#DataSourceManager

NocoBase provides DataSourceManager for managing multiple data sources. Each DataSource has its own Database, ResourceManager, and ACL instances, making it convenient for developers to flexibly manage and extend multiple data sources.

#Basic Concepts

Each DataSource instance contains the following:

• dataSource.collectionManager: Used to manage collections and fields.
• dataSource.resourceManager: Handles resource-related operations (such as CRUD, etc.).
• dataSource.acl: Access control (ACL) for resource operations.

For convenient access, aliases are provided for main data source members:

• app.db is equivalent to dataSourceManager.get('main').collectionManager.db
• app.acl is equivalent to dataSourceManager.get('main').acl
• app.resourceManager is equivalent to dataSourceManager.get('main').resourceManager

#Common Methods

#dataSourceManager.get(dataSourceKey)

This method returns the specified DataSource instance.

const dataSource = dataSourceManager.get('main');

#dataSourceManager.use()

Register middleware for all data sources. This will affect operations on all data sources.

dataSourceManager.use((ctx, next) => {
  console.log('This middleware applies to all data sources.');
  await next();
});

#dataSourceManager.beforeAddDataSource()

Executes before data source loading. Commonly used for static class registration, such as model classes and field type registration:

dataSourceManager.beforeAddDataSource((dataSource: DataSource) => {
  const collectionManager = dataSource.collectionManager;
  if (collectionManager instanceof SequelizeCollectionManager) {
    collectionManager.registerFieldTypes({
      belongsToArray: BelongsToArrayField, // Custom field type
    });
  }
});

#dataSourceManager.afterAddDataSource()

Executes after data source loading. Commonly used for registering operations, setting access control, etc.

dataSourceManager.afterAddDataSource((dataSource) => {
  dataSource.resourceManager.registerActionHandler('downloadXlsxTemplate', downloadXlsxTemplate);
  dataSource.resourceManager.registerActionHandler('importXlsx', importXlsx);
  dataSource.acl.allow('*', 'downloadXlsxTemplate', 'loggedIn'); // Set access permissions
});

#Data Source Extension

For complete data source extension, please refer to the data source extension chapter.