[storages] Add the ability to set upload extra args

cubicweb_s3storage/storages.py

@@ -98,7 +98,9 @@ class S3Storage(Storage):
             buffer = Binary(binary.read())
             binary.seek(0)
             suffixed_key = self.suffixed_key(key)
-            self.s3cnx.upload_fileobj(buffer, self.bucket, suffixed_key)
+            extra_args = self.get_upload_extra_args(entity, attr, key)
+            self.s3cnx.upload_fileobj(buffer, self.bucket, suffixed_key,
+                                      ExtraArgs=extra_args)
             buffer.close()
 
             # move to final key in post commit event
@@ -108,6 +110,13 @@ class S3Storage(Storage):
                       entity.eid, attr, self.bucket, suffixed_key)
         return binary
 
+    def get_upload_extra_args(self, _entity, _attr, _key):
+        """Additional options for boto3's upload_fileobj method.
+        Documentation for supported options can be found at:
+        https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-uploading-files.html#the-extraargs-parameter
+        """
+        return {}
+
     def entity_updated(self, entity, attr):
         """an entity using this storage for attr has been updatded"""
         return self.entity_added(entity, attr)

test/test_s3storage.py

 import re
 from contextlib import contextmanager
+from mock import patch
 
 from six import PY3
 
@@ -88,6 +89,21 @@ class S3StorageTC(testing.S3StorageTestMixin, CubicWebTC):
         keys = [x.key for x in self.s3_bucket.objects.all()]
         self.assertNotIn(key, keys)
 
+    def test_upload_content_type(self):
+        mime_type = 'x-custom/mime-type'
+        with self.admin_access.client_cnx() as cnx, \
+                patch('cubicweb_s3storage.storages.S3Storage'
+                      '.get_upload_extra_args',
+                      return_value={'ContentType': mime_type}):
+            image = create_image(cnx, b'some content')
+            cnx.commit()
+            s3storage = self.repo.system_source.storage('Image', 'data')
+            s3_key = s3storage.get_s3_key(image, 'data')
+            head = s3storage.s3cnx.head_object(
+                Bucket=self.s3_bucket.name,
+                Key=s3_key)
+            self.assertEqual(head['ContentType'], mime_type)
+
 
 class S3StorageMigrationTC(testing.S3StorageTestMixin, CubicWebTC):