Configuring AWS Signing in Reactive Elasticsearch Configuration - spring

Question

In one of our service I tried to configure AWS signing in Spring data Reactive Elasticsearch configuration.
Spring provides the configuring the webclient through webclientClientConfigurer
ClientConfiguration clientConfiguration = ClientConfiguration.builder()
.connectedTo("localhost:9200")
.usingSsl()
.withWebClientConfigurer(
webClient -> {
return webClient.mutate().filter(new AwsSigningInterceptor()).build();
})
. // ... other options to configure if required
.build();
through which we can configure to sign the requests but however AWS signing it requires url, queryparams, headers and request body(in case of POST,POST) to generate the signed headers.
Using this I created a simple exchange filter function to sign the request but in this function I was not able to access the request body and use it.
Below is the Filter function i was trying to use
#Component
public class AwsSigningInterceptor implements ExchangeFilterFunction
{
private final AwsHeaderSigner awsHeaderSigner;
public AwsSigningInterceptor(AwsHeaderSigner awsHeaderSigner)
{
this.awsHeaderSigner = awsHeaderSigner;
}
#Override
public Mono<ClientResponse> filter(ClientRequest request, ExchangeFunction next)
{
Map<String, List<String>> signingHeaders = awsHeaderSigner.createSigningHeaders(request, new byte[]{}, "es", "us-west-2"); // should pass request body bytes in place of new byte[]{}
ClientRequest.Builder requestBuilder = ClientRequest.from(request);
signingHeaders.forEach((key, value) -> requestBuilder.header(key, value.toArray(new String[0])));
return next.exchange(requestBuilder.build());
}
}
I also tried to access the request body inside ExchangeFilterFunction using below approach but once i get the request body using below approach.
ClientRequest.from(newRequest.build())
.body(
(outputMessage, context) -> {
ClientHttpRequestDecorator loggingOutputMessage =
new ClientHttpRequestDecorator(outputMessage) {
#Override
public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
log.info("Inside write with method");
body =
DataBufferUtils.join(body)
.map(
content -> {
// Log request body using
// 'content.toString(StandardCharsets.UTF_8)'
String requestBody =
content.toString(StandardCharsets.UTF_8);
Map<String, Object> signedHeaders =
awsSigner.getSignedHeaders(
request.url().getPath(),
request.method().name(),
multimap,
requestHeadersMap,
Optional.of(
requestBody.getBytes(StandardCharsets.UTF_8)));
log.info("Signed Headers generated:{}", signedHeaders);
signedHeaders.forEach(
(key, value) -> {
newRequest.header(key, value.toString());
});
return content;
});
log.info("Before returning the body");
return super.writeWith(body);
}
#Override
public Mono<Void>
setComplete() { // This is for requests with no body (e.g. GET).
Map<String, Object> signedHeaders =
awsSigner.getSignedHeaders(
request.url().getPath(),
request.method().name(),
multimap,
requestHeadersMap,
Optional.of("".getBytes(StandardCharsets.UTF_8)));
log.info("Signed Headers generated:{}", signedHeaders);
signedHeaders.forEach(
(key, value) -> {
newRequest.header(key, value.toString());
});
return super.setComplete();
}
};
return originalBodyInserter.insert(loggingOutputMessage, context);
})
.build();
But with above approach I was not able to change the request headers as adding headers throws UnsupportedOperationException inside writewith method.
Has anyone used the spring data reactive elastic search and configured to sign with AWS signed headers?
Any help would be highly appreciated.