Reading a ZIP file with alpakka

sigurd · June 23, 2021, 3:40pm

Hey guys,

I want to read a zip archive containing a big file.
I found in alpakka 3 the Archive including a tar reader, but whats about a zip reader?
There is also an inflator in Compression but still the recognition of the files itself is missing, right?

Is there a trick for that?

Best
Sigurd

tg44 · June 24, 2021, 6:49am

It is somewhat strange but even alpakka uses this ArchiveHelper in its tests and not some self-implemented thing… It is already “streams” from java land, so it shouldn’t be much work to wrap to scala code.

I will cook up a gist/PR later today/tomorrow bcs I get interested :D

sigurd · June 24, 2021, 7:41am

Nice link, thank you!
I also found in the contrib:

github.com

akka/akka-stream-contrib/blob/master/src/main/scala/akka/stream/contrib/ZipInputStreamSource.scala

/*
 * Copyright (C) 2016 Lightbend Inc. <http://www.lightbend.com>
 */

package akka.stream.contrib

import java.util.zip.{ZipEntry, ZipInputStream}
import akka.stream.Attributes.{name, InputBuffer}
import akka.stream.contrib.ZipInputStreamSource.ZipEntryData
import akka.stream.impl.Stages.DefaultAttributes.IODispatcher
import akka.stream.scaladsl.Source
import akka.stream.stage.{GraphStageLogic, GraphStageWithMaterializedValue, OutHandler}
import akka.stream.{Attributes, Outlet, SourceShape}
import akka.util.ByteString
import akka.util.ByteString.ByteString1C
import scala.annotation.tailrec
import scala.collection.immutable
import scala.concurrent.{Future, Promise}
import scala.util.control.NonFatal

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But since it does not support IOResult its more an experimental thing.

tg44 · June 24, 2021, 11:45am

I have no idea if it works in production env or not, but one implementation is this;

sigurd · June 24, 2021, 2:02pm

Looks great, the api is very similar to the tar reader. I really like that way. I’m currently testing it!

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Reading a ZIP file with alpakka

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