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kotlinlang

Why can’t I set the content type on a request? It fails saying the engine should handle the content type header, what does that mean?

You can set  `Content-type` if you’re using `OutgoingContent` as body.

Here is my code
```
    private suspend fun doUploadFile(data: ByteReadChannel, uploadUrl: String, contentType: ContentType): Unit =
        http.put(uploadUrl) {
            headers.clear() // Remove default headers for this request
            contentType(contentType)
            body = object : OutgoingContent.WriteChannelContent() {

                override suspend fun writeTo(channel: ByteWriteChannel) {
                    data.copyAndClose(channel)
                }

            }
        }
```

I get `Caused by: io.ktor.http.UnsafeHeaderException: Header Content-Type is controlled by the engine and cannot be set explicitly` with this code

Could you try something like this?
```
suspend fun HttpClient.doUploadFile(
        data: ByteReadChannel,
        uploadUrl: String,
        contentType: ContentType
): Unit = put(uploadUrl) {
        body = object : OutgoingContent.WriteChannelContent() {
            override val contentType: ContentType? get() = contentType

            override suspend fun writeTo(channel: ByteWriteChannel) {
                data.copyAndClose(channel)
            }

        }
    }
```

I see. I’ve been looking a bit more at the `OutgoingContent` file and I saw `ReadChannelContent`, can I use this code instead? What’s the difference?
```            body = object : OutgoingContent.ReadChannelContent() {
                override fun readFrom() = data
            }```
(Adding the contentType to that)

Yes, you can also override `contentType` in any `OutgoingContent`.

How do you chose if you use a `ReadChannelContent` or a `WriteChannelContent`?

`ReadChannelContent` obliges you to provide generating channel. `WriteChannelContent` allows you to write content directly.

So if I already have a `ByteReadChannel` I use `ReadChannelContent`, while if I have something else to write like a simple `String` or an `InputStream` I could write it directly using `WriteChannelContent`, am I understanding that correctly?

`override val contentType` works, thanks.

<@U4CP1J0QP> So I just realized that it uploads exactly 0 bytes

Maybe I need to set the content length but it doesn’t make sense as I don’t always know the length of the `ByteReadChannel`

Ok that was an error on my custom logger. Wasn’t splitting the channel when trying to log it