failing to add client credentials (clientid/clientsecret) at Spring Webclient: Request processing failed ... 401 UNAUTHORIZED - spring

Question

I am trying to use WebClient to consume an endpoint which provides a token.
Using Postman it works as expected. Exported curl from postman is:
curl --location --request POST 'https://mycomp.url/api/oauth/token' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'client_id=xxx' \
--data-urlencode 'client_secret=yyy' \
--data-urlencode 'grant_type=client_credentials'
I am configuring webclient call based on same curl above.
Here is my WebClient config:
#Configuration
class ClientConfiguration {
#Bean
fun webClient(): WebClient = WebClient.builder()
.clientConnector(
ReactorClientHttpConnector(
HttpClient.from(
TcpClient
.create()
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
.doOnConnected { connection: Connection ->
connection.addHandlerLast(ReadTimeoutHandler(10000, TimeUnit.MILLISECONDS))
connection.addHandlerLast(WriteTimeoutHandler(10000, TimeUnit.MILLISECONDS))
}))
)
.build()
}
Here is the webclient post in order to recieve a token:
#Service
class TokenService(private val webClient: WebClient) {
fun postAsynchronous(): Mono<TokenResponse> = webClient
.post()
.uri(UriComponentsBuilder
.fromHttpUrl("https://mycomp.url")
.path("/api/oauth/token")
.build()
.toUri())
.header("grant_type","client_credentials")
.header("client_id","xxx")
.header("client_secret","yyy")
.header(HttpHeaders.CONTENT_TYPE, "application/x-www-form-urlencoded")
.retrieve()
.onStatus(HttpStatus::is4xxClientError) { Mono.error(RuntimeException("4XX Error ${it.statusCode()}")) }
.onStatus(HttpStatus::is5xxServerError) { Mono.error(RuntimeException("5XX Error ${it.statusCode()}")) }
.bodyToMono(TokenResponse::class.java)
}
Here is my build.gradle.kts (the relevant part):
import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
plugins {
id("org.jetbrains.kotlin.jvm") version "1.4.10"
id("org.jetbrains.kotlin.kapt") version "1.4.10"
kotlin("plugin.spring") version "1.5.20"
id("org.springframework.boot") version "2.4.7"
//kotlin("jvm") version "1.5.30"
id("io.spring.dependency-management") version "1.0.10.RELEASE"
}
val kotlinVersion: String by project
val springVersion: String by project
val projectGroupId: String by project
val projectVersion: String by project
group = projectGroupId
version = projectVersion
repositories {
mavenLocal()
... some internal artifactories
mavenCentral()
}
// add dependencies
dependencies {
kapt(kotlin("stdlib", kotlinVersion))
implementation(kotlin("stdlib-jdk8"))
implementation(kotlin("reflect", kotlinVersion))
implementation("org.springframework.boot:spring-boot-dependencies:2.4.7")
implementation("org.springframework.boot:spring-boot-starter:2.4.7")
implementation("org.springframework.boot:spring-boot-starter-web:2.4.7")
implementation("org.springframework.boot:spring-boot-starter-webflux")
implementation("org.springframework.cloud:spring-cloud-starter-openfeign:3.0.3")
implementation("io.github.openfeign:feign-okhttp:10.2.0")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.11.2")
}
The whole exception is:
2021/09/23 17:33:53.123 [http-nio-8080-exec-2] INFO o.a.c.c.C.[Tomcat].[localhost].[/] - Initializing Spring DispatcherServlet 'dispatcherServlet'
2021/09/23 17:33:53.123 [http-nio-8080-exec-2] INFO o.s.web.servlet.DispatcherServlet - Initializing Servlet 'dispatcherServlet'
2021/09/23 17:33:53.124 [http-nio-8080-exec-2] INFO o.s.web.servlet.DispatcherServlet - Completed initialization in 1 ms
2021/09/23 17:33:54.396 [http-nio-8080-exec-2] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.RuntimeException: 4XX Error 401 UNAUTHORIZED] with root cause
java.lang.RuntimeException: 4XX Error 401 UNAUTHORIZED
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:32)
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ 401 from POST https://mycomp-url/api/oauth/token [DefaultWebClient]
Stack trace:
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:32)
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:15)
at org.springframework.web.reactive.function.client.DefaultWebClient$DefaultResponseSpec$StatusHandler.apply(DefaultWebClient.java:693)
at org.springframework.web.reactive.function.client.DefaultWebClient$DefaultResponseSpec.applyStatusHandlers(DefaultWebClient.java:652)
at org.springframework.web.reactive.function.client.DefaultWebClient$DefaultResponseSpec.handleBodyMono(DefaultWebClient.java:621)
at org.springframework.web.reactive.function.client.DefaultWebClient$DefaultResponseSpec.lambda$bodyToMono$2(DefaultWebClient.java:541)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:125)
I tried also other approach just in case.
I keep webclient as it is and I just change how I send the credentials.
Firstly I created a simple class containing all three parameters:
data class TokenRequest(
var grantType: String,
var clientId: String,
var clientSecret: String
)
And then I modified the webclient.post to
fun postAsynchronous(): Mono<TokenResponse> = webClient
.post()
.uri(UriComponentsBuilder
.fromHttpUrl("https://mycomp-url")
.path("/api/oauth/token")
.build()
.toUri())
.body(BodyInserters.fromValue(TokenRequest("client_credentials","xxx", "yyy")))
.header(HttpHeaders.CONTENT_TYPE, "application/json")
.retrieve()
.onStatus(HttpStatus::is4xxClientError) { Mono.error(RuntimeException("4XX Error ${it.statusCode()}")) }
.onStatus(HttpStatus::is5xxServerError) { Mono.error(RuntimeException("5XX Error ${it.statusCode()}")) }
.bodyToMono(TokenResponse::class.java)
And I got exact same issue:
2021/09/23 18:01:55.994 [http-nio-8080-exec-1] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.RuntimeException: 4XX Error 401 UNAUTHORIZED] with root cause
java.lang.RuntimeException: 4XX Error 401 UNAUTHORIZED
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:32)
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ 401 from POST https://mycomp.url/api/oauth/token [DefaultWebClient]
Stack trace:
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:32)
at com.mycomp.security.TokenService$postAsynchronous$2.apply(TokenService.kt:15)
at org.springframework.web.reactive.function.client.DefaultWebClient$DefaultResponseSpec$StatusHandler.apply(DefaultWebClient.java:693)
*** Edited in Oct 7th 2021
With Aniket Singla proposal I reached this new issue:
[reactor-tcp-nio-2] WARN r.n.http.client.HttpClientConnect - [id:9270e5dc-1, L:/10.92.12.165:58268 - R:mycomp-url/x.x.x.x:443] The connection observed an error
org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/x-www-form-urlencoded' not supported for bodyType=com.mycomp.application.models.token.TokenRequest
at org.springframework.web.reactive.function.BodyInserters.unsupportedError(BodyInserters.java:391)
...
[http-nio-8080-exec-1] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.web.reactive.function.client.WebClientRequestException: Content type 'application/x-www-form-urlencoded' not supported for bodyType=com.mycomp.application.models.token.TokenRequest; nested exception is org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/x-www-form-urlencoded' not supported for bodyType=com.mycomp.application.models.token.TokenRequest] with root cause
org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/x-www-form-urlencoded' not supported for bodyType=com.mycomp.application.models.token.TokenRequest
With Maciej Dobrowolski proposal I got this new exception:
2021/10/07 17:36:29.098 [http-nio-8080-exec-2] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.core.codec.DecodingException: JSON decoding error: Instantiation of [simple type, class com.mycomp.application.models.token.TokenResponse] value failed for JSON property result due to missing (therefore NULL) value for creator parameter result which is a non-nullable type; nested exception is com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException: Instantiation of [simple type, class com.mycomp.application.models.token.TokenResponse] value failed for JSON property result due to missing (therefore NULL) value for creator parameter result which is a non-nullable type
at [Source: (io.netty.buffer.ByteBufInputStream); line: 8, column: 1] (through reference chain: com.mycomp.application.models.token.TokenResponse["result"])] with root cause
com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException: Instantiation of [simple type, class com.mycomp.application.models.token.TokenResponse] value failed for JSON property result due to missing (therefore NULL) value for creator parameter result which is a non-nullable type
at [Source: (io.netty.buffer.ByteBufInputStream); line: 8, column: 1] (through reference chain: com.mycomp.application.models.token.TokenResponse["result"])
at com.fasterxml.jackson.module.kotlin.KotlinValueInstantiator.createFromObjectWith(KotlinValueInstantiator.kt:112)
*** Edited
data class TokenResponse (
val result: String
)

Answer 1

Using --data-urlencode curl option, you are adding a parameter to the request's body. In your Kotlin code, you are not passing the same data in the request's body, but in the headers.
What you should do (to mimic postman behavior) is to pass grant_type, client_id, client_secret in the request body by using BodyInserters, like this:
webClient
.post()
.uri(UriComponentsBuilder
.fromHttpUrl("https://mycomp.url")
.path("/api/oauth/token")
.build()
.toUri())
.body(BodyInserters.fromFormData("grant_type", "client_credentials")
.with("client_id", "xxx")
.with("client_secret", "yyy"))
.header(HttpHeaders.CONTENT_TYPE, "application/x-www-form-urlencoded")
.retrieve()
// ...

Answer 2

Supplying url encoded data in headers wont work , you just need to tell in headers that you are going to use "application/x-www-form-urlencoded" as content type, else will be taken care by webclient to convert the body into url encoded form. Made some changes to your postAsynchronous method, should solve your problem.
fun postAsynchronous(): Mono<TokenResponse> = webClient
.post()
.uri(UriComponentsBuilder
.fromHttpUrl("https://des-sts-int.mbi.cloud.ihf")
.path("/api/oauth/token")
.build()
.toUri())
.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
.body(BodyInserters.fromFormData("grant_type", "client_credentials")
.with("client_id", "xxx")
.with("client_secret", "yyy")) )
.retrieve()
.onStatus(HttpStatus::is4xxClientError) { Mono.error(RuntimeException("4XX Error ${it.statusCode()}")) }
.onStatus(HttpStatus::is5xxServerError) { Mono.error(RuntimeException("5XX Error ${it.statusCode()}")) }
.bodyToMono(TokenResponse::class.java)