add method to get downloaded files with meta-info from Grid

To track the downloading progress and wait for the full download completion,
we need to know this info about downloaded files:
1. File modification time
2. File size

Author: asolntsev

java/src/org/openqa/selenium/HasDownloads.java

@@ -57,6 +57,13 @@ static boolean isDownloadsEnabled(Capabilities capabilities) {
    */
   List<String> getDownloadableFiles();
 
+  /**
+   * Gets all files downloaded by browser.
+   *
+   * @return a list of files with their name, size and time.
+   */
+  List<DownloadedFile> getDownloadedFiles();
+
   /**
    * Downloads a file to a given location.
    *
@@ -68,4 +75,34 @@ static boolean isDownloadsEnabled(Capabilities capabilities) {
 
   /** Deletes the downloadable files. */
   void deleteDownloadableFiles();
+
+  class DownloadedFile {
+    private final String name;
+    private final long creationTime;
+    private final long lastModifiedTime;
+    private final long size;
+
+    public DownloadedFile(String name, long creationTime, long lastModifiedTime, long size) {
+      this.name = name;
+      this.creationTime = creationTime;
+      this.lastModifiedTime = lastModifiedTime;
+      this.size = size;
+    }
+
+    public String getName() {
+      return name;
+    }
+
+    public long getCreationTime() {
+      return creationTime;
+    }
+
+    public long getLastModifiedTime() {
+      return lastModifiedTime;
+    }
+
+    public long getSize() {
+      return size;
+    }
+  }
 }

java/src/org/openqa/selenium/grid/node/local/LocalNode.java

@@ -18,6 +18,8 @@
 package org.openqa.selenium.grid.node.local;
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static java.nio.file.Files.readAttributes;
+import static org.openqa.selenium.HasDownloads.DownloadedFile;
 import static org.openqa.selenium.concurrent.ExecutorServices.shutdownGracefully;
 import static org.openqa.selenium.grid.data.Availability.DOWN;
 import static org.openqa.selenium.grid.data.Availability.DRAINING;
@@ -44,6 +46,7 @@
 import java.io.UncheckedIOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.time.Clock;
 import java.time.Duration;
 import java.time.Instant;
@@ -753,15 +756,32 @@ public HttpResponse downloadFile(HttpRequest req, SessionId id) {
 
   /** User wants to list files that can be downloaded */
   private HttpResponse listDownloadedFiles(File downloadsDirectory) {
-    List<String> collected =
-      Arrays.stream(Optional.ofNullable(downloadsDirectory.listFiles()).orElse(new File[] {}))
-        .map(File::getName)
-        .collect(Collectors.toList());
-    Map<String, Object> data = Map.of("names", collected);
+    File[] files = Optional.ofNullable(downloadsDirectory.listFiles()).orElse(new File[] {});
+    List<String> fileNames = Arrays.stream(files).map(File::getName).collect(Collectors.toList());
+    List<DownloadedFile> fileInfos =
+        Arrays.stream(files).map(this::getFileInfo).collect(Collectors.toList());
+
+    Map<String, Object> data =
+        Map.of(
+            "names", fileNames,
+            "files", fileInfos);
     Map<String, Map<String, Object>> result = Map.of("value", data);
     return new HttpResponse().setContent(asJson(result));
   }
 
+  private DownloadedFile getFileInfo(File file) {
+    try {
+      BasicFileAttributes attributes = readAttributes(file.toPath(), BasicFileAttributes.class);
+      return new DownloadedFile(
+          file.getName(),
+          attributes.creationTime().toMillis(),
+          attributes.lastModifiedTime().toMillis(),
+          attributes.size());
+    } catch (IOException e) {
+      throw new RuntimeException("Failed to get file attributes: " + file.getAbsolutePath(), e);
+    }
+  }
+
   private HttpResponse getDownloadedFile(HttpRequest req, File downloadsDirectory)
       throws IOException {
     String raw = string(req);

java/src/org/openqa/selenium/remote/RemoteWebDriver.java

@@ -20,6 +20,7 @@
 import static java.util.Collections.singleton;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.logging.Level.SEVERE;
+import static org.openqa.selenium.HasDownloads.DownloadedFile;
 import static org.openqa.selenium.remote.CapabilityType.PLATFORM_NAME;
 
 import java.io.IOException;
@@ -672,9 +673,9 @@ public boolean isDownloadsEnabled() {
   }
 
   /**
-   * Retrieves the names of the downloadable files.
+   * Retrieves the names of the files downloaded by browser.
    *
-   * @return A list containing the names of the downloadable files.
+   * @return A list containing the names of the downloaded files.
    * @throws WebDriverException if capability to enable downloads is not set
    */
   @Override
@@ -683,8 +684,27 @@ public List<String> getDownloadableFiles() {
     requireDownloadsEnabled(capabilities);
 
     Response response = execute(DriverCommand.GET_DOWNLOADABLE_FILES);
-    Map<String, List<String>> value = (Map<String, List<String>>) response.getValue();
-    return value.get("names");
+    Map<String, Object> value = (Map<String, Object>) response.getValue();
+    return (List<String>) value.get("names");
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public List<DownloadedFile> getDownloadedFiles() {
+    requireDownloadsEnabled(capabilities);
+
+    Response response = execute(DriverCommand.GET_DOWNLOADABLE_FILES);
+    Map<String, Object> value = (Map<String, Object>) response.getValue();
+    List<Map<String, Object>> files = (List<Map<String, Object>>) value.get("files");
+    return files.stream()
+        .map(
+            file ->
+                new DownloadedFile(
+                    (String) file.get("name"),
+                    (Long) file.get("creationTime"),
+                    (Long) file.get("lastModifiedTime"),
+                    (Long) file.get("size")))
+        .collect(Collectors.toUnmodifiableList());
   }
 
   /**