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I'm about to write a small server using QTcpServer which is intended to be connected by e. g. a telnet client. Only text will be sent.

Qt's fortune cookie server example uses a QDataStream to send text via the following code using a QTcpSocket:

QByteArray block;
QDataStream out(&block, QIODevice::WriteOnly);
out.setVersion(QDataStream::Qt_5_10);
out << "Some Text";
socket->write(block);

If one does not want to send binary data, is there any drawback to send Unicode data directly (everyone involved knows we're using UTF-8) like so:

socket->write(QString::fromUtf8("Some text").toUtf8);

?

Tobias Leupold
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  • In both cases you're passing `QByteArray` as argument, so there shouldn't be any diffrence. If you want to send only text, you can use `QTextStream` instead. – Rhathin Sep 04 '18 at 13:53
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    The main advantage of `QDataStream` is that you don't have to care about serialization. otherwise you would have to do message seperation yourself – Felix Sep 04 '18 at 15:57

1 Answers1

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There are no drawbacks to sending UTF-8 data directly, but you need to have some means of separating the packets (units) of data on the receiving end. If it's all text, it'd be done by splitting the incoming data into lines at the receiving end. QDataStream doesn't care about any of it and, at the wire level, sends a 32-bit length of the sent string of bytes, followed by those bytes. So there's never any ambiguity as to how long the packet's payload is, no matter its contents: it could even be 0-bytes long.

Kuba hasn't forgotten Monica
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