This repository holds a minimal header-only C++ implementation of the RFC6455 (WebSocket protocol 13) handshake algorithm. When a WebSocket client requests an upgrade over HTTP/1.1 it passes a 24 byte base64 encoded string to be processed in a particular way according to the specification. With libwshandshake this entire procedure becomes very simple as displayed below:

#include "libwshandshake.hpp"
#include <iostream>

int main()
{
    // output is 28 bytes in base64 encoding, but we want an extra 0 to end the string a la C
    char output[29] = {};
    WebSocketHandshake::generate("dGhlIHNhbXBsZSBub25jZQ==", output);
    std::cout << output << std::endl;
}

This would output: s3pPLMBiTxaQ9kYGzzhZRbK+xOo= which of course is the response to send. Performance has been a factor of the development process and should be close (but not as fast) to the equivalent OpenSSL based alternatives. One million handshakes can be performed in about 200 milliseconds on a modern CPU.