Map SPA components to AEM components

Learn how to map React components to Adobe Experience Manager (AEM) components with the AEM SPA Editor JS SDK. Component mapping enables users to make dynamic updates to SPA components within the AEM SPA Editor, similar to traditional AEM authoring.

This chapter takes a deeper-dive into the AEM JSON model API and how the JSON content exposed by an AEM component can be automatically injected into a React component as props.

Objective

  1. Learn how to map AEM components to SPA Components.
  2. Inspect how a React component uses dynamic properties passed from AEM.
  3. Learn how to use out of the box React AEM Core Components.

What you will build

This chapter inspects how the provided Text SPA component is mapped to the AEM Textcomponent. React Core Components like the Image SPA component is used in the SPA and authored in AEM. Out of the box features of the Layout Container and Template Editor policies are also be used to create a view that is a little more varied in appearance.

Chapter sample final authoring

Prerequisites

Review the required tooling and instructions for setting up a local development environment. This chapter is a continuation of the Integrate the SPA chapter, however to follow along all you need is a SPA-enabled AEM project.

Mapping Approach

The basic concept is to map a SPA Component to an AEM Component. AEM components, run server-side, export content as part of the JSON model API. The JSON content is consumed by the SPA, running client-side in the browser. A 1:1 mapping between SPA components and an AEM component is created.

High-level overview of mapping an AEM Component to a React Component

High-level overview of mapping an AEM Component to a React Component

Inspect the Text Component

The AEM Project Archetype provides a Text component that is mapped to the AEM Text component. This is an example of a content component, in that it renders content from AEM.

Let’s see how the component works.

Inspect the JSON model

  1. Before jumping into the SPA code, it is important to understand the JSON model that AEM provides. Navigate to the Core Component Library and view the page for the Text component. The Core Component Library provides examples of all the AEM Core Components.

  2. Select the JSON tab for one of the examples:

    Text JSON model

    You should see three properties: text, richText, and :type.

    :type is a reserved property that lists the sling:resourceType (or path) of the AEM Component. The value of :type is what is used to map the AEM component to the SPA component.

    text and richText are additional properties that are exposed to the SPA component.

  3. View the JSON output at http://localhost:4502/content/wknd-spa-react/us/en.model.json. You should be able to find an entry similar to:

    "text": {
    "id": "text-a647cec03a",
    "text": "<p>Hello World! Updated content!</p>\r\n",
    "richText": true,
    ":type": "wknd-spa-react/components/text",
    "dataLayer": {}
   }

Inspect the Text SPA component

  1. In the IDE of your choice open up the AEM Project for the SPA. Expand the ui.frontend module and open the file Text.js under ui.frontend/src/components/Text/Text.js.

  2. The first area we will inspect is the class Text at ~line 40:

    
class Text extends Component {

    get richTextContent() {
        return (<div
                id={extractModelId(this.props.cqPath)}
                data-rte-editelement
                dangerouslySetInnerHTML={{__html: DOMPurify.sanitize(this.props.text)}} />
                );
    }

    get textContent() {
        return <div>{this.props.text}</div>;
    }

    render() {
        return this.props.richText ? this.richTextContent : this.textContent;
    }
}

    Text is a standard React component. The component uses this.props.richText to determine whether the content to render is going to be rich text or plain text. The actual “content” used comes from this.props.text.

    To avoid a potential XSS attack, the rich text is escaped via DOMPurify before using dangerouslySetInnerHTML to render the content. Recall the richText and text properties from the JSON model earlier in the exercise.

  3. Next, open ui.frontend/src/components/import-components.js take a look at the TextEditConfig at ~line 86:

    const TextEditConfig = {
emptyLabel: 'Text',

    isEmpty: function(props) {
        return !props || !props.text || props.text.trim().length < 1;
    }
};

    The above code is responsible for determining when to render the placeholder in the AEM author environment. If the isEmpty method returns true then the placeholder is rendered.

  4. Finally take a look at the MapTo call at ~line 94:

    export default MapTo('wknd-spa-react/components/text')(LazyTextComponent, TextEditConfig);

    MapTo is provided by the AEM SPA Editor JS SDK (@adobe/aem-react-editable-components). The path wknd-spa-react/components/text represents the sling:resourceType of the AEM component. This path gets matched with the :type exposed by the JSON model observed earlier. MapTo takes care of parsing the JSON model response and passing the correct values as props to the SPA component.

    You can find the AEM Text component definition at ui.apps/src/main/content/jcr_root/apps/wknd-spa-react/components/text.

Use React Core Components

AEM WCM Components - React Core implementation and AEM WCM Components - Spa editor - React Core implementation. These are a set of re-usable UI components that map to out of the box AEM components. Most projects can re-use these components as a starting point for their own implementation.

  1. In the project code open the file import-components.js at ui.frontend/src/components.
    This file imports all of the SPA components that map to AEM components. Given the dynamic nature of the SPA Editor implementation, we must explicitly reference any SPA components that are tied to AEM author-able components. This allows an AEM author to choose to use a component wherever they want in the application.

  2. The following import statements include SPA components written in the project:

    import './Page/Page';
import './Text/Text';
import './Container/Container';
import './ExperienceFragment/ExperienceFragment';

  3. There are several other imports from @adobe/aem-core-components-react-spa and @adobe/aem-core-components-react-base. These are importing the React Core components and making them available in the current project. These are then mapped to project specific AEM components using the MapTo, just like with the Text component example earlier.

Update AEM Policies

Policies are a feature of AEM templates gives developers and power-users granular control over which components are available to be used. The React Core Components are included in the SPA Code but need to be enabled via a policy before they can be used in the application.

  1. From the AEM Start screen navigate to Tools > Templates > WKND SPA React.

  2. Select and open the SPA Page template for editing.

  3. Select the Layout Container and click it’s policy icon to edit the policy:

    layout container policy

  4. Under Allowed Components > WKND SPA React - Content > check Image, Teaser, and Title.

    Updated Components available

    Under Default Components > Add mapping and choose the Image - WKND SPA React - Content component:

    Set default components

    Enter a mime type of image/*.

    Click Done to save the policy updates.

  5. In the Layout Container click the policy icon for the Text component.

    Create a new policy named WKND SPA Text. Under Plugins > Formatting > check all the boxes to enable additional formatting options:

    Enable RTE Formatting

    Under Plugins > Paragraph Styles > check the box to Enable paragraph styles:

    Enable paragraph styles

    Click Done to save the policy update.

Author Content

  1. Navigate to the Homepage http://localhost:4502/editor.html/content/wknd-spa-react/us/en/home.html.

  2. You should now be able to use the additional components Image, Teaser, and Title on the page.

    Additional components

  3. You should also be able to edit the Text component and add additional paragraph styles in full-screen mode.

    Full Screen Rich Text Editing

  4. You should also be able to drag+drop an image from the Asset finder:

    Drag and Drop image

  5. Experiement with the Title and Teaser components.

  6. Add your own images via AEM Assets or install the finished code base for the standard WKND reference site. The WKND reference site includes many images that can be re-used on the WKND SPA. The package can be installed using AEM’s Package Manager.

    Package Manager install wknd.all

Inspect the Layout Container

Support for the Layout Container is automatically provided by the AEM SPA Editor SDK. The Layout Container, as indicated by the name, is a container component. Container components are components that accept JSON structures which represent other components and dynamically instantiate them.

Let’s inspect the Layout Container further.

  1. In a browser navigate to http://localhost:4502/content/wknd-spa-react/us/en.model.json

    JSON model API - Responsive Grid

    The Layout Container component has a sling:resourceType of wcm/foundation/components/responsivegrid and is recognized by the SPA Editor using the :type property, just like the Text and Image components.

    The same capabilities of re-sizing a component using Layout Mode are available with the SPA Editor.

  2. Return to http://localhost:4502/editor.html/content/wknd-spa-react/us/en/home.html. Add additional Image components and try re-sizing them using the Layout option:

    Re-size image using Layout mode

  3. Re-open the JSON model http://localhost:4502/content/wknd-spa-react/us/en.model.json and observe the columnClassNames as part of the JSON:

    Cloumn Class names

    The class name aem-GridColumn--default--4 indicates the component should be 4 columns wide based on a 12 column grid. More details about the responsive grid can be found here.

  4. Return to the IDE and in the ui.apps module there is a client-side library defined at ui.apps/src/main/content/jcr_root/apps/wknd-spa-react/clientlibs/clientlib-grid. Open the file less/grid.less.

    This file determines the breakpoints (default, tablet, and phone) used by the Layout Container. This file is intended to be customized per project specifications. Currently the breakpoints are set to 1200px and 768px.

  5. You should be able to use the responsive capabilities and the updated rich text policies of the Text component to author a view like the following:

    Chapter sample final authoring

Congratulations!

Congratulations, you learned how to map SPA components to AEM Components and you used the React Core Components. You also got a chance to explore the responsive capabilities of the Layout Container.

Next Steps

Navigation and Routing - Learn how multiple views in the SPA can be supported by mapping to AEM Pages with the SPA Editor SDK. Dynamic navigation is implemented using React Router and React Core Components.

(Bonus) Persist configurations to source control

In many cases, especially at the beginning of an AEM project it is valuable to persist configurations, like templates and related content policies, to source control. This ensures that all developers are working against the same set of content and configurations and can ensure additional consistency between environments. Once a project reaches a certain level of maturity, the practice of managing templates can be turned over to a special group of power users.

The next few steps will take place using the Visual Studio Code IDE and VSCode AEM Sync but could be doing using any tool and any IDE that you have configured to pull or import content from a local instance of AEM.

  1. In the Visual Studio Code IDE, ensure that you have VSCode AEM Sync installed via the Marketplace extension:

    VSCode AEM Sync

  2. Expand the ui.content module in the Project explorer and navigate to /conf/wknd-spa-react/settings/wcm/templates.

  3. Right+Click the templates folder and select Import from AEM Server:

    VSCode import template

  4. Repeat the steps to import content but select the policies folder located at /conf/wknd-spa-react/settings/wcm/templates/policies.

  5. Inspect the filter.xml file located at ui.content/src/main/content/META-INF/vault/filter.xml.

    <!--ui.content filter.xml-->
<?xml version="1.0" encoding="UTF-8"?>
 <workspaceFilter version="1.0">
     <filter root="/conf/wknd-spa-react" mode="merge"/>
     <filter root="/content/wknd-spa-react" mode="merge"/>
     <filter root="/content/dam/wknd-spa-react" mode="merge"/>
     <filter root="/content/experience-fragments/wknd-spa-react" mode="merge"/>
 </workspaceFilter>

    The filter.xml file is responsible for identifying the paths of nodes that are installed with the package. Notice the mode="merge" on each of the filters which indicates that existing content will not be modified, only new content is added. Since content authors may be updating these paths, it is important that a code deployment does not overwrite content. See the FileVault documentation for more details on working with filter elements.

    Compare ui.content/src/main/content/META-INF/vault/filter.xml and ui.apps/src/main/content/META-INF/vault/filter.xml to understand the different nodes managed by each module.

(Bonus) Create custom Image Component

A SPA Image component has already been provided by the React Core components. However, if you want extra practice, create your own React implementation that maps to the AEM Image component. The Image component is another example of a content component.

Inspect the JSON

Before jumping into the SPA code, inspect the JSON model provided by AEM.

  1. Navigate to the Image examples in the Core Component library.

    Image Core Component JSON

    Properties of src, alt, and title are used to populate the SPA Image component.

    NOTE

    There are other Image properties exposed (lazyEnabled, widths) that allow a developer to create an adaptive and lazy-loading component. The component built in this tutorial is simple and does not use these advanced properties.

Implement the Image component

  1. Next, create a new folder named Image under ui.frontend/src/components.

  2. Beneath the Image folder create a new file named Image.js.

    Image.js file

  3. Add the following import statements to Image.js:

    import React, {Component} from 'react';
import {MapTo} from '@adobe/aem-react-editable-components';

  4. Then add the ImageEditConfig to determine when to show the placeholder in AEM:

    export const ImageEditConfig = {

    emptyLabel: 'Image',

    isEmpty: function(props) {
        return !props || !props.src || props.src.trim().length < 1;
    }
};

    The placeholder will show if the src property is not set.

  5. Next implement the Image class:

     export default class Image extends Component {

    get content() {
        return <img     className="Image-src"
                        src={this.props.src}
                        alt={this.props.alt}
                        title={this.props.title ? this.props.title : this.props.alt} />;
    }

    render() {
        if(ImageEditConfig.isEmpty(this.props)) {
            return null;
        }

        return (
                <div className="Image">
                    {this.content}
                </div>
        );
    }
}

    The above code will render an <img> based on the props src, alt, and title passed in by the JSON model.

  6. Add the MapTo code to map the React component to the AEM component:

    MapTo('wknd-spa-react/components/image')(Image, ImageEditConfig);

    Note the string wknd-spa-react/components/image corresponds to the location of the AEM component in ui.apps at: ui.apps/src/main/content/jcr_root/apps/wknd-spa-react/components/image.

  7. Create a new file named Image.css in the same directory and add the following:

    .Image-src {
    margin: 1rem 0;
    width: 100%;
    border: 0;
}

  8. In Image.js add a reference to the file at the top beneath the import statements:

    import React, {Component} from 'react';
import {MapTo} from '@adobe/aem-react-editable-components';

require('./Image.css');

  9. Open the file ui.frontend/src/components/import-components.js and add a reference to the new Image component:

    import './Page/Page';
import './Text/Text';
import './Container/Container';
import './ExperienceFragment/ExperienceFragment';
import './Image/Image'; //add reference to Image component

  10. In import-components.js comment out the React Core Component Image:

    //MapTo('wknd-spa-react/components/image')(ImageV2, {isEmpty: ImageV2IsEmptyFn});

    This will ensure that our custom Image component is used instead.

  11. From the root of the project deploy the SPA code to AEM using Maven:

    $ cd aem-guides-wknd-spa.react
$ mvn clean install -PautoInstallSinglePackage

  12. Inspect the SPA in AEM. Any Image components on the page should continue to work. Inspect the rendered output and you should see the markup for our custom Image component instead of the React Core Component.

    Custom Image component markup

    <div class="Image">
    <img class="Image-src" src="/content/image-src.jpg">
</div>

    React Core Component Image markup

    <div class="cmp-image cq-dd-image">
    <img src="/content/image-src.jpg" class="cmp-image__image">
</div>

    This is a good introduction to extending and implementing your own components.

On this page