Angelo Geels Angelo Geels - 24 days ago 12
C# Question

Getting the current tab's URL from Google Chrome using C#

There used to be a way to get the active tab's URL from Google Chrome by using

FindWindowEx
in combination with a
SendMessage
call to get the text currently in the omnibox. A recent (?) update seems to have broken this method, since Chrome seems to be rendering everything itself now. (You can check with Spy++, AHK Window Spy or Window Detective)

To get the current URL on Firefox and Opera, you can use DDE and
WWW_GetWindowInfo
. This doesn't seem to be possible on Chrome (anymore?).

This question has an answer with more info about how it used to work, which is this piece of code (which, as I explained, doesn't work anymore -
hAddressBox
is
0
):

var hAddressBox = FindWindowEx(
intPtr,
IntPtr.Zero,
"Chrome_OmniboxView",
IntPtr.Zero);

var sb = new StringBuilder(256);
SendMessage(hAddressBox, 0x000D, (IntPtr)256, sb);
temp = sb.ToString();


So my question is: Is there a new way to get the currently focused tab's URL? (Just the title is not enough)

Answer

The following code seems to work, (thanks to icemanind's comment) but is however resource intensive. It takes about 350ms to find elmUrlBar... a little slow.

Not to mention that we have the problem of working with multiple chrome processes running at the same time.

// there are always multiple chrome processes, so we have to loop through all of them to find the
// process with a Window Handle and an automation element of name "Address and search bar"
Process[] procsChrome = Process.GetProcessesByName("chrome");
foreach (Process chrome in procsChrome) {
  // the chrome process must have a window
  if (chrome.MainWindowHandle == IntPtr.Zero) {
    continue;
  }

  // find the automation element
  AutomationElement elm = AutomationElement.FromHandle(chrome.MainWindowHandle);
  AutomationElement elmUrlBar = elm.FindFirst(TreeScope.Descendants,
    new PropertyCondition(AutomationElement.NameProperty, "Address and search bar"));

  // if it can be found, get the value from the URL bar
  if (elmUrlBar != null) {
    AutomationPattern[] patterns = elmUrlBar.GetSupportedPatterns();
    if (patterns.Length > 0) {
      ValuePattern val = (ValuePattern)elmUrlBar.GetCurrentPattern(patterns[0]);
      Console.WriteLine("Chrome URL found: " + val.Current.Value);
    }
  }
}

Edit: I wasn't happy with the slow method above, so I made it faster (now 50ms) and added some URL validation to make sure we got the correct URL instead of something the user might be searching for on the web, or still being busy typing in the URL. Here's the code:

// there are always multiple chrome processes, so we have to loop through all of them to find the
// process with a Window Handle and an automation element of name "Address and search bar"
Process[] procsChrome = Process.GetProcessesByName("chrome");
foreach (Process chrome in procsChrome) {
  // the chrome process must have a window
  if (chrome.MainWindowHandle == IntPtr.Zero) {
    continue;
  }

  // find the automation element
  AutomationElement elm = AutomationElement.FromHandle(chrome.MainWindowHandle);

  // manually walk through the tree, searching using TreeScope.Descendants is too slow (even if it's more reliable)
  AutomationElement elmUrlBar = null;
  try {
    // walking path found using inspect.exe (Windows SDK) for Chrome 31.0.1650.63 m (currently the latest stable)
    var elm1 = elm.FindFirst(TreeScope.Children, new PropertyCondition(AutomationElement.NameProperty, "Google Chrome"));
    if (elm1 == null) { continue; } // not the right chrome.exe
    // here, you can optionally check if Incognito is enabled:
    //bool bIncognito = TreeWalker.RawViewWalker.GetFirstChild(TreeWalker.RawViewWalker.GetFirstChild(elm1)) != null;
    var elm2 = TreeWalker.RawViewWalker.GetLastChild(elm1); // I don't know a Condition for this for finding :(
    var elm3 = elm2.FindFirst(TreeScope.Children, new PropertyCondition(AutomationElement.NameProperty, ""));
    var elm4 = elm3.FindFirst(TreeScope.Children, new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.ToolBar));
    elmUrlBar = elm4.FindFirst(TreeScope.Children, new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.Custom));
  } catch {
    // Chrome has probably changed something, and above walking needs to be modified. :(
    // put an assertion here or something to make sure you don't miss it
    continue;
  }

  // make sure it's valid
  if (elmUrlBar == null) {
    // it's not..
    continue;
  }

  // elmUrlBar is now the URL bar element. we have to make sure that it's out of keyboard focus if we want to get a valid URL
  if ((bool)elmUrlBar.GetCurrentPropertyValue(AutomationElement.HasKeyboardFocusProperty)) {
    continue;
  }

  // there might not be a valid pattern to use, so we have to make sure we have one
  AutomationPattern[] patterns = elmUrlBar.GetSupportedPatterns();
  if (patterns.Length == 1) {
    string ret = "";
    try {
      ret = ((ValuePattern)elmUrlBar.GetCurrentPattern(patterns[0])).Current.Value;
    } catch { }
    if (ret != "") {
      // must match a domain name (and possibly "https://" in front)
      if (Regex.IsMatch(ret, @"^(https:\/\/)?[a-zA-Z0-9\-\.]+(\.[a-zA-Z]{2,4}).*$")) {
        // prepend http:// to the url, because Chrome hides it if it's not SSL
        if (!ret.StartsWith("http")) {
          ret = "http://" + ret;
        }
        Console.WriteLine("Open Chrome URL found: '" + ret + "'");
      }
    }
    continue;
  }
}