Exposing OAuth2RestTemplate as AsyncRestTemplate - spring

Question

I have a working OAuth2RestTemplate client (I'm using spring-security-oauth2 2.0.7.RELEASE). Now I'd like to expose/wrap it as AsyncRestTemplate to take advantage of asynchronous semantic of ListenableFuture. Unfortunately the following straightforward approach doesn't work:
// instantiate and configure OAuth2RestTemplate - works
OAuth2RestTemplate oAuth2RestTemplate = new OAuth2RestTemplate(...);
// wrap sync restTemplate with AsyncRestTemplate - doesn't work
AsyncRestTemplate asyncRestTemplate = new AsyncRestTemplate(
new HttpComponentsAsyncClientHttpRequestFactory(), oAuth2RestTemplate);
How can I get OAuth2 Rest client for my HTTP service as AsyncRestTemplate?

Answer 1

Ok, I was able to make AsyncRestTemplate work by manually setting "Authorization" header with accessToken from OAuth2RestTemplate; here's Spring java configuration for that:
#Bean
public OAuth2RestTemplate restTemplate() {
ClientCredentialsResourceDetails details = new ClientCredentialsResourceDetails();
// configure oauth details
OAuth2RestTemplate restTemplate = new OAuth2RestTemplate(details);
restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());
return restTemplate;
}
#Bean
public AsyncRestTemplate asyncRestTemplate(final OAuth2RestTemplate oAuth2RestTemplate) {
HttpComponentsAsyncClientHttpRequestFactory asyncRequestFactory = new HttpComponentsAsyncClientHttpRequestFactory() {
#Override
public AsyncClientHttpRequest createAsyncRequest(URI uri, HttpMethod httpMethod) throws IOException {
AsyncClientHttpRequest asyncRequest = super.createAsyncRequest(uri, httpMethod);
OAuth2AccessToken accessToken = oAuth2RestTemplate.getAccessToken();
asyncRequest.getHeaders().set("Authorization", String.format("%s %s", accessToken.getTokenType(), accessToken.getValue()));
return asyncRequest;
}
};
return new AsyncRestTemplate(asyncRequestFactory, oAuth2RestTemplate);
}
I wish there would be easier way to expose configured OAuth2RestTemplate as AsyncRestTemplate in Spring.

Answer 2

The above works, but I've found a much neater way of doing it.
Register an implementation AsyncClientHttpRequestInterceptor
Example code:
private class Oauth2RequestInterceptor implements AsyncClientHttpRequestInterceptor
{
private final OAuth2RestTemplate oAuth2RestTemplate;
public Oauth2RequestInterceptor( OAuth2RestTemplate oAuth2RestTemplate )
{
this.oAuth2RestTemplate = oAuth2RestTemplate;
}
public ListenableFuture<ClientHttpResponse> intercept( HttpRequest request, byte[] body,
AsyncClientHttpRequestExecution execution ) throws IOException
{
OAuth2AccessToken accessToken = oAuth2RestTemplate.getAccessToken();
request.getHeaders()
.set( "Authorization", String.format( "%s %s", accessToken.getTokenType(), accessToken.getValue() ) );
return execution.executeAsync( request, body );
}
}
Then register it with your AsyncRestTemplate:
#Bean
public AsyncRestTemplate asyncRestTemplate( AsyncClientHttpRequestFactory factory, OAuth2RestTemplate restTemplate )
{
AsyncRestTemplate asyncRestTemplate = new AsyncRestTemplate( factory, restTemplate );
asyncRestTemplate.setInterceptors( Collections.singletonList( new Oauth2RequestInterceptor( restTemplate ) ) );
return asyncRestTemplate;
}