server: added date taken detection for videos

- [server] added date taken detection for videos in `func/metadata.py`
  using subprocess and ffmpeg

server/szurubooru/func/metadata.py

@@ -1,12 +1,40 @@
+import json
 from datetime import datetime
+from subprocess import PIPE, Popen
 from typing import Optional
 
 from exif import Image
 
 
-def resolve_date_taken(content: bytes) -> Optional[datetime]:
+def resolve_image_date_taken(content: bytes) -> Optional[datetime]:
     img = Image(content)
 
     if img.has_exif and "datetime" in img.list_all():
         return datetime.strptime(img.datetime, "%Y:%m:%d %H:%M:%S")
     return None
+
+
+def resolve_video_date_taken(content: bytes) -> Optional[datetime]:
+    proc = Popen(
+        [
+            "ffprobe",
+            "-loglevel",
+            "8",
+            "-print_format",
+            "json",
+            "-show_format",
+            "-",
+        ],
+        stdin=PIPE,
+        stdout=PIPE,
+        stderr=PIPE,
+    )
+
+    output = proc.communicate(input=content)[0]
+    json_output = json.loads(output)
+
+    try:
+        creation_time = json_output["format"]["tags"]["creation_time"]
+        return datetime.fromisoformat(creation_time.rstrip("Z"))
+    except Exception:
+        return None

server/szurubooru/func/posts.py

@@ -674,8 +674,10 @@ def update_post_content(post: model.Post, content: Optional[bytes]) -> None:
             post.canvas_height = None
     setattr(post, "__content", content)
 
-    if post.type in [model.Post.TYPE_IMAGE, model.Post.TYPE_VIDEO]:
+    if post.type == model.Post.TYPE_IMAGE:
-        post.date_taken = metadata.resolve_date_taken(content)
+        post.date_taken = metadata.resolve_image_date_taken(content)
+    elif post.type == model.Post.TYPE_VIDEO:
+        post.date_taken = metadata.resolve_video_date_taken(content)
     else:
         post.date_taken = None