[AEM6.5] Create a service which receives the path of a folder in DAM as input, and Output as JSON

[tushaar_srivastava]

Hi Team,
I have a requirement, where
Create a service which receives the path of a folder in DAM as input and iterates through all image assets in that folder and returns a json response capturing the name and altText of each image in that folder. The output format should be -

[

{

"name":"<imageName>",

"altText": "<imageAltText>"

},

{

"name":"<imageName>",

"altText": "<imageAltText>"

},

...

]

Can anyone help me with this.

@Vijayalakshmi_S   @Himanshu_Singhal  @arunpatidar 

[BrianKasingli]

@tushaar_srivastava ,

Assuming that your use will be used within the author environment, I would create a Sling Servlet that will accept "path". The servlet will utilise the Query Manager, JCR-SQL2. Once when the results are obtained, then the backend logic will transform the result object, which will then output the formatted JSON.

// just a brief example below...

private static final String JCR_SQL_QUERY = "SELECT * FROM [dam:AssetContent] AS nodes WHERE ISDESCENDANTNODE ([{my_query}]";
...

@Override
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) {
    
    ...
    
    String formattedQuery = JCR_SQL_QUERY.replace("{my_query}", request.getParameter("path"));

    // JCR-SQL2 API (PICK ONE);
    Workspace workspace = session.getWorkspace();
    QueryManager queryManager = workspace.getQueryManager();
    Query query = queryManager.createQuery(formattedQuery, Query.JCR_SQL2);
    QueryResult result = query.execute();

    // return transform and return JSON
    Object formattedJSON = formattedJSON(result);

    // output the response in JSON 
    response.setContentType("application/json");
    response.setCharacterEncoding("utf-8");
    response.getWriter().write(formattedJSON);
}

[tushaar_srivastava]

Thank you BrianKasingli for this approach, I have created a textbox and on click on submit button invoked the servlet and based on that able to get the json.

[Vijayalakshmi_S · Accepted solution]

Hi @tushaar_srivastava,

Please find below sample snippet making use of Query Builder API to bring in the AEM assets under specific path.

• Result sets are adapted to Asset object (com.day.cq.dam.api.Asset)
• Assuming altText is a custom Metadata property, we can gain access to the same via Asset object.
• org.json API(org.json.JSONObject & org.json.JSONArray) is used for JSON output. 

@Component(service = Servlet.class, property = {"sling.servlet.methods=" + HttpConstants.METHOD_GET,
        "sling.servlet.paths=/bin/assetdetails", "sling.servlet.extensions=json"})
public class AssetDetailsJSON extends SlingSafeMethodsServlet {

    private static final long serialVersionUID = 1L;
    private final Logger LOG = LoggerFactory.getLogger(this.getClass());

    @Reference
    private QueryBuilder queryBuilder;

    @Override
    protected void doGet(final SlingHttpServletRequest req, final SlingHttpServletResponse resp) {
        //String assetFolderPath = req.getParameter("assetFolder");
        String assetFolderPath = "/content/dam/we-retail/en/features";
        Map<String, String> predicatesMap = new HashMap<String, String>();

        ResourceResolver rescResolver = req.getResourceResolver();
        Session session = rescResolver.adaptTo(Session.class);

        if (null != assetFolderPath) {
            predicatesMap.put("path", assetFolderPath);
            predicatesMap.put("type", "dam:Asset");
            predicatesMap.put("p.limit", "-1");
            Query query = queryBuilder.createQuery(PredicateGroup.create(predicatesMap), session);
            SearchResult queryResults = query.getResult();            
            JSONArray jsonArr = new JSONArray();
            queryResults.getHits().forEach((hit) -> {
                try {
                    String assetPath = hit.getPath();
                    Resource assetResc = rescResolver.resolve(assetPath);
                    Asset assetObj = assetResc.adaptTo(Asset.class);
                    String assetName = assetObj.getName();
                    String assetDAMPath = assetObj.getPath();
                    String assetFormat = assetObj.getMetadataValue("dc:format"); // can use getMetadataValueFromJcr as well

                    JSONObject jsonObj = new JSONObject();
                    jsonObj.put("name", assetName);
                    jsonObj.put("path", assetDAMPath); // can have altText here
                    jsonObj.put("assetFormat", assetFormat);
                    jsonArr.put(jsonObj);
                } catch (RepositoryException e) {
                    LOG.error("RepositoryException={}", e.getMessage());
                } catch (JSONException e) {
                    LOG.error("JSONException={}", e.getMessage());
                }
            });
            try {
                LOG.debug("JSON Output={}", jsonArr.toString());
                resp.setContentType("application/json");
                resp.setCharacterEncoding("UTF-8");
                resp.getWriter().write(jsonArr.toString());
            } catch (IOException e) {
                LOG.error("IOException={}", e.getMessage());
            }

        }
        else{
            LOG.debug("No asset folder input !!");
        }


    }
}