I am working with the Lift framework and Scala. I have a form to sign up to my application, and I want to validate all the fields in it. I have a snippet where I access my form values, and one validation class where I wrote my validation functions. The following code is what I've tried so far. In my Snippet:
if(validationClassObject.validateName(first_name)){
if(validationClassObject.validateName(last_name)){
if(validationClassObject.validateEmail(email)){
if(validationClassObject.validateUserName(name)){
// Adding values to the DB
S.redirectTo("/")
}
else{
S.notice("Invalid User Name")
}
}
else{
S.notice("Invalid Mail Id")
}
}
else{
S.notice("Invalid Last name")
}
}
else{
S.notice("Invalid First Name")
}
In the validationClass I wrote the validation code looks like:
//function for validating mail address
def validateEmail(email: String): Boolean =
"""(\w+)#([\w\.]+)""".r.unapplySeq(email).isDefined
//code for validating remaining fileds like above
This is working, but I know this is not the best way of coding this operation in Scala. How could I modify my code in a more scalable way? How can I use case classes here?
You could do:
def av[T,V](validationFunction: => Boolean, error: => T)(f: => V)={
if(!validationFunction) error
else f
}
def v[V](validationFunction: => Boolean, error: => String)(f: => V)=av(validationFunction,S.notice(error))(f)
import validationCalssObject._
v(validateName(last_name),"Invalid Last name"){v(validateName(name),"Invalid User Name"){...}}
av is a abstract method with T and V as result types for the error function and continue function f. v is the more specific function what expects a string for error and encapsulates the notice() call. we give f as the part in the curly braces v(validation, errormsg){/*todo when there is no problem*/}.
I can't do formatting in comments so I'll post a new answer.
def badName() = if ("name" == "") Some("bad name") else None
def badEmail() = if ("email" == "") Some("bad email") else None
val verifications = List[() => Option[String]](badName, badEmail)
val failed = verifications.flatMap(_())
if (failed.nonEmpty) {
// handle failed
} else {
// your custom logic here
}
if (badName) S.notice
else if (badEmail) S.notice
else if (badDay) S.notice
else { // everything OK...
// return a JsCmd or what else do you wanted here
}
An alternative solution can be written using Option and flatMap, without these all "if"-s hardcoded. If you're interested in that -- ask..
Related
I have a scenario like this.
private val feeder = Array(200, 404).map(e => Map("code" -> e)).random.circular
private val search = scenario("search")
.feed(feeder)
.exec(http("search")
.get("/search/")
.headers(headers)
.check( if "${code}".equals(200) jsonPath("$.body").exists else jsonPath("$.exception").exists )
Is there a way I can achieve this kinda conditional check. As of now, the observed behavior is, "${code}".equals(200) will always return false.
You can access a session inside jsonPath and extract code from it manually
.check(jsonPath(session =>
if (session("code").as[Int].equals(200)) "$.body"
else "$.exception"
).exists)
According to the documentation, there is the following construct to achieve this:
// with a Gatling EL String condition that resolves a Boolean
.checkIf("#{bool}") {
jsonPath("$..foo")
}
// with a function
.checkIf(session => session("key").as[String] == "executeCheck") {
jsonPath("$..foo")
}
I have a Java program that I must implement in Scala, but I am extremely new to Scala. After reading a number of SO question & answers as well as reading through a number of Google-retrieved resources on case classes, I am still having trouble grasping how to acquire a reference to the message I received? Example code is below:
case class SpecialMessage(key: Int) {
val id: Int = Main.idNum.getAndIncrement().intValue()
def getId(): Int = {
return id
}
}
Then in another class's receive I am trying to reference that number with:
def receive() = {
case SpecialMessage(key) {
val empID = ?? getId() // Get the id stored in the Special Message
// Do stuff with empID
}
}
I cannot figure out what to put on the right sight of empID = in order to get that id. Is this really simple, or something that isn't normally done?
These are 2 ways to do what you want, pick the one that suits best
case msg: SpecialMessage => {
val empID = msg.getId() // Get the id stored in the Special Message
// Do stuff with empID
}
case msg # SpecialMessage(key) => {
val empID = msg.getId() // Get the id stored in the Special Message
// Do stuff with empID
}
Pim's answer is good.
But maybe you can modify the structure of SpecialMessage like
case class SpecialMessage(key: Int,val id: Int = Main.idNum.getAndIncrement().intValue())
so you can get id directly from pattern matching.
def receive() = {
case SpecialMessage(key, empID) {
// Do stuff with empID
}
}
I have a variable param which has to be initialized at runtime.
Then, I have a part of the code which implements the following:
if (param has been initialized)
...do something...
else
print error and exit
What is the most idiomatic way to do this in Scala?
So far I have used Option[X] in this way:
var param : Option[TheType] = None
...
val param_value : TheType = x getOrElse {println("Error"); null}
But, since I have to return null it seems dirty.
How should I do it?
Simply map or foreach over it:
param.foreach { param_value =>
// Do everything you need to do with `param_value` here
} getOrElse sys.exit(3) # Param was empty, kill the program
You can also use the for comprehension style:
for {
param_value <- param
} yield yourOperation(param_value)
The upside of this is that if your calling code is expecting to do something with param_value as a return value from yourMethod you will encode the possibility of param_value not existing in your return type (it will be an Option[TheType] rather than a potentially null TheType.)
I might me wrong but it seems to me that the use of Future would fit with your problem: Instead of explicitly checking whether your required param_value has been initialized and finish the program if not, you could make your resource dependent code to execute when the resource has been rightly initialized:
val param: Future[TheType] = future {
INITIALIZATION CODE HERE
}
param onFailure {
case e => println("Error!");
}
param onSuccess {
case param_value: TheType => {
YOUR BUSINESS CODE HERE
}
}
I'm trying to register a tuple to a DB and upload the image to Amazon S3.
I divided the code to two parts : 1) Working Code and 2) Non Working Code.
Working code means It works as expected. The image file is uploaded sucessfully to S3.
Non working code is always folding to index_error page which I'm trying to solve but I can't figure out where I'm missing.
Thank you for help!
Working Code
def index = Action {
Ok(views.html.upload_test_index("File Upload In Play"))
}
def uploadFile = Action(parse.multipartFormData) { request =>
request.body.file("fileUpload").map { video =>
val newFile = File.createTempFile("temp-uploaded-", video.filename)
video.ref.moveTo(newFile, true)
new S3Sender(newFile, video.filename).send
}.getOrElse {
Redirect(routes.Application.index)
}
Ok("File has been uploaded")
}
Non Working Code - Controller
val anuncioForm = Form(
tuple(
"label" -> nonEmptyText,
"imgName" -> text
)
)
def createAnuncio = Action(parse.multipartFormData) { implicit request =>
anuncioForm.bindFromRequest.fold(
formWithErrors => BadRequest(views.html.index_error(formWithErrors)),
{
case (label, imgName) =>
request.body.file("imgName").map { imgName =>
val newFile = File.createTempFile("temp-uploaded-", imgName.filename)
val fileName = imgName.filename
imgName.ref.moveTo(newFile, true)
new S3Sender(newFile, fileName).send
Anuncio.create(label, fileName)
}
println("criou")
Redirect(routes.Application.anuncios)
}
)
}
def anuncios = Action {
Ok(views.html.index(Anuncio.all(), anuncioForm))
}
def newAnuncio = Action {
Ok(views.html.create(anuncioForm))
}
Non Working Code - Template
#(anuncioForm: Form[(String, String)])
#import helper._
#main("Criar um novo anuncio") {
#form(action = routes.Application.createAnuncio, 'enctype -> "multipart/form-data") {
#inputText(anuncioForm("label"))
#*<input type="file" name="imgName">*#
#inputFile(anuncioForm("imgName"))
<input type="submit" value="Create">
}
}
Edited
I used the code below to know the error message.
formWithErrors => BadRequest(views.html.index_error(formWithErrors.errorsAsJson))
Surprisingly I got the message below. I can't figure out why this message?!
{"imgName":["This field is required"]}
Do you need to have the file contents as a part of the form itself? You declare the imgName as a text in the form in your controller, but you use it as a input type="file" in your view, which I would imagine is contradictory.
A few things you could take a look at:
how to handle fileupload into a table in play framework? which talks about separating the file from the form as well as an (untested?) single submit for both a form and a file, and possible some other clues
How to include a picture type in a form in Play!2 in Scala? which is doing something similar to what you are doing
http://www.playframework.com/documentation/2.1.2/ScalaFileUpload
I am trying to do a simple case of /author/ and get the Lift to build a Person object based on the id passed in.
Currently i have an Author snippet
class Author(item: Person) {
def render = {
val s = item match { case Full(item) => "Name"; case _ => "not found" }
" *" #> s;
}
}
object Author{
val menu = Menu.param[Person]("Author", "Author", authorId => findPersonById(authorId), person => getIdForPerson(person)) / "author"
def findPersonById(id:String) : Box[Person] = {
//if(id == "bob"){
val p = new Person()
p.name="Bobby"
p.age = 32
println("findPersonById() id = " +id)
Full(p)
//}else{
//return Empty
//}
}
def getIdForPerson(person:Person) : String = {
return "1234"
}
}
What i am attempting to do is get the code to build a boxed person object and pass it in to the Author class's constructor. In the render method i want determine if the box is full or not and proceed as appropriate.
If i change
class Author(item: Person) {
to
class Author(item: Box[Person]) {
It no longer works but if i leave it as is it is no longer valid as Full(item) is incorrect. If i remove the val s line it works (and replace the s with item.name). So how do i do this. Thanks
The Box returned from findPersonById(id:String) : Box[Person] is evaluated and if the Box is Full, the unboxed value is passed into your function. If the Box is Empty or Failure the application will present a 404 or appropriate error page instead.
You can try double boxing your return if you want to handle this error checking yourself (so that the result of this method is always a Full Box).
def findPersonById(id:String) : Box[Box[Person]] = {
if(id == "bob"){
val p = new Person()
p.name="Bobby"
p.age = 32
println("findPersonById() id = " +id)
Full(Full(p))
}else{
return Full(Empty)
}
}
and then this should work:
class Author(item: Box[Person])