First to say, I'm newcomer in Scala and really need a little help. I need to build a web api, and I'll try to insert one record into database, but have some problems with mapping the entity (db table) into a model (class). I worked with .Net Core Web API (there I used Entity Framework Core, here in Scala use Slick) and try to keep same arhitecture in Scala, but need some more informations, because on the internet I find a lot of versions, and can not choose the best.
As database, MySQL is used.
User.scala
case class User(
id: Int = 0,
userName: String,
firstName: String,
lastName: String
) {
override def equals(that: Any): Boolean = true
}
object User {
implicit object UserFormat extends Format[User] {
def writes(user: User): JsValue = {
val userSeq = Seq(
"id" -> JsNumber(user.id),
"userName" -> JsString(user.userName),
"firstName" -> JsString(user.firstName),
"lastName" -> JsString(user.lastName)
)
JsObject(userSeq)
}
def reads(json: JsValue): JsResult[User] = {
JsSuccess(User(
(json \ "id").as[Int].value,
(json \ "userName").as[String].value,
(json \ "firstName").as[String].value,
(json \ "lastName").as[String].value)
)
}
}
def tupled = (this.apply _).tupled
}
class UserMap #Inject()(protected val dbConfigProvider: DatabaseConfigProvider)(implicit ex: ExecutionContext) {
val dbConfig: DatabaseConfig[JdbcProfile] = dbConfigProvider.get[JdbcProfile]
val db: JdbcBackend#DatabaseDef = dbConfig.db
val dbUsers = TableQuery[UserDef]
def getAll(): Unit = {
val action = sql"SELECT Id, UserName, FirstName, LastName FROM Users".as[(Int, String, String, String)]
return db.run(action)
}
def add(user: User): Future[Seq[User]] = {
dbUsers += user
db.run(dbUsers.result)
}
}
UserDef.scala (which is a mapper of db table / entity)
class UserDef(tag: Tag) extends Table[User](tag, "Users") {
def id = column[Int]("Id", O.PrimaryKey, O.AutoInc)
def userName = column[String]("UserName")
def firstName = column[String]("FirstName")
def lastName = column[String]("LastName")
override def * = (id, userName, firstName, lastName) <> (create, extract)
def create(user: (Int, String, String, String)): User = User(user._1, user._2, user._3, user._4)
def extract(user: User): Option[(Int, String, String, String)] = Some((user.id, user.userName,user.firstName,user.lastName))
}
UsersController.scala
def createUser = Action(parse.json) { implicit request => {
val userJson = request.body
var user = new User(
-1,
(userJson \ "userName").as[String].value,
(userJson \ "firstName").as[String].value,
(userJson \ "lastName").as[String].value
)
var users = TableQuery[UserDef]
Await.result(db.run(DBIO.seq(
users += user,
users.result.map(println))), Duration.Inf
)
Ok(Json.toJson(user))
}
}
How I see the problem:
UserDef is an Entity and must remain clean, only table columns definitions
UserMap is the bridge between User class and UserDef (entity), can be used as a repository with crud methods (getAll(), getById(id), create(user), update(user), delete(id)). This is in same file as User class, but probably must be moved in another.
User class is the model and need to contain only their parameters and writes/reads (Scala specifics)
and now in the controller:
If I try to insert a record into database, with current method, first I need to get all rows from table, and then to add the new record in the list. What happening if I have 3 4mil records in this table? Will get all these rows useless to insert only a new row.
Then, after inserting this new row, I need to return it into client, but how I can get it updated (Id is every time -1, but if I get entire list to see what it contain, I can see the correct id for the newest entity)
thx
Finally, I found a good solution and post it here, maybe somebody need this:
UserMap, for me at least will become UserRepository. There I have CRUD operations and maybe some extra :
def getAll(): Future[Seq[User]] = {
db.run(dbUsers.result)
}
def getById(id: Int): Future[Option[User]] ={
val action = dbUsers.filter(_.id === id).result.headOption
db.run(action)
}
def create(user: User): Future[User] = {
val insertQuery = dbUsers returning dbUsers.map(_.id) into ((x, id) => x.copy(id = id))
val action = insertQuery += user
db.run(action)
}
def update(user: User) {
Try( dbUsers.filter(_.id === user.id).update(user)) match {
case Success(response) => db.run(response)
case Failure(_) => println("An error occurred!")
}
}
def delete(id: Int) {
Try( dbUsers.filter(_.id === id).delete) match {
case Success(response) => db.run(response)
case Failure(_) => println("An error occurred!")
}
}
and UsersController:
def getAll() = Action {
var users = Await.result(usersRepository.getAll(), Duration.Inf)
Ok(Json.toJson(users))
}
def getById(id: Int) = Action { implicit request => {
val user = Await.result(usersRepository.getById(id), Duration.Inf)
Ok(Json.toJson(user))
}
}
def create = Action(parse.json) { implicit request => {
val userJson = request.body
var user = new User(
-1,
(userJson \ "userName").as[String].value,
(userJson \ "firstName").as[String].value,
(userJson \ "lastName").as[String].value
)
var createdUser = Await.result(usersRepository.create((user)), Duration.Inf)
Ok(Json.toJson(createdUser))
}
}
def update(id: Int) = Action(parse.json) { implicit request => {
val userJson = request.body
var user = new User(
(userJson \ "id").as[Int].value,
(userJson \ "userName").as[String].value,
(userJson \ "firstName").as[String].value,
(userJson \ "lastName").as[String].value
)
var updatedUser = usersRepository.update(user)
Ok(Json.toJson(user))
}
}
def delete(id: Int) = Action {
usersRepository.delete(id)
Ok("true")
}
Anyway, I know I have some bad blocks of code there...especially in create & update methods, where convert json to User.
I wanted to give it a try, and here is a full working example of a Play 2.7/Scala 2.13/Slick 4.0.2 REST-API controller bound to a MySQL database.
Since you are starting with Scala, maybe it is a bit overwhelming at first to get eased with Play, Slick, etc...
So here is an humble skeleton (derived from Play-Slick GitHub)
So first, since we want to write an API, here is the conf/routes file:
GET /users controllers.UserController.list()
GET /users/:uuid controllers.UserController.get(uuid: String)
POST /users controllers.UserController.create()
PUT /users controllers.UserController.update()
DELETE /users/:uuid controllers.UserController.delete(uuid: String)
Nothing to fancy here, we just bind routes to functions in the upcoming controller.
Just notice that the 2nd GET and the DELETE expect an UUID as query param, while Json bodies with be used for the POST and PUT.
It would be nice to see the model right now, in app/models/User.scala:
package models
import java.util.UUID
import play.api.libs.json.{Json, OFormat}
case class User(
uuid: UUID,
username: String,
firstName: String,
lastName: String
) {
}
object User {
// this is because defining a companion object shadows the case class function tupled
// see: https://stackoverflow.com/questions/22367092/using-tupled-method-when-companion-object-is-in-class
def tupled = (User.apply _).tupled
// provides implicit json mapping
implicit val format: OFormat[User] = Json.format[User]
}
I used an uuid instead using a numerical id, but basically, it is the same.
Notice that a Json serializer/deserializer can be written in just one line (you don't need to detail it with case classes). I think it is also a good practice to not override it to produce Seq as found on your code, since this serializer will be very usefull when converting objects to Json on the controller.
Now the tupled definition is most likelly a hack (see comment) that will be required later on the DAO...
Next, we need a controller in app/controllers/UserController.scala:
package controllers
import java.util.UUID
import forms.UserForm
import javax.inject.Inject
import play.api.Logger
import play.api.data.Form
import play.api.i18n.I18nSupport
import play.api.libs.json.Json
import play.api.mvc._
import services.UserService
import scala.concurrent.{ExecutionContext, Future}
import scala.util.{Failure, Success, Try}
class UserController #Inject()(userService: UserService)
(implicit ec: ExecutionContext) extends InjectedController with I18nSupport {
lazy val logger: Logger = Logger(getClass)
def create: Action[AnyContent] = Action.async { implicit request =>
withFormErrorHandling(UserForm.create, "create failed") { user =>
userService
.create(user)
.map(user => Created(Json.toJson(user)))
}
}
def update: Action[AnyContent] = Action.async { implicit request =>
withFormErrorHandling(UserForm.create, "update failed") { user =>
userService
.update(user)
.map(user => Ok(Json.toJson(user)))
}
}
def list: Action[AnyContent] = Action.async { implicit request =>
userService
.getAll()
.map(users => Ok(Json.toJson(users)))
}
def get(uuid: String): Action[AnyContent] = Action.async { implicit request =>
Try(UUID.fromString(uuid)) match {
case Success(uuid) =>
userService
.get(uuid)
.map(maybeUser => Ok(Json.toJson(maybeUser)))
case Failure(_) => Future.successful(BadRequest(""))
}
}
def delete(uuid: String): Action[AnyContent] = Action.async {
Try(UUID.fromString(uuid)) match {
case Success(uuid) =>
userService
.delete(uuid)
.map(_ => Ok(""))
case Failure(_) => Future.successful(BadRequest(""))
}
}
private def withFormErrorHandling[A](form: Form[A], onFailureMessage: String)
(block: A => Future[Result])
(implicit request: Request[AnyContent]): Future[Result] = {
form.bindFromRequest.fold(
errors => {
Future.successful(BadRequest(errors.errorsAsJson))
}, {
model =>
Try(block(model)) match {
case Failure(e) => {
logger.error(onFailureMessage, e)
Future.successful(InternalServerError)
}
case Success(eventualResult) => eventualResult.recover {
case e =>
logger.error(onFailureMessage, e)
InternalServerError
}
}
})
}
}
So here:
basically, each of our 5 functions referenced from the routes file check input, and then delegate the work to an injected UserService (more on that later)
for the create and update functions, you can see that we use Play Forms that I think is also a good practice. Their role is to validate the incoming Json, and that Marshall it into a User type.
Also, you can see that we use Action.async: Scala offers a very powerfull leverage with Futures so lets use it! Basically by doing so, you ensure that your code is not-blocking, thus easing the IOPS on your hardware.
Finally for the case of GET (one), GET (all), POST and PUT, since we return users, and have a deseralizer, a simple Json.toJson(user) do the work.
Before jumping to service and dao, lets see the form, in app/forms/UserForm.scala:
package forms
import java.util.UUID
import models.User
import play.api.data.Form
import play.api.data.Forms.{mapping, nonEmptyText, _}
object UserForm {
def create: Form[User] = Form(
mapping(
"uuid" -> default(uuid, UUID.randomUUID()),
"username" -> nonEmptyText,
"firstName" -> nonEmptyText,
"lastName" -> nonEmptyText,
)(User.apply)(User.unapply)
)
}
Nothing too fancy here, just as the doc says, although there is just a trick : when no uuid is defined (in the POST case, then we generate one).
Now, the service... not so much required in this very case, but in practice it might be a good thing to have an extra layer (dealing with acls for example), in app/services/UserService.scala:
package services
import java.util.UUID
import dao.UserDAO
import javax.inject.Inject
import models.User
import scala.concurrent.{ExecutionContext, Future}
class UserService #Inject()(dao: UserDAO)(implicit ex: ExecutionContext) {
def get(uuid: UUID): Future[Option[User]] = {
dao.get(uuid)
}
def getAll(): Future[Seq[User]] = {
dao.all()
}
def create(user: User): Future[User] = {
dao.insert(user)
}
def update(user: User): Future[User] = {
dao.update(user)
}
def delete(uuid: UUID): Future[Unit] = {
dao.delete(uuid)
}
}
As you can see, here, it is just a wrapper around the dao, and finnally the dao in app/dao/UserDao.scala:
package dao
import java.util.UUID
import javax.inject.Inject
import models.User
import play.api.db.slick.{DatabaseConfigProvider, HasDatabaseConfigProvider}
import play.db.NamedDatabase
import slick.jdbc.JdbcProfile
import scala.concurrent.{ExecutionContext, Future}
class UserDAO #Inject()(#NamedDatabase("mydb") protected val dbConfigProvider: DatabaseConfigProvider)(implicit executionContext: ExecutionContext) extends HasDatabaseConfigProvider[JdbcProfile] {
import profile.api._
private val users = TableQuery[UserTable]
def all(): Future[Seq[User]] = db.run(users.result)
def get(uuid: UUID): Future[Option[User]] = {
db.run(users.filter(_.uuid === uuid).result.headOption)
}
def insert(user: User): Future[User] = {
db.run(users += user).map(_ => user)
}
def update(user: User): Future[User] = {
db.run(users.filter(_.uuid === user.uuid).update(user)).map(_ => user)
}
def delete(uuid: UUID): Future[Unit] = {
db.run(users.filter(_.uuid === uuid).delete).map(_ => ())
}
private class UserTable(tag: Tag) extends Table[User](tag, "users") {
def uuid = column[UUID]("uuid", O.PrimaryKey)
def username = column[String]("username")
def firstName = column[String]("firstName")
def lastName = column[String]("lastName")
def * = (uuid, username, firstName, lastName) <> (User.tupled, User.unapply)
}
}
So, here I have just adapted the code from the official play-slick example, so I guess, I do not have better comment than theirs...
Hope, the whole things helps to get a better picture :)
If something is unclear, feel free to ask!
I have a Json type column in MySql and I am using Scala with Slick.
How can I Provide support for the Json Column via Slick.
class SampleTable(tag: Tag) extends Table[(String, ??)](tag, "test") {
override def * : ProvenShape[NodeReference] = (name, data)
def name: Rep[String] = column[String]("name", O.PrimaryKey)
def Data: Rep[??] = column[??]("data", O.PrimaryKey)
}
Any Help will be appreciated.
Thanks In Advance
You can use a BaseColumnType to convert your JSON to a String while writing it to the database and parsing it to JSON while reading from the database:
import play.api.libs.json.{JsValue, Json}
private implicit val jsValueMappedColumnType: BaseColumnType[JsValue] =
MappedColumnType.base[JsValue, String](Json.stringify, Json.parse)
class SampleTable(tag: Tag) extends Table[(String, JsValue)](tag, "test") {
def name: Rep[String] = column[String]("name", O.PrimaryKey)
def data: Rep[JsValue] = column[JsValue]("data", O.PrimaryKey)
def * = (name, data)
}
How can I connect the Scala.js controller method by using mySQL database?
This is what I have so far:
case class data(user_d: String, udid: String, image: String)
object mysqlDAO {
def findById(udid: Long): Option[data] = {
val connection = DriverManager.getConnection("jdbc:mysql://localhost:3307/umo", "root", "")
try {
val statement = connection.prepareStatement("""select * from messages where udid = ?""")
statement.setLong(1, udid)
val rs = statement.executeQuery()
if (rs.next())
Option(new data(rs.getString(1), rs.getString(2), rs.getString(3)))
else
Option.empty
} finally {
connection.close()
}
}
}
first of all you can create the case class in Model package then u can create object and serialize the your case class Data
----------
case class Data(user_id: String, id: String, image: String)
object Data {
/* this one is the serialization of the data*/
implicit val DataWrites = new Writes[Data] {
def writes(json_write: Data): JsValue = {
Json.obj(
"user_id" -> json_write.user_id,
"id" -> json_write.id,
"image" -> json_write.image
)
}
}
val simple = {
get[String]("user.user_id") ~
get[String]("user.id") ~
get[String]("user.image") map {
case user_id ~ id ~ image =>
Data(user_id, id, image)
}
}
/*to get the data */
def find(udid: String): Option[Data] = {
DB.withConnection { implicit connection =>
SQL(ConstantSQL.GET_DETAILS).on('uid -> id).as(Data.simple.singleOpt)
}
}
}
----------
//query for to get the data based on the uid
val GET_DETAILS = """select * from user_image where uid = ?"""
then u can create your own controller method
----------
var uDetails = Data.find(uid)
----------
use the above line to get the data in your class
I have a case classe to store my userOption that I insert into my User.
The structure of my user is as such:
{
"_id":ObjectId("55d54d05ece39a6cf774c3e4"),
"main":{
"providerId":"userpass",
"userId":"test1#email.com",
"firstName":"test",
"lastName":"one",
"fullName":"Test One",
"email":"test1#email.com",
"authMethod":{
"method":"userPassword"
},
"passwordInfo":{
"hasher":"bcrypt",
"password":"aslkdjfasdjh"
}
},
"userOption":{
"hotLeadNotification":{
"f":"IMMEDIATE"
}
}
}
now, I'd like to add an additional option: favoriteNotification.
I changed my case class adding favoriteNotification:
case class UserOption (
hotLeadNotification: Frequency = Frequency("IMMEDIATE"),
favoriteNotification: Frequency = Frequency("IMMEDIATE")
)
object UserOption{
implicit val userOptionFormat = Json.format[UserOption]
implicit object BSONObjectIDFormat extends Format[BSONObjectID] {
def writes(objectId: BSONObjectID): JsValue = JsString(objectId.toString())
def reads(json: JsValue): JsResult[BSONObjectID] = json match {
case JsString(x) => {
val maybeOID: Try[BSONObjectID] = BSONObjectID.parse(x)
if(maybeOID.isSuccess) JsSuccess(maybeOID.get) else {
JsError("Expected BSONObjectID as JsString")
}
}
case _ => JsError("Expected BSONObjectID as JsString")
}
}
val userOptionForm = Form(
mapping(
"hotLeadNotification" -> text,
"favoriteNotification" -> text
)((hotLeadNotification: String, favoriteNotification: String) =>
UserOption(
hotLeadNotification = Frequency(hotLeadNotification),
favoriteNotification = Frequency(favoriteNotification)
)
)((u:UserOption) => Some(u.hotLeadNotification.f, u.favoriteNotification.f))
)
implicit object UserOptionBSONReader extends BSONDocumentReader[UserOption] {
def read(doc: BSONDocument): UserOption =
UserOption(
doc.getAs[Frequency]("hotLeadNotification").getOrElse(Frequency("IMMEDIATE")),
doc.getAs[Frequency]("favoriteNotification").getOrElse(Frequency("IMMEDIATE"))
)
}
implicit object UserOptionBSONWriter extends BSONDocumentWriter[UserOption]{
def write(userOption: UserOption): BSONDocument =
BSONDocument(
"hotLeadNotification" -> userOption.hotLeadNotification,
"favoriteNotification" -> userOption.favoriteNotification
)
}
}
Since I added favoriteNotification, I get a RuntimeException:
java.lang.RuntimeException: (/userOption/favoriteNotification,List(ValidationError(error.path.missing,WrappedArray())))
at scala.sys.package$.error(package.scala:27) ~[scala-library-2.11.6.jar:na]
at play.api.libs.iteratee.Iteratee$$anonfun$run$1.apply(Iteratee.scala:355) ~[play-iteratees_2.11-2.3.9.jar:2.3.9]
at play.api.libs.iteratee.Iteratee$$anonfun$run$1.apply(Iteratee.scala:348) ~[play-iteratees_2.11-2.3.9.jar:2.3.9]
at play.api.libs.iteratee.StepIteratee$$anonfun$fold$2.apply(Iteratee.scala:670) ~[play-iteratees_2.11-2.3.9.jar:2.3.9]
at play.api.libs.iteratee.StepIteratee$$anonfun$fold$2.apply(Iteratee.scala:670) ~[play-iteratees_2.11-2.3.9.jar:2.3.9]
But there's not list in my code. What am I doing wrong?
Thanks for your help
The issue was that UserOption was an Option, but not it parameters. As I added only the new option is the case class and not in the database, it was throwing this error.
I changed the case class as adding options:
case class UserOption (
hotLeadNotification: Option[Frequency] = Some(Frequency("IMMEDIATE")),
favoriteNotification: Option[Frequency] = Some(Frequency("IMMEDIATE"))
)
I've the following classes running against a MySQL DB:
case class User(val userId: Option[String], val firstName: String, val lastName: String, val phoneNum: String, val email: Option[String]) {
}
class Users(tag: Tag) extends Table[User](tag, "USERS") {
def userId = column[String]("USER_ID", O.PrimaryKey)
def firstName = column[String]("FIRST_NAME")
def lastName = column[String]("LAST_NAME")
def phoneNum = column[String]("PHONE_NUM")
def email = column[String]("EMAIL")
def * = (userId.?, firstName, lastName, phoneNum, email.?) <> (User.tupled, User.unapply)
}
class MySQLUserRepository(private val db: Database)(implicit val executor: ExecutionContextExecutor) extends UserService {
val users = TableQuery[Users]
def findByFirstName(firstName: String): Future[immutable.Seq[User]] = {
val query = users.filter { _.firstName === firstName }
runAndThenCleanUp(query)
}
private def runAndThenCleanUp(query: Query[Users, User, Seq]): Future[immutable.Seq[User]] = {
try db.run(query.result).map { _.toList } finally db.close
}
def createUser(user: User) = {
val createAction: DBIO[Option[Int]] = users ++= Seq(user)
db.run(createAction.asTry.map {
_ match {
case Success(res) => res.map { _ => user }
case Failure(e) => println(e); None
}
})
}
}
And test:
class MySQLUserRepositorySpec extends fixture.FlatSpec with Matchers with BeforeAndAfterAll with ScalaFutures {
private val userRepository = new MySQLUserRepository(db)(global)
implicit val defaultPatience = PatienceConfig(timeout = Span(5, Seconds), interval = Span(500, Millis))
val query = TableQuery[Users]
type FixtureParam = User
def withFixture(test: OneArgTest) = {
val users = userRepository.findByFirstName("John")
users.futureValue shouldBe empty
dumpAllUsers
val testUser = User(Some("1"), "John", "Doe", "111-111-1111", Some("john.doe#gmail.com"))
val newUser = userRepository.createUser(testUser)
newUser.onFailure {case NonFatal(ex) => ex.printStackTrace }
val user = newUser.futureValue
user shouldBe defined
println("Before test")
dumpAllUsers
try {
println("Running test")
withFixture(test.toNoArgTest(user.get)) // "loan" the fixture to the test
} finally { // clean up the fixture
println("After test")
dumpAllUsers
// try db.run(query.delete) finally db.close
}
}
override def afterAll() {
println("Cleaning up")
// try db.run(query.delete) finally db.close
}
private def dumpAllUsers = {
println("Printing all users")
(query.result).map { _.toList }
}
it should "find user with first name" in { testUser =>
val users = userRepository.findByFirstName(testUser.firstName)
verifySingleUser(users.futureValue)
}
}
I keep getting the exception:
2015-09-12 00:45:14.592 [ScalaTest-main-running-MySQLUserRepositorySpec] [DEBUG] s.b.D.action - #1: [fused] asTry
java.util.concurrent.RejectedExecutionException: Task slick.backend.DatabaseComponent$DatabaseDef$$anon$2#43da41e rejected from java.util.concurrent.ThreadPoolExecutor#148c7c4b[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 1]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047)
I read this and this, to no avail. What am I doing wrong? I suspect that Slick is wrongly mapping the PK column as nullable (due to the Option type).
Table DDL:
CREATE TABLE `akka`.`users` (
`user_id` VARCHAR(16) NOT NULL COMMENT '',
`first_name` VARCHAR(50) NOT NULL COMMENT '',
`last_name` VARCHAR(50) NOT NULL COMMENT '',
`phone_num` VARCHAR(25) NOT NULL COMMENT '',
`email` VARCHAR(50) NULL COMMENT '',
PRIMARY KEY (`user_id`) COMMENT '',
UNIQUE INDEX `phone_num_UNIQUE` (`phone_num` ASC) COMMENT '',
UNIQUE INDEX `email_UNIQUE` (`email` ASC) COMMENT '');
The problem is your runAndThenCleanUp method. db has a database connection pool, which db.close shuts down. db.run submits a request to the execution pool, but then before it can execute the request, you shut down the pool.
Don't worry about cleaning up connections in your individual method calls - just make sure you call db.close when your application is shutting down to let the pool shutdown gracefully. Slick (and HikariCP under the hood) will take care of connection management for you.
In short, change this:
private def runAndThenCleanUp(query: Query[Users, User, Seq]): Future[immutable.Seq[User]] = {
try db.run(query.result).map { _.toList } finally db.close
}
to this:
private def runQuery(query: Query[Users, User, Seq]): Future[immutable.Seq[User]] = {
db.run(query.result).map { _.toList }
}