Can't set FormUrlEncoded header for ktor http client request

[wilyarti]

Ktor Version

1.1.1

Ktor Engine Used(client or server and name)

Apache

JVM Version, Operating System and Relevant Context

Ubuntu 18.04 Information:Kotlin: kotlinc-jvm 1.3.11 (JRE 1.8.0_191-8u191-b12-0ubuntu0.18.04.1-b12)

Feedback

I am trying to POST a request to an API that uses Content-Type: application/x-www-form-urlencoded.

val message = client.post<Unit> {
    url(URL("https://tapi.telstra.com/v2/oauth/token"))
    contentType(ContentType.Application.FormUrlEncoded)
    body = getAuth(client_id = "overriddenkey", client_secret = "overridenpass")
}

I get the error: io.ktor.http.UnsafeHeaderException: Header Content-Type is controlled by the engine and cannot be set explicitly

I can't figure out how to set the headers in the client constructor. The documentation https://ktor.io/clients/http-client/calls/requests.html specifies that custom headers can be set using HttpRequestBuilder.

How do I specify the contentType and set the header data? I could not figure it out from your documentation.

[tasmalinakis]

Hi, we bumped into this problem a while ago as well. Going through the code, I believe that the current way of doing this is by using FormDataContent like so (without specifying a contentType):

body = FormDataContent(parametersOf( "client_id" to "overriddenkey", "client_secret" to "overridenpass") )

Last time I checked this was not stated somewhere in the documentation though.

[wilyarti]

Thanks that seems to work. Although I still need to also be able to set the body of the message with JSON to communicate with the API.

But at least I am 50% there now.

[francos]

I'm having this same issue, I need to add the header and the body, but seems like it's not possible to add both, which makes the API call fail. Has anyone found a workaround for this?

[semyannikov]

@e5l I will start changing documentation in few days, any comments related to PR are welcome.

[oleg-larshin]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.

[woniupapa]

Anyone fixed this problem? help, the same problem.

[wilyarti]

Anyone fixed this problem? help, the same problem.

I haven't looked at this issues in a long time. What I did at the time was use a different http client.

[woniupapa]

Please help me!,There are many pictures.

[woniupapa]

@wilyarti I don't know how to post with formdata content.

[woniupapa]

@wilyarti Dear Wilyarti, I removed //contentType(ContentType.Application.Json) code,It work!!!

[Stexxe]

@wilyarti as a workaround you can override a contentType property of the OutgoingContent class. Here is an example:

val message = client.post<String> {
    url(URL("https://httpbin.org/post"))
    body = object : OutgoingContent.ByteArrayContent() {
        override val contentType = ContentType.Application.FormUrlEncoded
        override fun bytes(): ByteArray {
            return """{"x": 123}""".toByteArray(Charsets.UTF_8)
        }
    }
}

[EhsanMsz]

@e5l I'm currently working on this. to override contentType, it must be removed from UnsafeHeadersArray in HttpHeaders.kt. Is it ok to remove this from UnsafeHeadersArray?