How to resolve component links in Rich Text Field when getting content from BrokerQuery?

Question

By default DXA resolves Component Links in Rich Text field and Component Link fields when rendering the components directly. But when we get the contents as a result of our broker Query and then manipulate the population of our model view, during this process, we see that our content renders the url as a string and does not resolve the component link url.

ContentModelData answer = modelData.getContent().getAndCast("answer", ContentModelData.class);
TypeInformation typeInformation = 
    TypeInformation.builder().objectType(String.class).build();    
TypeInformation typeInformation = 
    TypeInformation.builder().objectType(RichTextData.class).build();
RichTextData rtd = answer.getAndCast("paraContent", RichTextData.class);
//RichText rt = new RichText((String)converter.convert(rtd, typeInformation, null, null, null));
lt.add(converter.convert(rtd, typeInformation, null, null, null));

RichTextData(fragments=[Please Click here])

where my RichText is (fragments=[Please <a title="Dining List" href="tcm:27-4850" >Click here</a> <!--CompLink tcm:27-4850-->])

How can I resolve the tcm links in my richText contentData?

Additional Information:

com.sdl.webapp.tridion.fields.exceptions.FieldConverterException: Cannot convert a entity model 16761 to class com.sdl.dxa.modules.products.model.Products for semantic field productName
    at com.sdl.dxa.tridion.mapping.converter.EntityModelDataConverter.convert(EntityModelDataConverter.java:43)
    at com.sdl.dxa.tridion.mapping.converter.EntityModelDataConverter.convert(EntityModelDataConverter.java:17)
    at com.sdl.dxa.tridion.mapping.converter.GenericSemanticModelDataConverter.convert(GenericSemanticModelDataConverter.java:65)

.... ....

Caused by: com.sdl.webapp.common.exceptions.DxaException: Exception happened while creating a entity model from: EntityModelData(id=16761, componentTemplate=ComponentTemplateData(id=169, title=null, revisionDate=0001-01-01T00:00:00.000Z, outputFormat=null, metadata=null), linkUrl=null, content={visuals={visualSize=KeywordModelData(id=644, description=null, key=null, taxonomyId=null, title=null), visualImage=EntityModelData(id=15390, componentTemplate=ComponentTemplateData(id=169, title=null, revisionDate=0001-01-01T00:00:00.000Z, outputFormat=null, metadata=null), linkUrl=null, content=null, binaryContent=BinaryContentData(fileName=products-15390_v20.jpg, fileSize=342991, mimeType=image/jpeg, url=/en/media/products-15390_v20_tcm27-15390.jpg), externalContent=null)}, extraLinks={targetFrame=KeywordModelData(id=405, description=null, key=null, taxonomyId=null, title=null)}, title=Title, introduction=Some introduction text here}, binaryContent=null, externalContent=null)
    at com.sdl.dxa.tridion.mapping.impl.DefaultModelBuilder.buildEntityModel(DefaultModelBuilder.java:133)
    at com.sdl.dxa.tridion.mapping.impl.ModelBuilderPipelineImpl.createEntityModel(ModelBuilderPipelineImpl.java:86)
    at com.sdl.dxa.tridion.mapping.converter.EntityModelDataConverter.convert(EntityModelDataConverter.java:37)
    ... 134 common frames omitted
Caused by: com.sdl.webapp.common.exceptions.DxaException: Cannot get a view model tpe because of semantic mapping exception
    at com.sdl.webapp.common.impl.model.ViewModelRegistryImpl.getMappedModelTypes(ViewModelRegistryImpl.java:109)
    at com.sdl.webapp.common.impl.model.ViewModelRegistryImpl.getMappedModelTypes(ViewModelRegistryImpl.java:78)
    at com.sdl.dxa.tridion.mapping.impl.DefaultModelBuilder.buildEntityModel(DefaultModelBuilder.java:107)
    ... 136 common frames omitted
Caused by: com.sdl.webapp.common.api.mapping.semantic.SemanticMappingException: Ambiguous semantic mapping for http://www.sdl.com/web/schemas/core:Products, found these mappings: [class com.sdl.dxa.modules.products.model.Products, class com.sdl.dxa.modules.products.model.Products]
    at com.sdl.webapp.common.impl.mapping.SemanticMappingRegistryImpl.getEntityClassByFullyQualifiedName(SemanticMappingRegistryImpl.java:334)
    at com.sdl.webapp.common.impl.model.ViewModelRegistryImpl.getMappedModelTypes(ViewModelRegistryImpl.java:107)
    ... 138 common frames omitted

Finally the EntityModel I get is this, where all my metadata fields (productName, faqsByProducts,faqsByTopic...) are null. I need these because I need this for filtering.

FAQs(question=How can you ask a question?, answer=[ParagraphMultiLevel(heading=null, paraContent=[Please contact our call center on <a href="tel:1xxxxxxx">xxxxxxx</a>], subParagraph=null, paraFootnote=null)], productName=null, faqsByProducts=null, faqsByTopic=null, active=Tag(displayText=null, key=360, tagCategory=null), analyticsTitle= Personal - How can you ask a question? {0} [7169] [EN], productTag=null, linkedURL=null, faqId=null, topViewedCategory=null, topViewedCount=null)

Answer 1

You should use the DXA API functions to retrieve that kind of content, instead of the regular Broker API.

The reason for that is that, these DXA API functions call the model service that takes care of these link resolving for you (or in case of earlier DXA versions, those functions also perform link resolving for you).

The function you need to call is the ContentProvider.GetEntityModel(string id, ILocalization localization). This function will return an EntityModel, which you can then use in your controller.

All DXA controllers inheriting from the BaseController have a ContentProvider property that you can use.

One more note : the string id attribute you need to pass is not just the TCM uri of the entity you want to retrieve, it is a combination of the item id of the component, and the item id of the template (from the documentation : <param name="id">The Entity Identifier. Must be in format {ComponentID}-{TemplateID}.</param>