server: Allow to delete blocks by hash

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

@@ -11,6 +11,8 @@ trait BlockDataHandler[F[_]] {
   def create(block: Block): F[Block]
 
   def getBy(blockhash: Blockhash): F[Block]
+
+  def delete(blockhash: Blockhash): F[Block]
 }
 
 trait BlockBlockingDataHandler extends BlockDataHandler[ApplicationResult]

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

@@ -26,4 +26,9 @@ class BlockPostgresDataHandler @Inject() (
     val maybe = blockPostgresDAO.getBy(blockhash)
     Or.from(maybe, One(BlockNotFoundError))
   }
+
+  override def delete(blockhash: Blockhash): ApplicationResult[Block] = database.withConnection { implicit conn =>
+    val maybe = blockPostgresDAO.delete(blockhash)
+    Or.from(maybe, One(BlockNotFoundError))
+  }
 }

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

@@ -70,4 +70,17 @@ class BlockPostgresDAO {
       "hash" -> blockhash.string
     ).as(parseBlock.singleOpt).flatten
   }
+
+  def delete(blockhash: Blockhash)(implicit conn: Connection): Option[Block] = {
+    SQL(
+      """
+        |DELETE FROM blocks
+        |WHERE hash = {hash}
+        |RETURNING hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |          height, version, time, median_time, nonce, bits, chainwork, difficulty
+      """.stripMargin
+    ).on(
+      "hash" -> blockhash.string
+    ).as(parseBlock.singleOpt).flatten
+  }
 }

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

@@ -54,6 +54,24 @@ class BlockPostgresDataHandlerSpec extends PostgresDataHandlerSpec {
     }
   }
 
+  "delete" should {
+    "delete a block" in {
+      val block = BlockLoader.get("1ca318b7a26ed67ca7c8c9b5069d653ba224bf86989125d1dfbb0973b7d6a5e0")
+      dataHandler.create(block)
+
+      val result = dataHandler.delete(block.hash)
+      result.isGood mustEqual true
+      matches(block, result.get)
+    }
+
+    "fail on block not found" in {
+      val blockhash = Blockhash.from("b858d38a3552c83aea58f66fe00ae220352a235e33fcf1f3af04507a61a9dc32").get
+
+      val result = dataHandler.delete(blockhash)
+      result mustEqual Bad(BlockNotFoundError).accumulating
+    }
+  }
+
   private def matches(expected: Block, result: Block) = {
     // NOTE: transactions and confirmations are not matched intentionally
     result.hash mustEqual expected.hash