I want to define a new RequestContext when using CefSharp OffScreen to prevent multiple browser instances sharing the same information (e.g. cookies).
I can simply do that with CefSharp WinForms like that:
RequestContextSettings requestContextSettings = new RequestContextSettings();
requestContextSettings.PersistSessionCookies = false;
requestContextSettings.PersistUserPreferences = false;
WebBrowser.RequestContext = new RequestContext(requestContextSettings);
But the RequestContext is readonly in the offscreen variant.
See http://cefsharp.github.io/api/57.0.0/html/P_CefSharp_OffScreen_ChromiumWebBrowser_RequestContext.htm
Why is that so? And are there other ways to accomplish it?
Related
I am very curious if there is a possibility in CEF Sharp , somehow to isolate each instance of browser from other instances.
I am creating 4 instances of browser. Logging in on of the instances ,
immediately 3 other instances become logged in as well.
Is it possible to achieve somehow in Current version that we got from Nuget ?
As of revision 2040, CEF now adds support for complete isolation of storage and permissions (cache, cookies, localStorage, access grants, etc) on a request context basis. This is also now in CEFSharp.
To make sure that no sessions overlap between multiple instances, simply create a new RequestContextSettings object, set PersistSessionCookies and/or PersistUserPreferences to false, and assign it to your browser while creating a new RequestContext - I am not sure if setting them to false is completely necessary for multiple instances, maybe someone else can give some info on that.
//usually ChromiumWebBrowser setup goes above this
RequestContextSettings requestContextSettings = new RequestContextSettings();
requestContextSettings.PersistSessionCookies = false;
requestContextSettings.PersistUserPreferences = false;
webBrowser.RequestContext = new RequestContext(requestContextSettings);
This had been giving me headaches for a while and this appears to finally solve that issue.
Just use this code, its working for me.
public MainWindow()
{
CefSharp.CefSettings settings = new CefSharp.CefSettings();
settings.CachePath = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData) + #"\CEF";
CefSharp.Cef.Initialize(settings);
InitializeComponent();
browser = new ChromiumWebBrowser("https://google.com/");
browser.BrowserSettings.ApplicationCache = CefSharp.CefState.Disabled;
}
In my WinForms application, I want to display the notifications count in the app launcher icon.
How can this be achieved ?
I believe this is what you're asking for, unfortunately it is in WPF. Winforms doesn't provide a way to do that. You need to P/Invoke manually.
Download Windows 7 API Code Pack - Shell
and use the following.
private void SetTaskBarOverlay()
{
string notificationCount = "3"; //To do: Add this as a parameter
var bmp = new Bitmap(32, 32);
using (Graphics g = Graphics.FromImage(bmp))
{
g.FillEllipse(Brushes.Blue, new Rectangle(Point.Empty, bmp.Size));
g.DrawString(notificationCount, new Font("Sans serif", 25, GraphicsUnit.Point),
Brushes.White, new Rectangle(Point.Empty, bmp.Size));
}
var overlay = Icon.FromHandle(bmp.GetHicon());
TaskbarManager.Instance.SetOverlayIcon(overlay, "");
}
private void RemoveTaskBarOverlay()
{
TaskbarManager.Instance.SetOverlayIcon(null, "");
}
You may alter the painting code to achieve the desired effect.
I was wondering how I can achieve something like an HTTPClient.
I tried WebBrowser class but it seems that the execution continues even though the URL specified has not yet loaded.
public void testWebBrowser(){
final WebBrowser b = new WebBrowser(){
#Override
public void onLoad(String url) {
BrowserComponent c = (BrowserComponent)this.getInternal();
JavascriptContext ctx = new JavascriptContext(c);
// I want this Javascript context here
}
};
// just a test URL
b.setURL("http://youtube.com");
// Suppose to get the Javascript context here though it executes without waiting for the whole page to load
}
How can I get the JS Context from within a WebBrowser context? Like a synchronous execution
WebBrowser browser = new WebBrowser();
browser.setURL("someURL");
// wait execution till the whole page in "someURL" loads till it executes the next line
BrowserComponent c = (BrowserComponent)browser.getInternal();
JavascriptContext ctx = new JavascriptContext(c);
If I understand correctly you are trying to create a scraping solution?
That's probably not the ideal approach since this will actually create a web browser which you then need to automate with JavaScript. I would suggest you create a webservice that encapsulates the HttpClient functionality and drive it with ConnectionRequest. This way when the web site changes you can just fix your server in a way seamless to your installed base.
There is a website that contains a single image from a webcam. Each time the site is hit, the most current image of the webcam is displayed. I want to make a real time video by hitting the site continuously.
I have searched and tried several things but cannot get it to refresh at a reasonable rate.
public MainWindow()
{
InitializeComponent();
this.picUri = "http://someurl";
this.thWatchVideo = new Thread(new ThreadStart(Watch));
_image = new BitmapImage();
_image.BeginInit();
_image.CacheOption = BitmapCacheOption.None;
_image.UriCachePolicy = new RequestCachePolicy(RequestCacheLevel.BypassCache);
_image.CacheOption = BitmapCacheOption.OnLoad;
_image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
_image.UriSource = new Uri(this.picUri);
_image.EndInit();
this.imgVideo.Source = _image;
this.thWatchVideo.Start();
}
public void Watch()
{
while(true)
{
UpdateImage();
}
}
public void UpdateImage()
{
if (this.imgVideo.Dispatcher.CheckAccess())
{
_image = new BitmapImage();
_image.BeginInit();
_image.CacheOption = BitmapCacheOption.None;
_image.UriCachePolicy = new RequestCachePolicy(RequestCacheLevel.BypassCache);
_image.CacheOption = BitmapCacheOption.OnLoad;
_image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
_image.UriSource = new Uri(this.picUri);
_image.EndInit();
this.imgVideo.Source = _image;
}
else
{
UpdateImageCallback del = new UpdateImageCallback(UpdateImage);
this.imgVideo.Dispatcher.Invoke(del);
}
}
Problem is, this is too slow and takes too long to refresh and the app just hangs.
I got this to work in Windows Forms with the PictureBox control but cannot get it to work in WPF. I refuse to believe that WPF is inferior to forms.
This app will always just hang (whether winforms or WPF) because you've got an infinite loop running everything it does on the UI thread. Your app hangs because you're not allowing the UI thread any time to process user input (such as resizing the window or trying to close the app).
With regard to your performance: have you tried profiling your code? I suspect that the problem is to do with you repeatedly hammering a webserver for an image, since you're never likely to get enough requests-per-second to make any kind of real-time video from static images. (There's a reason that we have video streaming codecs!)
instead of recreating whole image try to change only UriSource property.
Check out my answer to this: Showing processed images from an IP camera
Also, make sure the communication is done on a separate thread.
I suggest that the Bitmap image is a dependency object being created on a non-GUI thread. You then invoke UpdateImage on the GUI thread. Since the bitmap image dependency object wasn't created on/(owned by) the GUI thread, you get the "different thread owns it" error.
How about this as a workaround?
Copy the image temporarily to a local file location in your Watch routine.
Add a Thread.Sleep to the watch routine so that you don't hammer the CPU with the endless loop on this thread.
Use BeginInvoke instead of Invoke.
Load and update the image in the UpdateImage routine so that the image and the imgVideo objects are on the GUI thread. Update the image by reading it from your local file copy.
Without knowing the specifics of how you make Watch run on its own thread (using Background worker?) I think this approach will work for you.
Is there a way to read/write the cookies that a WebBrowser control uses?
I am doing something like this...
string resultHtml;
HttpWebRequest request = CreateMyHttpWebRequest(); // fills http headers and stuff
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (StreamReader sr = new StreamReader(response.GetResponseStream()))
{
resultHtml = sr.ReadToEnd();
}
WebBrowser browser = new WebBrowser();
browser.CookieContainer = request.CookieContainer; // i wish i could do this :(
browser.NavigateToString(resultHtml);
One of the potentially confusing things about the WebBrowser control and cookies is that at a first glance, it often looks like your app gets a separate cookie store. For example, if you log into a site that stores a persistent cookie to identify you, then whether you appear to be logged in for that site from inside an app hosting the control will be independent of whether you seem to be logged in via Internet Explorer.
In fact, you can even be logged in with different identities.
However, although it might be natural to draw the conclusion that each app hosting the WebBrowser therefore gets its own cookies, in fact that's not true. There are merely two sets of cookies: the ones used in 'low integrity' mode (which is what IE runs in by default), and the other set, which is what you'll get in a normal app that hosts the WebBrowser and also what you'll get if you run IE elevated.
the webbrowser control uses WinInet for networking, specifically use the InternetSetCookie(Ex) and InternetGetCookie(Ex) functions for Cookie management. There isn't a WinInet wrapper in .Net, but you can p-invoke.
Yes you are right, InternetGetCookieEx is the only way to retrieve HttpOnly cookies and it is the preferred way to grab cookie from WebBrowser control.
I posted a complete example here
You can use Application.GetCookie and Application.SetCookie methods.
Although Application is more or less related to WPF, you can use these methods in any desktop .NET code. In fact, they are wrappers on InternetGetCookieEx and InternetSetCookieEx Windows APIs.
I faced the same issue few days ago.
Besides the examples of the previous answers, here is a Win32 wrapper for the WebBrowser control. The advantage of this implementation is that it exposes more options that the default WebBrowser control.
Unfortunately if It's not WPF native, so you will have to create a wrapper if you're planning to use it in WPF.
http://code.google.com/p/csexwb2/
Here is sample from [link][1]
> public static class WinInetHelper
{
public static bool SupressCookiePersist()
{
// 3 = INTERNET_SUPPRESS_COOKIE_PERSIST
// 81 = INTERNET_OPTION_SUPPRESS_BEHAVIOR
return SetOption(81, 3);
}
public static bool EndBrowserSession()
{
// 42 = INTERNET_OPTION_END_BROWSER_SESSION
return SetOption(42, null);
}
static bool SetOption(int settingCode, int? option)
{
IntPtr optionPtr = IntPtr.Zero;
int size = 0;
if (option.HasValue)
{
size = sizeof(int);
optionPtr = Marshal.AllocCoTaskMem(size);
Marshal.WriteInt32(optionPtr, option.Value);
}
bool success = InternetSetOption(0, settingCode, optionPtr, size);
if (optionPtr != IntPtr.Zero) Marshal.Release(optionPtr);
return success;
}
[System.Runtime.InteropServices.DllImport("wininet.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool InternetSetOption(
int hInternet,
int dwOption,
IntPtr lpBuffer,
int dwBufferLength
);
}