bugmagnet bugmagnet - 8 months ago 283
C# Question

Selenium RemoteWebDriver against a Windows Service of ChromeDriver


  • Windows 10 Home;

  • Visual Studio 2015 Community;

  • C#;

  • NSSM;

  • ChromeDriver 2.23.409699 (49b0fa931cda1caad0ae15b7d1b68004acd05129);

  • Nuget package Selenium.WebDriver.2.53.1;

  • Nuget package Selenium.WebDriver.ChromeDriver.

I have used NSSM to create a Windows Service wrapping chromedriver.exe, with the following settings:

Path: c:\bin\chromedriver.exe
Startup Directory: c:\bin
Arguments: --port=12942 --log-path=c:\temp\chromedriver.log --verbose
Service Name: ChromeDriverService

In VS2015Community I've created a C# app as follows:

var uri = new Uri("http://localhost:12942");
DesiredCapabilities dc = DesiredCapabilities.Chrome();
ChromeOptions options = new ChromeOptions();
options.BinaryLocation = "C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe";
options.LeaveBrowserRunning = true;
dc.IsJavaScriptEnabled = true;
IWebDriver driver = new RemoteWebDriver(uri, dc);

When I step through the program, I get a
The HTTP request to the remote WebDriver server for URL http://localhost:12942/session timed out after 60 seconds.
on the
new RemoteWebDriver

In the
I get the following:

[44.717][INFO]: COMMAND InitSession {
"desiredCapabilities": {
"browserName": "chrome",
"javascriptEnabled": true,
"platform": "ANY",
"version": ""
[66.168][INFO]: Populating Preferences file: {
"alternate_error_pages": {
"enabled": false
"autofill": {
"enabled": false
"browser": {
"check_default_browser": false
"distribution": {
"import_bookmarks": false,
"import_history": false,
"import_search_engine": false,
"make_chrome_default_for_user": false,
"show_welcome_page": false,
"skip_first_run_ui": true
"dns_prefetching": {
"enabled": false
"profile": {
"content_settings": {
"pattern_pairs": {
"https://*,*": {
"media-stream": {
"audio": "Default",
"video": "Default"
"default_content_setting_values": {
"geolocation": 1
"default_content_settings": {
"geolocation": 1,
"mouselock": 1,
"notifications": 1,
"popups": 1,
"ppapi-broker": 1
"password_manager_enabled": false
"safebrowsing": {
"enabled": false
"search": {
"suggest_enabled": false
"translate": {
"enabled": false
[66.171][INFO]: Populating Local State file: {
"background_mode": {
"enabled": false
"ssl": {
"rev_checking": {
"enabled": false
[68.099][INFO]: Can not set to US keyboard layout - Some keycodes may beinterpreted incorrectly
[68.099][INFO]: Launching chrome: "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --disable-background-networking --disable-client-side-phishing-detection --disable-component-update --disable-default-apps --disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost --disable-sync --disable-web-resources --enable-logging --ignore-certificate-errors --load-component-extension="C:\WINDOWS\TEMP\scoped_dir5436_17406\internal" --log-level=0 --metrics-recording-only --no-first-run --password-store=basic --remote-debugging-port=12772 --safebrowsing-disable-auto-update --test-type=webdriver --use-mock-keychain --user-data-dir="C:\WINDOWS\TEMP\scoped_dir5436_20664" data:,
[68.127][DEBUG]: DevTools request: http://localhost:12772/json/version
[70.154][DEBUG]: DevTools response: {

"Browser": "Chrome/52.0.2743.116",

"Protocol-Version": "1.1",

"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36",

"WebKit-Version": "537.36 (@9115ecad1cae66fd5fe52bd9120af643384fd6f3)"


[70.155][DEBUG]: DevTools request: http://localhost:12772/json
[70.168][DEBUG]: DevTools response: [ ]

... a minute's worth of the above two lines removed ...

[128.264][INFO]: RESPONSE InitSession unknown error: unable to discover open pages
[128.264][DEBUG]: Log type 'driver' lost 0 entries on destruction
[128.264][DEBUG]: Log type 'browser' lost 0 entries on destruction

I have a distant memory of having successfully talked to an NSSM-wrapped chromedriver.exe earlier this year. I can't find the code now. What am I missing here?


You're using RemoteWebDriver as your client. The address you give should be the Selenium Grid hub URL, not the chromedriver URL.

You should either configure Selenium Grid to know about chromedriver, or switch from RemoteWebDriver to ChromeDriver as your client.

ChromeDriver connects to a service provided by chromedriver.exe on any machine, which may be where the confusion about RemoteWebDriver comes in. RemoteWebDriver means "any browser, anywhere, as chosen by a Selenium Grid hub using criteria that you provide". ChromeDriver means "any Chrome, in one specific location chosen by you".

If you switch to ChromeDriver, this code works well:

var service = ChromeDriverService.CreateDefaultService();
// service.EnableVerboseLogging = true;
service.Port = 12942;
var options = new ChromeOptions
    Proxy = new Proxy {Kind = ProxyKind.Direct}

return new ChromeDriver(service, options);

There are lots more options you can provide to the service.

Aside: note that you configure the service to customize how ChromeDriver talks to chromedriver.exe; you configure ChromeOptions to customize how Chrome talks to the internet (or to your webapp).