Registering custom objects for WebContent Templates with TemplateContextContributor

Sometimes you may need additional data to be available in the web content template.

TemplateContextContributor can help in this case:

1. Create class, that implements com.liferay.portal.kernel.template.TemplateContextContributor.
2. Add @Component annotation to rigister it as OSGi-component.
3. Override com.lif.app.display.contributor.AppDisplayContributor.prepare(Map<String, Object> contextObjects, HttpServletRequest request) method and put required object into contextObjects map.
4. Deploy module with template context contributor.
5. Use registered context in FTL template for web content.

Example:

@Component(
        immediate = true,
        property = "type=" + TemplateContextContributor.TYPE_GLOBAL,
        service = TemplateContextContributor.class)
public class AppDisplayContributor implements TemplateContextContributor {

    private static final String CHARSET_NAME = "UTF-8";
    private static final String PROPS_FILE_NAME = "app.properties";

    private Properties properties = null;

    @Activate    

    public void activate() {
        try {
            ClassLoader classLoader = AppDisplayContributor.class.getClassLoader();
            InputStream is = classLoader.getResourceAsStream(PROPS_FILE_NAME);
            properties = PropertiesUtil.load(Objects.requireNonNull(is), CHARSET_NAME);
        } catch (Exception e) {
            _log.error("Failed to load properties, cause: " + e.getMessage());
        }
    }

    @Override    

    public void prepare(Map<String, Object> contextObjects, HttpServletRequest request) {
        String appDisplayPage = properties.getProperty(AppDisplayKeys.APP_DISPLAY_PAGE_PROP);
        contextObjects.put(AppDisplayKeys.APP_DISPLAY_PAGE_ATTR, appDisplayPage);
    }

    private static final Log _log = LogFactoryUtil.getLog(AppDisplayContributor.class.getName());
}

Note: use TemplateContextContributor.TYPE_GLOBAL type to make it available for web content display. com.liferay.portal.kernel.template.TemplateContextContributor.TYPE_THEME will register context objects for theme only.