JarCastingSpray Extensions
spray-extensions its a simple library with useful tools for develop web apps with Spray.
Repository
Stable OSS Sonatype
"com.github.jarlakxen" %% "spray-extensions" % "1.0"
Changelog
1.0
- Add scalate support.
- Add json filtering.
- Add pagination support.
Pagination Support
The trait PaginationDirectives offers some helpers for handling pagination:
path("filter-test") {
pagination { page =>
complete {
page match {
case Some(page) => ... // A page was requested
case None => ... // No page was requested
}
}
}
}
The page object has this format
sealed trait Order
object Order {
case object Asc extends Order
case object Desc extends Order
}
case class PageRequest(index: Int, size: Int, sort: Map[String, Order])
This is an example of url: /filter-test?page=1&size=10 or /filter-test?page=1&size=10&sort=name,asc;age,desc
The name of the parameters can be configured through Typesafe Config:
spray {
extensions {
rest{
pagination{
index-param-name = "page"
size-param-name = "size"
sort-param-name = "sort"
asc-param-name = "asc"
desc-param-name = "desc"
sorting-separator = ";"
order-separator = ","
totalelements-header-name = "total_elements"
}
}
}
}
When you replay a page, you sometime needs to send te total number of elements. This is usefull for the client for knowing how many pages they are. For this scenario there is:
path("filter-test") {
pagination { page =>
complete {
page match {
case Some(page) => {
val response = PageResponse(List("test"), 10)
completePage(response)
}
case None => ... // No page was requested
}
}
}
}
The total number of elements is sended in the header total_elements
JSON filtering Support
The trait FiltersDirectives offers some helpers for filtering the json response:
val JsonArrayFull = """[
{
"name":"user1",
"password":"1234",
"meta":{"email":"[email protected]", "age": 12}
},
{
"name":"user2",
"password":"0000",
"meta":{"email":"[email protected]", "age": 20}
}
]"""
path("filter-test") {
pagination { page =>
filterResponse(resolver.json4s) {
complete { HttpEntity(ContentTypes.`application/json`, JsonArrayFull) }
}
}
}
The filterResponse directive required a resolver, depending of the json parser:
- resolver.json4s
- resolver.'spray-json'
You need to add the dependency to the json parser in you build.sbt ( "spray-json" or "json4s-jackson")
Using this url: /filter-test?filter=name. The result is: [{"name":"user1"},{"name":"user2"}]
Using this url: /filter-test?filter=name;meta;!meta.email. The result is: [{"name":"user1","meta":{"age":12}},{"name":"user2","meta":{"age":20}}]
In the last example the operator ! is used to exclude fields.
You can customize the filter separator, changing the property spray.extensions.rest.filter.separator.
Scalate Support
The trait ScalateSupport offers some helpers for using the scalate template engine. This is usefull if you, for example, want to use mustache.
path("filter-test") {
pagination { page =>
mustache("index", Map("USER_NAME" -> "Test"))
}
}
In this example the file /templates/index.mustache is loaded by scalate. The base path can be changed, by the property spray.extensions.view.templates-path.