Initial commit

site.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	// External
+	"github.com/chromedp/cdproto/target"
+	"github.com/chromedp/chromedp"
+	"github.com/google/uuid"
+
+	// Standard
+	"context"
+	"fmt"
+	"log"
+	"os/exec"
+	"sync"
+)
+
+var (
+	sites    map[string]*Site
+	siteLock *sync.Mutex
+)
+
+type Site struct {
+	UUID      string
+	URL       string
+	Watch     string
+	WatchLoop *exec.Cmd `json:"-"`
+	StopLoop  bool
+	Context   context.Context `json:"-"`
+}
+
+func init() {
+	siteLock = &sync.Mutex{}
+	sites = make(map[string]*Site)
+}
+
+func NewSite(wsURL, url, watch string) (s Site, err error) {
+	s.UUID = uuid.NewString()
+	s.URL = url
+	s.Watch = watch
+
+	allocatorContext, _ := chromedp.NewRemoteAllocator(context.Background(), wsURL)
+
+	// Used to optionally enable debugging output.
+	var opts []chromedp.ContextOption
+	if flagVerbose {
+		opts = append(opts, chromedp.WithDebugf(log.Printf))
+	}
+	s.Context, _ = chromedp.NewContext(allocatorContext, opts...)
+
+	// A tab is started up and navigated to in order to get a context for this instance.
+	if err = chromedp.Run(
+		s.Context,
+		chromedp.Navigate(url),
+	); err != nil {
+		err = fmt.Errorf("Failed getting body of %s: %v", url, err)
+		return
+	}
+
+	siteLock.Lock()
+	sites[s.UUID] = &s
+	defer siteLock.Unlock()
+
+	// chromedp.Run crashes something really hard and undetectable with recover().
+	// ListenBrowser gives the possibility to cancel the watch loop.
+	chromedp.ListenBrowser(s.Context, func(ev any) {
+		_, event1 := ev.(*target.EventDetachedFromTarget)
+		_, event2 := ev.(*target.EventTargetCrashed)
+		_, event3 := ev.(*target.EventTargetDestroyed)
+		if event1 || event2 || event3 {
+			log.Printf("Stopping loop for %s\n", s.UUID)
+			s.StopLoop = true
+			if s.WatchLoop != nil {
+				log.Printf("Killing inotifywait for %s\n", s.UUID)
+				s.WatchLoop.Process.Kill()
+			}
+
+		}
+	})
+
+	// Start watching file/dir for changes.
+	go s.watchLoop()
+
+	return
+}
+
+func (s *Site) watchLoop() {
+	for !s.StopLoop {
+		log.Println("Starting watching " + s.Watch)
+		s.WatchLoop = exec.Command("inotifywait", "-e", "close_write", s.Watch)
+		if err := s.WatchLoop.Run(); err != nil {
+			log.Println(err)
+		}
+		s.ReloadCSS()
+	}
+	log.Printf("Stopping watch loop [%s]\n", s.UUID)
+}
+
+func (s *Site) ReloadCSS() {
+	var buf []byte
+
+	cssReloadScript := chromedp.Evaluate(`
+		(()=>{
+			const stylesheets = document.querySelectorAll('link[rel="stylesheet"]')
+			for (const ss of stylesheets) {
+				const url = URL.parse(ss.href, location.protocol + '//' + location.host) 
+				const nextReloadCounter = parseInt(url.searchParams.get('reload') || 0) + 1
+				url.searchParams.set('reload', nextReloadCounter)
+				ss.href = url.toString()
+			}
+		})()
+		`, &buf)
+
+	err := chromedp.Run(s.Context, cssReloadScript)
+	if err != nil {
+		fmt.Println(err)
+	}
+}