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Scala

About​

Our Scala SDK, blockfrost-scala is tested to work with JDK11.

Installation​

To use blockfrost-scala as a dependency in your scala project you should clone this repository to your dev environment, build artifcat and publish it to your local maven repository:

$> git clone https://github.com/blockfrost/blockfrost-scala.git
$> cd blockfrost scala
$> sbt publishLocal

Usage​

Add blockfrost-scala dependency to your build.sbt

libraryDependencies += "io.blockfrost" %% "blockfrost-scala" % "0.1.0"

This library requires one of sttp backend in your classpath. Full list of supported backends: Supported backends.

Blockfrost-scala library has built-in support for Future sttp backend to transform response type from Future[Response[Either[ResponseException[String, Exception], R]]] to Future[R] and fetch all pages from APIs with pagination (see FuturePaginationSupport and FutureResponseConverter classes). Anyway, this library is designed to use it with any other functional effect wrapper like ZIO, Monix, Scalaz, cats-effect, fs2 etc.

For this example we will use async-http-client based on Future:

libraryDependencies += "com.softwaremill.sttp.client3" %% "async-http-client-backend" % $version,

Note: Replace '$version' with the correct version number

Following services are available:​

  • Cardano
    • AccountsApi
    • AddressesApi
    • AssetsApi
    • BlockApi
    • EpochsApi
    • HealthApi
    • LedgerApi
    • MetadataApi
    • MetricsApi
    • NetworkApi
    • PoolsApi
    • TransactionsApi
  • IPFS
    • IpfsApi
  • Nut.link
    • NutlinkApi

Example application with blockfrost-sdk and Future sttp backend​

import io.blockfrost.sdk.BlockfrostClient
import io.blockfrost.sdk.api.{AssetsApi, BlockApi, IpfsApi}
import io.blockfrost.sdk.common._
import io.blockfrost.sdk.util.FuturePaginationSupport
import io.blockfrost.sdk.util.FutureResponseConverter.FutureResponseOps
import org.json4s.jackson.Serialization
import org.json4s.{DefaultFormats, Formats}
import sttp.client3.SttpBackend
import sttp.client3.asynchttpclient.future.AsyncHttpClientFutureBackend

import java.io.File
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future

object Application extends App {

  implicit val formats: Formats = DefaultFormats
  implicit val serialization: Serialization.type = Serialization
  // SDK configuration for http client, concurrent requests and rate limiter
  implicit val sdkConfig: Config = Config(threadCount = 5, rateLimitPauseMillis = 500, readTimeoutMillis = 5000)
  // Explicitly pass you API key to the BlockfrostClient or set it to BLOCKFROST_API_KEY env variable
  val apiKey = "your-api-key"
  val sttpBackend: SttpBackend[Future, Any] = AsyncHttpClientFutureBackend()

  // Instantiate Mainnet BlockfrostClient
  val cardanoClient = BlockfrostClient[Future, Any](sttpBackend, Mainnet, apiKey)

  // Get latest Cardano block
  val latestBlockF: Future[BlockApi.BlockContent] = cardanoClient.getLatestBlock.extract

  // Get paginated assets: 10 elements from second page, sorted ascending
  val assetsPageF: Future[Seq[AssetsApi.AssetShort]] = cardanoClient.getAssets(SortedPageRequest.apply(count = 10, page = 2, order = Asc)).extract

  // Concurrently get all assets from all pages using 5 threads (configured in sdkConfig variable)
  val allAssetsF: Future[Seq[AssetsApi.AssetShort]] = FuturePaginationSupport.getAllPages((pr: PageRequest) => cardanoClient.getAssets(pr.asInstanceOf[SortedPageRequest]).extract, Some(Asc))

  // Instantiate IPFS BlockfrostClient
  val ipfsClient = BlockfrostClient[Future, Any](sttpBackend, IPFS, apiKey)

  // Create IPFS object and pin it
  val file = new File("<path to file>")
  val pinnedIpfsObjectF: Future[IpfsApi.PinnedObject] = ipfsClient.addObject(file).extract.flatMap { ipfsObject =>
    ipfsClient.pinObject(ipfsObject.ipfs_hash).extract
  }
}