Feat: Allow use of remote storage

exiffield/fields.py

@@ -26,22 +26,18 @@ def get_exif(file_: FieldFile) -> str:
 
     if not file_._committed:
         # pipe file content to exiftool
-        file_._file.seek(0)
-
-        process = subprocess.run(
-            [exiftool_path, '-j', '-l', '-'],
-            check=True,
-            input=file_._file.read(),
-            stdout=subprocess.PIPE,
-        )
-        return process.stdout
+        fo = file_._file
+        fo.seek(0)
     else:
-        # pass physical file to exiftool
-        file_path = file_.path
-        encoded_json = subprocess.check_output(
-            [exiftool_path, '-j', '-l', file_path],
-        )
-        return encoded_json.decode('utf8')
+        fo = file_.open()
+
+    process = subprocess.run(
+        [exiftool_path, '-j', '-l', '-'],
+        check=True,
+        input=fo.read(),
+        stdout=subprocess.PIPE,
+    )
+    return process.stdout
 
 
 class ExifField(JSONField):
@@ -219,7 +215,7 @@ def update_exif(
         # check whether extraction of the exif is required
         exif_data = getattr(instance, self.name, None) or {}
         has_exif = bool(exif_data)
-        filename = Path(file_.path).name
+        filename = Path(file_.name).name
         exif_for_filename = exif_data.get('FileName', {}).get('val', '')
         file_changed = exif_for_filename != filename or not file_._committed
 
@@ -230,7 +226,7 @@ def update_exif(
         try:
             exif_json = get_exif(file_)
         except Exception:
-            logger.exception('Could not read metainformation from file: %s', file_.path)
+            logger.exception('Could not read metainformation from file: %s', file_.name)
             return
 
         try:
@@ -244,7 +240,7 @@ def update_exif(
                 # the storage.
                 # In the worst case the exif is extracted twice...
                 exif_data['FileName'] = {
-                    'desc': 'Filename',
+                    'desc': 'File Name',
                     'val': filename,
                 }
             setattr(instance, self.name, exif_data)

tests/test_field.py

@@ -3,6 +3,7 @@
 
 import pytest
 from django.conf import settings
+from django.core.files.storage import FileSystemStorage
 from django.core.files.uploadedfile import SimpleUploadedFile
 
 from exiffield import fields
@@ -70,6 +71,39 @@ def img(request, uncommitted_img):
     return img
 
 
+@pytest.fixture
+def remotestorage(mocker):
+    """
+    Return a patched FileSystemStorage that does not support path()
+    """
+    storage = FileSystemStorage()
+
+    def remote_open(name, mode):
+        media_image_path = Path(settings.MEDIA_ROOT) / IMAGE_NAME
+        return open(media_image_path, mode)
+
+    def remote_path():
+        raise NotImplementedError("Remote storage does not implement path()")
+
+    mocker.patch.object(storage, 'path', remote_path)
+    mocker.patch.object(storage, 'open', remote_open)
+    yield storage
+
+
+@pytest.fixture
+def img_remotestorage(remotestorage, img):
+    """
+    Return a committed and uncommitted image instance using remote storage
+    """
+    temp_storage = img.image.storage
+
+    img.image.storage = remotestorage
+
+    yield img
+
+    img.image.storage = temp_storage
+
+
 @pytest.mark.django_db
 def test_unsupported_file():
     image_path = DIR / IMAGE_NAME
@@ -166,6 +200,17 @@ def test_do_not_extract_exif_without_file(mocker):
     assert img.exif == {}
 
 
+@pytest.mark.django_db
+def test_extract_remote_backend(mocker, img_remotestorage):
+    img = img_remotestorage
+
+    exif_field = img._meta.get_field('exif')
+    mocker.spy(fields, 'get_exif')
+
+    exif_field.update_exif(img)
+    assert fields.get_exif.call_count == 1
+
+
 @pytest.mark.django_db
 def test_extract_exif_if_missing(mocker, img):
     img.save()  # store image and extract exif