Indy 10 TidTCPServer encoding characters - delphi-xe2

Question

Indy 10 Sockets . TIdTCPServer component . There is a client program that connects to a server program using sockets. Everything working , there is no trouble in communicating , but I can not send a string with special characters from the server to the client. When sending a string like this:
AContext.Connection.IOHandler.WriteLn ( ' Usuário não existe' ) ;
Client receives the string :
usu?rio n?o existe
Anyone who has ever worked with this component knows how do I set the encoding correctly and to send this special string to the client ?

Answer 1

By default, Indy uses 7bit ASCII as its character encoding (for compatibility with various Internet protocols). To use a different character encoding, you need to either:
set the IOHandler.DefStringEncoding property before doing any reading/writing. The string-based I/O methods will then use this encoding by default.
// note: use TIdTextEncoding.UTF8 if not using Indy 10.6 or later...
AContext.Connection.IOHandler.DefStringEncoding := IndyTextEncoding_UTF8;
use the optional AByteEncoding parameter of the various string-based I/O methods, including WriteLn().
// note: use TIdTextEncoding.UTF8 if not using Indy 10.6 or later...
AContext.Connection.IOHandler.WriteLn('Usuário não existe', IndyTextEncoding_UTF8);
Needless to say, the client will also have to use an equivalent encoding when reading the server's data so it can decode the transmitted bytes back to Unicode. For example:
// note: use TIdTextEncoding.UTF8 if not using Indy 10.6 or later...
Client.IOHandler.DefStringEncoding := IndyTextEncoding_UTF8;
Or:
// note: use TIdTextEncoding.UTF8 if not using Indy 10.6 or later...
S := Client.IOHandler.ReadLn(IndyTextEncoding_UTF8);