SSE example

(* _ _ * | |__ _ __ ___ ___ | | __ * | '_ \| '__/ _ \ / _ \| |/ / * | |_) | | | (_) | (_) | < * |_.__/|_| \___/ \___/|_|\_\ * * Microframework which helps to develop web Pascal applications. * * Copyright (c) 2012-2020 Silvio Clecio * * Brook framework is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Brook framework is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Brook framework; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA *) program httpsrvsse; {$MODE DELPHI} {$WARN 5024 OFF} uses SysUtils, Classes, BrookHTTPRequest, BrookHTTPResponse, BrookHTTPServer; const PAGE = Concat( '', sLineBreak, '', sLineBreak, '', sLineBreak, 'SSE example', sLineBreak, '

Please wait ...

', sLineBreak, '', sLineBreak, '', sLineBreak, '' ); SSE_HEADER = 'text/event-stream'; IGNORED_ERROR = 'Connection was closed while sending response body.'; type { TSSEStream } TSSEStream = class(TStream) private FCount: Cardinal; public function Read(var ABuffer; ACount: LongInt): LongInt; override; end; { THTTPServer } THTTPServer = class(TBrookHTTPServer) protected procedure DoError(ASender: TObject; AException: Exception); override; procedure DoRequest(ASender: TObject; ARequest: TBrookHTTPRequest; AResponse: TBrookHTTPResponse); override; end; { TSSEStream } function TSSEStream.Read(var ABuffer; ACount: LongInt): LongInt; var VMsg: string; begin if FCount = 0 then VMsg := Concat('retry: 1000', sLineBreak) else begin VMsg := Concat('data: ', FCount.ToString, sLineBreak, sLineBreak); Sleep(1000); end; Inc(FCount); Result := Length(VMsg); Move(VMsg[1], ABuffer, Result); end; { THTTPServer } procedure THTTPServer.DoError(ASender: TObject; AException: Exception); begin if AException.Message.TrimRight <> IGNORED_ERROR then inherited DoError(ASender, AException); end; procedure THTTPServer.DoRequest(ASender: TObject; ARequest: TBrookHTTPRequest; AResponse: TBrookHTTPResponse); begin if ARequest.Headers['Accept'] = SSE_HEADER then begin AResponse.Headers.Add('Access-Control-Allow-Origin', '*'); AResponse.Headers.Add('Content-Type', SSE_HEADER); AResponse.SendStream(TSSEStream.Create, 200); end else AResponse.Send(PAGE, 'text/html; charset=utf-8', 200); end; begin with THTTPServer.Create(nil) do try NoFavicon := True; Threaded := True; Open; if not Active then Exit; WriteLn('Server running at http://localhost:', Port); ReadLn; finally Free; end; end.