- HTML injection adds reload script automatically
Usage:
dev := host.NewDevServer("public", "index.html", ".", "public/app.wasm")
dev.ListenAndServe(":8080")
Closes #9
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
81 lines
2.3 KiB
Go
81 lines
2.3 KiB
Go
package host
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import (
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"bytes"
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"strings"
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)
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// ReloadScript is the JavaScript code injected into HTML pages for hot reload.
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const ReloadScript = `<script>
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(function() {
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var wsUrl = 'ws://' + window.location.host + '/__livereload';
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var ws;
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var reconnectAttempts = 0;
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var maxReconnectDelay = 5000;
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function connect() {
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ws = new WebSocket(wsUrl);
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ws.onopen = function() {
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console.log('[iris] Hot reload connected');
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reconnectAttempts = 0;
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};
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ws.onmessage = function(event) {
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if (event.data === 'reload') {
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console.log('[iris] Reloading...');
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window.location.reload();
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}
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};
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ws.onclose = function() {
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var delay = Math.min(1000 * Math.pow(2, reconnectAttempts), maxReconnectDelay);
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reconnectAttempts++;
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console.log('[iris] Connection lost. Reconnecting in ' + delay + 'ms...');
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setTimeout(connect, delay);
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};
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ws.onerror = function() {
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ws.close();
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};
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}
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connect();
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})();
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</script>`
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// InjectReloadScript injects the live reload script into HTML content.
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// The script is inserted just before the closing </body> tag.
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func InjectReloadScript(html []byte) []byte {
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// Try to inject before </body>
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bodyEnd := bytes.LastIndex(html, []byte("</body>"))
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if bodyEnd != -1 {
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result := make([]byte, 0, len(html)+len(ReloadScript))
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result = append(result, html[:bodyEnd]...)
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result = append(result, []byte(ReloadScript)...)
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result = append(result, html[bodyEnd:]...)
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return result
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}
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// Try to inject before </html>
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htmlEnd := bytes.LastIndex(html, []byte("</html>"))
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if htmlEnd != -1 {
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result := make([]byte, 0, len(html)+len(ReloadScript))
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result = append(result, html[:htmlEnd]...)
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result = append(result, []byte(ReloadScript)...)
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result = append(result, html[htmlEnd:]...)
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return result
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}
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// Append at the end as fallback
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result := make([]byte, 0, len(html)+len(ReloadScript))
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result = append(result, html...)
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result = append(result, []byte(ReloadScript)...)
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return result
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}
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// IsHTMLContent checks if the content type indicates HTML.
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func IsHTMLContent(contentType string) bool {
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return strings.Contains(contentType, "text/html")
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}
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