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refactor: vectorstores & chat_message_histories #179

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refactor: vectorstores & chat_message_histories #179

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68 changes: 33 additions & 35 deletions langchain_postgres/chat_message_histories.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,67 +18,69 @@
logger = logging.getLogger(__name__)


def _create_table_and_index(table_name: str) -> List[sql.Composed]:
def _create_table_and_index(table_name: str, schema_name: str) -> List[sql.Composed]:
"""Make a SQL query to create a table."""
index_name = f"idx_{table_name}_session_id"
statements = [
sql.SQL(
"""
CREATE TABLE IF NOT EXISTS {table_name} (
CREATE TABLE IF NOT EXISTS {schema_name}.{table_name} (
id SERIAL PRIMARY KEY,
session_id UUID NOT NULL,
message JSONB NOT NULL,
created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);
"""
).format(table_name=sql.Identifier(table_name)),
).format(schema_name=sql.Identifier(schema_name), table_name=sql.Identifier(table_name)),
sql.SQL(
"""
CREATE INDEX IF NOT EXISTS {index_name} ON {table_name} (session_id);
CREATE INDEX IF NOT EXISTS {index_name} ON {schema_name}.{table_name} (session_id);
"""
).format(
table_name=sql.Identifier(table_name), index_name=sql.Identifier(index_name)
schema_name=sql.Identifier(schema_name), table_name=sql.Identifier(table_name), index_name=sql.Identifier(index_name)
),
]
return statements


def _get_messages_query(table_name: str) -> sql.Composed:
def _get_messages_query(table_name: str, schema_name: str) -> sql.Composed:
"""Make a SQL query to get messages for a given session."""
return sql.SQL(
"SELECT message "
"FROM {table_name} "
"FROM {schema_name}.{table_name} "
"WHERE session_id = %(session_id)s "
"ORDER BY id;"
).format(table_name=sql.Identifier(table_name))
).format(schema_name=sql.Identifier(schema_name), table_name=sql.Identifier(table_name))


def _delete_by_session_id_query(table_name: str) -> sql.Composed:
def _delete_by_session_id_query(table_name: str, schema_name: str) -> sql.Composed:
"""Make a SQL query to delete messages for a given session."""
return sql.SQL(
"DELETE FROM {table_name} WHERE session_id = %(session_id)s;"
).format(table_name=sql.Identifier(table_name))
"DELETE FROM {schema_name}.{table_name} WHERE session_id = %(session_id)s;"
).format(schema_name=sql.Identifier(schema_name) ,table_name=sql.Identifier(table_name))


def _delete_table_query(table_name: str) -> sql.Composed:
def _delete_table_query(table_name: str, schema_name: str) -> sql.Composed:
"""Make a SQL query to delete a table."""
return sql.SQL("DROP TABLE IF EXISTS {table_name};").format(
return sql.SQL("DROP TABLE IF EXISTS {schema_name}.{table_name};").format(
schema_name=sql.Identifier(schema_name),
table_name=sql.Identifier(table_name)
)


def _insert_message_query(table_name: str) -> sql.Composed:
def _insert_message_query(table_name: str, schema_name: str) -> sql.Composed:
"""Make a SQL query to insert a message."""
return sql.SQL(
"INSERT INTO {table_name} (session_id, message) VALUES (%s, %s)"
).format(table_name=sql.Identifier(table_name))
"INSERT INTO {schema_name}.{table_name} (session_id, message) VALUES (%s, %s)"
).format(schema_name=sql.Identifier(schema_name), table_name=sql.Identifier(table_name))


class PostgresChatMessageHistory(BaseChatMessageHistory):
def __init__(
self,
table_name: str,
session_id: str,
schema_name: str = "public",
/,
*,
sync_connection: Optional[psycopg.Connection] = None,
Expand Down Expand Up @@ -203,15 +205,17 @@ def __init__(
"characters and underscores."
)
self._table_name = table_name
self._schema_name = schema_name

@staticmethod
def create_tables(
connection: psycopg.Connection,
table_name: str,
schema_name: str = "public",
/,
) -> None:
"""Create the table schema in the database and create relevant indexes."""
queries = _create_table_and_index(table_name)
queries = _create_table_and_index(table_name, schema_name)
logger.info("Creating schema for table %s", table_name)
with connection.cursor() as cursor:
for query in queries:
Expand All @@ -220,18 +224,18 @@ def create_tables(

@staticmethod
async def acreate_tables(
connection: psycopg.AsyncConnection, table_name: str, /
connection: psycopg.AsyncConnection, table_name: str, schema_name: str = "public", /
) -> None:
"""Create the table schema in the database and create relevant indexes."""
queries = _create_table_and_index(table_name)
queries = _create_table_and_index(table_name, self._schema_name)
logger.info("Creating schema for table %s", table_name)
async with connection.cursor() as cur:
for query in queries:
await cur.execute(query)
await connection.commit()

@staticmethod
def drop_table(connection: psycopg.Connection, table_name: str, /) -> None:
def drop_table(connection: psycopg.Connection, table_name: str, schema_name: str = "public", /) -> None:
"""Delete the table schema in the database.

WARNING:
Expand All @@ -243,15 +247,15 @@ def drop_table(connection: psycopg.Connection, table_name: str, /) -> None:
table_name: The name of the table to create.
"""

query = _delete_table_query(table_name)
query = _delete_table_query(table_name, self._schema_name)
logger.info("Dropping table %s", table_name)
with connection.cursor() as cursor:
cursor.execute(query)
connection.commit()

@staticmethod
async def adrop_table(
connection: psycopg.AsyncConnection, table_name: str, /
connection: psycopg.AsyncConnection, table_name: str, schema_name: str = "public", /
) -> None:
"""Delete the table schema in the database.

Expand All @@ -263,7 +267,7 @@ async def adrop_table(
connection: Async database connection.
table_name: The name of the table to create.
"""
query = _delete_table_query(table_name)
query = _delete_table_query(table_name, self._schema_name)
logger.info("Dropping table %s", table_name)

async with connection.cursor() as acur:
Expand All @@ -283,7 +287,7 @@ def add_messages(self, messages: Sequence[BaseMessage]) -> None:
for message in messages
]

query = _insert_message_query(self._table_name)
query = _insert_message_query(self._table_name, self._schema_name)

with self._connection.cursor() as cursor:
cursor.executemany(query, values)
Expand All @@ -302,7 +306,7 @@ async def aadd_messages(self, messages: Sequence[BaseMessage]) -> None:
for message in messages
]

query = _insert_message_query(self._table_name)
query = _insert_message_query(self._table_name, self._schema_name)
async with self._aconnection.cursor() as cursor:
await cursor.executemany(query, values)
await self._aconnection.commit()
Expand All @@ -315,7 +319,7 @@ def get_messages(self) -> List[BaseMessage]:
"with a sync connection or use the async aget_messages method instead."
)

query = _get_messages_query(self._table_name)
query = _get_messages_query(self._table_name, self._schema_name)

with self._connection.cursor() as cursor:
cursor.execute(query, {"session_id": self._session_id})
Expand All @@ -332,7 +336,7 @@ async def aget_messages(self) -> List[BaseMessage]:
"with an async connection or use the sync get_messages method instead."
)

query = _get_messages_query(self._table_name)
query = _get_messages_query(self._table_name, self._schema_name)
async with self._aconnection.cursor() as cursor:
await cursor.execute(query, {"session_id": self._session_id})
items = [record[0] for record in await cursor.fetchall()]
Expand All @@ -345,12 +349,6 @@ def messages(self) -> List[BaseMessage]:
"""The abstraction required a property."""
return self.get_messages()

@messages.setter
def messages(self, value: list[BaseMessage]) -> None:
"""Clear the stored messages and appends a list of messages."""
self.clear()
self.add_messages(value)

def clear(self) -> None:
"""Clear the chat message history for the GIVEN session."""
if self._connection is None:
Expand All @@ -359,7 +357,7 @@ def clear(self) -> None:
"with a sync connection or use the async clear method instead."
)

query = _delete_by_session_id_query(self._table_name)
query = _delete_by_session_id_query(self._table_name, self._schema_name)
with self._connection.cursor() as cursor:
cursor.execute(query, {"session_id": self._session_id})
self._connection.commit()
Expand All @@ -372,7 +370,7 @@ async def aclear(self) -> None:
"with an async connection or use the sync clear method instead."
)

query = _delete_by_session_id_query(self._table_name)
query = _delete_by_session_id_query(self._table_name, self._schema_name)
async with self._aconnection.cursor() as cursor:
await cursor.execute(query, {"session_id": self._session_id})
await self._aconnection.commit()
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