What I want to achieve:

*Step-1*: when publishing, add embedded component in rich-text field to (json) output.

*Step-2*: href (tcm) should be replaced by field from embedded component.

note: embedded component is not/never on any page published.


**Step-1.** 

What is already done and works.

From DXA 2.2 framework there is an option to add embedded component to rich-text field. 

Example paragraaf.Text

    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry.</p>
    see website <a title="Lorem Ipsum" href="tcm:98-421996">Lorem Ipsum</a>

The hyperlink (href) added is type schema/class ExterneLink.

After adding line with 'schemasToEmbedInRichText' in 'Render Page Content' located ..\Building Blocks\Framework\Developer\Templates\DXA.R2 it is embedded in paragraaf.Text (defined as rich-text).

    <CompoundTemplate xmlns="http://www.tridion.com/ContentManager/5.3/CompoundTemplate"> 
      <TemplateInvocation>
        <Template xlink:href="tcm:105-416409-2048" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:title="Generate DXA R2 Page Model" />
        <TemplateParameters>
          <Parameters xmlns="http://www.sdl.com/web/schemas/dynamicpage">
            <schemasToEmbedInRichText>ExterneLink</schemasToEmbedInRichText>
            <expandLinkDepth xmlns="http://www.sdl.com/web/schemas/dynamicpage">3</expandLinkDepth>
            <modelBuilderTypeNames>DefaultModelBuilder;DefaultPageMetaModelBuilder;EclModelBuilder;ContextExpressionsModelBuilder</modelBuilderTypeNames>
          </Parameters>
        </TemplateParameters>
      </TemplateInvocation>
    </CompoundTemplate>


**Step-2.** 

Problem occurred while rendering this section

> Unable to map field 'item' to property Artikel.Items of type
> 'System.Collections.Generic.List`1[[Uwv.eDv.Web.Modules.Core.Models.Paragraaf,
> Uwv.eDv.Web.Modules.Core, Version=1.0.0.0, Culture=neutral,
> PublicKeyToken=null]]'. Unable to map field 'text' to property
> Paragraaf.Text of type 'Sdl.Web.Common.Models.RichText'. No semantic
> mapping found between Schema 418386
> (http://www.sdl.com/web/schemas/core:ExterneLink) and model type
> 'Sdl.Web.Common.Models.EntityModel'

Our models:

    public class Artikel : EntityModel
    {
       [SemanticProperty("item")]
       public List<Paragraaf> Items { get; set; }
	   ...
       public string Title { get; set; }
       public Afbeelding Afbeelding { get; set; }
    }

    public class Paragraaf : EntityModel
    {
        public RichText Text { get; set; }
		...
    }

    public class ExterneLink : EntityModel
    {
        [SemanticProperty("externalLink")]
        public string Url { get; set; }
    }`enter code here`

Below shows the JSON after step-1 (with content explorer preview/source).
The embed component is present, mapping for this must be set.

How to get value "https://www.lipsum.com/" as href from Text field here.
Content is here ExterneLink.Url property is here 'externalLink'.

"Content": {"externalLink": "https://www.lipsum.com/"

    ...
     "Regions": [
        {
          "Name": "Main",
          "Entities": [
            {
              "Id": "421995",
              "Namespace": "tcm",
              "ComponentTemplate": {
                "Id": "418420",
                "Namespace": "tcm",
                "Title": "Artikel",
                "RevisionDate": "2021-04-08T08:36:05.207",
                "OutputFormat": "HTML Fragment",
                "Metadata": {
                  "view": "Artikel",
                  "htmlClasses": "art_"
                }
              },
              "Folder": {
                "Id": "85214",
                "Title": "Artikel"
              },
              "Content": {
                "title": "Besluit op bezwaar over Wob-verzoek herbeoordelingen WB3000 dossiers",
                "afbeelding": {
                  "$type": "EntityModelData",
                  "Id": "418473",
                  "Namespace": "tcm",
                  "ComponentTemplate": {
                    "Id": "416497",
                    "Namespace": "tcm",
                    "RevisionDate": "0001-01-01T00:00:00"
                  },
                  "Folder": {
                    "Id": "85044",
                    "Title": "Afbeelding"
                  },
                  "BinaryContent": {
                    "Url": "/Preview/imagesdxa/visual-header-artikel_tcm102-418473.webp",
                    "FileName": "visual-header-artikel.webp",
                    "FileSize": 53454,
                    "MimeType": "image/webp"
                  },
                  "Metadata": {
                    "altText": "Automonteur"
                  },
                  "SchemaId": "418389"
                },
                "item": {
                  "$type": "ContentModelData",
                  "text": {
                    "$type": "RichTextData",
                    "Fragments": [
                      "<p>Lorem Ipsum is simply dummy text of the printing and typesetting industry.</p>\nsee website ",
                      {
                        "$type": "EntityModelData",
                        "Id": "421996",
                        "Namespace": "tcm",
                        "Folder": {
                          "Id": "84939",
                          "Title": "Links"
                        },
                        "Content": {
                          "externalLink": "https://www.lipsum.com/"
                        },
                        "Metadata": {
                          "html-title": "Lorem Ipsum",
                          "html-innerText": "Lorem Ipsum"
                        },
                        "SchemaId": "418386"
                      }
                    ]
                  }
                }
              },
    ...