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AEM Cloud Service - Dynamic Media Clear Scene7 CDN Cache on Asset ReUpload | AEM Community Blog Seeding

kautuk_sahni
Community Manager
Community Manager

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AEM Cloud Service - Dynamic Media Clear Scene7 CDN Cache on Asset ReUpload by Sreekanth Choudry Nalabotu

Abstract

Goal
Default Scene7 CDN TTL for an asset url is 10 hours. Deleting an asset uploaded to AEM (synced to Scene7) and uploading another binary with same name, will not serve the respective presets with latest binary on delivery until the previous ones expire in CDN or the cache invalidated using Tools > Assets > CDN Invalidation. This post is on automatically invalidating urls in CDN cache when the asset is reuploaded...

1) Add a Resource change listener apps.experienceaem.assets.core.listeners.S7CDNCacheInvalidateListener for invalidating the CDN cache using a configured template...

package apps.experienceaem.assets.core.listeners;

import com.day.cq.contentsync.handler.util.RequestResponseFactory;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.api.resource.observation.ResourceChange;
import org.apache.sling.api.resource.observation.ResourceChangeListener;
import org.apache.sling.commons.json.JSONArray;
import org.apache.sling.commons.json.JSONObject;
import org.apache.sling.engine.SlingRequestProcessor;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.propertytypes.ServiceDescription;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.util.*;

@Component(
service = ResourceChangeListener.class,
immediate = true,
property = {
ResourceChangeListener.CHANGES + "=CHANGED",
ResourceChangeListener.PATHS + "=glob:/content/dam"
})
@ServiceDescription("EAEM - Invalidate CDN Cache on Asset Create")
public class S7CDNCacheInvalidateListener implements ResourceChangeListener {
private final Logger logger = LoggerFactory.getLogger(getClass());

private static final String S7_CDN_INVALIDATE_SERVLET = "/mnt/overlay/dam/gui/content/s7dam/cdninvalidation/cdninvalidationwizard.s7cdninvalidation.json";

private static final String S7_CDN_INVALIDATE_URLS = "/mnt/overlay/dam/gui/content/s7dam/cdninvalidation/cdninvalidationwizard.s7cdncacheurls.json";

@Reference
ResourceResolverFactory resolverFactory;

@Reference
private SlingRequestProcessor slingRequestProcessor;

@Reference
private RequestResponseFactory requestResponseFactory;

public void onChange(List changes) {
String assetMetadataPath = null;
Iterator changesItr = changes.iterator();
ResourceChange change = null;

while(changesItr.hasNext()){
change = changesItr.next();

if(!change.getPath().endsWith("/jcr:content/metadata")){
continue;
}

assetMetadataPath = change.getPath();

break;
};

if(StringUtils.isEmpty(assetMetadataPath)){
return;
}

Map<String, Object> subServiceUser = new HashMap<String, Object>();
subServiceUser.put(ResourceResolverFactory.SUBSERVICE, "eaem-user-s7-admin");

ResourceResolver resourceResolver = null;

try {
resourceResolver = resolverFactory.getServiceResourceResolver(subServiceUser);

Resource assetMetaRes = resourceResolver.getResource(assetMetadataPath);

String scene7FileName = assetMetaRes.getValueMap().get("dam:scene7File", "");

if(StringUtils.isEmpty(scene7FileName)){
return;
}

List urls = getInvalidateUrls(resourceResolver, assetMetadataPath);

if(CollectionUtils.isEmpty(urls)){
logger.info("Nothing to s7 cdn invalidate for asset " + assetMetadataPath);
return;
}

logger.info("Invalidate the urls : " + urls);

invalidateS7CDNCache(resourceResolver, urls);
} catch (final Exception e) {
logger.error("Error invalidating cache : {}", e.getMessage(), e);
} finally {
if ((resourceResolver != null) && resourceResolver.isLive()) {
resourceResolver.close();
}
}
}

private void invalidateS7CDNCache(ResourceResolver resourceResolver, List urls) throws Exception{
Map<String, Object> requestParams = new LinkedHashMap<String, Object>();
requestParams.put("urls", String.join("&", urls));

HttpServletRequest request = requestResponseFactory.createRequest("POST", S7_CDN_INVALIDATE_SERVLET,
requestParams);
ByteArrayOutputStream bos = new ByteArrayOutputStream();

HttpServletResponse response = this.requestResponseFactory.createResponse(bos);
HttpServletRequestWrapper wrapperRequest = new URLsSlingServletRequestWrapper(request);

slingRequestProcessor.processRequest(wrapperRequest, response, resourceResolver);

response.getWriter().flush();

JSONObject invalidateResponse = new JSONObject(bos.toString());

if(!invalidateResponse.has("invalidationHandle")){
return;
}

logger.info("Successfully invalidate s7 cache for urls " + urls);
}

private List getInvalidateUrls(ResourceResolver resourceResolver, String assetMetadataPath) throws Exception{
Map<String, Object> requestParams = new HashMap<String, Object>();
requestParams.put("paths", assetMetadataPath.substring(0, assetMetadataPath.indexOf("/jcr:content")));
requestParams.put("template", "true");
requestParams.put("presets", "true");

HttpServletRequest request = requestResponseFactory.createRequest("POST", S7_CDN_INVALIDATE_URLS,
requestParams);
ByteArrayOutputStream bos = new ByteArrayOutputStream();

HttpServletResponse response = this.requestResponseFactory.createResponse(bos);

slingRequestProcessor.processRequest(request, response, resourceResolver);

response.getWriter().flush();

JSONObject invalidateURLsJSON = new JSONObject(bos.toString());

List invalidateUrls = new ArrayList();

if(!invalidateURLsJSON.has("urls")){
return invalidateUrls;
}

JSONArray invalidateArray = invalidateURLsJSON.getJSONArray("urls");

for(int i = 0; i < invalidateArray.length(); i++){
invalidateUrls.add(invalidateArray.getString(i));
}

return invalidateUrls;
}

private class URLsSlingServletRequestWrapper extends HttpServletRequestWrapper {
public URLsSlingServletRequestWrapper(final HttpServletRequest request) {
super(request);
}

public Map<String, String[]> getParameterMap() {
Map<String, String[]> pMap = super.getParameterMap();

String[] urls = String.valueOf(pMap.get("urls")[0]).split("&");

pMap.put("urls", urls);

return pMap;
}
}
}

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AEM Cloud Service - Dynamic Media Clear Scene7 CDN Cache on Asset ReUpload

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