QWebSockets is a pure Qt implementation of WebSockets - both client and server. It is implemented as a Qt source code module (.pri file), that can easily be embedded into existing Qt projects. It has no other dependencies that Qt.
- Text and binary sockets
- Frame-based and message-based signals
- Works through proxies
- Strict Unicode checking
Non-characters (according Unicode Standard 6.2) are rejected by QWebSockets, even if the UTF-8 sequence is valid.
The WebSocket specification is talking about Valid UTF-8 codes and sequences. Strictly speaking, UTF-xx encodings are reversible. That means, that the 66 non-character codes (including U+FFFE and U+FFFF), are valid UTF-8, and hence are perfectly acceptable within WebSocket text messages.
According to the Unicode standard, they SHOULD NOT be used in information interchange, but a recent corrigendum clarifies that non-characters CAN be exchanged.
However, non-characters are for internal use, and hence, they are implementation specific (e.g. non-characters can be used to carry meta-information). They have to be interpreted.
When used with QString, they are replaced with U+FFFD - REPLACEMENT CHARACTER, and rendered - non-standard - as a question mark (this is the QString rendering of the non-character U+FFFD: �). Browsers keep the control characters untouched (this is the browser rendering of the non-character U+FDD0: �).
With QWebSockets, text messages are just that: a collection of human-readable characters. Text messages never have to be interpreted to be rendered correctly. In case, you still want to do implementation specific trickery, use binary messages instead. Indeed, if non-characters were allowed in text messages, then every text message has to be parsed, character-per-character, to find out if it contains special control codes, or a protocol should be devised that indicates whether the message contains that kind of control codes. We keep it simple: text is text and nothing more.
Qt 5.x
QWebSockets is compliant with RFC6455 and has been tested with the Autobahn Testsuite.
Only tests with Unicode non-characters do not pass from the Autobahn Testsuite (see Restrictions).
- WSS protocol
- Extensions and sub-protocols
This code is licensed under LGPL v3.