The Telegram Bot API supports several forms of input:
We support GET and POST HTTP methods. We support four ways of passing parameters in Bot API requests:
- URL query string
- application/x-www-form-urlencoded
- application/json (except for uploading files)
- multipart/form-data (use to upload files)
You are using the last option.
Indy 9 does not support Delphi 2009+ or Unicode. All uses of string are assumed to be AnsiString, which is the case in Delphi 7. Any AnsiString you add to TIdMultipartFormDataStream or TStrings, even a UTF-8 encoded one, will be transmitted as-is by TIdHTTP. However, there is no option to specify to the server that the string data is actually using UTF-8 as a charset. But, according to the docs:
All queries must be made using UTF-8.
So not specifying an explicit charset might not be problem.
If you still have problems with multipart/form-data, then consider using application/x-www-form-urlencoded (use TIdHTTP.Post(TStrings)) or application/json (use TIdHTTP.Post(TStream)) instead:
procedure TBotThread.SendMessage(ChatID: String; Text: WideString; parse_mode: string; disable_notification: boolean);
var
Params: TStringList;
LHandler: TIdSSLIOHandlerSocket;
begin
if FShowBotLink then
Text := Text + LineBreak + FBotUser;
Params := TStringList.Create;
try
Params.Add('chat_id=' + UTF8Encode(ChatID));
if parse_mode <> '' then
Params.Add('parse_mode=' + UTF8Encode(parse_mode));
if disable_notification then
Params.Add('disable_notification=true')
else
Params.Add('disable_notification=false');
Params.Add('disable_web_page_preview=true');
Params.Add('text=' + UTF8Encode(Text));
LHandler := TIdSSLIOHandlerSocket.Create(nil);
try
LHandler.SSLOptions.Method := sslvTLSv1;
LHandler.SSLOptions.Mode := sslmClient;
FidHttpSend.HandleRedirects := true;
FidHttpSend.ReadTimeout := 30000;
FidHttpSend.IOHandler := LHandler;
try
try
FidHttpSend.Post(BaseUrl + API + '/sendmessage', Params, TStream(nil));
except
on E: EIdHTTPProtocolException do
begin
if E.ReplyErrorCode = 403 then
begin
WriteToLog('Bot was blocked by the user');
end;
end;
end;
finally
FidHttpSend.IOHandler := nil;
end;
finally
LHandler.Free;
end;
finally
Params.Free;
end;
end;
procedure TBotThread.SendMessage(ChatID: String; Text: WideString; parse_mode: string; disable_notification: boolean);
var
Params: TStringStream;
LHandler: TIdSSLIOHandlerSocket;
function JsonEncode(const wStr: WideString): string;
var
I: Integer;
Ch: WideChar;
begin
// JSON uses UTF-16 text, so no need to encode to UTF-8...
Result := '';
for I := 1 to Length(wStr) do
begin
Ch := wStr[i];
case Ch of
#8: Result := Result + '\b';
#9: Result := Result + '\t';
#10: Result := Result + '\n';
#12: Result := Result + '\f';
#13: Result := Result + '\r';
'"': Result := Result + '\"';
'\': Result := Result + '\\';
'/': Result := Result + '\/';
else
if (Ord(Ch) >= 32) and (Ord(Ch) <= 126) then
Result := Result + AnsiChar(Ord(wStr[i]))
else
Result := Result + '\u' + IntToHex(Ord(wStr[i]), 4);
end;
end;
end;
begin
if FShowBotLink then
Text := Text + LineBreak + FBotUser;
Params := TStringStream.Create('');
try
Params.WriteString('{');
Params.WriteString('chat_id: "' + JsonEncode(ChatID) + '",');
if parse_mode <> '' then
Params.WriteString('parse_mode: "' + JsonEncode(parse_mode) + '",')
if disable_notification then
Params.WriteString('disable_notification: True,')
else
Params.WriteString('disable_notification: False,');
Params.WriteString('disable_web_page_preview: True,');
Params.WriteString('text: "' + JsonEncode(Text) + '"');
Params.WriteString('}');
Params.Position := 0;
LHandler := TIdSSLIOHandlerSocket.Create(nil);
try
LHandler.SSLOptions.Method := sslvTLSv1;
LHandler.SSLOptions.Mode := sslmClient;
FidHttpSend.HandleRedirects := true;
FidHttpSend.ReadTimeout := 30000;
FidHttpSend.IOHandler := LHandler;
try
try
FidHttpSend.Request.ContentType := 'application/json';
FidHttpSend.Post(BaseUrl + API + '/sendmessage', Params, TStream(nil));
except
on E: EIdHTTPProtocolException do
begin
if E.ReplyErrorCode = 403 then
begin
WriteToLog('Bot was blocked by the user');
end;
end;
end;
finally
FidHttpSend.IOHandler := nil;
end;
finally
LHandler.Free;
end;
finally
Params.Free;
end;
end;
That being said, your function's Text parameter is a WideString, which uses UTF-16, so you should be able to send any Unicode text, including emojis. If you are trying to generate text in your code, just make sure you UTF-16 encode any non-ASCII characters correctly. For example, codepoint U+1F601 GRINNING FACE WITH SMILING EYES is wide chars $D83D $DE01 in UTF-16:
var
Text: WideString;
Text := 'hi ' + #$D83D#$DE01; // 'hi '
SendMessage('@channel', Text, 'Markup', False);
Alternatively, you can use HTML in your text messages, so you can encode non-ASCII characters using numerical HTML entities. According to the docs:
All numerical HTML entities are supported.
Codepoint U+1F601 is numeric entity $#128513; in HTML:
var
Text: WideString;
Text := 'hi $#128513;'; // 'hi '
SendMessage('@channel', Text, 'HTML', False);
