Add an Admin API endpoint for looking up users based on 3PID

[ashfame]

This PR adds an admin API endpoint for finding users with their Three PID.

As of now, it isn't possible to query users by their 3PID without database access, as documented in #13490

Signed-off-by: Ashish Kumar ashfame@users.noreply.github.com

[ashfame]

Also, please advice on how _Added in Synapse 1.XX.X._ in docs/admin_api/user_admin_api.md is to be managed.

[DMRobertson]

Thanks, this looks great. Other than a small tweak to the docs and changelog I think this is good to go.

[DMRobertson]

I think this is only going to find local users, i.e. we won't contact an identity server to lookup a 3PID bound to another homeserver? If so, it'd be good to say so in a short sentence.

[ashfame]

Yeah, that was my intention. I am not sure if its supposed to do remote user lookups too?

[DMRobertson]

It shouldn't. The function that gets called is

synapse/synapse/storage/databases/main/registration.py

Lines 934 to 972 in cc3a52b

	async def get_user_id_by_threepid(self, medium: str, address: str) -> Optional[str]:
	"""Returns user id from threepid
	Args:
	medium: threepid medium e.g. email
	address: threepid address e.g. me@example.com. This must already be
	in canonical form.
	Returns:
	The user ID or None if no user id/threepid mapping exists
	"""
	user_id = await self.db_pool.runInteraction(
	"get_user_id_by_threepid", self.get_user_id_by_threepid_txn, medium, address
	)
	return user_id
	def get_user_id_by_threepid_txn(
	self, txn: LoggingTransaction, medium: str, address: str
	) -> Optional[str]:
	"""Returns user id from threepid
	Args:
	txn (cursor):
	medium: threepid medium e.g. email
	address: threepid address e.g. me@example.com
	Returns:
	user id, or None if no user id/threepid mapping exists
	"""
	ret = self.db_pool.simple_select_one_txn(
	txn,
	"user_threepids",
	{"medium": medium, "address": address},
	["user_id"],
	True,
	)
	if ret:
	return ret["user_id"]
	return None

which amounts to SELECT user_id FROM user_threepids WHERE medium = ? AND address = ? LIMIT 1. AFAIK that table only contains threepids for local users.

[DMRobertson]

Can you merge in develop to see if that makes CI happy?

[ashfame]

CI is not completely happy :(

[DMRobertson]

CI is not completely happy :(

That's a known flake (#13199).

[DMRobertson]

Thanks!

[ashfame]

@DMRobertson This probably needs to be merged manually because of the flaky test?

[DMRobertson]

Thanks. I saw the failure and noted it on #13565, but forgot to manually merge.