Overview

The ezy_links table is used to store URLs, typically used to provide functionality related to articles and SEO. You can perform this in two ways:

Use the LinkService class to immediately add a record.
Create an appender class to periodically check and add records.

Using the LinkService Class

If you want to immediately add a record to the ezy_links table, you can use the pre-existing LinkService class in EzyPlatform and call the saveLink method. In the example below, I am developing a feature to create a post, and I want to immediately add a record to the ezy_links table:

public class PostService {

    private final LinkService linkService;
    // ...

    public PostService(
        LinkService linkService,
        // ...
    ) {
        this.linkService = linkService;
        // ...
    }

    private void savePostLink(String slug, Post post) {
        if (PostStatus.of(post.getStatus()) != PostStatus.PUBLISHED) {
            return;
        }
        linkService.saveLink(
            SaveLinkModel.builder()
                .linkType(post.getPostType())
                .linkUri(
                    postLinkExtractor.extract(
                        new EzyPair<>(post.getPostType(), slug)
                    )
                )
                .description("Created automatically by ezyarticle")
                .linkImageId(post.getFeaturedImageId())
                .build()
        );
    }
}

Creating an Appender Class

There are times when you don't want or can't immediately add data to the ezy_links table. For example, when upgrading your product and you don't want to modify the source code, you can create an appender class to periodically check and add data to the ezy_links table. To create an appender class, you can inherit from one of the following classes:

AdminLastUpdatedAtLinkAppender: If your data contains information about updated timestamps.
AdminAuthorLinkAppender: If you want to include author information in the ezy_links table; in reality, author information is retrieved from the ezy_users table.
AdminLinkAppender: If your data contains information other than updated_at to determine if there's a new update.

Inheriting AdminLastUpdatedAtLinkAppender

Suppose you have a table named ezyweb_projects with a field updated_at as follows:

CREATE TABLE IF NOT EXISTS ezyweb_projects (
	`id` bigint unsigned NOT NULL AUTO_INCREMENT,
    `name` varchar(128) COLLATE utf8mb4_unicode_520_ci NOT NULL DEFAULT '',
    `created_at` datetime NOT NULL,
    `updated_at` datetime NOT NULL,
	PRIMARY KEY (`id`),
    INDEX `index_created_at` (`created_at`),
    INDEX `index_updated_at` (`updated_at`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_520_ci;

You can create an appender class to save data to the ezy_links table as follows:

@EzySingleton
public class AdminEzyWebProjectLinkAppender
    extends AdminLastUpdatedAtLinkAppender<Project> {

    private final AdminProjectRepository projectRepository;

    public AdminEzyWebProjectLinkAppender(
        ClockProxy clock,
        ObjectMapper objectMapper,
        AdminSettingService settingService,
        AdminLinkRepository linkRepository,
        AdminProjectRepository projectRepository
    ) {
        super(clock, objectMapper, settingService, linkRepository);
        this.projectRepository = projectRepository;
    }

    @Override
    protected List<Project> getValueList(LastUpdatedAtPageToken pageToken) {
        return pageToken.isFetchGreaterThanOrEquals()
            ? projectRepository.findReleasedProjectsByLastUpdatedAtGte(
                pageToken.getUpdatedAt(),
                Next.limit(pageToken.getLimit())
            )
            : projectRepository.findReleasedProjectsByLastUpdatedAtGt(
                pageToken.getUpdatedAt(),
                Next.limit(pageToken.getLimit())
            );
    }

    @Override
    protected Link toLink(Project value) {
        Link link = new Link();
        link.setLinkType("PROJECT");
        link.setLinkUri("/market/items/" + value.getName());
        link.setImageId(value.getBannerImageId());
        link.setDescription(value.getDisplayName());
        return link;
    }

    @Override
    protected LocalDateTime extractLastUpdatedAt(Project value) {
        return value.getUpdatedAt();
    }

    @Override
    protected String getAppenderNamePrefix() {
        return "ezylink_project";
    }
}

@EzyRepository
public interface AdminProjectRepository extends EzyDatabaseRepository<Long, Project> {

    @EzyQuery(
        "SELECT e FROM Project e " +
            "WHERE e.status = 'RELEASED' AND e.updatedAt > ?0 " +
            "ORDER BY e.updatedAt ASC"
    )
    List<Project> findReleasedProjectsByLastUpdatedAtGt(
        LocalDateTime lastUpdatedAt,
        Next next
    );

    @EzyQuery(
        "SELECT e FROM Project e " +
            "WHERE e.status = 'RELEASED' AND e.updatedAt >= ?0 " +
            "ORDER BY e.updatedAt ASC"
    )
    List<Project> findReleasedProjectsByLastUpdatedAtGte(
        LocalDateTime lastUpdatedAt,
        Next next
    );
}

Inheriting AdminAuthorLinkAppender

Suppose you need to add URLs for users who are authors of published articles on your website. You can create an appender class inheriting AdminEzyWebAuthorLinkAppender as follows:

@EzySingleton
public class AdminEzyWebAuthorLinkAppender extends AdminAuthorLinkAppender {

    public AdminEzyWebAuthorLinkAppender(
        ClockProxy clock,
        ObjectMapper objectMapper,
        AdminSettingService settingService,
        AdminLinkRepository linkRepository,
        AdminUserRepository userRepository
    ) {
        super(
            clock,
            objectMapper,
            settingService,
            linkRepository,
            userRepository
        );
    }
}

Inheriting AdminLinkAppender

Suppose you want to add URLs for user roles to the ezy_links table, but the ezy_user_roles table below:

CREATE TABLE IF NOT EXISTS `ezy_user_roles` (
    `role_id` bigint unsigned NOT NULL,
    `user_id` bigint unsigned NOT NULL,
    `created_at` datetime NOT NULL,
    PRIMARY KEY (`role_id`, `user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_520_ci;

Lacks the updated_at field to determine whether a record has been updated. You can create an appender class inheriting AdminLinkAppender and implement the following methods:

public class UserRoleLinkAppender extends AdminLinkAppender<UserRole, String> {

    public UserRoleLinkAppender(
        ClockProxy clock,
        ObjectMapper objectMapper,
        AdminSettingService settingService,
        AdminLinkRepository linkRepository
    )

 {
        super(clock, objectMapper, settingService, linkRepository);
    }

    @Override
    protected List<UserRole> getValueList(String pageToken) {
        // need to implement
    }

    @Override
    protected String extractNewLastPageToken(List<UserRole> valueList, String currentLastPageToken) {
        // need to implement
    }

    @Override
    protected String getAppenderNamePrefix() {
        // need to implement
    }

    @Override
    protected String defaultPageToken() {
        // need to implement
    }

    @Override
    protected Class<String> pageTokenType() {
        // need to implement
    }

    @Override
    protected Link toLink(UserRole value) {
        // need to implement
    }
}