Add BIP21 support for Payjoin

jmbitcoin/jmbitcoin/bip21.py

@@ -4,7 +4,7 @@
 # this are expected to do address validation independently anyway.
 
 from jmbitcoin import amount_to_sat
-from urllib.parse import parse_qs, urlparse
+from urllib.parse import quote, parse_qs, urlencode, urlparse
 from url_decode import urldecode
 import re
 
@@ -15,7 +15,12 @@ def is_bip21_uri(uri):
 
 
 def is_bip21_amount_str(amount):
-    return re.compile("^[0-9]{1,8}(\.[0-9]{1,8})?$").match(amount) != None
+    return re.compile("^[0-9]{1,8}(\.[0-9]{1,8})?$").match(str(amount)) != None
+
+
+def validate_bip21_amount(amount):
+    if not is_bip21_amount_str(amount):
+        raise ValueError("Invalid BTC amount " + str(amount))
 
 
 def decode_bip21_uri(uri):
@@ -31,11 +36,18 @@ def decode_bip21_uri(uri):
                 " in BIP21 URI.")
         if key == 'amount':
             amount_str = params['amount'][0]
-            if not is_bip21_amount_str(amount_str):
-                raise ValueError("Invalid BTC amount " + amount_str +
-                    " vs. " + str(amount_to_sat(amount_str)) + " sat")
+            validate_bip21_amount(amount_str)
             # Convert amount to sats, as used internally by JM
             result['amount'] = amount_to_sat(amount_str + "btc")
         else:
             result[key] = urldecode(params[key][0])
     return result
+
+
+def encode_bip21_uri(address, params):
+    uri = 'bitcoin:' + address
+    if len(params) > 0:
+        if 'amount' in params:
+            validate_bip21_amount(params['amount'])
+        uri += '?' + urlencode(params, quote_via=quote)
+    return uri

jmbitcoin/setup.py

@@ -10,4 +10,5 @@ setup(name='joinmarketbitcoin',
       license='GPL',
       packages=['jmbitcoin'],
       install_requires=['future', 'coincurve', 'urldecode'],
+      python_requires='>=3.5',
       zip_safe=False)

jmbitcoin/test/test_bip21.py

@@ -2,7 +2,7 @@ import jmbitcoin as btc
 import pytest
 
 
-def test_bip21():
+def test_bip21_decode():
 
     # These should raise exception because of not being valid BIP21 URI's
     with pytest.raises(ValueError):
@@ -56,3 +56,61 @@ def test_bip21():
     assert(parsed['somethingyoudontunderstand'] == '50')
     assert(parsed['somethingelseyoudontget'] == '999')
 
+
+def test_bip21_encode():
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {}) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W'
+    )
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'label': 'Luke-Jr'
+        }) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?label=Luke-Jr'
+    )
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': 20.3,
+            'label': 'Luke-Jr'
+        }) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=20.3&label=Luke-Jr'
+    )
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': 50,
+            'label': 'Luke-Jr',
+            'message': 'Donation for project xyz'
+        }) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=50&label=Luke-Jr&message=Donation%20for%20project%20xyz'
+    )
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'req-somethingyoudontunderstand': 50,
+            'req-somethingelseyoudontget': 999
+        }) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?req-somethingyoudontunderstand=50&req-somethingelseyoudontget=999'
+    )
+    assert(
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'somethingyoudontunderstand': 50,
+            'somethingelseyoudontget': 999
+        }) ==
+        'bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?somethingyoudontunderstand=50&somethingelseyoudontget=999'
+    )
+    # Invalid amounts must raise ValueError
+    with pytest.raises(ValueError):
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': ''
+        })
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': 'XYZ'
+        })
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': '100\'000'
+        })
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': '100,000'
+        })
+        btc.encode_bip21_uri('175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W', {
+            'amount': '100000000'
+        })

jmclient/jmclient/maker.py

@@ -328,10 +328,16 @@ class P2EPMaker(Maker):
             self.receiving_amount) + " satoshis.")
         self.user_info("The sender also needs to know your ephemeral "
                   "nickname: " + jm_single().nickname)
-        self.user_info("This information has been stored in a file payjoin.txt;"
+        receive_uri = btc.encode_bip21_uri(self.destination_addr, {
+            'amount': btc.sat_to_btc(self.receiving_amount),
+            'jmnick': jm_single().nickname
+        })
+        self.user_info("Receive URI: " + receive_uri)
+        self.user_info("This information has also been stored in a file payjoin.txt;"
                   " send it to your counterparty when you are ready.")
         with open("payjoin.txt", "w") as f:
             f.write("Payjoin transfer details:\n\n")
+            f.write("Receive URI: " + receive_uri + "\n")
             f.write("Address: " + self.destination_addr + "\n")
             f.write("Amount (in sats): " + str(self.receiving_amount) + "\n")
             f.write("Receiver nick: " + jm_single().nickname + "\n")

scripts/sendpayment.py

@@ -74,6 +74,8 @@ def main():
                 parser.error("Given BIP21 URI does not contain amount.")
                 sys.exit(EXIT_ARGERROR)
             destaddr = parsed['address']
+            if 'jmnick' in parsed:
+                options.p2ep = parsed['jmnick']
         else:
             amount = btc.amount_to_sat(args[1])
             if amount == 0: