fix for slither on macOS

slither-proxy.js

var http = require('http'),
    httpProxy = require('http-proxy');
var crypto = require('crypto');

var proxy = httpProxy.createServer({
  //target: 'ws://139.99.130.166:444',
  target: 'ws://139.99.130.217:444',
  preserveHeaderKeyCase: false,
  ws: true
}).listen(4444);

proxy.on('proxyReqWs', function (proxyReq, req, res) {
 console.log ('hello ReqWs');
  console.log('RAW Req from the target', JSON.stringify(req.headers));
  var sha1 = crypto.createHash('sha1');
  var key = req.headers['sec-websocket-key'];
  sha1.update(key + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11');
  var acceptKey = sha1.digest('base64');
  console.log("expected response: ", acceptKey);


  proxyReq.on('upgrade', function(proxyRes, proxySocket, proxyHead) {
	console.log ("we are in upgrade", JSON.stringify (proxyRes.headers));
	proxyRes.headers['sec-websocket-accept'] = acceptKey;
  });

});

proxy.on('close', function (res, socket, head) {
  // view disconnected websocket connections
  console.log ('Disconnect: ', JSON.stringify(head));
  console.log('Client disconnected');
});

console.log("ok, now point slither to: localhost:4444");