[英]How to convert Source[ByteString, Any] to InputStream
akka-http represents a file uploaded using multipart/form-data encoding as Source[ByteString, Any]
. akka-http表示使用multipart / form-data编码作为
Source[ByteString, Any]
上传的文件。 I need to unmarshal it using Java library that expects an InputStream
. 我需要使用需要
InputStream
Java库来解组它。
How Source[ByteString, Any]
can be turned into an InputStream
? Source[ByteString, Any]
如何变成InputStream
?
As of version 2.x you achieve this with the following code: 从版本2.x开始,您可以使用以下代码实现此目的:
import akka.stream.scaladsl.StreamConverters
...
val inputStream: InputStream = entity.dataBytes
.runWith(
StreamConverters.asInputStream(FiniteDuration(3, TimeUnit.SECONDS))
)
See: http://doc.akka.io/docs/akka-stream-and-http-experimental/2.0.1/scala/migration-guide-1.0-2.x-scala.html 请参阅: http : //doc.akka.io/docs/akka-stream-and-http-experimental/2.0.1/scala/migration-guide-1.0-2.x-scala.html
Note: was broken in version 2.0.2 and fixed in 2.4.2 注意:在版本2.0.2中已中断,在2.4.2中已修复
You could try using an OutputStreamSink
that writes to a PipedOutputStream
and feed that into a PipedInputStream
that your other code uses as its input stream. 您可以尝试使用
OutputStreamSink
写入PipedOutputStream
并将其提供给PipedInputStream
,而其他代码将其用作其输入流。 It's a little rough of an idea but it could work. 这是一个有点粗略的想法,但它可以工作。 The code would look like this:
代码如下所示:
import akka.util.ByteString
import akka.stream.scaladsl.Source
import java.io.PipedInputStream
import java.io.PipedOutputStream
import akka.stream.io.OutputStreamSink
import java.io.BufferedReader
import java.io.InputStreamReader
import akka.actor.ActorSystem
import akka.stream.ActorFlowMaterializer
object PipedStream extends App{
implicit val system = ActorSystem("flowtest")
implicit val mater = ActorFlowMaterializer()
val lines = for(i <- 1 to 100) yield ByteString(s"This is line $i\n")
val source = Source(lines)
val pipedIn = new PipedInputStream()
val pipedOut = new PipedOutputStream(pipedIn)
val flow = source.to(OutputStreamSink(() => pipedOut))
flow.run()
val reader = new BufferedReader(new InputStreamReader(pipedIn))
var line:String = reader.readLine
while(line != null){
println(s"Reader received line: $line")
line = reader.readLine
}
}
You could extract an interator from ByteString and then get the InputStream. 您可以从ByteString中提取一个interator,然后获取InputStream。 Something like this (pseudocode):
像这样的东西(伪代码):
source.map { data: ByteString =>
data.iterator.asInputStream
}
Update 更新
A more elaborated sample starting with a Multipart.FormData 一个以Multipart.FormData开头的更详细的示例
def isSourceFromFormData(formData: Multipart.FormData): Source[InputStream, Any] =
formData.parts.map { part =>
part.entity.dataBytes
.map(_.iterator.asInputStream)
}.flatten(FlattenStrategy.concat)
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