Merge JoinMarket-Org/joinmarket-clientserver#1532: RPC-API: add getinfo endpoint.

c9f6ac8610 RPC-API: add getinfo endpoint. (Adam Gibson)

Pull request description:

  This commit creates a new endpoint /getinfo which currently returns only the version of Joinmarket (JM_CORE_VERSION) running in the backend joinmarketd. In future commits the returned dict may add more information, for example the current block height of the connected Bitcoin Core node.

  Additionally, this commit fixes the response type of the /rescanblockchain endpoint as defined in the OpenAPI spec.

ACKs for top commit:
  roshii:
    tACK c9f6ac8610
  kristapsk:
    utACK c9f6ac8610

Tree-SHA512: 4ec6ea7311451068fa7b2f053598744588ec60557282b8f3ab82a5a1041fc04d0df5a31f9fc0ba403ffc5508c564abf4cb0e308c76fee6cd0650d5939b55f4bc

docs/api/wallet-rpc.yaml

@@ -138,6 +138,16 @@ paths:
           $ref: '#/components/responses/401-Unauthorized'
         '404':
           $ref: '#/components/responses/404-NotFound'
+  /getinfo:
+    get:
+      security:
+        - {}
+      summary: get info on backend
+      operationId: version
+      description: get information about backend, including the version of Joinmarket running.
+      responses:
+        '200':
+          $ref: "#/components/responses/Getinfo-200-OK"
   /wallet/all:
     get:
       summary: get current available wallets
@@ -754,6 +764,22 @@ components:
       items:
         type: string
         example: "2021/10/26 16:40:21,133986791,1,200000000,2680,2680,0.08,"
+    GetinfoResponse:
+      type: object
+      required:
+        - version
+      properties:
+        version:
+          type: string
+          example: "0.9.10"
+    RescanBlockchainResponse:
+      type: object
+      required:
+        - walletname
+      properties:
+        walletname:
+          type: string
+          example: "wallet.jmdat"
     SessionResponse:
       type: object
       required:
@@ -1106,12 +1132,18 @@ components:
         application/json:
           schema:
             $ref: "#/components/schemas/SessionResponse"
+    Getinfo-200-OK:
+      description: "successful Joinmarket getinfo response"
+      content:
+        application/json:
+          schema:
+            $ref: "#/components/schemas/GetinfoResponse"
     RescanBlockchain-200-OK:
       description: "Blockchain rescan started successfully"
       content:
         application/json:
           schema:
-            $ref: "#/components/schemas/SessionResponse"
+            $ref: "#/components/schemas/RescanBlockchainResponse"
     Create-201-OK:
       description: "wallet created successfully"
       content:

jmclient/jmclient/wallet_rpc.py

@@ -27,7 +27,7 @@ from jmclient import Taker, jm_single, \
     tumbler_filter_orders_callback, tumbler_taker_finished_update, \
     validate_address, FidelityBondMixin, BaseWallet, WalletError, \
     ScheduleGenerationErrorNoFunds, BIP39WalletMixin
-from jmbase.support import get_log, utxostr_to_utxo
+from jmbase.support import get_log, utxostr_to_utxo, JM_CORE_VERSION
 
 jlog = get_log()
 
@@ -602,6 +602,10 @@ class JMWalletDaemon(Service):
             Note that it technically "shouldn't" require a wallet to be loaded,
             but since we hide all blockchain access behind the wallet service,
             it currently *does* require this.
+            An additional subtlety to bear in mind: the action of rescanblockchain
+            depends on the *currently loaded Bitcoin Core wallet*, that Core wallet
+            load event is currently done on startup of Joinmarket, depending on
+            the setting in the joinmarket.cfg file.
             """
             print_req(request)
             self.check_cookie(request)
@@ -615,6 +619,15 @@ class JMWalletDaemon(Service):
                 self.services["wallet"].rescanblockchain(blockheight)
                 return make_jmwalletd_response(request, walletname=walletname)
 
+        @app.route('/getinfo', methods=['GET'])
+        def version(self, request):
+            """ This route sends information about the backend, including
+            the running version of Joinmarket,
+            back to the client. It does *not* pay attention to any state,
+            including authentication tokens.
+            """
+            return make_jmwalletd_response(request,version=JM_CORE_VERSION)
+
         @app.route('/session', methods=['GET'])
         def session(self, request):
             """ This route functions as a heartbeat, and communicates

jmclient/test/test_wallet_rpc.py

@@ -10,7 +10,7 @@ from autobahn.twisted.websocket import WebSocketClientFactory, \
     connectWS
 
 from jmbase import get_nontor_agent, hextobin, BytesProducer, get_log
-from jmbase.support import get_free_tcp_ports
+from jmbase.support import get_free_tcp_ports, JM_CORE_VERSION
 from jmbitcoin import CTransaction
 from jmclient import (
     load_test_config,
@@ -685,6 +685,20 @@ class TrialTestWRPC_DisplayWallet(WalletRPCTestBase, unittest.TestCase):
         yield self.do_request(agent, b"POST", addr, body,
                               self.process_do_coinjoin_response)
 
+    @defer.inlineCallbacks
+    def test_getinfo(self):
+        agent = get_nontor_agent()
+        addr = self.get_route_root()
+        addr += "/getinfo"
+        addr = addr.encode()
+        yield self.do_request(agent, b"GET", addr, None,
+                              self.process_getinfo_response)
+
+    def process_getinfo_response(self, response, code):
+        assert code==200
+        responseobj = json.loads(response.decode("utf-8"))
+        assert responseobj["version"] == JM_CORE_VERSION
+
     def process_do_coinjoin_response(self, response, code):
         assert code == 202
         # response code is already checked to be 200