With Ktor Server how is a binary file read from the request body?

# ktor

[napperley]

With Ktor Server how is a binary file read from the request body?

[Tóth István Zoltán]

val bytes = ByteArray(length)
call.receiveChannel().readFully(bytes, 0, length)

This reads everything into a byte array which is fine if your upload limit is small. You can use the channel to read chunks if the upload is bigger.

Taken this example from: https://github.com/spxbhuhb/zakadabar-stack/blob/master/lib/blobs/src/jvmMain/kotlin/zakadabar/lib/blobs/business/BlobBlBase.kt

[napperley]

@Aleksei Tirman [JB] - The Ktor Server documentation is missing a section on reading binary data from a HTTP request body.

[napperley]

I found this code example by accident which covers reading the binary data (in chucks) from a HTTP response body 😄: https://github.com/Kotlin/kotlinx-io/issues/41#issuecomment-469137967

Luckily the code example can be adapted to work with an HTTP request body instead.

[napperley]

Here is what I have used in my project: https://gitlab.com/data-conduit/conduit-server/-/blob/master/src/linuxX64Main/kotlin/org.dataConduit.conduitServer/controller.kt#L17

[Aleksei Tirman [JB]]

I’ve created an issue about documentation.