feat: support hooks on websocket

[guox191]

add two rules:

• beforeSendWsMessageToClient
• beforeSendWsMessageToServer

[CLAassistant]

All committers have signed the CLA.

[azu]

I love this pull request ❤️
I have tested this patch on https://www.websocket.org/echo.html with following script.
It work!

module.exports = {
    summary: 'WebSocket Rule',
    * beforeDealHttpsRequest(requestDetail) {
        return requestDetail.host === "echo.websocket.org:443";
    },
    * beforeSendWsMessageToClient(requestDetail) {
        return {
          data: 'replaced by beforeSendWsMessageToClient'
        }
    }
};

[azu]

I noticed that some weboscet url has not :{port}.
So, you need to normalize port before building url.

/**
 * get request info from the ws client
 * @param @required wsClient the ws client of WebSocket
 */
function getWsReqInfo(wsReq) {
  const headers = wsReq.headers || {};
  const host = headers.host;
  const hostname = host.split(':')[0];
  const port = host.split(':')[1];
  // https://github.com/alibaba/anyproxy/pull/450
  const portPart = port ? `:${port}` : '';
  // TODO 如果是windows机器，url是不是全路径？需要对其过滤，取出
  const path = wsReq.url || '/';
  const isEncript = wsReq.connection && wsReq.connection.encrypted;

  return {
    url: `${isEncript ? 'wss' : 'ws'}://${hostname}${portPart}${path}`,
    headers: headers, // the full headers of origin ws connection
    noWsHeaders: getNoWsHeaders(headers),
    secure: Boolean(isEncript),
    hostname: hostname,
    port: port,
    path: path
  };
}

ref #450

This changes is patched and this ws proxy work on https://www.websocket.org/echo.html.

[wangxiaoji01]

Exc me , can I ask that how to set the websocket port?

[hreflee]

Will this PR be further processed? I am also looking forward to websocket hook functions! 🙏

[wujohns]

感觉anyproxy官方已经放弃维护了