server: Allow to reverse the block headers ordering

server/app/com/xsn/explorer/data/BlockDataHandler.scala

@@ -1,7 +1,7 @@
 package com.xsn.explorer.data
 
 import com.alexitc.playsonify.core.ApplicationResult
-import com.alexitc.playsonify.models.ordering.FieldOrdering
+import com.alexitc.playsonify.models.ordering.{FieldOrdering, OrderingCondition}
 import com.alexitc.playsonify.models.pagination.{Limit, PaginatedQuery, PaginatedResult}
 import com.xsn.explorer.models.fields.BlockField
 import com.xsn.explorer.models.persisted.{Block, BlockHeader}
@@ -25,7 +25,7 @@ trait BlockDataHandler[F[_]] {
 
   def getFirstBlock(): F[Block]
 
-  def getHeaders(limit: Limit, lastSeenHash: Option[Blockhash]): F[List[BlockHeader]]
+  def getHeaders(limit: Limit, orderingCondition: OrderingCondition, lastSeenHash: Option[Blockhash]): F[List[BlockHeader]]
 }
 
 trait BlockBlockingDataHandler extends BlockDataHandler[ApplicationResult]

server/app/com/xsn/explorer/data/anorm/BlockPostgresDataHandler.scala

@@ -1,7 +1,7 @@
 package com.xsn.explorer.data.anorm
 
 import com.alexitc.playsonify.core.ApplicationResult
-import com.alexitc.playsonify.models.ordering.FieldOrdering
+import com.alexitc.playsonify.models.ordering.{FieldOrdering, OrderingCondition}
 import com.alexitc.playsonify.models.pagination
 import com.alexitc.playsonify.models.pagination.{PaginatedQuery, PaginatedResult}
 import com.xsn.explorer.data.BlockBlockingDataHandler
@@ -58,13 +58,14 @@ class BlockPostgresDataHandler @Inject() (
 
   override def getHeaders(
       limit: pagination.Limit,
+      orderingCondition: OrderingCondition,
       lastSeenHash: Option[Blockhash]): ApplicationResult[List[BlockHeader]] = withConnection { implicit conn =>
 
     val result = lastSeenHash
         .map { hash =>
-          blockPostgresDAO.getHeaders(hash, limit)
+          blockPostgresDAO.getHeaders(hash, limit, orderingCondition)
         }
-        .getOrElse { blockPostgresDAO.getHeaders(limit) }
+        .getOrElse { blockPostgresDAO.getHeaders(limit, orderingCondition) }
 
     Good(result)
   }

server/app/com/xsn/explorer/data/anorm/dao/BlockPostgresDAO.scala

@@ -151,12 +151,14 @@ class BlockPostgresDAO @Inject() (fieldOrderingSQLInterpreter: FieldOrderingSQLI
     getBy(query, ordering).headOption
   }
 
-  def getHeaders(limit: Limit)(implicit conn: Connection): List[BlockHeader] = {
+  def getHeaders(limit: Limit, orderingCondition: OrderingCondition)(implicit conn: Connection): List[BlockHeader] = {
+    val order = toSQL(orderingCondition)
+
     SQL(
-      """
+      s"""
         |SELECT blockhash, previous_blockhash, merkle_root, height, time
         |FROM blocks
-        |ORDER BY height
+        |ORDER BY height $order
         |LIMIT {limit}
       """.stripMargin
     ).on(
@@ -164,9 +166,15 @@ class BlockPostgresDAO @Inject() (fieldOrderingSQLInterpreter: FieldOrderingSQLI
     ).as(parseHeader.*)
   }
 
-  def getHeaders(lastSeenHash: Blockhash, limit: Limit)(implicit conn: Connection): List[BlockHeader] = {
+  def getHeaders(lastSeenHash: Blockhash, limit: Limit, orderingCondition: OrderingCondition)(implicit conn: Connection): List[BlockHeader] = {
+    val order = toSQL(orderingCondition)
+    val comparator = orderingCondition match {
+      case OrderingCondition.DescendingOrder => "<"
+      case OrderingCondition.AscendingOrder => ">"
+    }
+
     SQL(
-      """
+      s"""
         |WITH CTE AS (
         |  SELECT height as lastSeenHeight
         |  FROM blocks
@@ -174,8 +182,8 @@ class BlockPostgresDAO @Inject() (fieldOrderingSQLInterpreter: FieldOrderingSQLI
         |)
         |SELECT b.blockhash, b.previous_blockhash, b.merkle_root, b.height, b.time
         |FROM CTE CROSS JOIN blocks b
-        |WHERE b.height > lastSeenHeight
-        |ORDER BY height
+        |WHERE b.height $comparator lastSeenHeight
+        |ORDER BY height $order
         |LIMIT {limit}
       """.stripMargin
     ).on(
@@ -183,4 +191,9 @@ class BlockPostgresDAO @Inject() (fieldOrderingSQLInterpreter: FieldOrderingSQLI
       'limit -> limit.int
     ).as(parseHeader.*)
   }
+
+  private def toSQL(condition: OrderingCondition): String = condition match {
+    case OrderingCondition.AscendingOrder => "ASC"
+    case OrderingCondition.DescendingOrder => "DESC"
+  }
 }

server/app/com/xsn/explorer/data/async/BlockFutureDataHandler.scala

@@ -1,7 +1,7 @@
 package com.xsn.explorer.data.async
 
 import com.alexitc.playsonify.core.{FutureApplicationResult, FuturePaginatedResult}
-import com.alexitc.playsonify.models.ordering.FieldOrdering
+import com.alexitc.playsonify.models.ordering.{FieldOrdering, OrderingCondition}
 import com.alexitc.playsonify.models.pagination
 import com.alexitc.playsonify.models.pagination.PaginatedQuery
 import com.xsn.explorer.data.{BlockBlockingDataHandler, BlockDataHandler}
@@ -42,7 +42,11 @@ class BlockFutureDataHandler @Inject() (
     blockBlockingDataHandler.getFirstBlock()
   }
 
-  override def getHeaders(limit: pagination.Limit, lastSeenHash: Option[Blockhash]): FutureApplicationResult[List[BlockHeader]] = Future {
-    blockBlockingDataHandler.getHeaders(limit, lastSeenHash)
+  override def getHeaders(
+      limit: pagination.Limit,
+      orderingCondition: OrderingCondition,
+      lastSeenHash: Option[Blockhash]): FutureApplicationResult[List[BlockHeader]] = Future {
+
+    blockBlockingDataHandler.getHeaders(limit, orderingCondition, lastSeenHash)
   }
 }

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

@@ -9,6 +9,7 @@ import com.xsn.explorer.errors.{BlockRewardsNotFoundError, BlockhashFormatError}
 import com.xsn.explorer.models._
 import com.xsn.explorer.models.rpc.{Block, TransactionVIN}
 import com.xsn.explorer.models.values.{Blockhash, Height}
+import com.xsn.explorer.parsers.OrderingConditionParser
 import com.xsn.explorer.services.logic.{BlockLogic, TransactionLogic}
 import com.xsn.explorer.util.Extensions.FutureOrExt
 import javax.inject.Inject
@@ -22,12 +23,17 @@ class BlockService @Inject() (
     blockDataHandler: BlockFutureDataHandler,
     paginatedQueryValidator: PaginatedQueryValidator,
     blockLogic: BlockLogic,
-    transactionLogic: TransactionLogic)(
+    transactionLogic: TransactionLogic,
+    orderingConditionParser: OrderingConditionParser)(
     implicit ec: ExecutionContext) {
 
   private val maxHeadersPerQuery = 1000
 
-  def getBlockHeaders(limit: Limit, lastSeenHashString: Option[String]): FutureApplicationResult[WrappedResult[List[persisted.BlockHeader]]] = {
+  def getBlockHeaders(
+      limit: Limit,
+      lastSeenHashString: Option[String],
+      orderingConditionString: String): FutureApplicationResult[WrappedResult[List[persisted.BlockHeader]]] = {
+
     val result = for {
       lastSeenHash <- {
         lastSeenHashString
@@ -38,8 +44,9 @@ class BlockService @Inject() (
       }
 
       _ <- paginatedQueryValidator.validate(PaginatedQuery(Offset(0), limit), maxHeadersPerQuery).toFutureOr
+      orderingCondition <- orderingConditionParser.parseReuslt(orderingConditionString).toFutureOr
 
-      headers <- blockDataHandler.getHeaders(limit, lastSeenHash).toFutureOr
+      headers <- blockDataHandler.getHeaders(limit, orderingCondition, lastSeenHash).toFutureOr
     } yield WrappedResult(headers)
 
     result.toFuture

server/app/controllers/BlocksController.scala

@@ -24,8 +24,8 @@ class BlocksController @Inject() (
     blockService.getLatestBlocks()
   }
 
-  def getBlockHeaders(lastSeenHash: Option[String], limit: Int) = public { _ =>
-    blockService.getBlockHeaders(Limit(limit), lastSeenHash)
+  def getBlockHeaders(lastSeenHash: Option[String], limit: Int, orderingCondition: String) = public { _ =>
+    blockService.getBlockHeaders(Limit(limit), lastSeenHash, orderingCondition)
   }
 
   /**

server/conf/routes

@@ -16,7 +16,7 @@ GET   /v2/addresses/:address/transactions            controllers.AddressesContro
 GET   /addresses/:address/utxos                      controllers.AddressesController.getUnspentOutputs(address: String)
 
 GET   /blocks                            controllers.BlocksController.getLatestBlocks()
-GET   /blocks/headers                    controllers.BlocksController.getBlockHeaders(lastSeenHash: Option[String], limit: Int ?= 10)
+GET   /blocks/headers                    controllers.BlocksController.getBlockHeaders(lastSeenHash: Option[String], limit: Int ?= 10, order: String ?= "asc")
 
 GET   /blocks/:query                     controllers.BlocksController.getDetails(query: String)
 GET   /blocks/:query/raw                 controllers.BlocksController.getRawBlock(query: String)

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

@@ -221,7 +221,8 @@ class LedgerSynchronizerServiceSpec extends PostgresDataHandlerSpec with BeforeA
       new BlockFutureDataHandler(blockDataHandler)(Executors.databaseEC),
       new PaginatedQueryValidator,
       new BlockLogic,
-      new TransactionLogic)
+      new TransactionLogic,
+      new OrderingConditionParser)
     val transactionRPCService = new TransactionRPCService(xsnService)
     new LedgerSynchronizerService(
       xsnService,