zulip/zerver/lib/stream_recipient.py

72 lines
2.4 KiB
Python

from typing import (Dict, List)
from django.db import connection
from psycopg2.sql import SQL
from zerver.models import Recipient
class StreamRecipientMap:
'''
This class maps stream_id -> recipient_id and vice versa.
It is useful for bulk operations. Call the populate_* methods
to initialize the data structures. You should try to avoid
excessive queries by finding ids up front, but you can call
this repeatedly, and it will only look up new ids.
You should ONLY use this class for READ operations.
Note that this class uses raw SQL, because we want to highly
optimize page loads.
'''
def __init__(self) -> None:
self.recip_to_stream: Dict[int, int] = dict()
self.stream_to_recip: Dict[int, int] = dict()
def populate_with(self, *, stream_id: int, recipient_id: int) -> None:
# We use * to enforce using named arguments when calling this function,
# to avoid confusion about the ordering of the two integers.
self.recip_to_stream[recipient_id] = stream_id
self.stream_to_recip[stream_id] = recipient_id
def populate_for_recipient_ids(self, recipient_ids: List[int]) -> None:
recipient_ids = sorted([
recip_id for recip_id in recipient_ids
if recip_id not in self.recip_to_stream
])
if not recipient_ids:
return
# see comment at the top of the class
query = SQL('''
SELECT
zerver_recipient.id as recipient_id,
zerver_recipient.type_id as stream_id
FROM
zerver_recipient
WHERE
zerver_recipient.type = %(STREAM)s
AND
zerver_recipient.id in %(recipient_ids)s
''')
cursor = connection.cursor()
cursor.execute(query, {
"STREAM": Recipient.STREAM,
"recipient_ids": tuple(recipient_ids),
})
rows = cursor.fetchall()
cursor.close()
for recip_id, stream_id in rows:
self.recip_to_stream[recip_id] = stream_id
self.stream_to_recip[stream_id] = recip_id
def recipient_id_for(self, stream_id: int) -> int:
return self.stream_to_recip[stream_id]
def stream_id_for(self, recip_id: int) -> int:
return self.recip_to_stream[recip_id]
def recipient_to_stream_id_dict(self) -> Dict[int, int]:
return self.recip_to_stream