No-magic Scala client to consume JSON home documents like this:
{
"resources": {
"http://spec.example.org/rels/artists": {
"href": "/artists"
},
"http://spec.example.org/rels/artist": {
"href-template": "/artists/{artist-id}",
"href-vars": {
"artist-id": "http://spec.example.org/params/artist"
}
}
}
}The json-home-client regularly loads json home documents from json home document providers, and caches them in memory. When your application retrieves some information from this json-home-client, the cached json home documents are used so that there'll be no network roundtrip.
This library uses Play's JSON library.
You must add the json-home-client to the dependencies of the build file, e.g. add to build.sbt:
libraryDependencies += "de.kaufhof" %% "json-home-client" % "3.0.3"
It is published to sonatype nexus for scala 2.11 and 2.12.
At first you setup the JsonHomeService for various hosts that provide json home documents.
The first host serves a json home like the one shown above.
import de.kaufhof.jsonhomeclient._
// Specify which service/host provides which link relations
// By default, json home docs are assumed to be served from `/.well-known/home`.
val host1 = JsonHomeHost("http://some.host", Seq(
// A link relation without params
DirectLinkRelationType("http://spec.example.org/rels/artists"),
// A link relation with template params
TemplateLinkRelationType("http://spec.example.org/rels/artist")
))
// Create the client, it loads the json home doc from the host
//Make sure to shutdown the ActorSystem after usage
implicit val system: ActorSystem = ActorSystem()
implicit val materializer: ActorMaterializer = ActorMaterializer()
val client1 = new JsonHomeClient(host1)
// Create the cache, it will regularly (using the Akka scheduler) load json home doc
// using the client. The initialTimeToWait is used for requests when the schedule did not yet
// kick in (might happen e.g. in tests) so that the json home doc was not yet requested/loaded.
// In this case the json home doc is directly loaded from the client and the cache will wait for
// the result using the given `initialTimeToWait`. Decide whether the cache
// should log output verbose or not.
val cache1 = new JsonHomeCache(
client1,
updateInterval = 5 minutes,
initialTimeToWait = 10 seconds,
logVerbose = false
)
// The json home service, the interface for applications, set up with several json home caches
val jsonHomeService = JsonHomeService(Seq(cache1, cache2, ...))Once the json home service is set up, you can use it to retrieve links for link-relations.
// Example 1: Get a link relation that does not expect template params
jsonHomeService.getUrl(
host1,
DirectLinkRelationType("http://spec.example.org/rels/artists")
) == Some("/artists")
// Example 2: Some link relation that expects template params
jsonHomeService.getUrl(
host1,
TemplateLinkRelationType("http://spec.example.org/rels/artist"),
Map("artist-id" -> "acdc")
) == Some("/artists/acdc")sbt
sbt Release
The license is Apache 2.0, see LICENSE.
