CLI options in the Selenium Grid

ChromeOptions options = new ChromeOptions();
options.setCapability("gsg:customcap", true);
WebDriver driver = new RemoteWebDriver(new URL("http://localhost:4444"), options);
driver.get("https://selenium.dev");
driver.quit();

options.setCapability("se:downloadsEnabled", true);

{
  "value": {
    "names": [
      "Red-blue-green-channel.jpg"
    ]
  }
}

{
	"value": {
		"filename": "Red-blue-green-channel.jpg",
		"contents": "Base64EncodedStringContentsOfDownloadedFileAsZipGoesHere"
	}
}

curl -X GET "http://localhost:4444/session/90c0149a-2e75-424d-857a-e78734943d4c/se/files"

{
  "value": {
    "names": [
      "Red-blue-green-channel.jpg"
    ]
  }
}

curl -H "Accept: application/json" \
-H "Content-Type: application/json; charset=utf-8" \
-X POST -d '{"name":"Red-blue-green-channel.jpg"}' \
"http://localhost:4444/session/18033434-fa4f-4d11-a7df-9e6d75920e19/se/files"

{
  "value": {
    "filename": "Red-blue-green-channel.jpg",
    "contents": "UEsDBBQACAgIAJpagVYAAAAAAAAAAAAAAAAaAAAAUmVkLWJsAAAAAAAAAAAAUmVkLWJsdWUtZ3JlZW4tY2hhbm5lbC5qcGdQSwUGAAAAAAEAAQBIAAAAcNkAAAAA"
  }
}

import com.google.common.collect.ImmutableMap;

import org.openqa.selenium.By;
import org.openqa.selenium.io.Zip;
import org.openqa.selenium.json.Json;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.openqa.selenium.remote.http.HttpClient;
import org.openqa.selenium.remote.http.HttpRequest;
import org.openqa.selenium.remote.http.HttpResponse;

import java.io.File;
import java.net.URL;
import java.nio.file.Files;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.TimeUnit;

import static org.openqa.selenium.remote.http.Contents.asJson;
import static org.openqa.selenium.remote.http.Contents.string;
import static org.openqa.selenium.remote.http.HttpMethod.GET;
import static org.openqa.selenium.remote.http.HttpMethod.POST;

public class DownloadsSample {

  public static void main(String[] args) throws Exception {
    // Assuming the Grid is running locally.
    URL gridUrl = new URL("http://localhost:4444");
    ChromeOptions options = new ChromeOptions();
    options.setCapability("se:downloadsEnabled", true);
    RemoteWebDriver driver = new RemoteWebDriver(gridUrl, options);
    try {
      demoFileDownloads(driver, gridUrl);
    } finally {
      driver.quit();
    }
  }

	private static void demoFileDownloads(RemoteWebDriver driver, URL gridUrl) throws Exception {
		driver.get("https://www.selenium.dev/selenium/web/downloads/download.html");
		// Download the two available files on the page
		driver.findElement(By.id("file-1")).click();
		driver.findElement(By.id("file-2")).click();

		// The download happens in a remote Node, which makes it difficult to know when the file
		// has been completely downloaded. For demonstration purposes, this example uses a
		// 10-second sleep which should be enough time for a file to be downloaded.
		// We strongly recommend to avoid hardcoded sleeps, and ideally, to modify your
		// application under test, so it offers a way to know when the file has been completely
		// downloaded.
		TimeUnit.SECONDS.sleep(10);

		//This is the endpoint which will provide us with list of files to download and also to
		//let us download a specific file.
		String downloadsEndpoint = String.format("/session/%s/se/files", driver.getSessionId());

		String fileToDownload;

		try (HttpClient client = HttpClient.Factory.createDefault().createClient(gridUrl)) {
			// To list all files that are were downloaded on the remote node for the current session
			// we trigger GET request.
			HttpRequest request = new HttpRequest(GET, downloadsEndpoint);
			HttpResponse response = client.execute(request);
			Map<String, Object> jsonResponse = new Json().toType(string(response), Json.MAP_TYPE);
			@SuppressWarnings("unchecked")
			Map<String, Object> value = (Map<String, Object>) jsonResponse.get("value");
			@SuppressWarnings("unchecked")
			List<String> names = (List<String>) value.get("names");
			// Let's say there were "n" files downloaded for the current session, we would like
			// to retrieve ONLY the first file.
			fileToDownload = names.get(0);
		}

		// Now, let's download the file
		try (HttpClient client = HttpClient.Factory.createDefault().createClient(gridUrl)) {
			// To retrieve a specific file from one or more files that were downloaded by the current session
			// on a remote node, we use a POST request.
			HttpRequest request = new HttpRequest(POST, downloadsEndpoint);
			request.setContent(asJson(ImmutableMap.of("name", fileToDownload)));
			HttpResponse response = client.execute(request);
			Map<String, Object> jsonResponse = new Json().toType(string(response), Json.MAP_TYPE);
			@SuppressWarnings("unchecked")
			Map<String, Object> value = (Map<String, Object>) jsonResponse.get("value");
			// The returned map would contain 2 keys,
			// filename - This represents the name of the file (same as what was provided by the test)
			// contents - Base64 encoded String which contains the zipped file.
			String zippedContents = value.get("contents").toString();
			// The file contents would always be a zip file and has to be unzipped.
			File downloadDir = Zip.unzipToTempDir(zippedContents, "download", "");
			// Read the file contents
			File downloadedFile = Optional.ofNullable(downloadDir.listFiles()).orElse(new File[]{})[0];
			String fileContent = String.join("", Files.readAllLines(downloadedFile.toPath()));
			System.out.println("The file which was "
					+ "downloaded in the node is now available in the directory: "
					+ downloadDir.getAbsolutePath() + " and has the contents: " + fileContent);
		}
	}


}