Files
lnbits/lnbits/utils/electrum.py
T

440 lines
14 KiB
Python

"""
Electrum protocol client (https://github.com/spesmilo/electrum-protocol).
JSON-RPC 2.0 over TCP / SSL (newline-delimited), with request/response
correlation, subscription dispatch, and automatic keepalive pings.
server.version is sent automatically on connect as required by the spec.
"""
import asyncio
import hashlib
import itertools
import json
import ssl
from collections.abc import Callable
from typing import Any
from urllib.parse import urlparse
from loguru import logger
from pydantic import BaseModel
class ElectrumError(Exception):
pass
def scripthash_from_scriptpubkey(scriptpubkey: bytes) -> str:
"""Electrum script hash: SHA-256 of scriptPubKey, byte-reversed to hex."""
return hashlib.sha256(scriptpubkey).digest()[::-1].hex()
# ---------------------------------------------------------------------------
# Response models
# ---------------------------------------------------------------------------
class Balance(BaseModel):
confirmed: int
unconfirmed: int
class HistoryEntry(BaseModel):
tx_hash: str
height: int
fee: int | None = None # present for mempool entries
class MempoolEntry(BaseModel):
tx_hash: str
height: int
fee: int
class UTXO(BaseModel):
tx_hash: str
tx_pos: int
height: int
value: int # satoshis
class BlockHeader(BaseModel):
height: int
hex: str
class BlockHeaderProof(BaseModel):
"""Returned by get_block_header when cp_height > 0."""
branch: list[str]
header: str
root: str
class BlockHeaders(BaseModel):
count: int
hex: str
max: int
class MerkleProof(BaseModel):
block_height: int
merkle: list[str]
pos: int
class TxIdWithMerkle(BaseModel):
tx_hash: str
merkle: list[str]
class FeeHistogramEntry(BaseModel):
fee_rate: float
vsize: float
class ServerFeatures(BaseModel):
class Config:
extra = "allow"
genesis_hash: str = ""
protocol_max: str = ""
protocol_min: str = ""
server_version: str = ""
pruning: int | None = None
hash_function: str = "sha256d"
hosts: dict[str, Any] = {}
# ---------------------------------------------------------------------------
# Client
# ---------------------------------------------------------------------------
class ElectrumClient:
"""
Async Electrum protocol client over plain TCP or SSL.
Messages are newline-terminated JSON-RPC 2.0, as required by the spec.
Handles request/response correlation by id, routes push notifications to
registered callbacks, and sends periodic pings to keep the connection alive.
Usage::
# Plain TCP
async with ElectrumClient("tcp://blockstream.info:110") as client:
height = await client.get_height()
# SSL
async with ElectrumClient("ssl://electrum.blockstream.info:50002") as c:
height = await c.get_height()
"""
def __init__(
self,
url: str,
client_name: str = "lnbits",
protocol_version: str = "1.4",
ping_interval: float = 60.0,
) -> None:
parsed = urlparse(url)
self.host = parsed.hostname or ""
self.port = parsed.port or (
50002 if parsed.scheme in ("ssl", "https") else 50001
)
self.use_ssl = parsed.scheme in ("ssl", "https")
self.client_name = client_name
self.protocol_version = protocol_version
self.ping_interval = ping_interval
self._counter = itertools.count(1)
self._pending: dict[int, asyncio.Future[Any]] = {}
self._subscriptions: dict[str, list[Callable[[list[Any]], Any]]] = {}
self._recv_task: asyncio.Task[None] | None = None
self._ping_task: asyncio.Task[None] | None = None
self._reader: asyncio.StreamReader | None = None
self._writer: asyncio.StreamWriter | None = None
self.server_version: str = ""
self.negotiated_protocol: str = ""
async def connect(self, timeout: float = 10.0) -> None:
ssl_ctx: ssl.SSLContext | None = None
if self.use_ssl:
ssl_ctx = ssl.create_default_context()
self._reader, self._writer = await asyncio.wait_for(
asyncio.open_connection(
self.host, self.port, ssl=ssl_ctx, limit=4 * 1024 * 1024
),
timeout=timeout,
)
self._recv_task = asyncio.create_task(self._recv_loop())
result = await self._call(
"server.version", [self.client_name, self.protocol_version], timeout=timeout
)
self.server_version, self.negotiated_protocol = result[0], result[1]
logger.debug(
f"Electrum connected: server={self.server_version}"
f" protocol={self.negotiated_protocol}"
)
if self.ping_interval > 0:
self._ping_task = asyncio.create_task(self._ping_loop())
async def close(self) -> None:
for task in (self._ping_task, self._recv_task):
if task:
task.cancel()
try:
await task
except asyncio.CancelledError:
pass
except Exception:
logger.debug("Electrum: error while cancelling task")
self._ping_task = None
self._recv_task = None
if self._writer:
self._writer.close()
try:
await asyncio.wait_for(self._writer.wait_closed(), timeout=5.0)
except Exception:
logger.debug("Electrum: error while closing writer")
self._reader = None
self._writer = None
async def __aenter__(self) -> "ElectrumClient":
try:
await self.connect()
except BaseException:
await self.close()
raise
return self
async def __aexit__(self, *_: Any) -> None:
await self.close()
# ---- internal plumbing ----
async def _call(
self,
method: str,
params: list[Any] | dict[str, Any] | None = None,
timeout: float = 30.0,
) -> Any:
if not self._writer:
raise ElectrumError("Not connected")
req_id = next(self._counter)
fut: asyncio.Future[Any] = asyncio.get_running_loop().create_future()
self._pending[req_id] = fut
self._writer.write(
json.dumps(
{
"jsonrpc": "2.0",
"id": req_id,
"method": method,
"params": params if params is not None else [],
}
).encode()
+ b"\n"
)
await self._writer.drain()
try:
return await asyncio.wait_for(asyncio.shield(fut), timeout=timeout)
except asyncio.TimeoutError as exc:
self._pending.pop(req_id, None)
raise ElectrumError(f"Timeout waiting for response to {method!r}") from exc
def _dispatch(self, msg: dict[str, Any]) -> None:
msg_id = msg.get("id")
if msg_id is not None:
fut = self._pending.pop(msg_id, None)
if fut and not fut.done():
err = msg.get("error")
if err:
fut.set_exception(ElectrumError(err))
else:
fut.set_result(msg.get("result"))
else:
method = msg.get("method", "")
params = msg.get("params", [])
for cb in list(self._subscriptions.get(method, [])):
try:
result = cb(params)
if asyncio.iscoroutine(result):
self._bg_tasks.add(asyncio.create_task(result))
except Exception:
logger.exception(f"Electrum: callback error for {method!r}")
async def _recv_loop(self) -> None:
assert self._reader
self._bg_tasks: set[asyncio.Task[Any]] = set()
buf = b""
try:
while True:
chunk = await self._reader.read(65536)
if not chunk:
break
buf += chunk
while b"\n" in buf:
line, buf = buf.split(b"\n", 1)
if not line.strip():
continue
try:
msg: dict[str, Any] = json.loads(line)
except json.JSONDecodeError:
logger.warning(f"Electrum: invalid JSON: {line!r}")
continue
self._dispatch(msg)
except asyncio.CancelledError:
pass
except Exception:
logger.exception("Electrum: recv loop error")
finally:
for fut in self._pending.values():
if not fut.done():
fut.set_exception(ElectrumError("Connection closed"))
self._pending.clear()
async def _ping_loop(self) -> None:
try:
while True:
await asyncio.sleep(self.ping_interval)
await self._call("server.ping")
except asyncio.CancelledError:
pass
except Exception:
logger.exception("Electrum: ping loop error")
# ---- subscription management ----
def on(self, method: str, callback: Callable[[list[Any]], Any]) -> None:
"""Register a notification callback for a subscription method."""
self._subscriptions.setdefault(method, []).append(callback)
def off(self, method: str, callback: Callable[[list[Any]], Any]) -> None:
"""Remove a previously registered notification callback."""
cbs = self._subscriptions.get(method)
if cbs and callback in cbs:
cbs.remove(callback)
# ---- server methods ----
async def server_ping(self) -> None:
await self._call("server.ping")
async def server_banner(self) -> str:
return await self._call("server.banner")
async def server_features(self) -> ServerFeatures:
data = await self._call("server.features")
return ServerFeatures.parse_obj(data)
async def server_peers(self) -> list[Any]:
return await self._call("server.peers.subscribe")
# ---- scripthash methods ----
async def get_balance(self, scripthash: str) -> Balance:
data = await self._call("blockchain.scripthash.get_balance", [scripthash])
return Balance.parse_obj(data)
async def get_history(self, scripthash: str) -> list[HistoryEntry]:
data = await self._call("blockchain.scripthash.get_history", [scripthash])
return [HistoryEntry.parse_obj(e) for e in data]
async def get_mempool(self, scripthash: str) -> list[MempoolEntry]:
data = await self._call("blockchain.scripthash.get_mempool", [scripthash])
return [MempoolEntry.parse_obj(e) for e in data]
async def listunspent(self, scripthash: str) -> list[UTXO]:
data = await self._call("blockchain.scripthash.listunspent", [scripthash])
return [UTXO.parse_obj(e) for e in data]
async def subscribe_scripthash(
self,
scripthash: str,
callback: Callable[[list[Any]], Any] | None = None,
) -> str | None:
"""Subscribe to status changes; returns current status hash or None."""
if callback:
self.on("blockchain.scripthash.subscribe", callback)
return await self._call("blockchain.scripthash.subscribe", [scripthash])
async def unsubscribe_scripthash(
self,
scripthash: str,
callback: Callable[[list[Any]], Any] | None = None,
) -> bool:
if callback:
self.off("blockchain.scripthash.subscribe", callback)
return await self._call("blockchain.scripthash.unsubscribe", [scripthash])
async def subscribe_headers(
self,
callback: Callable[[list[Any]], Any] | None = None,
) -> BlockHeader:
"""Subscribe to new block headers; returns current tip."""
if callback:
self.on("blockchain.headers.subscribe", callback)
data = await self._call("blockchain.headers.subscribe")
return BlockHeader.parse_obj(data)
# ---- transaction methods ----
async def broadcast(self, raw_tx: str) -> str:
"""Broadcast a raw transaction hex; returns txid on success."""
return await self._call("blockchain.transaction.broadcast", [raw_tx])
async def get_transaction(
self, txid: str, verbose: bool = False
) -> str | dict[str, Any]:
return await self._call("blockchain.transaction.get", [txid, verbose])
async def get_merkle(self, txid: str, height: int) -> MerkleProof:
data = await self._call("blockchain.transaction.get_merkle", [txid, height])
return MerkleProof.parse_obj(data)
async def get_tx_id_from_pos(
self, height: int, tx_pos: int, merkle: bool = False
) -> str | TxIdWithMerkle:
data = await self._call(
"blockchain.transaction.id_from_pos", [height, tx_pos, merkle]
)
if isinstance(data, dict):
return TxIdWithMerkle.parse_obj(data)
return data
# ---- block methods ----
async def get_tip(self) -> BlockHeader:
"""Returns current chain tip."""
data = await self._call("blockchain.headers.subscribe")
return BlockHeader.parse_obj(data)
async def get_height(self) -> int:
"""Returns the current best block height."""
return (await self.get_tip()).height
async def get_block_header(
self, height: int, cp_height: int = 0
) -> str | BlockHeaderProof:
data = await self._call("blockchain.block.header", [height, cp_height])
if isinstance(data, dict):
return BlockHeaderProof.parse_obj(data)
return data
async def get_block_headers(
self, start_height: int, count: int, cp_height: int = 0
) -> BlockHeaders:
data = await self._call(
"blockchain.block.headers", [start_height, count, cp_height]
)
return BlockHeaders.parse_obj(data)
# ---- fee methods ----
async def estimate_fee(self, num_blocks: int) -> float:
"""Returns estimated fee rate in BTC/kB for confirmation within num_blocks."""
return await self._call("blockchain.estimatefee", [num_blocks])
async def fee_histogram(self) -> list[FeeHistogramEntry]:
"""Returns mempool fee histogram as FeeHistogramEntry(fee_rate, vsize) list."""
data = await self._call("mempool.get_fee_histogram")
return [FeeHistogramEntry(fee_rate=r[0], vsize=r[1]) for r in data]