Properly form a download URL.

internal/handlers/handlers.go

@@ -14,6 +14,7 @@ import (
 	"io"
 	"io/fs"
 	"net/http"
+	"net/url"
 	"os"
 	"path"
 	"strings"
@@ -174,16 +175,18 @@ func (h *UploadHandlers) Upload(w http.ResponseWriter, r *http.Request) {
 	}
 
 	downloadURL := path.Join("/f", fSaltedHash, fHandler.Filename)
+	downloadURLParsed, _ := url.Parse(downloadURL)
 
 	if strings.Contains(r.UserAgent(), "curl") {
 		_, scheme := utils.NetworkType(r.Host)
-		w.Write([]byte(path.Join(scheme, "://", r.Host, downloadURL) + "\r\n"))
+		downloadURL = fmt.Sprint(scheme, "://", r.Host, downloadURLParsed, "\r\n")
+		w.Write([]byte(downloadURL))
 		return
 	}
 
 	if err := compiledTemplates["uploaded"].Execute(w, &UploadedData{
 		MainSite:     utils.MainSite(r.Host),
-		DownloadURL:  downloadURL,
+		DownloadURL:  downloadURLParsed.String(),
 		KeepForHours: h.conf.Uploads.Limits.KeepForHours,
 	}); err != nil {
 		w.WriteHeader(http.StatusInternalServerError)