play.api.mvc

QueryStringBindable

trait QueryStringBindable[A] extends AnyRef

Binder for query string parameters.

You can provide an implementation of QueryStringBindable[A] for any type A you want to be able to bind directly from the request query string.

For example, if you have the following type to encode pagination:

/**
* @param index Current page index
* @param size Number of items in a page
*/ *   case class Pager(index: Int, size: Int)

Play will create a Pager(5, 42) value from a query string looking like /foo?p.index=5&p.size=42 if you define an instance of QueryStringBindable[Pager] available in the implicit scope.

For example:

object Pager {
implicit def queryStringBinder(implicit intBinder: QueryStringBindable[Int]) = new QueryStringBindable[Pager] {
  override def bind(key: String, params: Map[String, Seq[String]]): Option[Either[String, Pager]] = {
    for {
      index <- intBinder.bind(key + ".index", params)
      size <- intBinder.bind(key + ".size", params)
    } yield {
      (index, size) match {
        case (Right(index), Right(size)) => Right(Pager(index, size))
        case _ => Left("Unable to bind a Pager")
      }
    }
  }
  override def unbind(key: String, pager: Pager): String = {
    intBinder.unbind(key + ".index", pager.index) + "&" + intBinder.unbind(key + ".size", pager.size)
  }
}
}

To use it in a route, just write a type annotation aside the parameter you want to bind:

GET  /foo        controllers.foo(p: Pager)
Self Type
QueryStringBindable[A]
Annotations
@implicitNotFound( ... )
Source
Binders.scala
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Abstract Value Members

  1. abstract def bind(key: String, params: Map[String, Seq[String]]): Option[Either[String, A]]

    Bind a query string parameter.

    Bind a query string parameter.

    key

    Parameter key

    params

    QueryString data

    returns

    None if the parameter was not present in the query string data. Otherwise, returns Some of either Right of the parameter value, or Left of an error message if the binding failed.

  2. abstract def unbind(key: String, value: A): String

    Unbind a query string parameter.

    Unbind a query string parameter.

    key

    Parameter key

    value

    Parameter value.

    returns

    a query string fragment containing the key and its value. E.g. "foo=42"

Concrete Value Members

  1. final def !=(arg0: AnyRef): Boolean

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  2. final def !=(arg0: Any): Boolean

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  3. final def ##(): Int

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  4. final def ==(arg0: AnyRef): Boolean

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  5. final def ==(arg0: Any): Boolean

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  6. final def asInstanceOf[T0]: T0

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  7. def clone(): AnyRef

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  8. final def eq(arg0: AnyRef): Boolean

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  9. def equals(arg0: Any): Boolean

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  10. def finalize(): Unit

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  11. final def getClass(): Class[_]

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  12. def hashCode(): Int

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  13. final def isInstanceOf[T0]: Boolean

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  14. def javascriptUnbind: String

    Javascript function to unbind in the Javascript router.

  15. final def ne(arg0: AnyRef): Boolean

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  16. final def notify(): Unit

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  17. final def notifyAll(): Unit

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  18. final def synchronized[T0](arg0: ⇒ T0): T0

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  19. def toString(): String

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  20. def transform[B](toB: (A) ⇒ B, toA: (B) ⇒ A): QueryStringBindable[B]

    Transform this QueryStringBindable[A] to QueryStringBindable[B]

  21. final def wait(): Unit

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    @throws()
  22. final def wait(arg0: Long, arg1: Int): Unit

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  23. final def wait(arg0: Long): Unit

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