Custom implementation for RemoteContentRendererRequestHandler

[arungm20]

Hello Members,

Has any one tried implementing custom usecase for RemoteContentRendererRequestHandler by following the below documentation?

https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/implementing/dev...

Below is our implementation which works fine in local SDK but not in cloud service. 

I refer to RemoteContentRendererRequestHandler defaultHandler; which is required for processing. Unfortunately this does not seem to become available and hence my custom implementation is never invoked.

I have also delayed the service activation with immediate=false which does not help

I have also tried so that my service gets activated and gets the reference when available which also does not help

@reference(
cardinality = ReferenceCardinality.OPTIONAL,
policy = ReferencePolicy.DYNAMIC,
policyOption = ReferencePolicyOption.GREEDY
)
private volatile RemoteContentRendererRequestHandler defaultHandler;

Kindly share your thoughts on what would be wrong in this implementation

import com.adobe.cq.export.json.ComponentExporter;
import com.adobe.cq.remote.content.renderer.RemoteContentRendererRequestHandler;
import com.adobe.cq.remote.content.renderer.RemoteContentRenderingException;
import com.google.gson.JsonParser;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.sling.api.SlingHttpServletRequest;
import org.osgi.framework.Constants;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

@Component(immediate = true,
	service = RemoteContentRendererRequestHandler.class,
	property={
		Constants.SERVICE_RANKING +":Integer=1000"
	})
public class CustomRemoteContentRendererRequestHandlerImpl implements RemoteContentRendererRequestHandler {

	private static final Logger LOGGER = LoggerFactory.getLogger(CustomRemoteContentRendererRequestHandlerImpl.class);

	public static final String HEAD_DATA = "headData";

	@Reference(
		cardinality = ReferenceCardinality.MANDATORY,
		policy = ReferencePolicy.DYNAMIC
	)
	private volatile RemoteContentRendererRequestHandler defaultHandler;

	private final ThreadLocal<SlingHttpServletRequest> currentRequest = new ThreadLocal<>();

	@Activate
	void init() {
		if (defaultHandler == null) {
			LOGGER.error("CustomRemoteContentRendererRequestHandlerImpl: Default RemoteContentRendererRequestHandler is null!");
			throw new IllegalStateException("Default RemoteContentRendererRequestHandler is not available.");
		}
		LOGGER.info("CustomRemoteContentRendererRequestHandlerImpl: initialized with defaultHandler: {}", defaultHandler);
	}

	public ThreadLocal<SlingHttpServletRequest> getCurrentRequest() {
		return currentRequest;
	}

	public void setCurrentRequest(final SlingHttpServletRequest request) {
		currentRequest.set(request);
	}

	private void clearCurrentRequest() {
		currentRequest.remove();
	}

	@Override
	public boolean canHandle(final SlingHttpServletRequest servletRequest) {
		return defaultHandler.canHandle(servletRequest);
	}

	@Override
	public RequestConfig getRequestConfig(final SlingHttpServletRequest servletRequest) {
		setCurrentRequest(servletRequest);
		return defaultHandler.getRequestConfig(servletRequest);
	}

	@Override
	public HttpUriRequest getRequest(final SlingHttpServletRequest servletRequest, final ComponentExporter componentExporter) throws RemoteContentRenderingException {
		return defaultHandler.getRequest(servletRequest, componentExporter);
	}

	/**
	 * This method grabs the response from Remote server and sets to request attribute
	 *
	 * Response from React will be in the form of
	 *
	 * { "html": "SSR constructed html", "headData": "{"attr1": "val1" ... }"}
	 *
	 * @Param httpResponse Response to the request sent to the remote endpoint
	 * @Return String response
	 * @throws IOException
	 */
	@Override
	public String getResponseMessage(final CloseableHttpResponse httpResponse) throws IOException {

		try {
			final String response = defaultHandler.getResponseMessage(httpResponse);

			final var jsonResponse = JsonParser.parseString(response).getAsJsonObject();

			final String htmlContent = jsonResponse.get("html").getAsString();

			final SlingHttpServletRequest request = currentRequest.get();
			if (request != null) {
				var headDataNode = jsonResponse.get(HEAD_DATA);
				if (headDataNode != null && !headDataNode.isJsonNull() && headDataNode.getAsJsonObject().size() > 0) {
					request.setAttribute(HEAD_DATA, headDataNode.toString());
					LOGGER.debug("CustomRemoteContentRendererRequestHandlerImpl: headData received for request : {} is : {}", request, headDataNode);
				}
			}

			return htmlContent;

		} finally {
			clearCurrentRequest();
		}

	}
}

[arunpatidar]

Hi @arungm20 
Could you please share the use case?

However, I have not tried implementing this. Just wanted to know what is the use case and if can be done with something else like Sling Filters or transformation pipeline.

[arungm20 · Accepted solution]

hi @arunpatidar 

Thanks for the comment. I was fortunate to fix it myself and was about to add a comment.

Use case is as below

We work on react spa on ssr hence we rely on RemoteContentRendererRequestHandler which does a post request to remote server to get the response built and inject to the body. This happens OOB.

However we came across a scenario where the remote server performs an API call and gets some data which needs to be updated on the <head> element of the page. Basically the SEO attributes from API

Hence we updated the remote server to send html and the required head attributes in json format so that i can grab the response from remote server and play around the page.

Solution :

Was to implement a Custom service and intercept the response from remote and update the page source

During this process i identified 2 issues which i could solve eventually.

1. This was happening only in cloud instance. However i had old version of SDK and could not reproduce the issue. Hence i updated to latest SDK

2. As i referenced RemoteContentRendererRequestHandler there was a cyclic dependency and the service was not brought up

@Reference(
		cardinality = ReferenceCardinality.MANDATORY,
		policy = ReferencePolicy.DYNAMIC
	)
	private volatile RemoteContentRendererRequestHandler defaultHandler;

  To solve this i had to use target attribute so that i could break the cyclic dependency

@Reference(
   cardinality = ReferenceCardinality.MANDATORY,
   policy = ReferencePolicy.DYNAMIC,
   policyOption = ReferencePolicyOption.GREEDY,
   target = "(!(component.name=<package.name>.CustomRemoteContentRendererRequestHandlerImpl))"
)
private volatile RemoteContentRendererRequestHandler defaultHandler;

 Thanks

Arun

[arunpatidar]

Hi @arungm20 
Thanks for sharing.