Creating a list of keywords in the Content Delivery

Question

Imagine I have a content type that has two fields of type category: one is a taxonomy Author and another one is a taxonomy Topics, these two taxonomies are unrelated, the only 'thing' they may have in common is the component itself.

Now we go to the website as a visitor, then when the visitor clicks on a given Author I want to create a list with all the Topics that are present in Components that also contain the specific Author.

I know I could create a query object with a criteria containing both keywords from the different taxonomies to check if it retrieves any values, the problem is that I would need to do that for every single topic i.e. Author and Topic1, Author and Topic2, Author and Topic 3 etc, in the end it may mean tens of queries which I obviously don't want to do.

As I see it the taxonomy API won't help because both taxonomies and thefore their keywords are completely unrelated. Any alternatives?

Answer 1

Based on the comment by Ram G and therefore taking as starting point the code example in live content, I have verified that the following solution works:

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Tridion.ContentDelivery.Taxonomies;
using Tridion.ContentDelivery.DynamicContent.Query;
using Tridion.ContentDelivery.DynamicContent;

namespace Asier.Web.UI
{
    public class TagCloud : System.Web.UI.WebControls.WebControl
    {
        protected override void Render(HtmlTextWriter writer)
        {
            TaxonomyRelationManager relationManager = new TaxonomyRelationManager();
            TaxonomyFactory taxFactory = new TaxonomyFactory();

            string taxonomyUriWhichIWantTheKeywordsFrom = "tcm:69-265-512";

            String[] componentUris = GetComponentUris();
            String[] contextKeywordUris = GetKeywordUris();
            Keyword[] contextKeywordArray = GetKeywordsFromKeywordUris(taxFactory, contextKeywordUris);
            Keyword[] cloudFacets = relationManager.GetTaxonomyKeywords(taxonomyUriWhichIWantTheKeywordsFrom, componentUris, contextKeywordArray, new CompositeFilter(), 16);

            ProcessKeywords(cloudFacets);
        }

        private static string[] GetComponentUris()
        {
            // This should probably be replaced with a Query object that
            // retrieves the URIs dynamically 
            return new String[] { "tcm:69-3645-16", "tcm:69-3648-16", "tcm:69-3651-16" };
        }

        private static string[] GetKeywordUris()
        {
            // this should probably be passed in as a property of the control
            return new string[] { "tcm:69-3078-1024" };
        }

        private static Keyword[] GetKeywordsFromKeywordUris(TaxonomyFactory taxFactory, String[] contextKeywordUris)
        {
            Keyword[] contextKeywordArray = new Keyword[contextKeywordUris.Length];

            for (int i = 0; i < contextKeywordUris.Length; i++)
            {
                contextKeywordArray[i] = taxFactory.GetTaxonomyKeyword(contextKeywordUris[i]);
            }

            return contextKeywordArray;
        }        

        private static void ProcessKeywords(Keyword[] cloudFacets)
        {
            for (int i = 0; i < cloudFacets.GetLength(0); i++)
            {

                if (cloudFacets[i].ReferencedContentCount > 0)
                {
                    // Do whatever...
                }
            }
        }
    }
}