Split functionality out of views/database/__init__.py, re-enable pylint (#8713)

* Split functionality out of __init__.py, re-enable pylint

* Black, isort

* Test fix

* Remove commented-out code bit

superset/views/database/validators.py

@@ -0,0 +1,55 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+from typing import Type
+
+from flask_babel import lazy_gettext as _
+from marshmallow import ValidationError
+from sqlalchemy.engine.url import make_url
+from sqlalchemy.exc import ArgumentError
+
+from superset import security_manager
+
+
+def sqlalchemy_uri_validator(
+    uri: str, exception: Type[ValidationError] = ValidationError
+) -> None:
+    """
+    Check if a user has submitted a valid SQLAlchemy URI
+    """
+    try:
+        make_url(uri.strip())
+    except (ArgumentError, AttributeError):
+        raise exception(
+            _(
+                "Invalid connnection string, a valid string follows: "
+                " 'DRIVER://USER:PASSWORD@DB-HOST/DATABASE-NAME'"
+                " <p>Example:'postgresql://user:password@your-postgres-db/database'</p>"
+            )
+        )
+
+
+def schema_allows_csv_upload(database, schema):
+    if not database.allow_csv_upload:
+        return False
+    schemas = database.get_schema_access_for_csv_upload()
+    if schemas:
+        return schema in schemas
+    return (
+        security_manager.database_access(database)
+        or security_manager.all_datasource_access()
+    )