make electrum watch-only export (#530)

cryptoadvance · Oct 20, 2020 · 2643538 · 2643538
1 parent d845c22
commit 2643538
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diff --git a/...ryptoadvance/specter/templates/wallet/settings/components/export_wallet_account_map.jinja b/...ryptoadvance/specter/templates/wallet/settings/components/export_wallet_account_map.jinja
@@ -10,9 +10,22 @@
 {{ wallet.account_map }}
 </pre>
     <button onclick="copyText(document.getElementById('account_map').innerText, 'Copied wallet data')" type="button" class="btn centered padded">Copy wallet data</button>
+    <br />
+    <hr />
+    <h4>Create Electrum Watch-Only Wallet</h4>
+    <a
+	id="electrum_watchonly_export"
+	download="{{ wallet.alias | ascii20 }}_electrum_watchonly.backup"
+	onclick="showNotification('Import wallet file to your Electrum: File -> Open -> Choose... -> {{ wallet.alias | ascii20 }}_electrum_watchonly.backup', 0)"
+	class="btn centered padded">
+	    Download Electrum Watch-Only File
+    </a>
 </div>
 <script>
 document.addEventListener("DOMContentLoaded", function(){
     document.getElementById('export_wallet_file').href = 'data:text/json,' + encodeURIComponent('{{ wallet.account_map }}');
 });
+document.addEventListener("DOMContentLoaded", function(){
+    document.getElementById('electrum_watchonly_export').href = 'data:text/plain,' + encodeURIComponent('{{ wallet.get_electrum_watchonly()|tojson }}');
+});
 </script>
diff --git a/src/cryptoadvance/specter/wallet.py b/src/cryptoadvance/specter/wallet.py
@@ -6,6 +6,7 @@
 from .util.merkleblock import is_valid_merkle_proof
 from .helpers import der_to_bytes, sort_descriptor, fslock, parse_utxo
 from .util.base58 import decode_base58
+from .util.descriptor import Descriptor
 from .util.xpub import get_xpub_fingerprint
 from .persistence import write_json_file
 from hwilib.serializations import PSBT, CTransaction
@@ -663,6 +664,52 @@ def get_descriptor(self, index=None, change=False, address=None):
                 pass
         return result
 
+    def get_electrum_watchonly(self):
+        if len(self.keys) == 1:
+            # Single-sig case:
+            key = self.keys[0]
+            return {
+                "keystore": {
+                    "derivation": key.derivation.replace("h", "'"),
+                    "root_fingerprint": key.fingerprint,
+                    "type": "bip32",
+                    "xprv": None,
+                    "xpub": key.original,
+                },
+                "wallet_type": "standard",
+            }
+
+        # Multisig case
+
+        # Build lookup table to convert from xpub to slip132 encoded xpub (while maintaining sort order)
+        LOOKUP_TABLE = {}
+        for key in self.keys:
+            LOOKUP_TABLE[key.xpub] = key
+
+        desc = Descriptor.parse(
+            desc=self.recv_descriptor,
+            # assume testnet status is the same across all keys
+            testnet=key.is_testnet,
+        )
+        slip132_keys = []
+        for desc_key in desc.base_key:
+            # Find corresponding wallet key
+            slip132_keys.append(LOOKUP_TABLE[desc_key])
+
+        to_return = {
+            "wallet_type": "{}of{}".format(self.sigs_required, len(self.keys)),
+        }
+        for cnt, slip132_key in enumerate(slip132_keys):
+            to_return["x{}/".format(cnt + 1)] = {
+                "derivation": slip132_key.derivation.replace("h", "'"),
+                "root_fingerprint": slip132_key.fingerprint,
+                "type": "bip32",
+                "xprv": None,
+                "xpub": slip132_key.original,
+            }
+
+        return to_return
+
     def get_balance(self):
         try:
             self.balance = self.rpc.getbalances()["watchonly"]