120 lines
2.4 KiB
Go
Executable File
120 lines
2.4 KiB
Go
Executable File
package main
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import (
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"context"
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"fmt"
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"io"
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"log"
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"net"
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"net/http"
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"os"
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"os/exec"
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"os/signal"
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"runtime"
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"strings"
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"syscall"
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"time"
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)
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// language=html
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const injectScript = `
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<script>
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const sendShutdown = () => navigator.sendBeacon('/shutdown');
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window.addEventListener('beforeunload', sendShutdown);
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window.addEventListener('unload', sendShutdown);
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</script>
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`
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func main() {
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if err := run(); err != nil {
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log.Fatal(err)
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}
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}
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func newHandler(html string, onShutdown func()) *http.ServeMux {
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handler := http.NewServeMux()
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handler.HandleFunc("POST /shutdown", func(w http.ResponseWriter, r *http.Request) {
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onShutdown()
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})
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handler.HandleFunc("GET /", func(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("Content-Type", "text/html")
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w.Write([]byte(html))
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})
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return handler
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}
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func run() error {
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html, err := io.ReadAll(os.Stdin)
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if err != nil {
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return fmt.Errorf("failed to read HTML from stdin: %w", err)
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}
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htmlStr := string(html)
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if strings.Contains(htmlStr, "</body>") {
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htmlStr = strings.ReplaceAll(string(html), "</body>", injectScript+"</body>")
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} else {
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htmlStr += injectScript
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}
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listener, err := net.Listen("tcp", ":0")
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if err != nil {
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return fmt.Errorf("failed to create listener: %w", err)
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}
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ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
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defer cancel()
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port := listener.Addr().(*net.TCPAddr).Port
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server := &http.Server{Addr: listener.Addr().String()}
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server.Handler = newHandler(htmlStr, func() {
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cancel()
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})
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servedURL := fmt.Sprintf("http://localhost:%d", port)
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go func() {
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log.Printf("serving at %s", servedURL)
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if err := server.Serve(listener); err != nil && err != http.ErrServerClosed {
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log.Fatalf("failed to serve: %v", err)
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}
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}()
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go func() {
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// wait for server to start
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time.Sleep(250 * time.Millisecond)
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if err := openBrowser(servedURL); err != nil {
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log.Fatalf("failed to open browser: %v", err)
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}
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}()
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<-ctx.Done()
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log.Printf("shutting down server")
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if err := server.Shutdown(ctx); err != nil {
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return fmt.Errorf("failed to shutdown server: %w", err)
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}
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return nil
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}
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func openBrowser(url string) error {
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var cmd *exec.Cmd
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switch runtime.GOOS {
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case "darwin":
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cmd = exec.Command("open", url)
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case "linux":
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cmd = exec.Command("xdg-open", url)
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case "windows":
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cmd = exec.Command("cmd", "/c", "start", url)
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default:
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return fmt.Errorf("invalid URL: %s", url)
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}
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return cmd.Run()
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}
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