Merge JoinMarket-Org/joinmarket-clientserver#1536: RPC-API: Implement message signing

646999179b RPC-API: Implement message signing (Kristaps Kaupe)

Pull request description:

  Resolves #1533.

  My first attempt at adding new RPC-API endpoint, there could be mistakes.

  Didn't add tests in `jmclient/test/test_wallet_rpc.py` as message signing is currently supported for mainnet only, not regtest (but I tested HTTP 400 response with regtest).

Top commit has no ACKs.

Tree-SHA512: 927b1f97ef903e48f82aa3ae70c7ead05c919a28d016d1ad4fd9c7a8299f8faa7606c30ef24af0ce3cd504e8e27b37bc55d1989bf89da88572ac79af0e60ec12

docs/api/wallet-rpc.yaml

@@ -605,6 +605,28 @@ paths:
           $ref: '#/components/responses/GetSeed-200-OK'
         '400':
           $ref: '#/components/responses/400-BadRequest'
+  /wallet/{walletname}/signmessage:
+    get:
+      security:
+        - bearerAuth: []
+      summary: Sign a message with the private key from an address in the wallet.
+      parameters:
+        - name: walletname
+          in: path
+          description: name of the wallet including .jmdat
+          required: true
+          schema:
+            type: string
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/SignMessageRequest'
+      responses:
+        '200':
+          $ref: '#/components/responses/SignMessage-200-OK'
+        '400':
+          $ref: '#/components/responses/400-BadRequest'
 components:
   securitySchemes:
     bearerAuth:
@@ -1156,6 +1178,31 @@ components:
           type: integer
           example: 6
           description: Bitcoin miner fee to use for transaction. A number higher than 1000 is used as satoshi per kvB tx fee. The number lower than that uses the dynamic fee estimation of blockchain provider as confirmation target.
+    SignMessageRequest:
+      type: object
+      required:
+        - hd_path
+        - message
+      properties:
+        hd_path:
+          type: string
+          example: m/84'/0'/0'/0/0
+        message:
+          type: string
+    SignMessageResponse:
+      type: object
+      required:
+        - signature
+        - message
+        - address
+      properties:
+        signature:
+          type: string
+        message:
+          type: string
+        address:
+          type: string
+          example: bcrt1qu7k4dppungsqp95nwc7ansqs9m0z95h72j9mze
     ErrorMessage:
         type: object
         properties:
@@ -1292,6 +1339,12 @@ components:
         application/json:
           schema:
             $ref: "#/components/schemas/YieldGenReportResponse"
+    SignMessage-200-OK:
+      description: "return signed message"
+      content:
+        application/json:
+          schema:
+            $ref: "#/components/schemas/SignMessageResponse"
     202-Accepted:
       description: The request has been submitted successfully for processing, but the processing has not been completed. 
     # Clientside error responses

src/jmclient/__init__.py

@@ -60,7 +60,7 @@ from .wallet_utils import (
     wallet_tool_main, wallet_generate_recover_bip39, open_wallet,
     open_test_wallet_maybe, create_wallet, get_wallet_cls, get_wallet_path,
     wallet_display, get_utxos_enabled_disabled, wallet_gettimelockaddress,
-    wallet_change_passphrase)
+    wallet_change_passphrase, wallet_signmessage)
 from .wallet_service import WalletService
 from .maker import Maker
 from .yieldgenerator import YieldGenerator, YieldGeneratorBasic, ygmain, \

src/jmclient/wallet_rpc.py

@@ -23,7 +23,7 @@ from jmclient import Taker, jm_single, \
     get_schedule, get_tumbler_parser, schedule_to_text, \
     tumbler_filter_orders_callback, tumbler_taker_finished_update, \
     validate_address, FidelityBondMixin, BaseWallet, WalletError, \
-    ScheduleGenerationErrorNoFunds, BIP39WalletMixin, auth
+    ScheduleGenerationErrorNoFunds, BIP39WalletMixin, auth, wallet_signmessage
 from jmbase.support import get_log, utxostr_to_utxo, JM_CORE_VERSION
 
 jlog = get_log()
@@ -1375,6 +1375,25 @@ class JMWalletDaemon(Service):
             seedphrase, _ = self.services["wallet"].get_mnemonic_words()
             return make_jmwalletd_response(request, seedphrase=seedphrase)
 
+        @app.route('/wallet/<string:walletname>/signmessage', methods=['POST'])
+        def signmessage(self, request, walletname):
+            self.check_cookie(request)
+            if not self.services["wallet"]:
+                raise NoWalletFound()
+            if not self.wallet_name == walletname:
+                raise InvalidRequestFormat()
+
+            request_data = self.get_POST_body(request, ["hd_path", "message"])
+            result = wallet_signmessage(self.services["wallet"],
+                request_data["hd_path"], request_data["message"],
+                out_str=False)
+            if type(result) == str:
+                return make_jmwalletd_response(request, status=400,
+                    message=result)
+            else:
+                return make_jmwalletd_response(request,
+                    signature=result[0], message=result[1], address=result[2])
+
         @app.route('/wallet/<string:walletname>/taker/schedule', methods=['POST'])
         def start_tumbler(self, request, walletname):
             self.check_cookie(request)

src/jmclient/wallet_utils.py

@@ -9,7 +9,7 @@ from optparse import OptionParser
 from numbers import Integral
 from collections import Counter, defaultdict
 from itertools import islice, chain
-from typing import Callable, Optional, Tuple
+from typing import Callable, Optional, Tuple, Union
 from jmclient import (get_network, WALLET_IMPLEMENTATIONS, Storage, podle,
     jm_single, WalletError, BaseWallet, VolatileStorage,
     StoragePasswordError, is_segwit_mode, SegwitLegacyWallet, LegacyWallet,
@@ -1176,7 +1176,8 @@ def wallet_dumpprivkey(wallet, hdpath):
     return wallet.get_wif_path(path)  # will raise exception on invalid path
 
 
-def wallet_signmessage(wallet, hdpath, message, out_str=True):
+def wallet_signmessage(wallet, hdpath: str, message: str,
+                       out_str: bool = True) -> Union[Tuple[str, str, str], str]:
     """ Given a wallet, a BIP32 HD path (as can be output
     from the display method) and a message string, returns
     a base64 encoded signature along with the corresponding