Refactor: Add shared base classes for Cursor and Connection

pyproject.toml

@@ -174,7 +174,7 @@ lint.per-file-ignores."tests/*" = [
     "S310", # False positive; it's a https url
     "S311", # Standard pseudo-random generators are not suitable for cryptographic purposes
 ]
-lint.per-file-ignores."src/crate/client/{connection.py,http.py,_pool.py,_response.py}" = [
+lint.per-file-ignores."src/crate/client/{connection.py,http.py,_connection_base.py,_pool.py,_response.py}" = [
     "A004", # Import `ConnectionError` is shadowing a Python builtin
     "A005", # Import `ConnectionError` is shadowing a Python builtin
 ]

src/crate/client/_connection_base.py

@@ -0,0 +1,106 @@
+# -*- coding: utf-8; -*-
+#
+# Licensed to CRATE Technology GmbH ("Crate") under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  Crate 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.
+#
+# However, if you have executed another commercial license agreement
+# with Crate these terms will supersede the license and you may use the
+# software solely pursuant to the terms of the relevant commercial agreement.
+import typing as t
+
+from verlib2 import Version
+
+from .exceptions import ConnectionError, ProgrammingError
+
+
+class ConnectionBase:
+    """
+    Connection state shared by the sync and async connections.
+
+    Public methods that do IO, or that are coroutines on the async
+    connection, live on the subclasses.
+    """
+
+    client: t.Any
+
+    @property
+    def _cursor_class(self) -> t.Type[t.Any]:
+        """The class `cursor()` creates."""
+        raise NotImplementedError
+
+    @property
+    def _blob_container_class(self) -> t.Type[t.Any]:
+        """The class `get_blob_container()` creates."""
+        raise NotImplementedError
+
+    def __init__(self, converter=None, time_zone=None):
+        self._converter = converter
+        self.time_zone = time_zone
+        self._closed = False
+
+    def cursor(self, **kwargs):
+        """
+        Return a new Cursor Object using the connection.
+        """
+        converter = kwargs.pop("converter", self._converter)
+        time_zone = kwargs.pop("time_zone", self.time_zone)
+        self._check_open()
+        return self._cursor_class(
+            connection=self,
+            converter=converter,
+            time_zone=time_zone,
+        )
+
+    def get_blob_container(self, container_name):
+        """Retrieve a BlobContainer for `container_name`
+
+        :param container_name: the name of the BLOB container.
+        :returns: a :class:ContainerObject
+        """
+        return self._blob_container_class(container_name, self)
+
+    def _check_open(self):
+        if self._closed:
+            raise ProgrammingError("Connection closed")
+
+    @staticmethod
+    def _lowest_version(
+        versions: t.Iterable[t.Union[str, BaseException]],
+    ) -> Version:
+        """
+        Return the lowest of the versions reported by the servers.
+        """
+        lowest = None
+        connection_errors = []
+        for version in versions:
+            if isinstance(version, ConnectionError):
+                connection_errors.append(version)
+                continue
+            if isinstance(version, ValueError):
+                continue
+            if isinstance(version, BaseException):
+                raise version
+            try:
+                parsed = Version(version)
+            except ValueError:
+                continue
+            if not lowest or parsed < lowest:
+                lowest = parsed
+        if connection_errors and not lowest:
+            raise ConnectionError("; ".join(str(e) for e in connection_errors))
+        return lowest or Version("0.0.0")
+
+    def __repr__(self):
+        return f"<{self.__class__.__qualname__} {self.client!r}>"