I am using the http cio client -- how can I send an input stream to the client as the body?

# ktor

[rocketraman]

I am using the http cio client -- how can I send an input stream to the client as the body?

[rocketraman]

Clearly I need to adapt the stream to an OutgoingContent.WriteChannelContent somehow, but its unclear to me how.

[rocketraman]

Actually, check that, I want to adapt a java.io.Writer (or OutputStream) to the body.

[Deactivated User]

suspend fun InputStream.toByteChannel(dispatcher: CoroutineDispatcher = ioCoroutineDispatcher): ByteReadChannel {
    val inputStream = this
    return writer(dispatcher) {
        while (true) {
            val temp = ByteArray(1024)
            val readSize = inputStream.read(temp)
            if (readSize <= 0) break
            channel.writeFully(temp, 0, readSize)
        }
    }.channel
}

[Deactivated User]

suspend fun OutputStream.toByteWriteChannel(dispatcher: CoroutineDispatcher = ioCoroutineDispatcher): ByteWriteChannel {
    val outputStream = this
    return reader(dispatcher) {
        while (true) {
            val temp = ByteArray(1024)
            val readSize = channel.readAvailable(temp)
            if (readSize <= 0) break
            outputStream.write(temp, 0, readSize)
        }
    }.channel
}

[rocketraman]

Thanks @Deactivated User, no built-ins for this? I see that coroutines io does have the analogue ByteReadChannel.toInputStream().

[rocketraman]

Also, this assumes the existence of an OutputStream... I'd rather create an OutputStream connected to a ByteWriteChannel. So I think I just need to create a new ByteWriteChannel and call toOutputStream on it.

[rocketraman]

But where do I get the ByteWriteChannel from?

[rocketraman]

Can I just do ByteChannel(true).toOutputStream()?

[Deactivated User]

https://github.com/Kotlin/kotlinx-io/issues/4

[Deactivated User]

I’m not sure if there are already for inputstream

[Deactivated User]

Maybe for those cases there are already

[Deactivated User]

https://github.com/Kotlin/kotlinx-io/blob/f7150df011d25a40453bcbf75e8bb9f83687b377/kotlinx-io-jvm/src/main/kotlin/kotlinx/io/streams/Streams.kt#L78

[rocketraman]

Hmm, I'm still a little confused. I want to create a OutgoingContent that is a ByteWriteChannel, from which it looks like I can do toOutputStream. But it seems that class is internal, so I don't have a way to create it.

[rocketraman]

@Deactivated User ideas?

[Deactivated User]

Sorry, was AFK

[Deactivated User]

What about WriterContent?

[Deactivated User]

WriterContent({ … channel.write(…)… }, ContentType…)

[Deactivated User]

OutgoingContent has several abstract inner classes, (if you look at the implementations of those classes)

[rocketraman]

So if I pass in an implementation of WriteChannelContent I'll get a writeTo callback in which I can write to the output stream?

[Deactivated User]

https://github.com/ktorio/ktor/blob/8e65dafbe7fdb36804fc0ccc357082140763fe79/ktor-server/ktor-server-core/src/io/ktor/content/WriterContent.kt#L8

[Deactivated User]

if you have a bytewritechannel, I guess you can copy from one to another

[rocketraman]

@Deactivated User WriterContent worked as expected, BUT I note this class is in the server-core package, so it cannot easily be used as OutgoingContent in the ktor client. Should this and other implementations of OutgoingContent be moved to somewhere common to client and server?

[Deactivated User]

I would file an issue suggesting it: https://github.com/ktorio/ktor/issues

[rocketraman]

Done, thanks: https://github.com/ktorio/ktor/issues/465