-
-
Save jirick1/50cfd6f66d1bc2dd2b8847dd634f3993 to your computer and use it in GitHub Desktop.
Slick support for dynamic sort with pagination
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import slick.lifted.Rep | |
| import slick.ast.Ordering.Direction | |
| import slick.ast.Ordering | |
| import slick.lifted.Query | |
| import slick.lifted.ColumnOrdered | |
| import slick.lifted.Ordered | |
| import scala.util.control.NoStackTrace | |
| case class PageRequest(offset: Int, | |
| limit: Int, | |
| sort: Vector[(String, Direction)]) | |
| // Based off https://stackoverflow.com/questions/42383842/dynamic-order-by-in-scala-slick-with-several-columns | |
| object DynamicSortBySupport { | |
| case class InvalidSort(invalidField: String) | |
| extends Exception with NoStackTrace | |
| trait HasSortColumns { | |
| /** The runtime map between string names and table columns */ | |
| val sortColumns: Map[String, Rep[_]] | |
| } | |
| implicit class MultiSortableQuery[E <: HasSortColumns, U, C[_]]( | |
| query: Query[E, U, C]) { | |
| /** Sorts the query by multiple columns in order. Invalid sort names are skipped */ | |
| def dynamicSortBy(sortBy: Seq[(String, Direction)]) | |
| : Either[InvalidSort, Query[E, U, C]] = { | |
| val zero: Either[InvalidSort, Query[E, U, C]] = Right(query) | |
| sortBy.foldRight(zero) { | |
| // foldRight specifically because stacking sortBy invocations on a query operates in reverse order, | |
| // so the reversed order of a right fold means the final result is in the desired order. | |
| case (_, err @ Left(_)) => err | |
| case ((sortColumn, sortOrder), Right(queryToSort)) => | |
| val sortOrderRep: Rep[_] => Ordered = | |
| ColumnOrdered(_, Ordering(sortOrder)) | |
| val sortColumnRep: E => Rep[_] = | |
| _.sortColumns.getOrElse(sortColumn, throw InvalidSort(sortColumn)) | |
| try { | |
| Right(queryToSort.sortBy(sortColumnRep)(sortOrderRep)) | |
| } catch { | |
| case ex: InvalidSort => Left(ex) | |
| } | |
| } | |
| } | |
| def paginated(paging: PageRequest): Either[InvalidSort, Query[E, U, C]] = | |
| dynamicSortBy(paging.sort).map(q => | |
| q.drop(paging.offset).take(paging.limit)) | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment