Implement `check_same_thread` = False storage adapter.

Add start of AsyncSQLStorageAdapter

chatter/storage_adapters.py

@@ -0,0 +1,73 @@
+from chatterbot.storage import StorageAdapter, SQLStorageAdapter
+
+
+class MyDumbSQLStorageAdapter(SQLStorageAdapter):
+    def __init__(self, **kwargs):
+        super(SQLStorageAdapter, self).__init__(**kwargs)
+
+        from sqlalchemy import create_engine
+        from sqlalchemy.orm import sessionmaker
+
+        self.database_uri = kwargs.get("database_uri", False)
+
+        # None results in a sqlite in-memory database as the default
+        if self.database_uri is None:
+            self.database_uri = "sqlite://"
+
+        # Create a file database if the database is not a connection string
+        if not self.database_uri:
+            self.database_uri = "sqlite:///db.sqlite3"
+
+        self.engine = create_engine(
+            self.database_uri, convert_unicode=True, connect_args={"check_same_thread": False}
+        )
+
+        if self.database_uri.startswith("sqlite://"):
+            from sqlalchemy.engine import Engine
+            from sqlalchemy import event
+
+            @event.listens_for(Engine, "connect")
+            def set_sqlite_pragma(dbapi_connection, connection_record):
+                dbapi_connection.execute("PRAGMA journal_mode=WAL")
+                dbapi_connection.execute("PRAGMA synchronous=NORMAL")
+
+        if not self.engine.dialect.has_table(self.engine, "Statement"):
+            self.create_database()
+
+        self.Session = sessionmaker(bind=self.engine, expire_on_commit=True)
+
+
+class AsyncSQLStorageAdapter(SQLStorageAdapter):
+    def __init__(self, **kwargs):
+        super(SQLStorageAdapter, self).__init__(**kwargs)
+
+        self.database_uri = kwargs.get("database_uri", False)
+
+        # None results in a sqlite in-memory database as the default
+        if self.database_uri is None:
+            self.database_uri = "sqlite://"
+
+        # Create a file database if the database is not a connection string
+        if not self.database_uri:
+            self.database_uri = "sqlite:///db.sqlite3"
+
+    async def initialize(self):
+        # from sqlalchemy import create_engine
+        from aiomysql.sa import create_engine
+        from sqlalchemy.orm import sessionmaker
+
+        self.engine = await create_engine(self.database_uri, convert_unicode=True)
+
+        if self.database_uri.startswith("sqlite://"):
+            from sqlalchemy.engine import Engine
+            from sqlalchemy import event
+
+            @event.listens_for(Engine, "connect")
+            def set_sqlite_pragma(dbapi_connection, connection_record):
+                dbapi_connection.execute("PRAGMA journal_mode=WAL")
+                dbapi_connection.execute("PRAGMA synchronous=NORMAL")
+
+        if not self.engine.dialect.has_table(self.engine, "Statement"):
+            self.create_database()
+
+        self.Session = sessionmaker(bind=self.engine, expire_on_commit=True)