Init work on Lightning functionality

.env-sample

@@ -1,3 +1,9 @@
+# base64 ~/.lnd/tls.cert | tr -d '\n'
+LND_CERT_BASE64=''
+# base64 ~/.lnd/data/chain/bitcoin/testnet/admin.macaroon | tr -d '\n'
+LND_MACAROON_BASE64=''
+LND_GRPC_HOST='127.0.0.1:10009'
+
 # Market price public API
 MARKET_PRICE_API = 'https://blockchain.info/ticker'
 
@@ -5,8 +11,8 @@ MARKET_PRICE_API = 'https://blockchain.info/ticker'
 FEE = 0.002
 # Bond size in percentage %     
 BOND_SIZE = 0.01
-# Time out penalty for canceling takers in MINUTES
-PENALTY_TIMEOUT = 2
+# Time out penalty for canceling takers in SECONDS
+PENALTY_TIMEOUT = 60
 
 # Trade limits in satoshis
 MIN_TRADE = 10000 

.gitignore

@@ -642,4 +642,5 @@ frontend/static/frontend/main*
 # robosats
 frontend/static/assets/avatars*
 api/lightning/lightning*
+api/lightning/invoices*
 api/lightning/googleapis*

api/lightning/node.py

@@ -1,37 +1,83 @@
-import codecs, grpc, os
-from . import lightning_pb2 as ln
-from . import lightning_pb2_grpc as lnrpc
+import grpc, os, hashlib, secrets, json
+import lightning_pb2 as lnrpc, lightning_pb2_grpc as lightningstub
+import invoices_pb2 as invoicesrpc, invoices_pb2_grpc as invoicesstub
 
-from datetime import timedelta
+from decouple import config
+from base64 import b64decode
+
+from datetime import timedelta, datetime
 from django.utils import timezone
 
-import random
-import string
-
 #######
-# Placeholder functions
-# Should work with LND (maybe c-lightning in the future)
+# 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():
-    '''
-    Place holder functions to interact with Lightning Node
-    '''
 
-    # macaroon = codecs.encode(open('LND_DIR/data/chain/bitcoin/simnet/admin.macaroon', 'rb').read(), 'hex')
-    # os.environ['GRPC_SSL_CIPHER_SUITES'] = 'HIGH+ECDSA'
-    # cert = open('LND_DIR/tls.cert', 'rb').read()
-    # ssl_creds = grpc.ssl_channel_credentials(cert)
-    # channel = grpc.secure_channel('localhost:10009', ssl_creds)
-    # stub = lightningstub.LightningStub(channel)
-    
-    def gen_hold_invoice(num_satoshis, description, expiry):
-        '''Generates hold invoice to publish an order'''
-        # TODO
-        invoice = ''.join(random.choices(string.ascii_uppercase + string.digits, k=80)) #FIX
-        payment_hash = ''.join(random.choices(string.ascii_uppercase + string.digits, k=40)) #FIX
-        expires_at = timezone.now() + timedelta(hours=8)  ##FIX
+    os.environ["GRPC_SSL_CIPHER_SUITES"] = 'HIGH+ECDSA'
 
-        return invoice, payment_hash, expires_at 
+    creds = grpc.ssl_channel_credentials(CERT)
+    channel = grpc.secure_channel(LND_GRPC_HOST, creds)
+
+    lightningstub = lightningstub.LightningStub(channel)
+    invoicesstub = invoicesstub.InvoicesStub(channel)
+
+    def decode_payreq(invoice):
+        '''Decodes a lightning payment request (invoice)'''
+        request = lnrpc.PayReqString(pay_req=invoice)
+        response = lightningstub.DecodePayReq(request, metadata=[('macaroon', MACAROON.hex())])
+        return response
+
+    def cancel_return_hold_invoice(payment_hash):
+        '''Cancels or returns a hold invoice'''
+        request = invoicesrpc.CancelInvoiceMsg(payment_hash=bytes.fromhex(payment_hash))
+        response = invoicesstub.CancelInvoice(request, metadata=[('macaroon', MACAROON.hex())])
+
+        # Fix this: tricky because canceling sucessfully an invoice has no response. TODO
+        if response == None:
+            return True
+        else:
+            return False
+
+    def settle_hold_invoice(preimage):
+        # SETTLING A HODL INVOICE
+        request = invoicesrpc.SettleInvoiceMsg(preimage=preimage)
+        response = invoicesstub.SettleInvoice(request, metadata=[('macaroon', MACAROON.hex())])
+        # Fix this: tricky because canceling sucessfully an invoice has no response. TODO
+        if response == None:
+            return True
+        else:
+            return False
+
+    @classmethod
+    def gen_hold_invoice(cls, num_satoshis, description, expiry):
+        '''Generates hold invoice'''
+
+        # The preimage will be a random hash of 256 bits entropy
+        preimage =  hashlib.sha256(secrets.token_bytes(nbytes=32)).digest() 
+
+        # Its hash is used to generate the hold invoice
+        preimage_hash = hashlib.sha256(preimage).digest()
+
+        request = invoicesrpc.AddHoldInvoiceRequest(
+                memo=description,
+                value=num_satoshis,
+                hash=preimage_hash,
+                expiry=expiry)
+        response = invoicesstub.AddHoldInvoice(request, metadata=[('macaroon', MACAROON.hex())])
+
+        invoice = response.payment_request
+
+        payreq_decoded = cls.decode_payreq(invoice)
+        payment_hash = payreq_decoded.payment_hash
+        created_at = timezone.make_aware(datetime.fromtimestamp(payreq_decoded.timestamp))
+        expires_at = created_at + timedelta(seconds=payreq_decoded.expiry)
+
+        return invoice, preimage, payment_hash, created_at, expires_at 
 
     def validate_hold_invoice_locked(payment_hash):
         '''Checks if hodl invoice is locked'''
@@ -43,43 +89,30 @@ class LNNode():
 
         return True
 
-    def validate_ln_invoice(invoice, num_satoshis):
-        '''Checks if the submited LN invoice is as expected'''
+    @classmethod
+    def validate_ln_invoice(cls, invoice, num_satoshis):
+        '''Checks if the submited LN invoice comforms to expectations'''
 
-        # request = lnrpc.PayReqString(pay_req=invoice)
-        # response = stub.DecodePayReq(request, metadata=[('macaroon', macaroon)])
+        try:
+            payreq_decoded = cls.decode_payreq(invoice)
+        except:
+            return False, {'bad_invoice':'Does not look like a valid lightning invoice'}
 
-        #     # { 
-        #     #     "destination": <string>,
-        #     #     "payment_hash": <string>,
-        #     #     "num_satoshis": <int64>,
-        #     #     "timestamp": <int64>,
-        #     #     "expiry": <int64>,
-        #     #     "description": <string>,
-        #     #     "description_hash": <string>,
-        #     #     "fallback_addr": <string>,
-        #     #     "cltv_expiry": <int64>,
-        #     #     "route_hints": <array RouteHint>,
-        #     #     "payment_addr": <bytes>,
-        #     #     "num_msat": <int64>,
-        #     #     "features": <array FeaturesEntry>,
-        #     # }
-        
-        # if not response['num_satoshis'] == num_satoshis:
-        #     return False, {'bad_invoice':f'The invoice provided is not for {num_satoshis}. '}, None, None, None
-        # description = response['description']
-        # payment_hash = response['payment_hash']
-        # expires_at = timezone(response['expiry'])
-        # if payment_hash and expires_at > timezone.now():
-        #   return True, None, description, payment_hash, expires_at
+        if not payreq_decoded.num_satoshis == num_satoshis:
+            context = {'bad_invoice':f'The invoice provided is not for {num_satoshis}'}
+            return False, context, None, None, None, None
 
-        valid = True
-        context = None
-        description = 'Placeholder desc' # TODO decrypt from LN invoice
-        payment_hash = '567&*GIHU126' # TODO decrypt
-        expires_at = timezone.now() # TODO decrypt
+        created_at = timezone.make_aware(datetime.fromtimestamp(payreq_decoded.timestamp))
+        expires_at = created_at + timedelta(seconds=payreq_decoded.expiry)
 
-        return valid, context, description, payment_hash, expires_at
+        if expires_at < timezone.now():
+            context = {'bad_invoice':f'The invoice provided has already expired'}
+            return False, context, None, None, None, None
+
+        description = payreq_decoded.expiry.description
+        payment_hash = payreq_decoded.payment_hash
+
+        return True, None, description, payment_hash, created_at, expires_at
 
     def pay_invoice(invoice):
         '''Sends sats to buyer, or cancelinvoices'''
@@ -92,14 +125,6 @@ class LNNode():
         
         return True
 
-    def settle_hold_htlcs(payment_hash):
-        '''Charges a LN hold invoice'''
-        return True
-
-    def return_hold_htlcs(payment_hash):
-        '''Returns sats'''
-        return True
-
     def double_check_htlc_is_settled(payment_hash):
         ''' Just as it sounds. Better safe than sorry!'''
         return True

api/logics.py

@@ -254,7 +254,7 @@ class Logics():
         description = f'RoboSats - Publishing {str(order)} - This bond will return to you if you do not cheat.'
 
         # Gen hold Invoice
-        invoice, payment_hash, expires_at = LNNode.gen_hold_invoice(bond_satoshis, description, BOND_EXPIRY*3600)
+        invoice, preimage, payment_hash, expires_at = LNNode.gen_hold_invoice(bond_satoshis, description, BOND_EXPIRY*3600)
         
         order.maker_bond = LNPayment.objects.create(
             concept = LNPayment.Concepts.MAKEBOND, 
@@ -262,6 +262,7 @@ class Logics():
             sender = user,
             receiver = User.objects.get(username=ESCROW_USERNAME),
             invoice = invoice,
+            preimage = preimage,
             status = LNPayment.Status.INVGEN,
             num_satoshis = bond_satoshis,
             description =  description,

api/models.py

@@ -46,6 +46,7 @@ class LNPayment(models.Model):
     # payment info
     invoice = models.CharField(max_length=300, unique=False, null=True, default=None, blank=True)
     payment_hash = models.CharField(max_length=300, unique=False, null=True, default=None, blank=True)
+    preimage = models.CharField(max_length=300, unique=False, null=True, default=None, blank=True)
     description = models.CharField(max_length=300, unique=False, null=True, default=None, blank=True)
     created_at = models.DateTimeField(auto_now_add=True)
     expires_at = models.DateTimeField()

setup.md

@@ -58,6 +58,11 @@ git clone https://github.com/googleapis/googleapis.git
 curl -o lightning.proto -s https://raw.githubusercontent.com/lightningnetwork/lnd/master/lnrpc/lightning.proto
 python3 -m grpc_tools.protoc --proto_path=googleapis:. --python_out=. --grpc_python_out=. lightning.proto
 ```
+We also use the *Invoices* subservice for invoice validation.
+```
+curl -o invoices.proto -s https://raw.githubusercontent.com/lightningnetwork/lnd/master/lnrpc/invoicesrpc/invoices.proto
+python3 -m grpc_tools.protoc --proto_path=googleapis:. --python_out=. --grpc_python_out=. invoices.proto
+```
 
 ## React development environment
 ### Install npm