commands: add command to fetch nostr swap providers
What the developer wrote
Authored by f321x
commands: add command to fetch nostr swap providers
What changed, and why it matters
This commit adds a new Electrum command that lets users discover submarine swap providers over the Nostr peer-to-peer network. It also adds safety checks so users must configure a provider before performing swaps, and replaces an indefinite wait with a 15-second timeout. There is no obvious vulnerability in the diff itself; it is a feature addition with minor hardening.
Review the new RPC command for input sanitization (e.g., enforce a reasonable maximum `query_time`), ensure Nostr provider announcements are validated or rate-limited, and confirm that the command is not exposed in contexts where untrusted callers can abuse it. No immediate patch appears necessary from this diff alone.
Security signals we found
New network-facing RPC command added
Relies on external Nostr relays for provider discovery
No explicit validation of query_time parameter
Adds assertion requiring swap provider configuration before swap execution
Replaces indefinite wait with bounded 15-second timeout
No authentication or trust model described for Nostr provider announcements
Evidence from the diff
The patch introduces get_submarine_swap_providers, an async RPC command that opens a NostrTransport, waits query_time seconds (default 15), and returns a dict of recently announced submarine swap offers. It also modifies normal_swap and reverse_swap to require SWAPSERVER_NPUB or SWAPSERVER_URL and to time out after 15 seconds if the swap manager is not initialized. The new command is decorated with @command('wnl'), meaning it requires a wallet, network, and lightning worker. No input validation is added for query_time, and the command blindly trusts Nostr relay data for provider advertisements.
Changed components
electrum/commands.pyRPC command layerSubmarine swap / Nostr transport integrationInspect captured patch +39 / −2
diff --git a/electrum/commands.py b/electrum/commands.py
index 4639a5e..6bc172e 100644
--- a/electrum/commands.py
+++ b/electrum/commands.py
@@ -46,6 +46,7 @@ from . import util
from .lnmsg import OnionWireSerializer
from .logging import Logger
from .onion_message import create_blinded_path, send_onion_message_to
+from .submarine_swaps import NostrTransport
from .util import (
bfh, json_decode, json_normalize, is_hash256_str, is_hex_str, to_bytes, parse_max_spend, to_decimal,
UserFacingException, InvalidPassword
@@ -1966,6 +1967,32 @@ class Commands(Logger):
'log': [x.formatted_tuple() for x in log]
}
+ @command('wnl')
+ async def get_submarine_swap_providers(self, query_time=15, wallet: Abstract_Wallet = None):
+ """
+ Queries nostr relays for available submarine swap providers.
+
+ To configure one of the providers use:
+ setconfig swapserver_npub 'npub...'
+
+ arg:int:query_time:Optional timeout how long the relays should be queried for provider announcements. Default: 15 sec
+ """
+ sm = wallet.lnworker.swap_manager
+ async with sm.create_transport() as transport:
+ assert isinstance(transport, NostrTransport)
+ await asyncio.sleep(query_time)
+ offers = transport.get_recent_offers()
+ result = {}
+ for offer in offers:
+ result[offer.server_npub] = {
+ "percentage_fee": offer.pairs.percentage,
+ "max_forward_sat": offer.pairs.max_forward,
+ "max_reverse_sat": offer.pairs.max_reverse,
+ "min_amount_sat": offer.pairs.min_amount,
+ "provider_mining_fee": offer.pairs.mining_fee,
+ }
+ return result
+
@command('wnpl')
async def normal_swap(self, onchain_amount, lightning_amount, password=None, wallet: Abstract_Wallet = None):
"""
@@ -1975,8 +2002,13 @@ class Commands(Logger):
arg:decimal_or_dryrun:onchain_amount:Amount to be sent, in BTC. Set it to 'dryrun' to receive a value
"""
sm = wallet.lnworker.swap_manager
+ assert self.config.SWAPSERVER_NPUB or self.config.SWAPSERVER_URL, \
+ "Configure swap provider first. See 'get_submarine_swap_providers'."
async with sm.create_transport() as transport:
- await sm.is_initialized.wait()
+ try:
+ await asyncio.wait_for(sm.is_initialized.wait(), timeout=15)
+ except asyncio.TimeoutError:
+ raise TimeoutError("Could not find configured swap provider. Setup another one. See 'get_submarine_swap_providers'")
if lightning_amount == 'dryrun':
onchain_amount_sat = satoshis(onchain_amount)
lightning_amount_sat = sm.get_recv_amount(onchain_amount_sat, is_reverse=False)
@@ -2013,8 +2045,13 @@ class Commands(Logger):
arg:decimal_or_dryrun:provider_mining_fee:Mining fee required by the swap provider, in BTC. Set it to 'dryrun' to receive a value
"""
sm = wallet.lnworker.swap_manager
+ assert self.config.SWAPSERVER_NPUB or self.config.SWAPSERVER_URL, \
+ "Configure swap provider first. See 'get_submarine_swap_providers'."
async with sm.create_transport() as transport:
- await sm.is_initialized.wait()
+ try:
+ await asyncio.wait_for(sm.is_initialized.wait(), timeout=15)
+ except asyncio.TimeoutError:
+ raise TimeoutError("Could not find configured swap provider. Setup another one. See 'get_submarine_swap_providers'")
if onchain_amount == 'dryrun':
lightning_amount_sat = satoshis(lightning_amount)
onchain_amount_sat = sm.get_recv_amount(lightning_amount_sat, is_reverse=True)
Why this scored 19/100
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