Scala Play:使用可选字段实现自定义QueryStringBindable
我将Scala与Play framework(2.8.1)一起使用,并有一个Scala Play:使用可选字段实现自定义QueryStringBindable,scala,playframework,Scala,Playframework,我将Scala与Play framework(2.8.1)一起使用,并有一个Sort类用于捕获基于排序的查询字符串参数。示例url:http://myurl:9000?sortBy=name&sortOrder=asc。这里,sortOrder字段是可选的,如果未提供任何内容,则默认值为“asc”。我实现了自己的QueryStringBindable类,如下所示: object Sort { val asc = "asc" implicit def queryStri
Sort
类用于捕获基于排序的查询字符串参数。示例url:http://myurl:9000?sortBy=name&sortOrder=asc
。这里,sortOrder
字段是可选的,如果未提供任何内容,则默认值为“asc”
。我实现了自己的QueryStringBindable
类,如下所示:
object Sort {
val asc = "asc"
implicit def queryStringBinder(implicit stringBinder: QueryStringBindable[String]) = new QueryStringBindable[Sort] {
override def bind(key: String, params: Map[String, Seq[String]]): Option[Either[String, Sort]] = {
for {
sortBy <- stringBinder.bind("sortBy", params)
if(params.contains("sortOrder")) {sortOrder <- stringBinder.bind("sortOrder", params)}
} yield {
(sortBy, sortOrder) match {
case (Right(sortBy), Right(sortOrder)) => Right(Sort(sortBy, Some(sortOrder)))
case _ => Left("Unable to bind Sort")
}
}
}
override def unbind(key: String, sort: Sort): String = {
stringBinder.unbind("sortBy", sort.sortBy) + "&" + stringBinder.unbind("sortOrder", sort.sortOrder.getOrElse(asc))
}
}
}
case class Sort(sortBy: String, sortOrder: Option[String] = Some(Sort.asc))
对象排序{
val asc=“asc”
隐式def queryStringBinder(隐式stringBinder:QueryStringBindable[String])=新QueryStringBindable[Sort]{
覆盖def绑定(键:String,参数:Map[String,Seq[String]]):选项[String,Sort]={
为了{
sortBy Left(“无法绑定排序”)
}
}
}
override def unbind(键:字符串,排序:排序):字符串={
stringBinder.unbind(“sortBy”,sort.sortBy)+“&”+stringBinder.unbind(“sortOrder”,sort.sortOrder.getOrElse(asc))
}
}
}
案例类排序(sortBy:String,sortOrder:Option[String]=Some(Sort.asc))
但是,如果url的查询字符串中没有提供任何内容,我无法使用默认值捕获可选字段
sortOrder
。我想要http://myurl:9000?sortBy=name
即使未提供&sortOrder
,仍按升序排序(默认值)。不使用升序可能更容易理解:
object Sort {
val asc = "asc"
implicit def queryStringBinder(implicit stringBinder: QueryStringBindable[String]) = new QueryStringBindable[Sort] {
override def bind(key: String, params: Map[String, Seq[String]]): Option[Either[String, Sort]] = {
val sortBy = stringBinder.bind("sortBy", params) // Option[Either[String, String]]
val sortOrder = stringBinder.bind("sortOrder", params) // Option[Either[String, String]]
val result = // Either[String, Sort]
(sortBy, sortOrder) match {
case (Some(Right(field)), Some(Right(order))) => Right(Sort(field, Some(order)))
case (Some(Right(field)), None) => Right(Sort(field))
case _ => Left("Unable to bind Sort")
}
Option(result)
}
override def unbind(key: String, sort: Sort): String = {
stringBinder.unbind("sortBy", sort.sortBy) + "&" + stringBinder.unbind("sortOrder", sort.sortOrder.getOrElse(asc))
}
}
}
case class Sort(sortBy: String, sortOrder: Option[String] = Some(Sort.asc))
不使用a来理解可能更容易:
object Sort {
val asc = "asc"
implicit def queryStringBinder(implicit stringBinder: QueryStringBindable[String]) = new QueryStringBindable[Sort] {
override def bind(key: String, params: Map[String, Seq[String]]): Option[Either[String, Sort]] = {
val sortBy = stringBinder.bind("sortBy", params) // Option[Either[String, String]]
val sortOrder = stringBinder.bind("sortOrder", params) // Option[Either[String, String]]
val result = // Either[String, Sort]
(sortBy, sortOrder) match {
case (Some(Right(field)), Some(Right(order))) => Right(Sort(field, Some(order)))
case (Some(Right(field)), None) => Right(Sort(field))
case _ => Left("Unable to bind Sort")
}
Option(result)
}
override def unbind(key: String, sort: Sort): String = {
stringBinder.unbind("sortBy", sort.sortBy) + "&" + stringBinder.unbind("sortOrder", sort.sortOrder.getOrElse(asc))
}
}
}
case class Sort(sortBy: String, sortOrder: Option[String] = Some(Sort.asc))
工作得很有魅力!谢谢你,工作很有魅力!非常感谢。