/// <summary>
/// Execute a method call over the DevTools protocol. This method can be called on any thread.
/// See the DevTools protocol documentation at https://chromedevtools.github.io/devtools-protocol/ for details
/// of supported methods and the expected <paramref name="parameters"/> dictionary contents.
/// </summary>
/// <typeparam name="T">The type into which the result will be deserialzed.</typeparam>
/// <param name="method">is the method name</param>
/// <param name="parameters">are the method parameters represented as a dictionary,
/// which may be empty.</param>
/// <returns>return a Task that can be awaited to obtain the method result</returns>
public Task <T> ExecuteDevToolsMethodAsync <T>(string method, IDictionary <string, object> parameters = null) where T : DevToolsDomainResponseBase
{
if (browser == null || browser.IsDisposed)
{
//TODO: Queue up commands where possible
throw new ObjectDisposedException(nameof(IBrowser));
}
var messageId = Interlocked.Increment(ref lastMessageId);
var taskCompletionSource = new TaskCompletionSource <T>();
var methodResultContext = new DevToolsMethodResponseContext(
type: typeof(T),
setResult: o => taskCompletionSource.TrySetResult((T)o),
setException: taskCompletionSource.TrySetException,
syncContext: CaptureSyncContext ? SynchronizationContext.Current : SyncContext
);
if (!queuedCommandResults.TryAdd(messageId, methodResultContext))
{
throw new DevToolsClientException(string.Format("Unable to add MessageId {0} to queuedCommandResults ConcurrentDictionary.", messageId));
}
var browserHost = browser.GetHost();
//Currently on CEF UI Thread we can directly execute
if (CefThread.CurrentlyOnUiThread)
{
ExecuteDevToolsMethod(browserHost, messageId, method, parameters, methodResultContext);
}
//ExecuteDevToolsMethod can only be called on the CEF UI Thread
else if (CefThread.CanExecuteOnUiThread)
{
CefThread.ExecuteOnUiThread(() =>
{
ExecuteDevToolsMethod(browserHost, messageId, method, parameters, methodResultContext);
return((object)null);
});
}
else
{
queuedCommandResults.TryRemove(messageId, out methodResultContext);
throw new DevToolsClientException("Unable to invoke ExecuteDevToolsMethod on CEF UI Thread.");
}
return(taskCompletionSource.Task);
}
private void ExecuteDevToolsMethod(IBrowserHost browserHost, int messageId, string method, IDictionary <string, object> parameters, DevToolsMethodResponseContext methodResultContext)
{
try
{
var returnedMessageId = browserHost.ExecuteDevToolsMethod(messageId, method, parameters);
if (returnedMessageId == 0)
{
throw new DevToolsClientException(string.Format("Failed to execute dev tools method {0}.", method));
}
else if (returnedMessageId != messageId)
{
//For some reason our message Id's don't match
throw new DevToolsClientException(string.Format("Generated MessageId {0} doesn't match returned Message Id {1}", returnedMessageId, messageId));
}
}
catch (Exception ex)
{
queuedCommandResults.TryRemove(messageId, out _);
methodResultContext.SetException(ex);
}
}
