Using TCustomHTTPApplication in GUI Application
lazarus / 38-Networking and Web Programming

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d.ioannidis · 2023-09-11 08:30

Hi,

  I wanted to see if TCustomHTTPApplication can be used in GUI
Application's and the following code is working .  As I'm not too
familiar with the LCL, can someone review the code and see if there is
a catch or bad practice ?

EDIT: Free Pascal 3.2.2 / Lazarus 2.2.6

TCustomHTTPApplication  in a Thread
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
uHTTPSrv; {$mode ObjFPC}{$H+} interface uses  Classes, SysUtils,
custhttpapp; type   { TWebServerThread }   TWebServerThread =
class(TThread)  private    FHTTPApp: TCustomHTTPApplication; 
protected    procedure Execute; override;  public    constructor
Create(APort: word);    destructor Destroy; override;    procedure
TerminateHTTPApp;  end; implementation { TWebServerThread } procedure
TWebServerThread.Execute;begin  FHTTPApp.Run;  while not (Terminated
and FHTTPApp.Terminated) do Sleep(1);end; constructor
TWebServerThread.Create(APort: word);begin  FHTTPApp :=
TCustomHTTPApplication.Create(nil);  FHTTPApp.Port := (APort); 
FHTTPApp.Threaded := True;  FHTTPApp.Initialize;  inherited
Create(False);end; destructor TWebServerThread.Destroy;begin 
FreeAndNil(FHTTPApp);  inherited Destroy;end; procedure
TWebServerThread.TerminateHTTPApp;begin  if Assigned(FHTTPApp) then  
FHTTPApp.Terminate;end; end.


Managing TCustomHTTPApplication  from main form thread.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
 ........, uHTTPSrv,  HTTPDefs, httproute;     { TfrmAppMain }  
TfrmAppMain = class(TForm)    .........    procedure
FormCreate(Sender: TObject);    .........  private    FWebServer:
TWebServerThread;    procedure StartHTTPApiServer;    procedure
StopHTTPApiServer;  public procedure TfrmAppMain.FormCreate(Sender:
TObject);begin   HTTPRouter.RegisterRoute('/', TDefaultRoute, True); 
HTTPRouter.RegisterRoute('/echo/:echo', TEchoRoute); end; procedure
TfrmAppMain.StartHTTPApiServer;begin  if not Assigned(FWebServer)
then    FWebServer := TWebServerThread.Create(22100);end; procedure
TfrmAppMain.StopHTTPApiServer;begin  if Assigned(FWebServer) then 
begin    FWebServer.TerminateHTTPApp;    FWebServer.Terminate;   
FWebServer.WaitFor();    FreeAndNil(FWebServer);  end;end;  


The routes
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   {
TDefaultRoute }   TDefaultRoute = class(TRouteObject)    procedure
HandleRequest(ARequest: TRequest; AResponse: TResponse); override; 
end;   { TEchoRoute }   TEchoRoute = class(TRouteObject)    procedure
HandleRequest(ARequest: TRequest; AResponse: TResponse); override; 
end; { TDefaultRoute } procedure TDefaultRoute.HandleRequest(ARequest:
TRequest; AResponse: TResponse);begin  if ARequest.URI <> '/' then 
begin    AResponse.Code := 404;    AResponse.CodeText := 'Not Found'; 
end  else  begin    AResponse.Content := ApplicationName;   
AResponse.Code := 200;    AResponse.CodeText := 'OK';   
AResponse.ContentLength := Length(AResponse.Content);  end;end; {
TEchoRoute } procedure TEchoRoute.HandleRequest(ARequest: TRequest;
AResponse: TResponse);begin  AResponse.Content :=
ARequest.RouteParams['echo'];  AResponse.Code := 200; 
AResponse.CodeText := 'OK';  AResponse.ContentLength :=
Length(AResponse.Content);end; 
regards,

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Leledumbo · 2023-09-12 09:04

Quote from: d.ioannidis on September 11, 2023, 10:30:53 amAs I'm not
too familiar with the LCL, can someone review the code and see if
there is a catch or bad practice ?
Don't use the CustomXXX classes directly, they're meant to be
extended. That's what THTTPApplication is for if you want something
out of the box.
Apart from that, you're creating the thread UNsuspended, meaning it
will directly call Execute after creation. Just be aware and ensure
route registration is executed before calling FHTTPApp.Run as I don't
think you can register routes on the fly, they might be cached.