/* Title: Pure/General/json_api.scala
Author: Makarius
Support for JSON:API: https://jsonapi.org/format
*/
package isabelle
import java.net.URL
object JSON_API {
val mime_type = "application/vnd.api+json"
def api_error(msg: String): Nothing = error("JSON API error: " + msg)
def api_errors(msgs: List[String]): Nothing = error(("JSON API errors:" :: msgs).mkString("\n "))
class Service(val url: URL) {
override def toString: String = url.toString
def get(route: String): HTTP.Content =
HTTP.Client.get(if (route.isEmpty) url else new URL(url, route))
def get_root(route: String = ""): Root =
Root(get(if (route.isEmpty) "" else "/" + route).json)
}
sealed case class Root(json: JSON.T) {
def get_links: Option[Links] = JSON.value(json, "links").map(Links)
def get_next: Option[Service] = get_links.flatMap(_.get_next)
def get_included: List[Resource] = JSON.list(json, "included", Resource.some).getOrElse(Nil)
def get_data: Option[Data] = JSON.value(json, "data").map(Data(_, get_included))
def get_errors: Option[List[JSON.T]] = JSON.list(json, "errors", Some(_))
def ok: Boolean = get_errors.isEmpty
def check: Root =
get_errors match {
case None => this
case Some(List(err)) => api_error(JSON.Format(err))
case Some(errs) => api_errors(errs.map(JSON.Format.apply))
}
def check_data: Data = check.get_data getOrElse api_error("missing data")
def check_resource: Resource = check_data.resource
def check_resources: List[Resource] = check_data.resources
def iterator: Iterator[Root] = {
val init = Some(this)
new Iterator[Root] {
private var state: Option[Root] = init
def hasNext: Boolean = state.nonEmpty
def next(): Root =
state match {
case None => Iterator.empty.next()
case Some(res) =>
state = res.get_next.map(_.get_root())
res
}
}
}
def iterator_data: Iterator[Data] = iterator.map(_.check_data)
def iterator_resource: Iterator[Resource] = iterator.map(_.check_resource)
def iterator_resources: Iterator[Resource] = iterator.flatMap(_.check_resources)
override def toString: String = "Root(" + (if (ok) "ok" else "errors") + ")"
}
sealed case class Links(json: JSON.T) {
def get_next: Option[Service] =
for {
JSON.Value.String(next) <- JSON.value(json, "next")
if Url.is_wellformed(next)
} yield new Service(Url(next))
override def toString: String =
if (get_next.isEmpty) "Links()" else "Links(next)"
}
sealed case class Data(data: JSON.T, included: List[Resource]) {
def is_multi: Boolean = JSON.Value.List.unapply(data, Some(_)).nonEmpty
def resource: Resource =
if (is_multi) api_error("singleton resource expected")
else Resource.some(data).get
def resources: List[Resource] =
JSON.Value.List.unapply(data, Resource.some)
.getOrElse(api_error("multiple resources expected"))
override def toString: String =
if (is_multi) "Data(resources)" else "Data(resource)"
}
object Resource {
def some(json: JSON.T): Some[Resource] = Some(Resource(json))
}
sealed case class Resource(json: JSON.T) {
val id: JSON.T = JSON.value(json, "id") getOrElse api_error("missing id")
val type_ : JSON.T = JSON.value(json, "type") getOrElse api_error("missing type")
val fields: JSON.Object.T =
JSON.value(json, "attributes", JSON.Object.unapply).getOrElse(JSON.Object.empty) ++
JSON.value(json, "relationships", JSON.Object.unapply).getOrElse(JSON.Object.empty)
override def toString: String = JSON.Format(json)
}
}