feat: support streaming response for search results (#5630)

Co-authored-by: manx98 <1323517022@qq.com>

http/search.go

@@ -1,28 +1,82 @@
 package fbhttp
 
 import (
+	"context"
+	"encoding/json"
+	"errors"
 	"net/http"
 	"os"
+	"sync"
+	"time"
 
 	"github.com/filebrowser/filebrowser/v2/search"
 )
 
+const searchPingInterval = 5
+
 var searchHandler = withUser(func(w http.ResponseWriter, r *http.Request, d *data) (int, error) {
-	response := []map[string]interface{}{}
+	response := make(chan map[string]interface{})
+	ctx, cancel := context.WithCancelCause(r.Context())
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		// Avoid connection timeout
+		timeout := time.NewTimer(searchPingInterval * time.Second)
+		defer timeout.Stop()
+		for {
+			var err error
+			var infoBytes []byte
+			select {
+			case info := <-response:
+				if info == nil {
+					return
+				}
+				infoBytes, err = json.Marshal(info)
+			case <-timeout.C:
+				// Send a heartbeat packet
+				infoBytes = nil
+			case <-ctx.Done():
+				return
+			}
+			if err != nil {
+				cancel(err)
+				return
+			}
+			_, err = w.Write(infoBytes)
+			if err == nil {
+				_, err = w.Write([]byte("\n"))
+			}
+			if err != nil {
+				cancel(err)
+				return
+			}
+			if flusher, ok := w.(http.Flusher); ok {
+				flusher.Flush()
+			}
+		}
+	}()
 	query := r.URL.Query().Get("query")
 
-	err := search.Search(d.user.Fs, r.URL.Path, query, d, func(path string, f os.FileInfo) error {
-		response = append(response, map[string]interface{}{
+	err := search.Search(ctx, d.user.Fs, r.URL.Path, query, d, func(path string, f os.FileInfo) error {
+		select {
+		case <-ctx.Done():
+		case response <- map[string]interface{}{
 			"dir":  f.IsDir(),
 			"path": path,
-		})
-
-		return nil
+		}:
+		}
+		return context.Cause(ctx)
 	})
-
-	if err != nil {
+	close(response)
+	wg.Wait()
+	if err == nil {
+		err = context.Cause(ctx)
+	}
+	// ignore cancellation errors from user aborts
+	if err != nil && !errors.Is(err, context.Canceled) {
 		return http.StatusInternalServerError, err
 	}
 
-	return renderJSON(w, r, response)
+	return 0, nil
 })