add download handler

handlers/download/handler.go

@@ -0,0 +1,47 @@
+package download
+
+import (
+	"fmt"
+	"librapi/services"
+	"net/http"
+	"path/filepath"
+
+	"github.com/rs/zerolog/log"
+)
+
+const URL = "/download"
+
+func Handler(bs services.IStore) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method {
+		case http.MethodGet:
+			getDownload(w, r, bs)
+		default:
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		}
+	}
+}
+
+func getDownload(w http.ResponseWriter, r *http.Request, bs services.IStore) {
+	queryParams := r.URL.Query()
+	downloadFiles, ok := queryParams["file"]
+	if !ok {
+		log.Error().Msg("file query param does not exist")
+		http.Error(w, "file does not exists", http.StatusBadRequest)
+		return
+	}
+
+	if len(downloadFiles) != 1 {
+		log.Error().Msg("only one file is allowed to download")
+		http.Error(w, "only one file is allowed to download", http.StatusBadRequest)
+		return
+	}
+
+	filename := downloadFiles[0]
+	filePath := filepath.Join(bs.GetStoreDir(), filename)
+
+	http.ServeFile(w, r, filePath)
+
+	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	w.Header().Set("Content-Type", "application/pdf")
+}