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This plugin automates the process of extracting data from a Microsoft SQL Server (MSSQL) database backup file (.bak). When a user uploads a .bak file to a Flatfile Space, this plugin triggers a multi-step process. First, it uploads the backup file to a secure storage location. Then, it restores the backup to a Flatfile-hosted MSSQL database instance. After the database is restored and available, the plugin inspects its schema to identify all tables. Finally, it creates a read-only Flatfile Workbook where each database table is represented as a separate Sheet. This allows users to view and interact with data from large MSSQL databases directly within the Flatfile UI without needing to manually export data to CSV or Excel first. It is ideal for scenarios where the source of truth is an MSSQL database and users need to bring that data into the Flatfile ecosystem for review or processing.

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Installation

Install the plugin using npm: 
npm install @flatfile/plugin-foreign-db-extractor

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Configuration & Parameters

This plugin does not have any user-configurable options that are passed during initialization. The plugin operates with a default, built-in configuration that automatically listens for file:created events. If the uploaded file has a .bak extension and is not for export, it initiates a job named ‘extract-foreign-mssql-db’. This job handles the entire workflow: creating a workbook, uploading the file to S3, restoring the database, polling for status, generating sheets from the database tables, and linking everything together. The process is entirely self-contained.

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Usage Examples

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Basic Usage

import { foreignDBExtractor } from '@flatfile/plugin-foreign-db-extractor';

export default function (listener) {
  // Simply use the plugin
  listener.use(foreignDBExtractor());

  // Add other listeners as needed
}

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Complete Setup Example

import { FlatfileListener } from '@flatfile/listener';
import { foreignDBExtractor } from '@flatfile/plugin-foreign-db-extractor';

const listener = new FlatfileListener();

// Register the plugin with the listener instance
listener.use(foreignDBExtractor());

// The listener is now configured to handle .bak file extractions
export default listener;

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API Reference

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foreignDBExtractor()

A factory function that returns a pre-configured plugin for a Flatfile Listener. The returned plugin contains all the necessary logic to listen for .bak file uploads and manage the extraction process. This includes creating a corresponding job, restoring the database on a Flatfile-managed service, polling for its availability, generating Sheets from the database tables, and updating the Flatfile Workbook and File entities with the results. Parameters:
  • None
Return Value:
  • (listener: FlatfileListener) => void - A function that accepts a FlatfileListener instance and registers the necessary event handlers
Error Handling: The plugin has built-in error handling. If any step in the extraction job fails (e.g., database restore fails, polling times out), the try...catch block within the job:ready listener will catch the exception. It then updates the associated File status to ‘failed’ and fails the Job with a descriptive error message, making the failure visible in the Flatfile UI. 
// Error handling is automatic - failures will be visible in the Flatfile UI
try {
  listener.use(foreignDBExtractor());
} catch (error) {
  console.error('Plugin registration failed:', error);
}

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Troubleshooting

To troubleshoot issues, check the status and outcome message of the ‘extract-foreign-mssql-db’ job in the Flatfile dashboard. The error message from the failed step (e.g., “Database restore failed”, “Failed to retrieve user credentials”, or an error from the API) will be available in the job’s info field. Common causes of failure could be a corrupted .bak file or the database restore process exceeding the built-in timeout.

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Notes

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Requirements

  • The @flatfile/plugin-foreign-db-extractor and @flatfile/listener packages must be installed
  • This feature must be enabled for your Flatfile account. Please contact Flatfile support to get access
  • The environment where the listener runs must have AGENT_INTERNAL_URL and FLATFILE_BEARER_TOKEN environment variables set, which are typically provided by the Flatfile platform

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Limitations

  • The plugin only activates for files with a .bak extension. Other file types are ignored
  • The created Workbook and Sheets are read-only representations of the restored database
  • The database restore process has a polling timeout of 3 minutes. If the restore takes longer, the job will fail
  • The process to retrieve database user credentials has a polling timeout of 50 seconds (10 attempts with a 5-second delay)

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Error Handling Patterns

The primary error handling is centralized in the job:ready listener. It uses a try...catch block to wrap the entire extraction workflow. Upon catching an error, it uses the Flatfile API to update the status of the associated file and job to reflect the failure:
  • api.files.update(fileId, { status: 'failed' })
  • api.jobs.fail(jobId, { info: e.message })
This ensures that failures are clearly communicated to the user through the Flatfile UI. Internal helper functions throw standard Error objects with specific messages that are propagated up to this central handler.