[py][bidi]: add set_download_behavior command

py/selenium/webdriver/common/bidi/browser.py

@@ -14,8 +14,7 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-
-
+import os
 from typing import Any, Optional
 
 from selenium.webdriver.common.bidi.common import command_builder
@@ -236,3 +235,46 @@ def get_client_windows(self) -> list[ClientWindowInfo]:
         """
         result = self.conn.execute(command_builder("browser.getClientWindows", {}))
         return [ClientWindowInfo.from_dict(window) for window in result["clientWindows"]]
+
+    def set_download_behavior(
+        self,
+        *,
+        allowed: Optional[bool] = None,
+        destination_folder: Optional[str | os.PathLike] = None,
+        user_contexts: Optional[list[str]] = None,
+    ) -> None:
+        """Set the download behavior for the browser or specific user contexts.
+
+        Args:
+            allowed: True to allow downloads, False to deny downloads, or None to
+                clear download behavior (revert to default).
+            destination_folder: Required when allowed is True. Specifies the folder
+                to store downloads in.
+            user_contexts: Optional list of user context IDs to apply this
+                behavior to. If omitted, updates the default behavior.
+
+        Raises:
+            ValueError: If allowed=True and destination_folder is missing, or if
+                allowed=False and destination_folder is provided.
+        """
+        params: dict[str, Any] = {}
+
+        if allowed is None:
+            params["downloadBehavior"] = None
+        else:
+            if allowed:
+                if not destination_folder:
+                    raise ValueError("destination_folder is required when allowed=True.")
+                params["downloadBehavior"] = {
+                    "type": "allowed",
+                    "destinationFolder": os.fspath(destination_folder),
+                }
+            else:
+                if destination_folder:
+                    raise ValueError("destination_folder should not be provided when allowed=False.")
+                params["downloadBehavior"] = {"type": "denied"}
+
+        if user_contexts is not None:
+            params["userContexts"] = user_contexts
+
+        self.conn.execute(command_builder("browser.setDownloadBehavior", params))

py/test/selenium/webdriver/common/bidi_browser_tests.py

@@ -16,17 +16,21 @@
 # under the License.
 
 import http.server
+import os
 import socketserver
 import threading
 
 import pytest
 
+from selenium.common.exceptions import TimeoutException
 from selenium.webdriver.common.bidi.browser import ClientWindowInfo, ClientWindowState
+from selenium.webdriver.common.bidi.browsing_context import ReadinessState
 from selenium.webdriver.common.bidi.session import UserPromptHandler, UserPromptHandlerType
 from selenium.webdriver.common.by import By
 from selenium.webdriver.common.proxy import Proxy, ProxyType
 from selenium.webdriver.common.utils import free_port
 from selenium.webdriver.common.window import WindowTypes
+from selenium.webdriver.support.ui import WebDriverWait
 
 
 class FakeProxyHandler(http.server.SimpleHTTPRequestHandler):
@@ -262,3 +266,96 @@ def test_create_user_context_with_unhandled_prompt_behavior(driver, pages):
 
     # Clean up
     driver.browser.remove_user_context(user_context)
+
+
+@pytest.mark.xfail_firefox
+def test_set_download_behavior_allowed(driver, pages, tmp_path):
+    print(f"Driver info: {driver.capabilities}")
+    try:
+        driver.browser.set_download_behavior(allowed=True, destination_folder=tmp_path)
+
+        context_id = driver.current_window_handle
+        url = pages.url("downloads/download.html")
+        driver.browsing_context.navigate(context=context_id, url=url, wait=ReadinessState.COMPLETE)
+
+        driver.find_element(By.ID, "file-1").click()
+
+        WebDriverWait(driver, 5).until(lambda d: "file_1.txt" in os.listdir(tmp_path))
+
+        files = os.listdir(tmp_path)
+        assert "file_1.txt" in files, f"Expected file_1.txt in {tmp_path}, but found: {files}"
+    finally:
+        driver.browser.set_download_behavior(allowed=None)
+
+
+@pytest.mark.xfail_firefox
+def test_set_download_behavior_denied(driver, pages, tmp_path):
+    try:
+        driver.browser.set_download_behavior(allowed=False)
+
+        context_id = driver.current_window_handle
+        url = pages.url("downloads/download.html")
+        driver.browsing_context.navigate(context=context_id, url=url, wait=ReadinessState.COMPLETE)
+
+        driver.find_element(By.ID, "file-1").click()
+
+        try:
+            WebDriverWait(driver, 3, poll_frequency=0.2).until(lambda _: len(os.listdir(tmp_path)) > 0)
+            files = os.listdir(tmp_path)
+            pytest.fail(f"A file was downloaded unexpectedly: {files}")
+        except TimeoutException:
+            pass  # Expected, no file downloaded
+    finally:
+        driver.browser.set_download_behavior(allowed=None)
+
+
+@pytest.mark.xfail_firefox
+def test_set_download_behavior_user_context(driver, pages, tmp_path):
+    user_context = driver.browser.create_user_context()
+
+    try:
+        bc = driver.browsing_context.create(type=WindowTypes.WINDOW, user_context=user_context)
+        driver.switch_to.window(bc)
+
+        try:
+            driver.browser.set_download_behavior(
+                allowed=True, destination_folder=tmp_path, user_contexts=[user_context]
+            )
+
+            url = pages.url("downloads/download.html")
+            driver.browsing_context.navigate(context=bc, url=url, wait=ReadinessState.COMPLETE)
+
+            driver.find_element(By.ID, "file-1").click()
+
+            WebDriverWait(driver, 5).until(lambda d: "file_1.txt" in os.listdir(tmp_path))
+
+            files = os.listdir(tmp_path)
+            assert "file_1.txt" in files, f"Expected file_1.txt in {tmp_path}, but found: {files}"
+
+            initial_file_count = len(files)
+
+            driver.browser.set_download_behavior(allowed=False, user_contexts=[user_context])
+
+            driver.find_element(By.ID, "file-2").click()
+
+            try:
+                WebDriverWait(driver, 3, poll_frequency=0.2).until(
+                    lambda _: len(os.listdir(tmp_path)) > initial_file_count
+                )
+                files_after = os.listdir(tmp_path)
+                pytest.fail(f"A file was downloaded unexpectedly: {files_after}")
+            except TimeoutException:
+                pass  # Expected, no file downloaded
+        finally:
+            driver.browser.set_download_behavior(allowed=None, user_contexts=[user_context])
+    finally:
+        driver.browser.remove_user_context(user_context)
+
+
+@pytest.mark.xfail_firefox
+def test_set_download_behavior_validation(driver):
+    with pytest.raises(ValueError, match="destination_folder is required when allowed=True"):
+        driver.browser.set_download_behavior(allowed=True)
+
+    with pytest.raises(ValueError, match="destination_folder should not be provided when allowed=False"):
+        driver.browser.set_download_behavior(allowed=False, destination_folder="/tmp")