feat: Add missing onAdd and onAdded called in File and implement …

…`set_image_meta`

`set_image_meta` fills the `width` and `height` bones of a `FileSkel`
with the image dimensions.

src/viur/core/modules/file.py

@@ -1,26 +1,28 @@
 import base64
 import datetime
-import google.auth
 import hashlib
 import hmac
 import html
 import io
 import json
 import logging
-import PIL
-import PIL.ImageCms
 import re
-import requests
 import string
 import typing as t
 import warnings
 from collections import namedtuple
-from google.appengine.api import images, blobstore
 from urllib.parse import quote as urlquote, urlencode
 from urllib.request import urlopen
 
+import PIL
+import PIL.ImageCms
+import google.auth
+import requests
+from PIL import Image
+from google.appengine.api import blobstore, images
 from google.cloud import storage
 from google.oauth2.service_account import Credentials as ServiceAccountCredentials
+
 from viur.core import conf, current, db, errors, utils
 from viur.core.bones import BaseBone, BooleanBone, KeyBone, NumericBone, StringBone
 from viur.core.decorators import *
@@ -29,7 +31,6 @@
 from viur.core.skeleton import SkeletonInstance, skeletonByKind
 from viur.core.tasks import CallDeferred, DeleteEntitiesIter, PeriodicTask
 
-
 # Globals for connectivity
 
 VALID_FILENAME_REGEX = re.compile(
@@ -477,6 +478,9 @@ class File(Tree):
     DOWNLOAD_URL_PREFIX = "/file/download/"
     INTERNAL_SERVING_URL_PREFIX = "/file/serve/"
     MAX_FILENAME_LEN = 256
+    IMAGE_META_MAX_SIZE: t.Final[int] = 10 * 1024 ** 2
+    """Maximum size of image files that should be analysed in :meth:`set_image_meta`.
+    Default: 10 MiB"""
 
     leafSkelCls = FileLeafSkel
     nodeSkelCls = FileNodeSkel
@@ -575,12 +579,12 @@ def create_internal_serving_url(
 
         # Append additional parameters
         if params := {
-                k: v for k, v in {
-                    "download": download,
-                    "filename": filename,
-                    "options": options,
-                    "size": size,
-                }.items() if v
+            k: v for k, v in {
+                "download": download,
+                "filename": filename,
+                "options": options,
+                "size": size,
+            }.items() if v
         }:
             serving_url += f"?{urlencode(params)}"
 
@@ -1198,7 +1202,9 @@ def add(self, skelType: SkelType, node: db.Key | int | str | None = None, *args,
             skel["weak"] = rootNode is None
             skel["crc32c_checksum"] = base64.b64decode(blob.crc32c).hex()
             skel["md5_checksum"] = base64.b64decode(blob.md5_hash).hex()
+            self.onAdd("leaf", skel)
             skel.write()
+            self.onAdded("leaf", skel)
 
             # Add updated download-URL as the auto-generated isn't valid yet
             skel["downloadUrl"] = self.create_download_url(skel["dlkey"], skel["name"])
@@ -1214,7 +1220,6 @@ def get_download_url(
         dlkey: t.Optional[str] = None,
         filename: t.Optional[str] = None,
         derived: bool = False,
-
     ):
         """
         Request a download url for a given file
@@ -1278,6 +1283,47 @@ def onEdit(self, skelType: SkelType, skel: SkeletonInstance):
         bucket.copy_blob(old_blob, bucket, new_path, if_generation_match=0)
         bucket.delete_blob(old_path)
 
+    def onAdded(self, skelType: SkelType, skel: SkeletonInstance) -> None:
+        super().onAdded(skelType, skel)
+        logging.info(f"Added  {skel=}")
+        if skel["mimetype"].startswith("image/"):
+            if skel["size"] > self.IMAGE_META_MAX_SIZE:
+                logging.warning(f'File size {skel['size']} exceeds limit {self.IMAGE_META_MAX_SIZE=}')
+                return
+            self.set_image_meta(skel["key"])
+
+    @CallDeferred
+    def set_image_meta(self, key: db.Key) -> None:
+        """Write image metadata (height and width) to FileSkel"""
+        skel = self.editSkel("leaf", key)
+        if not skel.read(key):
+            logging.error(f"File {key} does not exist")
+            return
+        if skel["width"] and skel["height"]:
+            logging.info(f'File {skel["key"]} has already {skel["width"]=} and {skel["height"]=}')
+            return
+        file_name = html.unescape(skel["name"])
+        blob = self.get_bucket(skel["dlkey"]).get_blob(f"""{skel["dlkey"]}/source/{file_name}""")
+        if not blob:
+            logging.error(f'Blob {skel["dlkey"]}/source/{file_name} is missing in Cloud Storage!')
+            return
+
+        file_obj = io.BytesIO()
+        blob.download_to_file(file_obj)
+        file_obj.seek(0)
+        try:
+            img = Image.open(file_obj)
+        except Image.UnidentifiedImageError:  # Can't load this image
+            logging.error(f'Cannot open {skel["key"]} | {skel["name"]} to set image meta data', exc_info=True)
+            return
+
+        skel.patch(
+            values={
+                "width": img.width,
+                "height": img.height,
+            },
+        )
+
     def mark_for_deletion(self, dlkey: str) -> None:
         """
         Adds a marker to the datastore that the file specified as *dlkey* can be deleted.
@@ -1409,8 +1455,8 @@ def start_delete_pending_files():
 
 def __getattr__(attr: str) -> object:
     if entry := {
-            # stuff prior viur-core < 3.7
-            "GOOGLE_STORAGE_BUCKET": ("File.get_bucket()", _private_bucket),
+        # stuff prior viur-core < 3.7
+        "GOOGLE_STORAGE_BUCKET": ("File.get_bucket()", _private_bucket),
     }.get(attr):
         msg = f"{attr} was replaced by {entry[0]}"
         warnings.warn(msg, DeprecationWarning, stacklevel=2)