add pagination and order support to /datasets query (#32)

Author: realstraw

acdc-core/src/main/scala/com/salesforce/mce/acdc/db/DatasetQuery.scala

@@ -15,6 +15,12 @@ import slick.jdbc.PostgresProfile.api._
 
 object DatasetQuery {
 
+  object OrderColumn extends Enumeration {
+
+    val CreatedAt = Value("created_at")
+    val UpdatedAt = Value("updated_at")
+  }
+
   def now() = LocalDateTime.now()
 
   case class ForName(name: String) {
@@ -62,7 +68,23 @@ object DatasetQuery {
 
   }
 
-  def filter(like: String): DBIO[Seq[DatasetTable.R]] =
-    DatasetTable().filter(_.name.like(s"$like")).result
+  def filter(
+    like: String,
+    order: OrderColumn.Value,
+    limit: Int,
+    offset: Int
+  ): DBIO[Seq[DatasetTable.R]] = {
+    val ordering = order match {
+      case OrderColumn.CreatedAt => t: DatasetTable => t.createdAt
+      case OrderColumn.UpdatedAt => t: DatasetTable => t.updatedAt
+      case _ => throw new MatchError("unexpected order")
+    }
+    DatasetTable()
+      .filter(_.name.like(s"$like"))
+      .sortBy(ordering(_).desc)
+      .drop(offset)
+      .take(limit)
+      .result
+  }
 
 }

acdc-ws/app/Module.scala

@@ -7,8 +7,8 @@
 
 import com.google.inject.AbstractModule
 
-import utils.{Authorization, AuthorizationSettings}
 import tasks.AuthSettingReloadTask
+import utils.{Authorization, AuthorizationSettings}
 
 class Module extends AbstractModule {
 

acdc-ws/app/controllers/DatasetController.scala

@@ -19,9 +19,9 @@ import com.salesforce.mce.acdc.db.DatasetQuery
 import com.salesforce.mce.acdc.db.DatasetTable
 import models.CreateDatasetRequest
 import models.DatasetResponse
+import play.api.libs.json.JsString
 import services.DatabaseService
 import utils.{AuthTransformAction, InvalidApiRequest, ValidApiRequest}
-import play.api.libs.json.JsString
 
 @Singleton
 class DatasetController @Inject() (
@@ -90,11 +90,50 @@ class DatasetController @Inject() (
     case InvalidApiRequest(_) => Future.successful(Unauthorized(JsNull))
   }
 
-  def filter(like: String) = authAction.async {
-    case ValidApiRequest(apiRole, _) =>
-      db.async(DatasetQuery.filter(like)).map(rs => Ok(Json.toJson(rs.map(toResponse))))
-    case InvalidApiRequest(_) =>
-      Future.successful(Unauthorized(JsNull))
+  def filter(like: String, order: Option[String], page: Option[Int], perPage: Option[Int]) =
+    authAction.async {
+      case ValidApiRequest(apiRole, _) =>
+        val validated = for {
+          vOrder <- DatasetController.validateOrder(order)
+          vPage <- DatasetController.validateOne(page.getOrElse(1), "page")
+          limit <- DatasetController.validateOne(perPage.getOrElse(50), "per_page")
+        } yield (vOrder, limit, (vPage - 1) * limit)
+
+        validated match {
+          case Right((o, limit, offset)) =>
+            db.async(DatasetQuery.filter(like, o, limit, offset))
+              .map(rs => Ok(Json.toJson(rs.map(toResponse))))
+          case Left(msg) =>
+            Future.successful(BadRequest(JsString(msg)))
+        }
+
+      case InvalidApiRequest(_) =>
+        Future.successful(Unauthorized(JsNull))
+    }
+
+}
+
+object DatasetController {
+
+  private def validateOrder(
+    order: Option[String]
+  ): Either[String, DatasetQuery.OrderColumn.Value] = {
+    order
+      .fold[Either[String, DatasetQuery.OrderColumn.Value]](
+        Right(DatasetQuery.OrderColumn.CreatedAt)
+      ) { o =>
+        try {
+          Right(DatasetQuery.OrderColumn.withName(o))
+        } catch {
+          case e: NoSuchElementException =>
+            Left(s"Unknow order $o")
+        }
+      }
+  }
+
+  private def validateOne(num: Int, name: String): Either[String, Int] = {
+    if (num < 1) Left(s"$name must be at least 1")
+    else Right(num)
   }
 
 }

acdc-ws/app/routers/ApiRouter.scala

@@ -24,7 +24,14 @@ class ApiRouter @Inject() (
     case POST(p"/dataset") => dataset.create()
     case PUT(p"/dataset/$name") => dataset.update(name)
     case GET(p"/dataset/$name") => dataset.get(name)
-    case GET(p"/datasets" ? q"like=$like") => dataset.filter(like)
+    case GET(
+          p"/datasets" ?
+          q"like=$like" &
+          q_o"order=$order" &
+          q_o"page=${int(page)}" &
+          q_o"per_page=${int(perPage)}"
+        ) =>
+      dataset.filter(like, order, page, perPage)
     case DELETE(p"/dataset/$name") => dataset.delete(name)
 
     case POST(p"/instance") => instance.create()

version.sbt

@@ -1 +1 @@
- ThisBuild / version := "0.6.2"
+ ThisBuild / version := "0.6.3"