From 6d7ba58f880be618ade07f8ea080fe8c4bf8a896 Mon Sep 17 00:00:00 2001
From: cyfraeviolae <cyfraeviolae>
Date: Wed, 3 Apr 2024 03:10:44 -0400
Subject: venv

---
 .../litestar/channels/backends/psycopg.py          | 54 ++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 venv/lib/python3.11/site-packages/litestar/channels/backends/psycopg.py

(limited to 'venv/lib/python3.11/site-packages/litestar/channels/backends/psycopg.py')

diff --git a/venv/lib/python3.11/site-packages/litestar/channels/backends/psycopg.py b/venv/lib/python3.11/site-packages/litestar/channels/backends/psycopg.py
new file mode 100644
index 0000000..14b53bc
--- /dev/null
+++ b/venv/lib/python3.11/site-packages/litestar/channels/backends/psycopg.py
@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from contextlib import AsyncExitStack
+from typing import AsyncGenerator, Iterable
+
+import psycopg
+
+from .base import ChannelsBackend
+
+
+def _safe_quote(ident: str) -> str:
+    return '"{}"'.format(ident.replace('"', '""'))  # sourcery skip
+
+
+class PsycoPgChannelsBackend(ChannelsBackend):
+    _listener_conn: psycopg.AsyncConnection
+
+    def __init__(self, pg_dsn: str) -> None:
+        self._pg_dsn = pg_dsn
+        self._subscribed_channels: set[str] = set()
+        self._exit_stack = AsyncExitStack()
+
+    async def on_startup(self) -> None:
+        self._listener_conn = await psycopg.AsyncConnection.connect(self._pg_dsn, autocommit=True)
+        await self._exit_stack.enter_async_context(self._listener_conn)
+
+    async def on_shutdown(self) -> None:
+        await self._exit_stack.aclose()
+
+    async def publish(self, data: bytes, channels: Iterable[str]) -> None:
+        dec_data = data.decode("utf-8")
+        async with await psycopg.AsyncConnection.connect(self._pg_dsn) as conn:
+            for channel in channels:
+                await conn.execute("SELECT pg_notify(%s, %s);", (channel, dec_data))
+
+    async def subscribe(self, channels: Iterable[str]) -> None:
+        for channel in set(channels) - self._subscribed_channels:
+            # can't use placeholders in LISTEN
+            await self._listener_conn.execute(f"LISTEN {_safe_quote(channel)};")  # pyright: ignore
+
+            self._subscribed_channels.add(channel)
+
+    async def unsubscribe(self, channels: Iterable[str]) -> None:
+        for channel in channels:
+            # can't use placeholders in UNLISTEN
+            await self._listener_conn.execute(f"UNLISTEN {_safe_quote(channel)};")  # pyright: ignore
+        self._subscribed_channels = self._subscribed_channels - set(channels)
+
+    async def stream_events(self) -> AsyncGenerator[tuple[str, bytes], None]:
+        async for notify in self._listener_conn.notifies():
+            yield notify.channel, notify.payload.encode("utf-8")
+
+    async def get_history(self, channel: str, limit: int | None = None) -> list[bytes]:
+        raise NotImplementedError()
-- 
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