feat: caching & logging

backend/handlers/video.go

@@ -0,0 +1,109 @@
+package handlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"strings"
+
+	"DownLink/models"
+	"DownLink/services"
+
+	"github.com/google/uuid"
+)
+
+type VideoHandler struct {
+	videoService *services.VideoService
+}
+
+func NewVideoHandler(videoService *services.VideoService) *VideoHandler {
+	return &VideoHandler{
+		videoService: videoService,
+	}
+}
+
+func (vh *VideoHandler) DownloadVideo(w http.ResponseWriter, r *http.Request) {
+	var req models.VideoDownloadRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		slog.Error("Failed to decode request body", "error", err)
+		vh.writeError(w, http.StatusBadRequest, "Invalid JSON")
+		return
+	}
+
+	if req.URL == "" || req.Quality == "" {
+		slog.Warn("Invalid request parameters", "url", req.URL, "quality", req.Quality)
+		vh.writeError(w, http.StatusBadRequest, "URL and Quality are required")
+		return
+	}
+
+	slog.Info("Starting video download", "url", req.URL, "quality", req.Quality)
+
+	outputPath, err := vh.videoService.DownloadVideo(req.URL, req.Quality)
+	if err != nil {
+		slog.Error("Video download failed", "url", req.URL, "quality", req.Quality, "error", err)
+		vh.writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	// Determine if this was a cached response
+	isCached := !strings.Contains(outputPath, "dl_") && strings.Contains(outputPath, "cache")
+
+	// Only cleanup if it's a fresh download (not cached)
+	if strings.Contains(outputPath, "dl_") {
+		defer vh.videoService.CleanupTempDir(outputPath)
+	}
+
+	uid := uuid.New().String()
+	filename := fmt.Sprintf("video_%s.mp4", uid)
+
+	// Add cache status header
+	if isCached {
+		w.Header().Set("X-Cache-Status", "HIT")
+		slog.Info("Serving cached video", "url", req.URL, "quality", req.Quality, "file", outputPath)
+	} else {
+		w.Header().Set("X-Cache-Status", "MISS")
+		slog.Info("Serving fresh download", "url", req.URL, "quality", req.Quality, "file", outputPath)
+	}
+
+	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	w.Header().Set("Content-Type", "video/mp4")
+
+	http.ServeFile(w, r, outputPath)
+}
+
+func (vh *VideoHandler) HealthCheck(w http.ResponseWriter, r *http.Request) {
+	slog.Debug("Health check requested", "remote_addr", r.RemoteAddr)
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("Backend for DownLink is running.\n"))
+}
+
+func (vh *VideoHandler) ClearCache(w http.ResponseWriter, r *http.Request) {
+	slog.Info("Cache clear requested")
+	if err := vh.videoService.CleanupExpiredCache(0); err != nil {
+		slog.Error("Failed to clear cache", "error", err)
+		vh.writeError(w, http.StatusInternalServerError, fmt.Sprintf("Failed to clear cache: %v", err))
+		return
+	}
+
+	slog.Info("Cache cleared successfully")
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(map[string]string{"message": "Cache cleared successfully"})
+}
+
+func (vh *VideoHandler) GetCacheStatus(w http.ResponseWriter, r *http.Request) {
+	slog.Debug("Cache status requested")
+	status := vh.videoService.GetCacheStats()
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(status)
+}
+
+func (vh *VideoHandler) writeError(w http.ResponseWriter, status int, message string) {
+	slog.Error("HTTP error response", "status", status, "message", message)
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(models.ErrorResponse{Error: message})
+}