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Hi all. I need to implement an OPC UA Server in a Delphi program. Actually, I've used an external QT C++ application to do OPC UA things but is complex to maintain changes in the server and share an interface between this external program and the main program written with Delphi and I would like to know if there is a valid native Delphi library to use, better if open-source, but this is not mandatory. Thank you for your suggestions.

Hi all, First of all, I apologise if what is required is poorly described, but unfortunately I know very little about networks and their knowledge. But let's get down to facts. In an industrial machine control application, I have inserted a server, a TCP/IP server based on JSON messages, which allows the connection of several clients at the same time and enables motor movement commands to be executed or information to be retrieved from the system. A client programme connects to the server and from then on can do anything with the device it has connected to. At this point, security problems arise, especially for the operator standing at the machine, since a malicious client intruding into the network could trigger dangerous operations for the operator standing near the machine and unaware that someone unauthorised has taken control of it remotely. Now I have been asked to add a security layer, but as a complete ignoramus on the subject, I deal mainly with compilers of languages and UI environments and not with networks, I was wondering how to add a system of certification and authorisation of the client to the server connection. For the client I use python while the server is done with Indy 10 using TIdTCPServer. Thank you in advance for any suggestions and help. Best regards Silverio

I am trying to connect with web-browser to Indy HTTP server runing on https://127.0.0.1:4567. I have read many tutorials and some of them are interesting, like: 1. https://mikejustin.wordpress.com/2019/06/14/how-to-lets-encrypt-certificates-with-indy-http-server/ 2. https://synaptica.info/en/2016/09/21/build-your-own-https-server-with-delphi/ I have created self signed certificates with help of this example tutorial: https://github.com/glenkleidon/DelphiCertAuth As a passphrase for testing I used "123456". After that I have installed newly generated file root_cert.crt in Trusted Root CA in Windows (using "WinKey+R" and certmgr.msc) In my code I have set: ... // create IOHandler for OpenSSL IdServerIOHandlerSSLOpenSSL1.SSLOptions.CertFile := 'mycomputerCertificate.pem'; IdServerIOHandlerSSLOpenSSL1.SSLOptions.KeyFile := 'mycomputerPrivateKey.pem'; IdServerIOHandlerSSLOpenSSL1.SSLOptions.RootCertFile := 'certificateAuthorityCertificate.pem'; IdServerIOHandlerSSLOpenSSL1.SSLOptions.Mode := sslmServer; IdServerIOHandlerSSLOpenSSL1.SSLOptions.SSLVersions := [sslvTLSv1, sslvTLSv1_1, sslvTLSv1_2]; ... procedure TForm1.IdServerIOHandlerSSLOpenSSL1GetPassword(var Password: string); begin Password := '123456'; end; ... procedure TForm1.IdHTTPServer1QuerySSLPort(APort: Word; var VUseSSL: Boolean); // This will not be called when the request is a HTTPS request // It facilitates the use of the server for testing via HTTP://localhost:8080 (i.e. without SSL) begin VUseSSL := (APort <> 8080); end; ... function TForm1.IdServerIOHandlerSSLOpenSSL1VerifyPeer(Certificate: TIdX509; AOk: Boolean; ADepth, AError: Integer): Boolean; begin if ADepth = 0 then Result := AOk else Result := True; end; ... Unfortunately, when I try to connect to https://127.0.0.1:4567 I get an warning (check image). In application I can see messages and exception raised: IdServerIOHandlerSSLOpenSSL1StatusInfo(const AMsg: string); AMsg := SSL status: "before/accept initialization"; AMsg := SSL status: "before/accept initialization"; AMsg := SSL status: "SSLv3 read client hello A"; AMsg := SSL status: "SSLv3 write server hello A"; AMsg := SSL status: "SSLv3 write certificate A"; AMsg := SSL status: "SSLv3 write server done A"; AMsg := SSL status: "SSLv3 flush data"; AMsg := SSL status: "SSLv3 read client certificate A"; AMsg := SSL status: "SSLv3 read client key exchange A"; AMsg := SSL status: "error"; 127.0.0.1:55810 Stat Disconnected. IdHTTPServer1Exception(AContext: TIdContext; AException: Exception); EIdOSSLUnderlyingCryptoError: Error accepting connection with SSL. error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown Am I doing something wrong or I am missing something? Why I can't connect to IP address without warning?

Hi all Delphier , good morning 😀😀 i have rest firemonkey app ,server , client im trying to check if the server is up or down from the client side using the code below , the code work fine , but when i run it its freeze the app for a while is there any proper way to do this ,thank you ,🤓☺️ try RequestLogin.Execute; if FrmLogin.RequestLogin.Response.Status.Success then begin showmessage ('server up') do something ..... end else except on e : exception do begin showmessage (' server down.... go home ') end end;

The Daraja HTTP Framework is a free open source library for Object Pascal (Free Pascal 3.0.4, Delphi 2009+), based on the stand-alone HTTP server component in Internet Direct (Indy). The 1.2.5 release improves UTF-8 support for Free Pascal by “using” the LazUTF8 unit. More information Home page: https://www.habarisoft.com/daraja_framework.html API documentation: https://www.habarisoft.com/daraja_framework/1.2/docs/api/ Getting started PDF: https://www.habarisoft.com/daraja_framework/1.2/docs/DarajaFrameworkGettingStarted.pdf GitHub: https://github.com/michaelJustin/daraja-framework Wiki: https://github.com/michaelJustin/daraja-framework/wiki