displayaddress: descriptor support, make --path a named argument

hwilib/cli.py

@@ -15,7 +15,7 @@ def backup_device_handler(args, client):
     return backup_device(client, label=args.label, backup_passphrase=args.backup_passphrase)
 
 def displayaddress_handler(args, client):
-    return displayaddress(client, path=args.path, sh_wpkh=args.sh_wpkh, wpkh=args.wpkh)
+    return displayaddress(client, desc=args.desc, path=args.path, sh_wpkh=args.sh_wpkh, wpkh=args.wpkh)
 
 def enumerate_handler(args):
     return enumerate(password=args.password)
@@ -95,7 +95,9 @@ def process_commands(args):
     getkeypool_parser.set_defaults(func=getkeypool_handler)
 
     displayaddr_parser = subparsers.add_parser('displayaddress', help='Display an address')
-    displayaddr_parser.add_argument('path', help='The BIP 32 derivation path of the key embedded in the address')
+    group = displayaddr_parser.add_mutually_exclusive_group()
+    group.add_argument('--desc', help='Descriptor request for which to return a descriptor with keys, e.g. wpkh([00000000/84h/1h/0h]/0/*). Alternatively, use --path with --sh_wpkh / --wpkh')
+    group.add_argument('--path', help='The BIP 32 derivation path of the key embedded in the address, default follows BIP43 convention, e.g. m/84h/0h/0h/1/*')
     displayaddr_parser.add_argument('--sh_wpkh', action='store_true', help='Display the p2sh-nested segwit address associated with this key path')
     displayaddr_parser.add_argument('--wpkh', action='store_true', help='Display the bech32 version of the address associated with this key path')
     displayaddr_parser.set_defaults(func=displayaddress_handler)

hwilib/commands.py

@@ -9,6 +9,7 @@
 from .base58 import xpub_to_address, xpub_to_pub_hex, get_xpub_fingerprint_as_id, get_xpub_fingerprint_hex
 from os.path import dirname, basename, isfile
 from .hwwclient import NoPasswordError, UnavailableActionError, DeviceAlreadyInitError, DeviceAlreadyUnlockedError
+from .descriptor import Descriptor
 
 # Error codes
 NO_DEVICE_PATH = -1
@@ -184,10 +185,23 @@ def getkeypool(client, path, start, end, internal=False, keypool=False, account=
     import_data.append(this_import)
     return import_data
 
-def displayaddress(client, path, sh_wpkh=False, wpkh=False):
-    if sh_wpkh == True and wpkh == True:
-        return {'error':'Both `--wpkh` and `--sh_wpkh` can not be selected at the same time.','code':BAD_ARGUMENT}
-    return client.display_address(path, sh_wpkh, wpkh)
+def displayaddress(client, path=None, desc=None, sh_wpkh=False, wpkh=False):
+    if path is not None:
+        if sh_wpkh == True and wpkh == True:
+            return {'error':'Both `--wpkh` and `--sh_wpkh` can not be selected at the same time.','code':BAD_ARGUMENT}
+        client.display_address(path, sh_wpkh, wpkh)
+    elif desc is not None:
+        descriptor = Descriptor.parse(desc, client.is_testnet)
+        if descriptor is None:
+            return {'error':'Unable to parse descriptor: ' + desc,'code':BAD_ARGUMENT}
+        if descriptor.m_path is None:
+            return {'error':'Descriptor missing origin info: ' + desc,'code':BAD_ARGUMENT}
+        if descriptor.origin_fingerprint != client.fingerprint:
+            return {'error':'Descriptor fingerprint does not match device: ' + desc,'code':BAD_ARGUMENT}
+        xpub = client.get_pubkey_at_path(descriptor.m_path_base)['xpub']
+        if descriptor.base_key != xpub:
+            return {'error':'Key in descriptor does not match device: ' + desc,'code':BAD_ARGUMENT}
+        client.display_address(descriptor.m_path, descriptor.sh_wpkh, descriptor.wpkh)
 
 def setup_device(client, label='', backup_passphrase=''):
     try:

test/test_device.py

@@ -380,15 +380,16 @@ def tearDown(self):
         self.emulator.stop()
 
     def test_display_address_bad_args(self):
-        result = process_commands(self.dev_args + ['displayaddress', '--sh_wpkh', '--wpkh', 'm/49h/1h/0h/0/0'])
+        result = process_commands(self.dev_args + ['displayaddress', '--sh_wpkh', '--wpkh', '--path', 'm/49h/1h/0h/0/0'])
         self.assertIn('error', result)
         self.assertIn('code', result)
         self.assertEqual(result['code'], -7)
 
     def test_display_address(self):
-        process_commands(self.dev_args + ['displayaddress', 'm/44h/1h/0h/0/0'])
-        process_commands(self.dev_args + ['displayaddress', '--sh_wpkh', 'm/49h/1h/0h/0/0'])
-        process_commands(self.dev_args + ['displayaddress', '--wpkh', 'm/84h/1h/0h/0/0'])
+        process_commands(self.dev_args + ['displayaddress', '--path', 'm/44h/1h/0h/0/0'])
+        process_commands(self.dev_args + ['displayaddress', '--sh_wpkh', '--path', 'm/49h/1h/0h/0/0'])
+        process_commands(self.dev_args + ['displayaddress', '--wpkh', '--path', 'm/84h/1h/0h/0/0'])
+        process_commands(self.dev_args + ['displayaddress', '--desc', 'wpkh(m/84h/1h/0h/0/0)'])
 
 class TestSignMessage(DeviceTestCase):
     def setUp(self):