pi: handle lud-17 URI payment identifier

LNURL-W/P can also be encoded in lud-17 form instead of bech32.
https://github.com/lnurl/luds/blob/luds/17.md
e.g.
lnurlw://example.com/api/test123
lnurlp://example.com/api/test123

contrib/android/bitcoin_intent.xml

@@ -5,4 +5,6 @@
   <category android:name="android.intent.category.BROWSABLE" />
   <data android:scheme="bitcoin" />
   <data android:scheme="lightning" />
+  <data android:scheme="lnurlw" />
+  <data android:scheme="lnurlp" />
 </intent-filter>

contrib/build-wine/electrum.nsi

@@ -189,7 +189,7 @@ Section
   CreateShortCut "$SMPROGRAMS\${PRODUCT_NAME}\${PRODUCT_NAME} Testnet.lnk" "$INSTDIR\electrum-${PRODUCT_VERSION}.exe" "--testnet" "$INSTDIR\electrum-${PRODUCT_VERSION}.exe" 0
 
 
-  ;Links bitcoin: and lightning: URIs to Electrum
+  ;Links bitcoin:, lightning: and lnurl LUD-17 URIs to Electrum
   WriteRegStr HKCU "Software\Classes\bitcoin" "" "URL:bitcoin Protocol"
   WriteRegStr HKCU "Software\Classes\bitcoin" "URL Protocol" ""
   WriteRegStr HKCU "Software\Classes\bitcoin" "DefaultIcon" "$\"$INSTDIR\electrum.ico, 0$\""
@@ -198,6 +198,14 @@ Section
   WriteRegStr HKCU "Software\Classes\lightning" "URL Protocol" ""
   WriteRegStr HKCU "Software\Classes\lightning" "DefaultIcon" "$\"$INSTDIR\electrum.ico, 0$\""
   WriteRegStr HKCU "Software\Classes\lightning\shell\open\command" "" "$\"$INSTDIR\electrum-${PRODUCT_VERSION}.exe$\" $\"%1$\""
+  WriteRegStr HKCU "Software\Classes\lnurlp" "" "URL:lnurlp Protocol"
+  WriteRegStr HKCU "Software\Classes\lnurlp" "URL Protocol" ""
+  WriteRegStr HKCU "Software\Classes\lnurlp" "DefaultIcon" "$\"$INSTDIR\electrum.ico, 0$\""
+  WriteRegStr HKCU "Software\Classes\lnurlp\shell\open\command" "" "$\"$INSTDIR\electrum-${PRODUCT_VERSION}.exe$\" $\"%1$\""
+  WriteRegStr HKCU "Software\Classes\lnurlw" "" "URL:lnurlw Protocol"
+  WriteRegStr HKCU "Software\Classes\lnurlw" "URL Protocol" ""
+  WriteRegStr HKCU "Software\Classes\lnurlw" "DefaultIcon" "$\"$INSTDIR\electrum.ico, 0$\""
+  WriteRegStr HKCU "Software\Classes\lnurlw\shell\open\command" "" "$\"$INSTDIR\electrum-${PRODUCT_VERSION}.exe$\" $\"%1$\""
 
   ;Adds an uninstaller possibility to Windows Uninstall or change a program section
   WriteRegStr HKCU "${PRODUCT_UNINST_KEY}" "DisplayName" "$(^Name)"

contrib/osx/pyinstaller.spec

@@ -135,7 +135,7 @@ app = BUNDLE(
         'CFBundleURLTypes':
             [{
                 'CFBundleURLName': 'bitcoin',
-                'CFBundleURLSchemes': ['bitcoin', 'lightning', ],
+                'CFBundleURLSchemes': ['bitcoin', 'lightning', 'lnurlp', 'lnurlw', ],
             }],
         'LSMinimumSystemVersion': '11',
         'NSCameraUsageDescription': 'Electrum would like to access the camera to scan for QR codes',

electrum.desktop

@@ -15,7 +15,7 @@ StartupNotify=true
 StartupWMClass=electrum
 Terminal=false
 Type=Application
-MimeType=x-scheme-handler/bitcoin;x-scheme-handler/lightning;
+MimeType=x-scheme-handler/bitcoin;x-scheme-handler/lightning;x-scheme-handler/lnurlp;x-scheme-handler/lnurlw;
 Actions=Testnet;
 Keywords=crypto;currency;BTC
 

electrum/gui/qml/qeapp.py

@@ -23,6 +23,7 @@ from electrum.network import Network
 from electrum.plugin import run_hook
 from electrum.gui.common_qt.util import get_font_id
 from electrum.util import profiler
+from electrum.lnurl import SUPPORTED_LNURL_SCHEMES
 
 from .qeconfig import QEConfig
 from .qedaemon import QEDaemon
@@ -235,7 +236,9 @@ class QEAppController(BaseCrashReporter, QObject):
         data = str(intent.getDataString())
         self.logger.debug(f'received intent: {repr(data)}')
         scheme = str(intent.getScheme()).lower()
-        if scheme == BITCOIN_BIP21_URI_SCHEME or scheme == LIGHTNING_URI_SCHEME:
+        if scheme == BITCOIN_BIP21_URI_SCHEME \
+                or scheme == LIGHTNING_URI_SCHEME \
+                or scheme in SUPPORTED_LNURL_SCHEMES:
             self.uriReceived.emit(data)
 
     def startup_finished(self):

electrum/lnurl.py

@@ -21,6 +21,9 @@ from electrum.i18n import _
 _logger = get_logger(__name__)
 
 
+SUPPORTED_LNURL_SCHEMES = ('lnurlp', 'lnurlw')
+
+
 class LNURLError(Exception): pass
 
 class UntrustedLNURLError(LNURLError):

electrum/payment_identifier.py

@@ -16,7 +16,7 @@ from .util import get_asyncio_loop, log_exceptions
 from .transaction import PartialTxOutput
 from .lnurl import (decode_lnurl, request_lnurl, callback_lnurl, LNURLError,
                     lightning_address_to_url, try_resolve_lnurlpay, LNURL6Data,
-                    LNURL3Data, LNURLData)
+                    LNURL3Data, LNURLData, SUPPORTED_LNURL_SCHEMES)
 from .bitcoin import opcodes, construct_script
 from .lnaddr import LnInvoiceException
 from .lnutil import IncompatibleOrInsaneFeatures
@@ -45,6 +45,22 @@ def remove_uri_prefix(data: str, *, prefix: str) -> str:
     return data
 
 
+def maybe_extract_url_from_lud_17_uri(data: str) -> Optional[str]:
+    """https://github.com/lnurl/luds/blob/luds/17.md"""
+    data = data.strip()
+    try:
+        parsed = urllib.parse.urlsplit(data)
+    except ValueError:
+        return None
+    if parsed.scheme not in SUPPORTED_LNURL_SCHEMES:
+        return None
+    if not (host := parsed.hostname) or not parsed.path:
+        return None
+    is_onion = host.endswith('.onion')
+    url_scheme = 'http' if is_onion else 'https'
+    return urllib.parse.urlunsplit(parsed._replace(scheme=url_scheme))
+
+
 RE_ALIAS = r'(.*?)\s*\<([0-9A-Za-z]{1,})\>'
 RE_EMAIL = r'\b[A-Za-z0-9._%+-]+@([A-Za-z0-9-]+\.)+[A-Z|a-z]{2,7}\b'
 RE_DOMAIN = r'\b([A-Za-z0-9-]+\.)+[A-Z|a-z]{2,7}\b'
@@ -98,6 +114,7 @@ class PaymentIdentifier(Logger):
         * openalias
         * bip21 URI
         * lightning-URI (containing bolt11 or lnurl)
+        * lnurl-URI (lud17 lnurlw/lnurlp URI)
         * bolt11 invoice
         * lnurl
         * lightning address
@@ -228,6 +245,10 @@ class PaymentIdentifier(Logger):
                     self.logger.debug(f'Exception cause {e.args!r}')
                     return
                 self.set_state(PaymentIdentifierState.AVAILABLE)
+        elif lnurl_url := maybe_extract_url_from_lud_17_uri(text):
+            self._type = PaymentIdentifierType.LNURL
+            self.lnurl = lnurl_url
+            self.set_state(PaymentIdentifierState.NEED_RESOLVE)
         elif text.lower().startswith(BITCOIN_BIP21_URI_SCHEME + ':'):
             try:
                 out = parse_bip21_URI(text)

tests/test_payment_identifier.py

@@ -184,6 +184,17 @@ class TestPaymentIdentifier(ElectrumTestCase):
         self.assertEqual(PaymentIdentifierType.LNURL, pi.type)
         self.assertTrue(pi.need_resolve())
 
+        # test with lud17 prefix
+        unsupported_lud_17_lnurl_c = f"lnurlc://service.io/?q=3fc3645b439ce8e7"
+        pi = PaymentIdentifier(None, unsupported_lud_17_lnurl_c)
+        self.assertFalse(pi.is_valid())
+
+        valid_lud_17_lnurl_w = f"lnurlw://service.io/?q=3fc3645b439ce8e7"
+        pi = PaymentIdentifier(None, valid_lud_17_lnurl_w)
+        self.assertTrue(pi.is_valid())
+        self.assertEqual(PaymentIdentifierType.LNURL, pi.type)
+        self.assertTrue(pi.need_resolve())
+
     @patch('electrum.payment_identifier.request_lnurl')
     def test_lnurl_pay_resolve(self, mock_request_lnurl):
         """Test LNURL-pay (LNURL6) with mocked resolve"""