Chapter 7: WebSockets#

uses  Tina4WebSocketClient;​var  WSClient: TTina4WebSocketClient;begin  WSClient := TTina4WebSocketClient.Create(Self);  WSClient.URL := 'wss://api.example.com/ws';end;

procedure TForm1.FormCreate(Sender: TObject);begin  Tina4WebSocket1.URL := 'wss://api.example.com/ws';  Tina4WebSocket1.AutoReconnect := True;  Tina4WebSocket1.ReconnectInterval := 5000;​  Tina4WebSocket1.OnConnected := WebSocketConnected;  Tina4WebSocket1.OnMessage := WebSocketMessage;  Tina4WebSocket1.OnDisconnected := WebSocketDisconnected;  Tina4WebSocket1.OnError := WebSocketError;​  Tina4WebSocket1.Connect;end;

procedure TForm1.WebSocketConnected(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Connected';    LabelStatus.TextSettings.FontColor := TAlphaColorRec.Green;  end);end;​procedure TForm1.WebSocketMessage(Sender: TObject; const AMessage: string);begin  TThread.Synchronize(nil, procedure  begin    MemoMessages.Lines.Add(FormatDateTime('hh:nn:ss', Now) + ' ' + AMessage);  end);end;​procedure TForm1.WebSocketDisconnected(Sender: TObject; const ACode: Integer;  const AReason: string);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Disconnected: ' + AReason;    LabelStatus.TextSettings.FontColor := TAlphaColorRec.Red;  end);end;​procedure TForm1.WebSocketError(Sender: TObject; const AError: string);begin  TThread.Synchronize(nil, procedure  begin    MemoMessages.Lines.Add('ERROR: ' + AError);  end);end;

procedure TForm1.ButtonSendClick(Sender: TObject);begin  Tina4WebSocket1.Send(EditMessage.Text);  EditMessage.Text := '';end;

procedure TForm1.SendJSON;var  Obj: TJSONObject;begin  Obj := TJSONObject.Create;  try    Obj.AddPair('type', 'subscribe');    Obj.AddPair('channel', 'notifications');    Obj.AddPair('userId', TJSONNumber.Create(1001));​    Tina4WebSocket1.Send(Obj.ToString);  finally    Obj.Free;  end;end;

procedure TForm1.SafeSend(const AMessage: string);begin  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Send(AMessage)  else    ShowMessage('Not connected to server');end;

Tina4WebSocket1.AutoReconnect := True;Tina4WebSocket1.ReconnectInterval := 5000;  // 5 seconds between attempts

Connected -> Connection Lost -> Wait 5s -> Reconnect Attempt 1  -> Fail -> Wait 5s -> Reconnect Attempt 2  -> Success -> Connected

procedure TForm1.WebSocketConnected(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Connected';​    // Re-subscribe to channels after reconnection    var Sub := TJSONObject.Create;    try      Sub.AddPair('type', 'subscribe');      Sub.AddPair('channel', 'updates');      Tina4WebSocket1.Send(Sub.ToString);    finally      Sub.Free;    end;  end);end;

Tina4WebSocket1.PingInterval := 30000;  // Send ping every 30 seconds

procedure TForm1.WebSocketMessage(Sender: TObject; const AMessage: string);var  JSON: TJSONObject;begin  JSON := StrToJSONObject(AMessage);  if Assigned(JSON) then  try    var MsgType := JSON.GetValue<String>('type', '');​    TThread.Synchronize(nil, procedure    begin      if MsgType = 'price_update' then        UpdatePriceDisplay(JSON)      else if MsgType = 'notification' then        ShowNotification(JSON)      else if MsgType = 'error' then        HandleServerError(JSON);    end);  finally    JSON.Free;  end;end;

procedure TForm1.WebSocketBinaryMessage(Sender: TObject; const AData: TBytes);begin  TThread.Synchronize(nil, procedure  begin    // Save binary data to file    var Stream := TFileStream.Create('received_data.bin', fmCreate);    try      Stream.WriteBuffer(AData[0], Length(AData));    finally      Stream.Free;    end;  end);end;

procedure TForm1.ButtonDisconnectClick(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  // Prevent reconnection  Tina4WebSocket1.Disconnect;end;

procedure TForm1.FormDestroy(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Disconnect;end;

unit ChatForm;​interface​uses  System.SysUtils, System.Types, System.Classes, System.JSON,  FMX.Types, FMX.Controls, FMX.Forms, FMX.StdCtrls, FMX.Edit,  FMX.Memo, FMX.Layouts,  Tina4WebSocketClient, Tina4HTMLRender, Tina4Core;​type  TFormChat = class(TForm)    Tina4WebSocket1: TTina4WebSocketClient;    HTMLRender1: TTina4HTMLRender;    EditMessage: TEdit;    ButtonSend: TButton;    EditUsername: TEdit;    ButtonConnect: TButton;    LabelStatus: TLabel;    procedure FormCreate(Sender: TObject);    procedure FormDestroy(Sender: TObject);    procedure ButtonConnectClick(Sender: TObject);    procedure ButtonSendClick(Sender: TObject);    procedure EditMessageKeyDown(Sender: TObject; var Key: Word;      var KeyChar: Char; Shift: TShiftState);  private    FChatHistory: TStringList;    FOnlineUsers: TStringList;    FIsConnected: Boolean;    procedure OnWSOpen(Sender: TObject);    procedure OnWSMessage(Sender: TObject; const AMessage: string);    procedure OnWSClose(Sender: TObject; const ACode: Integer;      const AReason: string);    procedure OnWSError(Sender: TObject; const AError: string);    procedure AddChatMessage(const AUser, AMessage, ATime: string;      AIsOwn: Boolean);    procedure RefreshChatDisplay;    procedure UpdateOnlineStatus;  end;​var  FormChat: TFormChat;​implementation​{$R *.fmx}​procedure TFormChat.FormCreate(Sender: TObject);begin  FChatHistory := TStringList.Create;  FOnlineUsers := TStringList.Create;  FIsConnected := False;​  Tina4WebSocket1.AutoReconnect := True;  Tina4WebSocket1.ReconnectInterval := 3000;  Tina4WebSocket1.PingInterval := 25000;​  Tina4WebSocket1.OnConnected := OnWSOpen;  Tina4WebSocket1.OnMessage := OnWSMessage;  Tina4WebSocket1.OnDisconnected := OnWSClose;  Tina4WebSocket1.OnError := OnWSError;​  ButtonSend.Enabled := False;  LabelStatus.Text := 'Disconnected';​  // Show empty chat  RefreshChatDisplay;end;​procedure TFormChat.FormDestroy(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Disconnect;  FChatHistory.Free;  FOnlineUsers.Free;end;​procedure TFormChat.ButtonConnectClick(Sender: TObject);begin  if FIsConnected then  begin    Tina4WebSocket1.AutoReconnect := False;    Tina4WebSocket1.Disconnect;  end  else  begin    if EditUsername.Text.Trim.IsEmpty then    begin      ShowMessage('Please enter a username');      Exit;    end;​    Tina4WebSocket1.URL := 'wss://chat.example.com/ws';    Tina4WebSocket1.AutoReconnect := True;    Tina4WebSocket1.Connect;    LabelStatus.Text := 'Connecting...';  end;end;​procedure TFormChat.OnWSOpen(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    FIsConnected := True;    LabelStatus.Text := 'Connected';    ButtonConnect.Text := 'Disconnect';    ButtonSend.Enabled := True;    EditUsername.Enabled := False;​    // Send join message    var JoinMsg := TJSONObject.Create;    try      JoinMsg.AddPair('type', 'join');      JoinMsg.AddPair('username', EditUsername.Text);      Tina4WebSocket1.Send(JoinMsg.ToString);    finally      JoinMsg.Free;    end;  end);end;​procedure TFormChat.OnWSMessage(Sender: TObject; const AMessage: string);begin  TThread.Synchronize(nil, procedure  var    JSON: TJSONObject;  begin    JSON := StrToJSONObject(AMessage);    if not Assigned(JSON) then Exit;    try      var MsgType := JSON.GetValue<String>('type', '');​      if MsgType = 'chat' then      begin        var User := JSON.GetValue<String>('username', 'Unknown');        var Text := JSON.GetValue<String>('message', '');        var Time := JSON.GetValue<String>('time', FormatDateTime('hh:nn', Now));        var IsOwn := (User = EditUsername.Text);​        AddChatMessage(User, Text, Time, IsOwn);      end      else if MsgType = 'user_list' then      begin        FOnlineUsers.Clear;        var Users := JSON.GetValue<TJSONArray>('users');        if Assigned(Users) then          for var I := 0 to Users.Count - 1 do            FOnlineUsers.Add(Users.Items[I].Value);        UpdateOnlineStatus;      end      else if MsgType = 'user_joined' then      begin        var User := JSON.GetValue<String>('username', '');        if not FOnlineUsers.Contains(User) then          FOnlineUsers.Add(User);        AddChatMessage('System', User + ' joined the chat', '', False);        UpdateOnlineStatus;      end      else if MsgType = 'user_left' then      begin        var User := JSON.GetValue<String>('username', '');        var Idx := FOnlineUsers.IndexOf(User);        if Idx >= 0 then          FOnlineUsers.Delete(Idx);        AddChatMessage('System', User + ' left the chat', '', False);        UpdateOnlineStatus;      end;    finally      JSON.Free;    end;  end);end;​procedure TFormChat.OnWSClose(Sender: TObject; const ACode: Integer;  const AReason: string);begin  TThread.Synchronize(nil, procedure  begin    FIsConnected := False;    LabelStatus.Text := 'Disconnected';    ButtonConnect.Text := 'Connect';    ButtonSend.Enabled := False;    EditUsername.Enabled := True;    FOnlineUsers.Clear;    UpdateOnlineStatus;  end);end;​procedure TFormChat.OnWSError(Sender: TObject; const AError: string);begin  TThread.Synchronize(nil, procedure  begin    AddChatMessage('System', 'Error: ' + AError, '', False);  end);end;​procedure TFormChat.ButtonSendClick(Sender: TObject);begin  if EditMessage.Text.Trim.IsEmpty then Exit;  if not Tina4WebSocket1.IsConnected then Exit;​  var Msg := TJSONObject.Create;  try    Msg.AddPair('type', 'chat');    Msg.AddPair('message', EditMessage.Text.Trim);    Tina4WebSocket1.Send(Msg.ToString);  finally    Msg.Free;  end;​  EditMessage.Text := '';  EditMessage.SetFocus;end;​procedure TFormChat.EditMessageKeyDown(Sender: TObject; var Key: Word;  var KeyChar: Char; Shift: TShiftState);begin  if Key = vkReturn then    ButtonSendClick(Sender);end;​procedure TFormChat.AddChatMessage(const AUser, AMessage, ATime: string;  AIsOwn: Boolean);var  Alignment, BgColor, TextColor: string;begin  if AIsOwn then  begin    Alignment := 'right';    BgColor := '#1abc9c';    TextColor := 'white';  end  else if AUser = 'System' then  begin    Alignment := 'center';    BgColor := '#f0f0f0';    TextColor := '#666';  end  else  begin    Alignment := 'left';    BgColor := '#ecf0f1';    TextColor := '#333';  end;​  FChatHistory.Add(Format(    '<div style="text-align: %s; margin: 5px 0;">' +    '  <div style="display: inline-block; background: %s; color: %s; ' +    '    padding: 8px 12px; border-radius: 12px; max-width: 70%%;">' +    '    <small><strong>%s</strong> %s</small><br>%s' +    '  </div>' +    '</div>',    [Alignment, BgColor, TextColor, AUser, ATime, AMessage]));​  RefreshChatDisplay;end;​procedure TFormChat.RefreshChatDisplay;begin  HTMLRender1.HTML.Text :=    '<div style="font-family: Arial, sans-serif; padding: 10px;">' +    '<h3 style="color: #2c3e50; border-bottom: 1px solid #eee; padding-bottom: 5px;">Chat</h3>' +    FChatHistory.Text +    '</div>';end;​procedure TFormChat.UpdateOnlineStatus;begin  // Update status label with online user count  if FOnlineUsers.Count > 0 then    LabelStatus.Text := Format('Connected (%d online)', [FOnlineUsers.Count])  else if FIsConnected then    LabelStatus.Text := 'Connected'  else    LabelStatus.Text := 'Disconnected';end;​end.

unit PriceFeedForm;​interface​uses  System.SysUtils, System.Types, System.Classes, System.JSON,  System.Generics.Collections, FMX.Types, FMX.Controls, FMX.Forms,  FMX.StdCtrls, FMX.Layouts,  Tina4WebSocketClient, Tina4HTMLRender, Tina4Core;​type  TPriceInfo = record    Symbol: string;    Price: Double;    PrevPrice: Double;    Change: Double;    ChangePercent: Double;    LastUpdate: TDateTime;  end;​  TFormPriceFeed = class(TForm)    Tina4WebSocket1: TTina4WebSocketClient;    HTMLRender1: TTina4HTMLRender;    ButtonConnect: TButton;    LabelStatus: TLabel;    procedure FormCreate(Sender: TObject);    procedure FormDestroy(Sender: TObject);    procedure ButtonConnectClick(Sender: TObject);  private    FPrices: TDictionary<string, TPriceInfo>;    procedure OnWSOpen(Sender: TObject);    procedure OnWSMessage(Sender: TObject; const AMessage: string);    procedure OnWSClose(Sender: TObject; const ACode: Integer;      const AReason: string);    procedure OnWSError(Sender: TObject; const AError: string);    procedure UpdatePriceDisplay;    function GetChangeColor(AChange: Double): string;    function GetChangeArrow(AChange: Double): string;  end;​var  FormPriceFeed: TFormPriceFeed;​implementation​{$R *.fmx}​procedure TFormPriceFeed.FormCreate(Sender: TObject);begin  FPrices := TDictionary<string, TPriceInfo>.Create;​  Tina4WebSocket1.URL := 'wss://feeds.example.com/prices';  Tina4WebSocket1.AutoReconnect := True;  Tina4WebSocket1.ReconnectInterval := 5000;  Tina4WebSocket1.PingInterval := 20000;​  Tina4WebSocket1.OnConnected := OnWSOpen;  Tina4WebSocket1.OnMessage := OnWSMessage;  Tina4WebSocket1.OnDisconnected := OnWSClose;  Tina4WebSocket1.OnError := OnWSError;​  LabelStatus.Text := 'Disconnected';  UpdatePriceDisplay;end;​procedure TFormPriceFeed.FormDestroy(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Disconnect;  FPrices.Free;end;​procedure TFormPriceFeed.ButtonConnectClick(Sender: TObject);begin  if Tina4WebSocket1.IsConnected then  begin    Tina4WebSocket1.AutoReconnect := False;    Tina4WebSocket1.Disconnect;    ButtonConnect.Text := 'Connect';  end  else  begin    Tina4WebSocket1.AutoReconnect := True;    Tina4WebSocket1.Connect;    LabelStatus.Text := 'Connecting...';    ButtonConnect.Text := 'Disconnect';  end;end;​procedure TFormPriceFeed.OnWSOpen(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Connected - Receiving prices';​    // Subscribe to price updates    var Sub := TJSONObject.Create;    try      Sub.AddPair('type', 'subscribe');      var Symbols := TJSONArray.Create;      Symbols.Add('BTC-USD');      Symbols.Add('ETH-USD');      Symbols.Add('AAPL');      Symbols.Add('GOOGL');      Symbols.Add('MSFT');      Sub.AddPair('symbols', Symbols);      Tina4WebSocket1.Send(Sub.ToString);    finally      Sub.Free;    end;  end);end;​procedure TFormPriceFeed.OnWSMessage(Sender: TObject; const AMessage: string);begin  TThread.Synchronize(nil, procedure  var    JSON: TJSONObject;    Info: TPriceInfo;  begin    JSON := StrToJSONObject(AMessage);    if not Assigned(JSON) then Exit;    try      var MsgType := JSON.GetValue<String>('type', '');​      if MsgType = 'price' then      begin        var Symbol := JSON.GetValue<String>('symbol', '');        var NewPrice := JSON.GetValue<Double>('price', 0);​        if FPrices.TryGetValue(Symbol, Info) then        begin          Info.PrevPrice := Info.Price;          Info.Price := NewPrice;          Info.Change := NewPrice - Info.PrevPrice;          if Info.PrevPrice > 0 then            Info.ChangePercent := (Info.Change / Info.PrevPrice) * 100          else            Info.ChangePercent := 0;        end        else        begin          Info.Symbol := Symbol;          Info.Price := NewPrice;          Info.PrevPrice := NewPrice;          Info.Change := 0;          Info.ChangePercent := 0;        end;​        Info.LastUpdate := Now;        FPrices.AddOrSetValue(Symbol, Info);        UpdatePriceDisplay;      end;    finally      JSON.Free;    end;  end);end;​procedure TFormPriceFeed.OnWSClose(Sender: TObject; const ACode: Integer;  const AReason: string);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Disconnected - Reconnecting...';    ButtonConnect.Text := 'Connect';  end);end;​procedure TFormPriceFeed.OnWSError(Sender: TObject; const AError: string);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Error: ' + AError;  end);end;​function TFormPriceFeed.GetChangeColor(AChange: Double): string;begin  if AChange > 0 then    Result := '#27ae60'  else if AChange < 0 then    Result := '#e74c3c'  else    Result := '#666';end;​function TFormPriceFeed.GetChangeArrow(AChange: Double): string;begin  if AChange > 0 then    Result := '&#9650;'  // up triangle  else if AChange < 0 then    Result := '&#9660;'  // down triangle  else    Result := '&#9644;'; // dashend;​procedure TFormPriceFeed.UpdatePriceDisplay;var  HTML: TStringBuilder;  Pair: TPair<string, TPriceInfo>;begin  HTML := TStringBuilder.Create;  try    HTML.AppendLine('<div style="font-family: Arial, sans-serif; padding: 15px;">');    HTML.AppendLine('<h2 style="color: #2c3e50;">Live Price Feed</h2>');    HTML.AppendLine('<table style="width: 100%; border-collapse: collapse;">');    HTML.AppendLine('<thead>');    HTML.AppendLine('<tr style="background: #2c3e50; color: white;">');    HTML.AppendLine('  <th style="padding: 10px; text-align: left;">Symbol</th>');    HTML.AppendLine('  <th style="padding: 10px; text-align: right;">Price</th>');    HTML.AppendLine('  <th style="padding: 10px; text-align: right;">Change</th>');    HTML.AppendLine('  <th style="padding: 10px; text-align: right;">%</th>');    HTML.AppendLine('  <th style="padding: 10px; text-align: right;">Updated</th>');    HTML.AppendLine('</tr>');    HTML.AppendLine('</thead>');    HTML.AppendLine('<tbody>');​    for Pair in FPrices do    begin      var Color := GetChangeColor(Pair.Value.Change);      var Arrow := GetChangeArrow(Pair.Value.Change);​      HTML.AppendFormat(        '<tr style="border-bottom: 1px solid #eee;">' +        '  <td style="padding: 10px; font-weight: bold;">%s</td>' +        '  <td style="padding: 10px; text-align: right; font-size: 1.1em;">$%.2f</td>' +        '  <td style="padding: 10px; text-align: right; color: %s;">%s %.2f</td>' +        '  <td style="padding: 10px; text-align: right; color: %s;">%.2f%%</td>' +        '  <td style="padding: 10px; text-align: right; color: #999; font-size: 0.85em;">%s</td>' +        '</tr>',        [Pair.Value.Symbol, Pair.Value.Price, Color, Arrow,         Abs(Pair.Value.Change), Color, Pair.Value.ChangePercent,         FormatDateTime('hh:nn:ss', Pair.Value.LastUpdate)]);    end;​    HTML.AppendLine('</tbody>');    HTML.AppendLine('</table>');​    if FPrices.Count = 0 then      HTML.AppendLine('<p style="color: #999; text-align: center; padding: 40px;">Waiting for price data...</p>');​    HTML.AppendLine('</div>');​    HTMLRender1.HTML.Text := HTML.ToString;  finally    HTML.Free;  end;end;​end.

unit NotificationForm;​interface​uses  System.SysUtils, System.Types, System.Classes, System.JSON,  System.Generics.Collections,  FMX.Types, FMX.Controls, FMX.Forms, FMX.StdCtrls, FMX.Layouts,  FMX.Objects,  Tina4WebSocketClient, Tina4HTMLRender, Tina4Core;​type  TNotification = record    ID: string;    Title: string;    Message: string;    NotifType: string;  // info, warning, error    Timestamp: TDateTime;    IsRead: Boolean;  end;​  TFormNotifications = class(TForm)    Tina4WebSocket1: TTina4WebSocketClient;    HTMLRender1: TTina4HTMLRender;    LabelBadge: TLabel;    LabelStatus: TLabel;    TimerFade: TTimer;    procedure FormCreate(Sender: TObject);    procedure FormDestroy(Sender: TObject);    procedure TimerFadeTimer(Sender: TObject);  private    FNotifications: TList<TNotification>;    procedure OnWSOpen(Sender: TObject);    procedure OnWSMessage(Sender: TObject; const AMessage: string);    procedure OnWSClose(Sender: TObject; const ACode: Integer;      const AReason: string);    procedure RefreshDisplay;    procedure UpdateBadge;    procedure MarkAsRead(const AID: string);    function GetTypeColor(const AType: string): string;    function GetTypeIcon(const AType: string): string;    function UnreadCount: Integer;  end;​var  FormNotifications: TFormNotifications;​implementation​{$R *.fmx}​procedure TFormNotifications.FormCreate(Sender: TObject);begin  FNotifications := TList<TNotification>.Create;​  Tina4WebSocket1.URL := 'wss://api.example.com/notifications';  Tina4WebSocket1.AutoReconnect := True;  Tina4WebSocket1.ReconnectInterval := 5000;  Tina4WebSocket1.PingInterval := 30000;  Tina4WebSocket1.OnConnected := OnWSOpen;  Tina4WebSocket1.OnMessage := OnWSMessage;  Tina4WebSocket1.OnDisconnected := OnWSClose;​  // Timer checks for notifications older than 10 seconds  TimerFade.Interval := 2000;  TimerFade.Enabled := True;​  // Register click handler for mark-as-read  HTMLRender1.RegisterObject('Notif', Self);​  Tina4WebSocket1.Connect;  LabelStatus.Text := 'Connecting...';  UpdateBadge;  RefreshDisplay;end;​procedure TFormNotifications.FormDestroy(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Disconnect;  FNotifications.Free;end;​procedure TFormNotifications.OnWSOpen(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Connected';  end);end;​procedure TFormNotifications.OnWSMessage(Sender: TObject; const AMessage: string);begin  TThread.Synchronize(nil, procedure  var    JSON: TJSONObject;    Notif: TNotification;  begin    JSON := StrToJSONObject(AMessage);    if not Assigned(JSON) then Exit;    try      var MsgType := JSON.GetValue<String>('type', '');​      if (MsgType = 'notification') or (MsgType = 'info') or         (MsgType = 'warning') or (MsgType = 'error') then      begin        Notif.ID := JSON.GetValue<String>('id', GetGUID);        Notif.Title := JSON.GetValue<String>('title', 'Notification');        Notif.Message := JSON.GetValue<String>('message', '');        Notif.NotifType := JSON.GetValue<String>('type', 'info');        Notif.Timestamp := Now;        Notif.IsRead := False;​        FNotifications.Insert(0, Notif);  // Newest first        UpdateBadge;        RefreshDisplay;      end;    finally      JSON.Free;    end;  end);end;​procedure TFormNotifications.OnWSClose(Sender: TObject; const ACode: Integer;  const AReason: string);begin  TThread.Synchronize(nil, procedure  begin    LabelStatus.Text := 'Reconnecting...';  end);end;​procedure TFormNotifications.TimerFadeTimer(Sender: TObject);var  Changed: Boolean;  I: Integer;begin  Changed := False;​  // Remove unread notifications older than 10 seconds  for I := FNotifications.Count - 1 downto 0 do  begin    var Notif := FNotifications[I];    if (not Notif.IsRead) and (SecondsBetween(Now, Notif.Timestamp) > 10) then    begin      Notif.IsRead := True;      FNotifications[I] := Notif;      Changed := True;    end;  end;​  if Changed then  begin    UpdateBadge;    RefreshDisplay;  end;end;​procedure TFormNotifications.MarkAsRead(const AID: string);var  I: Integer;begin  for I := 0 to FNotifications.Count - 1 do  begin    var Notif := FNotifications[I];    if Notif.ID = AID then    begin      Notif.IsRead := True;      FNotifications[I] := Notif;​      // Notify the server      if Tina4WebSocket1.IsConnected then      begin        var Msg := TJSONObject.Create;        try          Msg.AddPair('type', 'mark_read');          Msg.AddPair('id', AID);          Tina4WebSocket1.Send(Msg.ToString);        finally          Msg.Free;        end;      end;​      UpdateBadge;      RefreshDisplay;      Break;    end;  end;end;​function TFormNotifications.UnreadCount: Integer;var  I: Integer;begin  Result := 0;  for I := 0 to FNotifications.Count - 1 do    if not FNotifications[I].IsRead then      Inc(Result);end;​procedure TFormNotifications.UpdateBadge;var  Count: Integer;begin  Count := UnreadCount;  if Count > 0 then  begin    LabelBadge.Text := Count.ToString;    LabelBadge.Visible := True;  end  else    LabelBadge.Visible := False;end;​function TFormNotifications.GetTypeColor(const AType: string): string;begin  if AType = 'error' then    Result := '#e74c3c'  else if AType = 'warning' then    Result := '#f39c12'  else    Result := '#3498db';end;​function TFormNotifications.GetTypeIcon(const AType: string): string;begin  if AType = 'error' then    Result := '&#10060;'  else if AType = 'warning' then    Result := '&#9888;'  else    Result := '&#8505;';end;​procedure TFormNotifications.RefreshDisplay;var  HTML: TStringBuilder;  Notif: TNotification;begin  HTML := TStringBuilder.Create;  try    HTML.AppendLine('<div style="font-family: Arial, sans-serif; padding: 10px;">');    HTML.AppendLine('<h3 style="color: #2c3e50;">Notifications</h3>');​    if FNotifications.Count = 0 then    begin      HTML.AppendLine('<p style="color: #999; text-align: center; padding: 30px;">No notifications</p>');    end    else    begin      for Notif in FNotifications do      begin        var Color := GetTypeColor(Notif.NotifType);        var Icon := GetTypeIcon(Notif.NotifType);        var Opacity: string;        if Notif.IsRead then          Opacity := '0.5'        else          Opacity := '1.0';​        HTML.AppendFormat(          '<div style="border-left: 4px solid %s; padding: 10px 15px; margin: 8px 0; ' +          '  background: white; border-radius: 0 4px 4px 0; opacity: %s; ' +          '  box-shadow: 0 1px 3px rgba(0,0,0,0.1); cursor: pointer;" ' +          '  onclick="Notif:MarkAsRead(''%s'')">' +          '  <div style="display: flex; justify-content: space-between;">' +          '    <strong>%s %s</strong>' +          '    <small style="color: #999;">%s</small>' +          '  </div>' +          '  <p style="margin: 5px 0 0; color: #555;">%s</p>' +          '  %s' +          '</div>',          [Color, Opacity, Notif.ID, Icon, Notif.Title,           FormatDateTime('hh:nn:ss', Notif.Timestamp),           Notif.Message,           IfThen(not Notif.IsRead,             '<small style="color: ' + Color + ';">Click to mark as read</small>', '')]);      end;    end;​    HTML.AppendLine('</div>');    HTMLRender1.HTML.Text := HTML.ToString;  finally    HTML.Free;  end;end;​end.

// Wrong -- will crashprocedure TForm1.OnWSMessage(Sender: TObject; const AMessage: string);begin  Label1.Text := AMessage;  // Access violation!end;​// Rightprocedure TForm1.OnWSMessage(Sender: TObject; const AMessage: string);begin  TThread.Synchronize(nil, procedure  begin    Label1.Text := AMessage;  end);end;

procedure TForm1.OnWSOpen(Sender: TObject);begin  TThread.Synchronize(nil, procedure  begin    // This runs on every connect, including reconnects    Tina4WebSocket1.Send('{"type": "subscribe", "channel": "updates"}');  end);end;

procedure TForm1.OnWSMessage(Sender: TObject; const AMessage: string);var  JSON: TJSONObject;begin  JSON := StrToJSONObject(AMessage);  if not Assigned(JSON) then Exit;  try    // Extract values here    var Name := JSON.GetValue<String>('name', '');    // Use the values...  finally    JSON.Free;  // Always free  end;end;

procedure TForm1.FormDestroy(Sender: TObject);begin  Tina4WebSocket1.AutoReconnect := False;  // Stop reconnection first  if Tina4WebSocket1.IsConnected then    Tina4WebSocket1.Disconnect;end;