Set default Region and generate public_url from minio

The default Region is set to us-east-1
the public URL generated for AWS specific resources is diferent than
minio specific servers. Still, minio SDK has a special reference to
figure out how to generate URLs if AWS is used in the backend.

django_minio_backend/models.py

@@ -93,7 +93,7 @@ def __init__(self,
         self.__MINIO_ACCESS_KEY: str = get_setting("MINIO_ACCESS_KEY")
         self.__MINIO_SECRET_KEY: str = get_setting("MINIO_SECRET_KEY")
         self.__MINIO_USE_HTTPS: bool = get_setting("MINIO_USE_HTTPS")
-        self.__MINIO_REGION: str = get_setting("MINIO_REGION", None)
+        self.__MINIO_REGION: str = get_setting("MINIO_REGION", "us-east-1") # MINIO defaults to "us-east-1" when region is set to None
         self.__MINIO_EXTERNAL_ENDPOINT_USE_HTTPS: bool = get_setting("MINIO_EXTERNAL_ENDPOINT_USE_HTTPS", self.__MINIO_USE_HTTPS)
         self.__MINIO_BUCKET_CHECK_ON_SAVE: bool = get_setting("MINIO_BUCKET_CHECK_ON_SAVE", False)
 
@@ -249,7 +249,8 @@ def url(self, name: str):
         :return: (str) URL to object
         """
         if self.is_bucket_public:
-            return f'{self.base_url_external}/{self.bucket}/{name}'
+            base_url = self.client._base_url.build("GET", self.__MINIO_REGION).geturl()
+            return f'{base_url}{self.bucket}/{name}'
         if self.same_endpoints:
             # in this scenario the fake client is not needed
             client = self.client