server: Add getServerStatistics method to XSNService

server/app/com/xsn/explorer/models/rpc/ServerStatistics.scala

@@ -0,0 +1,25 @@
+package com.xsn.explorer.models.rpc
+
+import com.xsn.explorer.models.Height
+import play.api.libs.functional.syntax._
+import play.api.libs.json.{Json, Reads, Writes, __}
+
+case class ServerStatistics(
+    height: Height,
+    transactions: Int,
+    totalSupply: BigDecimal)
+
+object ServerStatistics {
+
+  implicit val reads: Reads[ServerStatistics] = {
+    val builder = (__ \ 'height).read[Height] and
+        (__ \ 'transactions).read[Int] and
+        (__ \ 'total_amount).read[BigDecimal]
+
+    builder.apply { (height, transactions, totalSupply) =>
+      ServerStatistics(height, transactions, totalSupply)
+    }
+  }
+
+  implicit val writes: Writes[ServerStatistics] = Json.writes[ServerStatistics]
+}

server/app/com/xsn/explorer/services/XSNService.scala

@@ -9,7 +9,7 @@ import com.xsn.explorer.config.RPCConfig
 import com.xsn.explorer.errors._
 import com.xsn.explorer.executors.ExternalServiceExecutionContext
 import com.xsn.explorer.models._
-import com.xsn.explorer.models.rpc.{AddressBalance, Block, Transaction}
+import com.xsn.explorer.models.rpc.{AddressBalance, Block, ServerStatistics, Transaction}
 import org.scalactic.{Bad, Good}
 import org.slf4j.LoggerFactory
 import play.api.libs.json.{JsNull, JsValue, Reads}
@@ -28,6 +28,8 @@ trait XSNService {
   def getBlock(blockhash: Blockhash): FutureApplicationResult[Block]
 
   def getLatestBlock(): FutureApplicationResult[Block]
+
+  def getServerStatistics(): FutureApplicationResult[ServerStatistics]
 }
 
 class XSNServiceRPCImpl @Inject() (
@@ -159,6 +161,27 @@ class XSNServiceRPCImpl @Inject() (
         }
   }
 
+  override def getServerStatistics(): FutureApplicationResult[ServerStatistics] = {
+    val body = s"""
+                  |{
+                  |  "jsonrpc": "1.0",
+                  |  "method": "gettxoutsetinfo",
+                  |  "params": []
+                  |}
+                  |""".stripMargin
+
+    server
+        .post(body)
+        .map { response =>
+          val maybe = getResult[ServerStatistics](response)
+          maybe.getOrElse {
+            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")
+
+            Bad(XSNUnexpectedResponseError).accumulating
+          }
+        }
+  }
+
   private def mapError(json: JsValue, errorCodeMapper: Map[Int, ApplicationError]): Option[ApplicationError] = {
     val jsonErrorMaybe = (json \ "error")
         .asOpt[JsValue]

server/test/com/xsn/explorer/helpers/DummyXSNService.scala

@@ -2,7 +2,7 @@ package com.xsn.explorer.helpers
 
 import com.alexitc.playsonify.core.FutureApplicationResult
 import com.xsn.explorer.models._
-import com.xsn.explorer.models.rpc.{AddressBalance, Block, Transaction}
+import com.xsn.explorer.models.rpc.{AddressBalance, Block, ServerStatistics, Transaction}
 import com.xsn.explorer.services.XSNService
 
 class DummyXSNService extends XSNService {
@@ -12,4 +12,5 @@ class DummyXSNService extends XSNService {
   override def getTransactions(address: Address): FutureApplicationResult[List[TransactionId]] = ???
   override def getBlock(blockhash: Blockhash): FutureApplicationResult[Block] = ???
   override def getLatestBlock(): FutureApplicationResult[Block] = ???
+  override def getServerStatistics(): FutureApplicationResult[ServerStatistics] = ???
 }

server/test/com/xsn/explorer/services/XSNServiceRPCImplSpec.scala

@@ -3,7 +3,7 @@ package com.xsn.explorer.services
 import com.xsn.explorer.config.RPCConfig
 import com.xsn.explorer.errors._
 import com.xsn.explorer.helpers.{BlockLoader, DataHelper, Executors, TransactionLoader}
-import com.xsn.explorer.models.{Address, Blockhash}
+import com.xsn.explorer.models.{Address, Blockhash, Height}
 import org.mockito.ArgumentMatchers._
 import org.mockito.Mockito._
 import org.scalactic.Bad
@@ -312,4 +312,37 @@ class XSNServiceRPCImplSpec extends WordSpec with MustMatchers with ScalaFutures
       }
     }
   }
+
+  "getServerStatistics" should {
+    "return the statistics" in {
+      val content =
+        """
+          |{
+          |  "height": 45204,
+          |  "bestblock": "60da3eccf50f10254dcc35c9a25006e129bc5f0d101f83bad5ce008cc4b47c75",
+          |  "transactions": 93047,
+          |  "txouts": 142721,
+          |  "hash_serialized_2": "1f439c1d43753b9935abeb8a8de9f9010b96f7533ccfdde4432de3648a6f20de",
+          |  "disk_size": 7105097,
+          |  "total_amount": 77634169.93285364
+          |}
+        """.stripMargin
+
+      val responseBody = createRPCSuccessfulResponse(Json.parse(content))
+      val json = Json.parse(responseBody)
+
+      when(response.status).thenReturn(200)
+      when(response.json).thenReturn(json)
+      when(request.post[String](anyString())(any())).thenReturn(Future.successful(response))
+
+      whenReady(service.getServerStatistics()) { result =>
+        result.isGood mustEqual true
+
+        val stats = result.get
+        stats.height mustEqual Height(45204)
+        stats.transactions mustEqual 93047
+        stats.totalSupply mustEqual BigDecimal("77634169.93285364")
+      }
+    }
+  }
 }