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Version: 2.x

Introduction to ZIO NIO

ZIO-NIO is a ZIO wrapper on Java NIO, an opinionated interface with deep ZIO integration that provides type and resource safety.

Installation​

ZIO-NIO is available via maven repo. Add this to your dependencies in sbt:

libraryDependencies += "dev.zio" %% "zio-nio" % "2.0.0"

Main Abstractions​

  • Using Blocking APIs — How to deal with NIO APIs that block the calling thread
  • File Channel — For processing files that are available locally. For every operation a new fiber is started to perform the operation.
  • Socket Channel — Provides an API for remote communication with InetSockets.
  • Resource Management - Avoiding resource leaks
  • Character Sets - For encoding or decoding character data.

End-Of-Stream Handling​

When reading from channels, the end of the stream may be reached at any time. This is indicated by the read effect failing with an java.io.EOFException. If you would prefer to explicitly represent the end-of-stream condition in the error channel, use the eofCheck extension method:

import zio._
import zio.blocking.Blocking
import zio.nio._
import zio.nio.channels._
import zio.nio.file.Path
import java.io.IOException

val read100: ZIO[Blocking, Option[IOException], Chunk[Byte]] =
  FileChannel.open(Path("foo.txt"))
    .useNioBlockingOps(_.readChunk(100))
    .eofCheck

End-of-stream will be signalled with None. Any errors will be wrapped in Some.

References​