robosats/api/lightning/node.py

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import grpc, os, hashlib, secrets, json
from . import lightning_pb2 as lnrpc, lightning_pb2_grpc as lightningstub
from . import invoices_pb2 as invoicesrpc, invoices_pb2_grpc as invoicesstub
from . import router_pb2 as routerrpc, router_pb2_grpc as routerstub
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from decouple import config
from base64 import b64decode
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from datetime import timedelta, datetime
from django.utils import timezone
from api.models import LNPayment
#######
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# Should work with LND (c-lightning in the future if there are features that deserve the work)
#######
CERT = b64decode(config('LND_CERT_BASE64'))
MACAROON = b64decode(config('LND_MACAROON_BASE64'))
LND_GRPC_HOST = config('LND_GRPC_HOST')
class LNNode():
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os.environ["GRPC_SSL_CIPHER_SUITES"] = 'HIGH+ECDSA'
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creds = grpc.ssl_channel_credentials(CERT)
channel = grpc.secure_channel(LND_GRPC_HOST, creds)
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lightningstub = lightningstub.LightningStub(channel)
invoicesstub = invoicesstub.InvoicesStub(channel)
routerstub = routerstub.RouterStub(channel)
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lnrpc = lnrpc
invoicesrpc = invoicesrpc
routerrpc = routerrpc
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payment_failure_context = {
0: "Payment isn't failed (yet)",
1: "There are more routes to try, but the payment timeout was exceeded.",
2: "All possible routes were tried and failed permanently. Or were no routes to the destination at all.",
3: "A non-recoverable error has occured.",
4: "Payment details incorrect (unknown hash, invalid amt or invalid final cltv delta)",
5: "Insufficient local balance."}
@classmethod
def decode_payreq(cls, invoice):
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'''Decodes a lightning payment request (invoice)'''
request = lnrpc.PayReqString(pay_req=invoice)
response = cls.lightningstub.DecodePayReq(request, metadata=[('macaroon', MACAROON.hex())])
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return response
@classmethod
def cancel_return_hold_invoice(cls, payment_hash):
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'''Cancels or returns a hold invoice'''
request = invoicesrpc.CancelInvoiceMsg(payment_hash=bytes.fromhex(payment_hash))
response = cls.invoicesstub.CancelInvoice(request, metadata=[('macaroon', MACAROON.hex())])
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# Fix this: tricky because canceling sucessfully an invoice has no response. TODO
return str(response) == "" # True if no response, false otherwise.
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@classmethod
def settle_hold_invoice(cls, preimage):
'''settles a hold invoice'''
request = invoicesrpc.SettleInvoiceMsg(preimage=bytes.fromhex(preimage))
response = cls.invoicesstub.SettleInvoice(request, metadata=[('macaroon', MACAROON.hex())])
# Fix this: tricky because settling sucessfully an invoice has None response. TODO
return str(response)=="" # True if no response, false otherwise.
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@classmethod
def gen_hold_invoice(cls, num_satoshis, description, invoice_expiry, cltv_expiry_secs):
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'''Generates hold invoice'''
hold_payment = {}
# The preimage is a random hash of 256 bits entropy
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preimage = hashlib.sha256(secrets.token_bytes(nbytes=32)).digest()
# Its hash is used to generate the hold invoice
r_hash = hashlib.sha256(preimage).digest()
# timelock expiry for the last hop, computed based on a 10 minutes block with 30% padding (~7 min block)
cltv_expiry_blocks = int(cltv_expiry_secs / (7*60))
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request = invoicesrpc.AddHoldInvoiceRequest(
memo=description,
value=num_satoshis,
hash=r_hash,
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expiry=int(invoice_expiry*1.5), # actual expiry is padded by 50%, if tight, wrong client system clock will say invoice is expired.
cltv_expiry=cltv_expiry_blocks,
)
response = cls.invoicesstub.AddHoldInvoice(request, metadata=[('macaroon', MACAROON.hex())])
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hold_payment['invoice'] = response.payment_request
payreq_decoded = cls.decode_payreq(hold_payment['invoice'])
hold_payment['preimage'] = preimage.hex()
hold_payment['payment_hash'] = payreq_decoded.payment_hash
hold_payment['created_at'] = timezone.make_aware(datetime.fromtimestamp(payreq_decoded.timestamp))
hold_payment['expires_at'] = hold_payment['created_at'] + timedelta(seconds=payreq_decoded.expiry)
hold_payment['cltv_expiry'] = cltv_expiry_blocks
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return hold_payment
@classmethod
def validate_hold_invoice_locked(cls, lnpayment):
'''Checks if hold invoice is locked'''
request = invoicesrpc.LookupInvoiceMsg(payment_hash=bytes.fromhex(lnpayment.payment_hash))
response = cls.invoicesstub.LookupInvoiceV2(request, metadata=[('macaroon', MACAROON.hex())])
print('status here')
print(response.state)
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# TODO ERROR HANDLING
# Will fail if 'unable to locate invoice'. Happens if invoice expiry
# time has passed (but these are 15% padded at the moment). Should catch it
# and report back that the invoice has expired (better robustness)
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if response.state == 0: # OPEN
print('STATUS: OPEN')
pass
if response.state == 1: # SETTLED
pass
if response.state == 2: # CANCELLED
pass
if response.state == 3: # ACCEPTED (LOCKED)
print('STATUS: ACCEPTED')
lnpayment.expiry_height = response.htlcs[0].expiry_height
lnpayment.status = LNPayment.Status.LOCKED
lnpayment.save()
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return True
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@classmethod
def resetmc(cls):
request = routerrpc.ResetMissionControlRequest()
response = cls.routerstub.ResetMissionControl(request, metadata=[('macaroon', MACAROON.hex())])
return True
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@classmethod
def validate_ln_invoice(cls, invoice, num_satoshis):
'''Checks if the submited LN invoice comforms to expectations'''
payout = {
'valid': False,
'context': None,
'description': None,
'payment_hash': None,
'created_at': None,
'expires_at': None,
}
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try:
payreq_decoded = cls.decode_payreq(invoice)
print(payreq_decoded)
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except:
payout['context'] = {'bad_invoice':'Does not look like a valid lightning invoice'}
return payout
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if payreq_decoded.num_satoshis == 0:
payout['context'] = {'bad_invoice':'The invoice provided has no explicit amount'}
return payout
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if not payreq_decoded.num_satoshis == num_satoshis:
payout['context'] = {'bad_invoice':'The invoice provided is not for '+'{:,}'.format(num_satoshis)+ ' Sats'}
return payout
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payout['created_at'] = timezone.make_aware(datetime.fromtimestamp(payreq_decoded.timestamp))
payout['expires_at'] = payout['created_at'] + timedelta(seconds=payreq_decoded.expiry)
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if payout['expires_at'] < timezone.now():
payout['context'] = {'bad_invoice':f'The invoice provided has already expired'}
return payout
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payout['valid'] = True
payout['description'] = payreq_decoded.description
payout['payment_hash'] = payreq_decoded.payment_hash
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return payout
@classmethod
def pay_invoice(cls, invoice, num_satoshis):
'''Sends sats to buyer'''
fee_limit_sat = int(max(num_satoshis * float(config('PROPORTIONAL_ROUTING_FEE_LIMIT')), float(config('MIN_FLAT_ROUTING_FEE_LIMIT')))) # 200 ppm or 10 sats
request = routerrpc.SendPaymentRequest(
payment_request=invoice,
fee_limit_sat=fee_limit_sat,
timeout_seconds=60)
for response in cls.routerstub.SendPaymentV2(request, metadata=[('macaroon', MACAROON.hex())]):
print(response)
print(response.status)
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# TODO ERROR HANDLING
if response.status == 0 : # Status 0 'UNKNOWN'
pass
if response.status == 1 : # Status 1 'IN_FLIGHT'
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return True, 'In flight'
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if response.status == 3 : # 4 'FAILED' ??
'''0 Payment isn't failed (yet).
1 There are more routes to try, but the payment timeout was exceeded.
2 All possible routes were tried and failed permanently. Or were no routes to the destination at all.
3 A non-recoverable error has occured.
4 Payment details incorrect (unknown hash, invalid amt or invalid final cltv delta)
5 Insufficient local balance.
'''
context = cls.payment_failure_context[response.failure_reason]
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return False, context
if response.status == 2 : # STATUS 'SUCCEEDED'
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return True, None
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# How to catch the errors like:"grpc_message":"invoice is already paid","grpc_status":6}
# These are not in the response only printed to commandline
return False
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@classmethod
def double_check_htlc_is_settled(cls, payment_hash):
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''' Just as it sounds. Better safe than sorry!'''
request = invoicesrpc.LookupInvoiceMsg(payment_hash=bytes.fromhex(payment_hash))
response = cls.invoicesstub.LookupInvoiceV2(request, metadata=[('macaroon', MACAROON.hex())])
return response.state == 1 # LND states: 0 OPEN, 1 SETTLED, 3 ACCEPTED, GRPC_ERROR status 5 when cancelled/returned
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