From 38bc6430d31e0cd57d9e335d4d5c12c6796167a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mike=20F=C3=A4hrmann?= <mike_faehrmann@web.de>
Date: Fri, 10 Apr 2020 22:24:32 +0200
Subject: [PATCH] [downloader:http] don't overwrite existing '_mtime' fields

---
 gallery_dl/downloader/http.py |  6 +++++-
 gallery_dl/util.py            | 17 ++++++++---------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/gallery_dl/downloader/http.py b/gallery_dl/downloader/http.py
index 844e422c..64a29789 100644
--- a/gallery_dl/downloader/http.py
+++ b/gallery_dl/downloader/http.py
@@ -164,7 +164,11 @@ class HttpDownloader(DownloaderBase):
 
         self.downloading = False
         if self.mtime:
-            pathfmt.kwdict["_mtime"] = response.headers.get("Last-Modified")
+            pathfmt.kwdict.setdefault(
+                "_mtime", response.headers.get("Last-Modified"))
+        else:
+            pathfmt.kwdict["_mtime"] = None
+
         return True
 
     def receive(self, response, file):
diff --git a/gallery_dl/util.py b/gallery_dl/util.py
index 47fad9ec..83cf84bb 100644
--- a/gallery_dl/util.py
+++ b/gallery_dl/util.py
@@ -840,16 +840,15 @@ class PathFormat():
                 shutil.copyfile(self.temppath, self.realpath)
                 os.unlink(self.temppath)
 
-        if "_mtime" in self.kwdict:
+        mtime = self.kwdict.get("_mtime")
+        if mtime:
             # Set file modification time
-            mtime = self.kwdict["_mtime"]
-            if mtime:
-                try:
-                    if isinstance(mtime, str):
-                        mtime = mktime_tz(parsedate_tz(mtime))
-                    os.utime(self.realpath, (time.time(), mtime))
-                except Exception:
-                    pass
+            try:
+                if isinstance(mtime, str):
+                    mtime = mktime_tz(parsedate_tz(mtime))
+                os.utime(self.realpath, (time.time(), mtime))
+            except Exception:
+                pass
 
 
 class DownloadArchive():