programmatically setting cq:tags save blank value in the node in AEM - aem

Question

I am trying to programmatically extract data from a json string, converts into a string array and adding it as cq:tags property and corresponding values into a node, however when I do so, though cq:tags property is added but with blank values.
My node is something like this: /content/<my project node>/ContentPage/jcr:content
ResourceResolver resolver = CommonUtils.getResourceResolver(resourceResolverFactory);
String[] strValue = tagList.stream().toArray(String[]::new); // tagList has String values in form of array.
Resource resource = resolver.getResource(CONTENT_DATA_NODE);
if (resource != null) {
Node node = resource.adaptTo(Node.class);
if (node != null) {
NodeIterator nodeIterator = node.getNodes();
while (nodeIterator.hasNext()) {
innerNode = nodeIterator.nextNode();
innerNode.setProperty(CQ_TAGS, strValue);
innerNode.getSession().save();
}
}
}
and my sling user mapper service is mybundle.core:datawrite=userdatawriter , also if my resource resolverfactory is null, I get resolver from request directly.
Initially, I thought it could be an access issue, so I programmatically tried with any random property and value:
property: xyz , values: aa,bb,cc,dd
Which is written by my code without any issues,
it is only when programmatically adding cq:tags is when the problem arises. Though I can add cq:tags with any long list of values manually without any issues, either from page properties or in the crxde node itself.
What am I missing here and doing wrong in the code which can not only add cq:tags but also overwrite if cq:tags exists.
P.S: my AEM version is AEM 6.5 SP2

Answer 1

I can see the same thing happen in AEM 6.4.3. Immediately upon saving the property, the value can be read as expected. Here's a few quick examples I ran in the AEM Groovy console.
def node = getNode('/content/screens/we-retail/apps/virtual-showroom/en/jcr:content')
String[] arr = ['a', 'b', 'c'];
String[] tagArr = ['we-retail:equipment', 'we-retail:activity/biking']
node.setProperty('foo', arr)
println node.getProperty('foo').values // prints the a, b,c tags
node.setProperty('cq:tags', tagArr)
session.save()
println node.getProperty('cq:tags').values // prints the a, b,c tags
println node.getProperty('foo').values // prints the a, b,c tags
However, upon inspecting the page in CRXDE, I can see that the property is empty. This does not happen when the values you use match existing tags in AEM. For example:
def node = getNode('/content/screens/we-retail/apps/virtual-showroom/en/jcr:content')
String[] arr = ['a', 'b', 'c'];
String[] tagArr = ['we-retail:equipment', 'we-retail:activity/biking']
node.setProperty('foo', arr)
println node.getProperty('foo').values
node.setProperty('cq:tags', tagArr)
println node.getProperty('cq:tags').values // prints the we-retail tags
session.save()
println node.getProperty('foo').values
println node.getProperty('cq:tags').values // prints the we-retail tags
and the same values are visible in CRXDE.
This behaviour, I believe, is controlled by the Day CQ Tagging Service (com.day.cq.tagging.impl.JcrTagManagerFactoryImpl)
Unchecking the box will disable validation and allow you to persist those values. However, tagging a page with tags that don't exist will cause its own share of problems. Instead, I would suggest making sure to create those tags before using them.