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Keesver

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Everything posted by Keesver

  1. Hello, I'm using a TIdHTTPProxyServer component to create a proxy server for our application. Unfortunately the proxy server frequently blocks communication. As a test, I put a TIdHTTPProxyServer on a form and use this proxy i.c.m. with a call to a RemObjects server. I added an interceptor to log the output of the proxy component (see attachment). From this file I can see that the proxy server hangs on this call (see also attachment): 127.0.0.1:12719 Stat Connected. 127.0.0.1:12719 Recv 12/08/2022 15:59:26: POST http://service.a-dato.net:80/handler.ashx/binmessage HTTP/1.1 Host: service.a-dato.net Keep-Alive: 300 Proxy-Connection: keep-alive User-Agent: Remoting SDK Content-Type: text/html Content-Length: 17 Accept-Encoding: identity Connection: keep-alive }Ðm�BÐ�@�Fx8‘¯®V� (data is binary) Comments: The first call to the server succeeds The problem comes on subsequent calls to the server (pressing 'Call service (8081)' multiple times) This problem only occurs when I use 'http' (using 'https' it works) It works when I use no proxy It works when I use another proxy (the second button will use Fiddler as a proxy server) When you run the test application, a logfile is written to 'c:\Temp\Log' I have attached a test application to replicate the problem. Thanks for your support and comments. Kees SimpleProxy.log ProxyTestMain.zip
  2. Keesver

    Vcl to Fmx

    I purchased MIDA some time ago, it did what it had to do. Unfortunately it stopped working because the tool contacts a registration server at startup and this server has been down for a long time now (I think more than 2 years). I could never reach the developer/company behind MIDA. There is another tool that can help out though: INNOVA Solutions - Delphi Code Converter - VCL Form to FireMonkey FMX Form Sorry for bringing the bad news.
  3. Keesver

    Chain of two HttpProxyServer servers

    Hello, We want to add remote support to our application and for this we want to use two idHttpProxyServer's chained together. The first server resides on our public server, the second instance resides on the customers network. This is the code we are using: public server: constructor TRemoteServer.Create(IP: string; Port: Integer); begin IdHTTPProxyServer1 := TIdHTTPProxyServer.Create(nil); IdHTTPProxyServer1.ReuseSocket := rsTrue; IdHTTPProxyServer1.DefaultPort := Port; IdHTTPProxyServer1.OnHTTPBeforeCommand := HTTPBeforeCommandHandler; var handler := IdHTTPProxyServer1.CommandHandlers.Add; handler.Command := 'DEST'; handler.HelpSuperScript := 'Sets caller as a DESTINATION for remote support (usage DEST PIN URL)'; handler.OnCommand := DEST_Handler; if (IP <> '') and (Port <> 0) then begin Writeln('Starting server, binding to: ' + IP + '-' + Port.ToString); var bind := IdHTTPProxyServer1.Bindings.Add; bind.IP := IP; bind.Port := Port; bind.ReuseSocket := rsTrue; end else Writeln('Starting server, default binding'); IdHTTPProxyServer1.Active := True; Writeln('Server running, listening on: ' + IdHTTPProxyServer1.Bindings[0].IP + ' - ' + IdHTTPProxyServer1.Bindings[0].Port.ToString); end; procedure TRemoteServer.DEST_Handler(ASender: TIdCommand); begin Writeln(ASender.RawLine); dest_ip := ASender.Context.Binding.PeerIP; dest_port := ASender.Context.Binding.PeerPort; dest_pin := ASender.Params[0]; dest_url := ASender.Params[1]; Writeln('Address: ' + dest_ip + ' - ' + dest_port.ToString); end; procedure TRemoteServer.HTTPBeforeCommandHandler(AContext: TIdHTTPProxyServerContext); begin if dest_ip <> '' then begin Writeln('Command redirected to DESTINATION: ' + dest_ip + ' - ' + dest_port.ToString); var tempIO := TIdIOHandlerStack.Create(AContext.OutboundClient); tempIO.ReuseSocket := rsTrue; // tempIO.BoundIP := '10.0.2.4'; //IdHTTPProxyServer1.Bindings[0].IP; tempIO.BoundPort := 443; // IdHTTPProxyServer1.Bindings[0].Port; var tempProxy := TIdConnectThroughHttpProxy.Create(AContext.OutboundClient); tempProxy.Enabled := True; tempProxy.Host := dest_ip; tempProxy.Port := dest_port; tempIO.TransparentProxy := tempProxy; AContext.OutboundClient.IOHandler := tempIO; end; end; Client code: procedure TForm1.ConnectToRemote(Connection: string); begin HTTPProxyServer.Active := False; IdTCPClient1.Disconnect; IdTCPClient1.Host := <SERVER IP/URL>; //Connection.Split([':'])[0]; IdTCPClient1.Port := <SERVER PORT>; // Connection.Split([':'])[1].ToInteger; IdTCPClient1.Connect; // Tell server we are there IdTCPClient1.SendCmd('DEST 4444 https://abc.com'); HTTPProxyServer.Bindings.Clear; var bind := HTTPProxyServer.Bindings.Add; bind.IP := IdTCPClient1.Socket.Binding.IP; bind.Port := IdTCPClient1.Socket.Binding.Port; bind.ReuseSocket := rsTrue; HTTPProxyServer.Active := True; end; This setup works when we run both server and client on the same computer. However, when we put the server on a remote computer, it does not work. Should this work, or do we need other means to make this happen? Thanks and regards, Kees
  4. Keesver

    Chain of two HttpProxyServer servers

    I have done some more testing and found that my setup fails because the proxy on the server tries to connect to the local proxy from a different port number/connection. This communication is (logically) blocked by the firewall. I thought this code made the server proxy communicate through the same channel as previously established between client and server: var tempIO := TIdIOHandlerStack.Create(AContext.OutboundClient); tempIO.OnBeforeBind := IOHandlerStack_BeforeBind; tempIO.ReuseSocket := rsTrue; tempIO.BoundPort := IdHTTPProxyServer1.Bindings[0].Port; <== Re-use outbound port from server to prevent blocking by firewall I think this cannot work because the server proxy cannot reach the local proxy through the firewall. The connection between the two proxies must be initiated from the "inside". This is what I'm trying to achieve: Remote <x> Server proxy <x> local (reverse) proxy < > Internal network 'x' = firewall 1. local proxy opens connection with Server proxy 2. local proxy sends 'DEST commend' to register itself with Server proxy 3. Remote queries Server proxy for available clients 4. Remote sends 'REMOTE' command to server to to connect to a certain 'DEST' 5. Remote starts HTTP communication with given 'DEST' ==> here it failes because server proxy opens new channel to local proxy Maybe my setup will never work and should I follow a very different path. Hints and tips more than welcome. Greetings
  5. Keesver

    Chain of two HttpProxyServer servers

    Thanks for the tips, I'll try to implement them.
  6. Keesver

    Chain of two HttpProxyServer servers

    Update: It works when I turn off the Firewall on my internet router (one step forward). Apparently there are other ports/channels needed to make a HTTPProxy work? Investigating......
  7. Keesver

    Chain of two HttpProxyServer servers

    There is no error, the call from the remote server back into the client simply does not reach it's destination. The remote server does receive a HTTPBeforeCommand event, this line is being called on the server: Writeln('Command redirected to DESTINATION: ' + dest_ip + ' - ' + dest_port.ToString); The connection between client and server seems to be working. When I use telnet to connect to the server, I do get a response from the server when I execute the 'HELP' command. Similar the call to SendCmd('DEST') in our client returns '200 OK'. Also 'netstat' shows an active connection between client and server. Maybe my question is: what do I need more that an active (TCP) connection between client and server? Does the HTTP Proxy server requires additional channels to be opened to make this work? Or should the single channel suffice?
  8. Keesver

    Interbase Int64 support

    Which data type should be used for Int64 values? I tried Int64 and bigint, both return an error: create table Test(ID Int64) create table Test(ID bigint) Error message: Project IBTest.exe raised exception class EIBNativeException with message '[FireDAC][Phys][IB]Dynamic SQL Error SQL error code = -607 Invalid command Specified domain or source column does not exist'. Thanks
  9. Keesver

    Interbase Int64 support

    ok, will do. I was trying to use FDBatchMove + FDBatchMoveSQLWriter to import a table from MSSql into Interbase. The internal table generator uses 'Int64' for such fields, am I using the wrong generator? Greetings, Kees
  10. According to this document ISO 8601 - Wikipedia Monday 29 December 2008 is written as "2009-W01-1" when a week number is used. As you can see, instead of 2008, the value 2009 is shown. What date formatting function supports this in Delphi? Thanks
  11. Keesver

    ISO8901: Week numbers and year

    WeekOfTheYear is working. I was looking for something like DateTimeToString which supports displaying dates like above using week numbers (aka "2009-W01")
  12. Hello, We are looking at safely handling queued calls. The problem is that under some circumstances the object used inside the queued method is freed before the method gets executed. This raises an exception. Can we use this construct to fix it: type ITest = interface ['{10DD63EA-490E-45D5-9250-72AEB1FF6D19}'] function GetName: string; procedure SetName(const Value: string); end; TTest = class(TInterfacedObject, ITest) protected FName: string; function GetName: string; procedure SetName(const Value: string); end; TObjectWithTest = class private FTest: ITest; public constructor Create(const AInterface: ITest); procedure QueueCallSafe([weak]AInterface: ITest); function GetTest: ITest; end; implementation procedure TObjectWithTest.QueueCallSafe([weak]AInterface: ITest); begin TThread.ForceQueue(nil, procedure begin if AInterface = nil then ShowMessage('nil') else ShowMessage('not nil'); end); end; procedure TForm1.Button3Click(Sender: TObject); begin var obj := TObjectWithTest.Create(TTest.Create); obj.QueueCallSafe(obj.GetTest); // Free object --> [weak] reference will be cleared (no exception!!) obj.Free; end;
  13. Can you explain why supports/queryinterface can't be used?
  14. Keesver

    SmartScreen troubles

    We are using EV (extended validation) code signing certificates to add trust, this should prevent Windows from asking additional confirmation when installing our software. In addition, when the certificate is renewed, trust statistics are kept because the new certificate is recognized as being the same as the 'old' one. Requesting such a certificate requires extra steps during the certification process. (I can send you an installation url if you want to see how this works out)
  15. Keesver

    Android : EGL PBuffer Surface Errcode : 12297

    This seems to be related: 6546 – EglCreateWindowSurface failed with error 12297 (0x3009) (xamarin.github.io)
  16. Keesver

    Learning Delphi

    Hello, We extended our team with new (inexperienced) developers. What would be the best way to teach them Delphi? Greetings, Kees
  17. Keesver

    Learning Delphi

    Thanks everyone for your comments. Enough information to look into. The Delphi language guide looks like a good starting point, this is something the person can do by themselves. @David: your comments include a good list of topics that need to be touched in the learnings. Greetings, Kees Vermeulen
  18. Keesver

    Learning Delphi

    VCL and FMX and Oxygene (much of our code is reused in our web application using WebAssembly)
  19. Keesver

    Learning Delphi

    New to Delphi, they have completed their bachelor's degree in software engineering.
  20. Keesver

    Retrieve Delphi version used from within an App?

    MadExcept includes the name of the Delphi compiler in their reports. I checked their code, they use a defines to get to the name of the compiler: {$ifdef ver340} // 'compiled with', 'Delphi 10.4 Sydney' {$endif}
  21. I can remember that Remy Lebeau posted some messages on this. Searching for "openssl android remy" will bring you to StackOverflow.
  22. Keesver

    Thinfinity VirtualUI - cloud-based conversion

    We run on Azure...
  23. Keesver

    Thinfinity VirtualUI - cloud-based conversion

    We are preparing to release our software using Thinfinity as an alternative to the desktop version. We did some tests and this showed it worked pretty good. We do want to change our application to make it look more 'web' alike. This means hiding the menu for example. Can't tell yet how performant it will be. You do need a server capable of handling the number of concurrent users of your application though. We were told RDS licenses are not required because Thinfinity does not use the RDS services (which I can confirm after running multiple sessions on the same server without such license). I can't say if Microsoft agrees on this....
  24. Got my copy as well, thanks!
  25. Keesver

    Per monitor DPI awareness - how to prevent flickering?

    A 'trick' we used to improve the behavior while moving windows between monitors was to create a bitmap when the user starts dragging and use this image while dragging. It works very good and only when the user releases the mouse you need to do rescaling.
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