[add] progress streaming

api/streamer.go

@@ -0,0 +1,79 @@
+package api
+
+import (
+	"bytes"
+	"html/template"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+type streamer struct {
+	templates  map[string]*template.Template
+	writer     gin.ResponseWriter
+	mutex      sync.Mutex
+	completeCh chan struct{}
+}
+
+func (api *API) newStreamer(c *gin.Context) *streamer {
+	stream := &streamer{
+		templates:  api.Templates,
+		writer:     c.Writer,
+		completeCh: make(chan struct{}),
+	}
+
+	// Set Headers
+	header := stream.writer.Header()
+	header.Set("Transfer-Encoding", "chunked")
+	header.Set("Content-Type", "text/html; charset=utf-8")
+	header.Set("X-Content-Type-Options", "nosniff")
+	stream.writer.WriteHeader(http.StatusOK)
+
+	// Send Open Element Tags
+	stream.write(`
+	  <div class="absolute top-0 left-0 w-full h-full z-50">
+	    <div class="fixed top-0 left-0 bg-black opacity-50 w-screen h-screen"></div>
+	    <div id="stream-main" class="relative max-h-[95%] -translate-x-2/4 top-1/2 left-1/2 w-5/6">`)
+
+	// Keep Alive
+	go func() {
+		closeCh := stream.writer.CloseNotify()
+		for {
+			select {
+			case <-stream.completeCh:
+				return
+			case <-closeCh:
+				return
+			default:
+				stream.write("<!-- ping -->")
+				time.Sleep(2 * time.Second)
+			}
+		}
+	}()
+
+	return stream
+}
+
+func (stream *streamer) write(str string) {
+	stream.mutex.Lock()
+	stream.writer.WriteString(str)
+	stream.writer.(http.Flusher).Flush()
+	stream.mutex.Unlock()
+}
+
+func (stream *streamer) send(templateName string, templateVars gin.H) {
+	t := stream.templates[templateName]
+	buf := &bytes.Buffer{}
+	_ = t.ExecuteTemplate(buf, templateName, templateVars)
+	stream.write(buf.String())
+}
+
+func (stream *streamer) close() {
+	// Send Close Element Tags
+	stream.write(`</div></div>`)
+
+	// Close
+	close(stream.completeCh)
+}