3. **Gradually migrate** from GSA query format to Fess's native API

**Alternative Approach**: Instead of relying on GSA API compatibility, we recommend migrating client applications to use Fess's modern JSON API (`/api/v1/documents`), which provides more features and better performance.

---

### Google Site Search (GSS) / Google Custom Search (GSE)

│   ├── web/                   # User-facing controllers
│   ├── web/admin/             # Admin controllers
│   ├── service/               # Business logic
│   └── job/                   # Background jobs
├── api/                       # REST API endpoints
├── opensearch/                # OpenSearch integration
│   ├── config/                # Config index (crawl configs, schedules)
│   ├── log/                   # Log index

			<artifactId>poi-ooxml</artifactId>
			<version>${poi.version}</version>
			<exclusions>
				<exclusion>
					<groupId>stax</groupId>
					<artifactId>stax-api</artifactId>
				</exclusion>
				<exclusion>
					<groupId>xml-apis</groupId>
					<artifactId>xml-apis</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>org.apache.poi</groupId>

    protected String[] acceptedRoles = { "admin" };

    /**
     * Default constructor.
     * Initializes the API manager with the admin server path prefix.
     */
    public SearchEngineApiManager() {
        super();
        setPathPrefix(ADMIN_SERVER);
    }

    /**
     * Registers this API manager with the web API manager factory.

## Migration from another search provider

Please see [MIGRATION.md](MIGRATION.md).

## Data Store

Currently, Fess supports crawling the following [storage locations and APIs](https://fess.codelibs.org/15.3/admin/dataconfig-guide.html):

 - [Confluence/Jira](https://github.com/codelibs/fess-ds-atlassian)
 - [Box](https://github.com/codelibs/fess-ds-box)
 - [CSV](https://github.com/codelibs/fess-ds-csv)

import org.codelibs.fess.app.service.ScheduledJobService;
import org.codelibs.fess.app.web.CrudMode;
import org.codelibs.fess.app.web.api.ApiResult;
import org.codelibs.fess.app.web.api.ApiResult.ApiResponse;
import org.codelibs.fess.app.web.api.ApiResult.Status;
import org.codelibs.fess.app.web.api.admin.FessApiAdminAction;
import org.codelibs.fess.opensearch.config.exentity.ScheduledJob;
import org.lastaflute.web.Execute;

import org.codelibs.fess.app.web.CrudMode;
import org.codelibs.fess.app.web.api.ApiResult;
import org.codelibs.fess.app.web.api.admin.FessApiAdminAction;
import org.codelibs.fess.opensearch.user.exentity.User;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.JsonResponse;

import jakarta.annotation.Resource;

/**
 * API action for admin user management.
 */

### Asynchronous request

```java
import org.codelibs.curl.Curl;

Curl.post("https://api.example.com/items")
    .body("{\"name\":\"item1\"}")
    .header("Content-Type", "application/json")
    .execute(
        response -> System.out.println("Async status: " + response.getHttpStatusCode()),
        error -> error.printStackTrace());
```

## API Overview

     * For files larger than {@value #MAX_BUF_SIZE} bytes (10MB), an
     * {@link IORuntimeException} will be thrown to prevent OutOfMemoryError.
     * For large files, use streaming APIs instead.
     * </p>
     *
     * @param file
     *            The file. Must not be {@literal null}.
     * @return A byte array containing the contents of the file.

    private static final Logger logger = LogManager.getLogger(ApiExtractor.class);

    /** The URL of the API endpoint. */
    protected String url;

    /** The access timeout in seconds. */
    protected Integer accessTimeout; // sec

    /** The HTTP client used for API calls. */
    protected CloseableHttpClient httpClient;

    /** The connection timeout in milliseconds. */