Fetch binary chunk and draw on canvas

src/main/scala/grib/GribParser.scala

@@ -45,6 +45,8 @@ object GribParser {
       (conversion, bitsPerDataPoint, len5) = res5
       ptr6 = ptr5 + len5
       len6 <- parse6(path, ptr6)
+      ptr7 = ptr6 + len6
+      len7 <- parse7(path, ptr7)
       sections = List(
         GribSection(0, ptr, len0),
         GribSection(1, ptr1, len1),
@@ -52,6 +54,7 @@ object GribParser {
         GribSection(4, ptr4, len4),
         GribSection(5, ptr5, len5),
         GribSection(6, ptr6, len6),
+        GribSection(7, ptr7, len7),
       )
       title = Codes.codesToString(meteo.discipline, meteo.category, meteo.product)
       grib = Grib(version, gribLength, title, grid, meteo, time, conversion, bitsPerDataPoint, sections)
@@ -147,6 +150,13 @@ object GribParser {
     } yield length
   }
 
+  private def parse7(path: Path, ptr: Long): IO[Int] = {
+    for {
+      bytes <- readBytes(path, ptr, 64)
+      length = ByteBuffer.wrap(bytes.slice(0, 4)).getInt
+    } yield length
+  }
+
   private def readBytes(path: Path, ptr: Long, len: Int): IO[Array[Byte]] = {
     Files[IO].readRange(path, 1024, ptr, ptr + len)
       .compile

src/main/scala/server/Server.scala

@@ -7,7 +7,7 @@ import data.DataService
 import db.PostgresService
 import fetch.FetchService
 import parse.Aggregate
-import server.ValidateRoutes.{AggFieldList, AggKey, CityList, DateTimeRange, Granularity, ValidateDate, ValidateDateTime, ValidateMonths, ValidateZonedDateTime}
+import server.ValidateRoutes.{AggFieldList, AggKey, CityList, DateTimeRange, Granularity, ValidateDate, ValidateDateTime, ValidateMonths, ValidateInt, ValidateZonedDateTime}
 import io.circe.{Json, Printer}
 import org.http4s._
 import org.http4s.dsl.io._
@@ -62,6 +62,9 @@ class Server(postgresService: PostgresService, fetch: FetchService, log: Logger[
     case GET -> Root / "show" / "grib-list" =>
       DataService.getFileList().flatMap(fileList => Ok(fileList.asJson))
 
+      // TODO implement binary-chunk/ get request
+    case GET -> Root / "grib" / "binary-chunk" / ValidateInt(binaryOffset) / ValidateInt(binaryLength) / fileName =>
+      DataService.getBinaryChunk(binaryOffset, binaryLength, fileName).flatMap(buffer => Ok(buffer))
 
 
 

src/main/scala/server/ValidateRoutes.scala

@@ -89,4 +89,10 @@ object ValidateRoutes {
       }
     }
   }
+
+  object ValidateInt {
+    def unapply(str: String): Option[Int] = {
+      Option(str.toInt)
+    }
+  }
 }