private async void AddChatButton_OnClick(object sender, RoutedEventArgs e)
{
var dialog = new AddChatDialog();
string username = "", name = "";
byte delegateResult = 0; // 0 is running, 1 is done, 2 is canceled
Exception error = null;
await DialogHost.Show(dialog, "MainWindowDialogHost", async delegate(object sender1, DialogClosingEventArgs args)
{
if (!(bool)args.Parameter)
{
delegateResult = 2;
// check if the dialog is canceled
return;
}
username = dialog.IdTextBox.Text;
// check if the ID exists in database
var dbResult = await SharedStuff.Database.Table <DatabaseHelper.Users>().Where(user => user.Username == username)
.ToArrayAsync();
if (dbResult.Length == 0) // get the user's key from server
{
NameValueCollection queryString = HttpUtility.ParseQueryString(string.Empty);
queryString.Add("username", username);
string url = SharedStuff.CreateUrlWithQuery(
"https://" + Properties.Settings.Default.ServerAddress + "/users/getData", queryString);
string result;
try
{
using (WebClient wc = new WebClient()) // request other user's public key
result = await wc.DownloadStringTaskAsync(url);
}
catch (Exception ex)
{
error = new Exception("Cannot connect to server", ex);
delegateResult = 1;
return;
}
// check if the username exists
try
{
var data = JsonConvert.DeserializeObject <JsonTypes.UserDataStruct>(result);
if (data.PublicKey == "")
{
throw new Exception("User is not logged in.");
}
string key = Convert.ToBase64String(SharedStuff.Curve.calculateAgreement(
Convert.FromBase64String(_savedData.PrivateKey),
Convert.FromBase64String(data.PublicKey)));
await SharedStuff.Database.InsertAsync(
new DatabaseHelper.Users // save the key in database
{
Username = data.Username,
Name = data.Name,
Key = key,
});
name = data.Name;
}
catch (Exception)
{
var data = JsonConvert.DeserializeObject <JsonTypes.ServerStatus>(result);
error = new Exception("Server returned an error", new Exception(data.Message));
}
finally
{
delegateResult = 1;
}
}
});
// wait until the results are gathered
while (delegateResult == 0)
{
await Task.Delay(50);
}
if (delegateResult == 2)
{
return;
}
if (error != null)
{
var errDialog = new ErrorDialogSample
{
ErrorTitle = { Text = error.Message },
ErrorText = { Text = error.InnerException.Message }
};
await DialogHost.Show(errDialog, "MainWindowDialogHost");
return;
}
// check if messages list does not contain this user
if (MessagesList.All(x => x.Username != username))
{
MessagesList.Insert(0, new MainMessagesNotify
{
FullDate = DateTime.Now,
IsLastMessageForUser = false,
Message = "",
Name = name,
Username = username
});
}
// open the chat page
OpenWindowsList.Add(username, new ChatWindow(username));
OpenWindowsList[username].Show();
}
private async void OpenFileClicked(object sender, RoutedEventArgs e)
{
if (sender is Button btn)
{
if (btn.CommandParameter is string token)
{
DatabaseHelper.Files f = new DatabaseHelper.Files();
try
{
f = await SharedStuff.Database.Table <DatabaseHelper.Files>()
.Where(file => file.Token == token).FirstAsync();
if (string.IsNullOrEmpty(f.Location))
{
throw new InvalidOperationException();
}
if (f.Location == " ") // null means the file is not downloaded. ' ' means it does not exists
{
throw new FileNotFoundException();
}
if (File.Exists(f.Location)) // check if the downloaded file exists
{
System.Diagnostics.Process.Start(f.Location);
}
else
{
await SharedStuff.Database.ExecuteAsync(
"UPDATE Files SET Location = ? WHERE Token = ?"
, " ", token);
throw new FileNotFoundException();
}
}
catch (FileNotFoundException)
{
// at first check if server has the file
var err = new ErrorDialogSample
{
ErrorText =
{
Text =
"This file does not exists on your computer. Ask other user to send this file again."
},
ErrorTitle = { Text = "Cannot Open File" }
};
await DialogHost.Show(err, "ChatDialogHost" + Username);
}
catch (InvalidOperationException) // this token does not exists in database
{
// download this file
await Application.Current.Dispatcher.Invoke(async delegate
{
ProgressBar bar = ((StackPanel)((DockPanel)((Button)sender).Parent).Parent)
.Children[1] as ProgressBar;
try
{
string downloadFileUrl =
$"https://{Properties.Settings.Default.ServerAddress}/download?token={token}"; // token does not contain special characters so we are good
string destinationFilePath = Path.GetTempFileName();
using (var client =
new HttpClientDownloadWithProgress(downloadFileUrl, destinationFilePath))
{
client.ProgressChanged +=
(totalFileSize, totalBytesDownloaded, progressPercentage) =>
{
bar.Value = progressPercentage ?? 0;
};
await client.StartDownload();
}
// get the key
string key = (await SharedStuff.Database.Table <DatabaseHelper.Users>()
.Where(user => user.Username == Username).FirstAsync()).Key;
BouncyCastleHelper.AesGcmDecrypt(new FileInfo(destinationFilePath),
new FileInfo(Path.Combine(SharedStuff.DownloadPath, f.Name)), key);
await SharedStuff.Database.ExecuteAsync(
"UPDATE Files SET Location = ? WHERE Token = ?"
, Path.Combine(SharedStuff.DownloadPath, f.Name), token);
}
catch (FileNotFoundException) // This error means that the files does not exists on server. (it's too old)
{
await SharedStuff.Database.ExecuteAsync(
"UPDATE Files SET Location = ? WHERE Token = ?"
, " ", token); // this will make the File.Exists always return false
MessagesList.First(msg => msg.Token == token).DownloadButtonIcon =
PackIconKind.DownloadOff;
var err = new ErrorDialogSample
{
ErrorText =
{
Text = "This file is too old and could not be downloaded. Ask other user to send this file again."
},
ErrorTitle = { Text = "Cannot Download File" }
};
await DialogHost.Show(err, "ChatDialogHost" + Username);
}
catch (Exception ex)
{
var err = new ErrorDialogSample
{
ErrorText =
{
Text = ex.Message
},
ErrorTitle = { Text = "Cannot Download File" }
};
await DialogHost.Show(err, "ChatDialogHost" + Username);
}
finally
{
bar.Value = 101;
}
});
}
}
}
}
private async void LoginButtonClicked(object sender, RoutedEventArgs e)
{
LoadingDialogSample loadingDialog = new LoadingDialogSample // simple dialog with a spinning indicator
{
LoadingTextText = { Text = "Connecting to server..." } // set the text of the dialog
};
Exception error = null;
await DialogHost.Show(loadingDialog, "LoginDialogHost", delegate(object sender1, DialogOpenedEventArgs args) // show the dialog
{
string serverAddress = ServerUrlTxt.Text, username = UsernameTxt.Text, password = PasswordTxt.Password;
bool trustEveryThing = TrustSslCheckBox.IsChecked.HasValue && TrustSslCheckBox.IsChecked.Value;
Task.Factory.StartNew(async() => // connect to server from another thread
{
// let's see to trust all certificates or not
if (trustEveryThing)
{
ServicePointManager.ServerCertificateValidationCallback = (a, b, c, d) => true;
}
else
{
ServicePointManager.ServerCertificateValidationCallback = null;
}
// at first get server's public RSA key
try
{
if (SharedStuff.ServerPublicKey == null)
{
using (var wc = new WebClient())
{
string key = wc.DownloadString("https://" + serverAddress + "/publicKey");
SharedStuff.ServerPublicKey = BouncyCastleHelper.ReadAsymmetricKeyParameter(key);
}
}
}
catch (Exception ex)
{
error = new Exception("Can't get public key", ex);
// close dialog on main thread (because it is not running from main thread)
await Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => args.Session.Close()));
return;
}
// now login the user
string toSave;
try
{
// at first generate a ecdh curve25519 key pair
var curveKeys = SharedStuff.Curve.generateKeyPair();
// encrypt the password with server's public key
string rsaPassword = Convert.ToBase64String(BouncyCastleHelper.RsaEncrypt(SharedStuff.ServerPublicKey, password));
// build the request
var postValues = new FormUrlEncodedContent(new[]
{
new KeyValuePair <string, string>("username", username),
new KeyValuePair <string, string>("password", rsaPassword),
new KeyValuePair <string, string>("key", Convert.ToBase64String(curveKeys.getPublicKey())),
});
var result = await SharedStuff.Client.PostAsync("https://" + serverAddress + "/users/registerClient", postValues);
string resultContent = await result.Content.ReadAsStringAsync();
// parse the server result
var jsonRes = JsonConvert.DeserializeObject <JsonTypes.ServerStatus>(resultContent);
if (!jsonRes.Ok)
{
throw new Exception("Server returned an error: " + jsonRes.Message);
}
// save the login details
toSave = JsonConvert.SerializeObject(new JsonTypes.SavedData
{
Username = username,
Password = password,
PublicKey = Convert.ToBase64String(curveKeys.getPublicKey()),
PrivateKey = Convert.ToBase64String(curveKeys.getPrivateKey())
});
Properties.Settings.Default.Name = jsonRes.Message;
Properties.Settings.Default.ServerAddress = serverAddress;
}
catch (Exception ex)
{
error = new Exception("Can't login you", ex);
// close dialog on main thread (because it is not running from main thread)
await Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => args.Session.Close()));
return;
}
// save the data (we had a successful login)
try
{
byte[] encrypted = ProtectedData.Protect(Encoding.UTF8.GetBytes(toSave), null, DataProtectionScope.CurrentUser); // encrypt the data
Properties.Settings.Default.LoginData = Convert.ToBase64String(encrypted); // save data to application settings
Properties.Settings.Default.TrustInvalidSSL = trustEveryThing;
Properties.Settings.Default.Save();
}
catch (Exception ex)
{
error = new Exception("Cannot save data", ex);
// TODO: logout the user if this fails
// close dialog on main thread (because it is not running from main thread)
await Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => args.Session.Close()));
return;
}
// close dialog on main thread (because it is not running from main thread)
await Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => args.Session.Close()));
});
});
// check for errors
if (error != null)
{
ErrorDialogSample errorDialog = new ErrorDialogSample
{
ErrorTitle = { Text = error.Message },
ErrorText = { Text = error.InnerException.Message } // Inner exception is never empty
};
await DialogHost.Show(errorDialog, "LoginDialogHost");
}
else // login the user
{
Hide();
new MainChatsWindow().Show();
}
}
