server: Add keyset-based method for retrieving address transactions

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

@@ -2,7 +2,7 @@ package com.xsn.explorer.data
 
 import com.alexitc.playsonify.core.ApplicationResult
 import com.alexitc.playsonify.models.ordering.FieldOrdering
-import com.alexitc.playsonify.models.pagination.{PaginatedQuery, PaginatedResult}
+import com.alexitc.playsonify.models.pagination.{Limit, PaginatedQuery, PaginatedResult}
 import com.xsn.explorer.models._
 import com.xsn.explorer.models.fields.TransactionField
 import org.scalactic.Every
@@ -16,6 +16,8 @@ trait TransactionDataHandler[F[_]] {
       paginatedQuery: PaginatedQuery,
       ordering: FieldOrdering[TransactionField]): F[PaginatedResult[TransactionWithValues]]
 
+  def getBy(address: Address, before: Long, limit: Limit): F[List[Transaction]]
+
   def getUnspentOutputs(address: Address): F[List[Transaction.Output]]
 
   def getByBlockhash(

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

@@ -2,7 +2,7 @@ package com.xsn.explorer.data.anorm
 
 import com.alexitc.playsonify.core.ApplicationResult
 import com.alexitc.playsonify.models.ordering.FieldOrdering
-import com.alexitc.playsonify.models.pagination.{PaginatedQuery, PaginatedResult}
+import com.alexitc.playsonify.models.pagination.{Limit, PaginatedQuery, PaginatedResult}
 import com.xsn.explorer.data.TransactionBlockingDataHandler
 import com.xsn.explorer.data.anorm.dao.TransactionPostgresDAO
 import com.xsn.explorer.models._
@@ -29,6 +29,11 @@ class TransactionPostgresDataHandler @Inject() (
     Good(result)
   }
 
+  def getBy(address: Address, before: Long, limit: Limit): ApplicationResult[List[Transaction]] = withConnection { implicit conn =>
+    val transactions = transactionPostgresDAO.getBy(address, before, limit)
+    Good(transactions)
+  }
+
   override def getUnspentOutputs(address: Address): ApplicationResult[List[Transaction.Output]] = withConnection { implicit conn =>
     val result = transactionPostgresDAO.getUnspentOutputs(address)
     Good(result)

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

@@ -4,7 +4,7 @@ import java.sql.Connection
 
 import anorm._
 import com.alexitc.playsonify.models.ordering.FieldOrdering
-import com.alexitc.playsonify.models.pagination.{Count, PaginatedQuery}
+import com.alexitc.playsonify.models.pagination.{Count, Limit, PaginatedQuery}
 import com.alexitc.playsonify.sql.FieldOrderingSQLInterpreter
 import com.xsn.explorer.data.anorm.parsers.TransactionParsers._
 import com.xsn.explorer.models._
@@ -88,6 +88,22 @@ class TransactionPostgresDAO @Inject() (fieldOrderingSQLInterpreter: FieldOrderi
         .getOrElse { throw new RuntimeException("Failed to delete transactions consistently")} // this should not happen
   }
 
+  def getBy(address: Address, before: Long, limit: Limit)(implicit conn: Connection): List[Transaction] = {
+    SQL(
+      """
+        |SELECT t.txid, t.blockhash, t.time, t.size
+        |FROM transactions t JOIN address_transaction_details USING (txid)
+        |WHERE t.time < {before} AND address = {address}
+        |ORDER BY time DESC
+        |LIMIT {limit}
+      """.stripMargin
+    ).on(
+      'address -> address.string,
+      'limit -> limit.int,
+      'before -> before
+    ).as(parseTransaction.*).flatten
+  }
+
   def getBy(
       address: Address,
       paginatedQuery: PaginatedQuery,

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

@@ -2,7 +2,7 @@ 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.pagination.PaginatedQuery
+import com.alexitc.playsonify.models.pagination.{Limit, PaginatedQuery}
 import com.xsn.explorer.data.{TransactionBlockingDataHandler, TransactionDataHandler}
 import com.xsn.explorer.executors.DatabaseExecutionContext
 import com.xsn.explorer.models._
@@ -25,6 +25,14 @@ class TransactionFutureDataHandler @Inject() (
     blockingDataHandler.getBy(address, paginatedQuery, ordering)
   }
 
+  override def getBy(
+      address: Address,
+      before: Long,
+      limit: Limit): FutureApplicationResult[List[Transaction]] = Future {
+
+    blockingDataHandler.getBy(address, before, limit)
+  }
+
   override def getUnspentOutputs(address: Address): FutureApplicationResult[List[Transaction.Output]] = Future {
     blockingDataHandler.getUnspentOutputs(address)
   }

server/test/com/xsn/explorer/data/TransactionPostgresDataHandlerSpec.scala

@@ -319,6 +319,12 @@ class TransactionPostgresDataHandlerSpec extends PostgresDataHandlerSpec with Be
     }
   }
 
+  "getBy keyset pagination" should {
+    "work" in {
+      pending
+    }
+  }
+
   private def createBlock(block: Block) = {
     val transactions = block.transactions
         .map(_.string)

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

@@ -2,6 +2,7 @@ package com.xsn.explorer.helpers
 
 import com.alexitc.playsonify.core.ApplicationResult
 import com.alexitc.playsonify.models.ordering.FieldOrdering
+import com.alexitc.playsonify.models.pagination
 import com.alexitc.playsonify.models.pagination.{PaginatedQuery, PaginatedResult}
 import com.xsn.explorer.data.TransactionBlockingDataHandler
 import com.xsn.explorer.models._
@@ -12,6 +13,8 @@ class TransactionDummyDataHandler extends TransactionBlockingDataHandler {
 
   override def getBy(address: Address, paginatedQuery: PaginatedQuery, ordering: FieldOrdering[TransactionField]): ApplicationResult[PaginatedResult[TransactionWithValues]] = ???
 
+  override def getBy(address: Address, before: Long, limit: pagination.Limit): ApplicationResult[List[Transaction]] = ???
+
   override def getUnspentOutputs(address: Address): ApplicationResult[List[Transaction.Output]] = ???
 
   override def getByBlockhash(blockhash: Blockhash, paginatedQuery: PaginatedQuery, ordering: FieldOrdering[TransactionField]): ApplicationResult[PaginatedResult[TransactionWithValues]] = ???