support hooks on websocket

Author: guox191

lib/handlers/ws-handler.js

@@ -0,0 +1,236 @@
+'use strict';
+
+const co = require('co');
+const WebSocket = require('ws');
+const logUtil = require('../log');
+
+/**
+ * construct the request headers based on original connection,
+ * but delete the `sec-websocket-*` headers as they are already consumed by AnyProxy
+ */
+function getNoWsHeaders(headers) {
+  const originHeaders = Object.assign({}, headers);
+
+  Object.keys(originHeaders).forEach((key) => {
+    // if the key matchs 'sec-websocket', delete it
+    if (/sec-websocket/ig.test(key)) {
+      delete originHeaders[key];
+    }
+  });
+
+  delete originHeaders.connection;
+  delete originHeaders.upgrade;
+  return originHeaders;
+}
+
+/**
+ * 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];
+  // 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}:${port}${path}`,
+    headers: headers, // the full headers of origin ws connection
+    noWsHeaders: getNoWsHeaders(headers),
+    secure: Boolean(isEncript),
+    hostname: hostname,
+    port: port,
+    path: path
+  };
+}
+
+/**
+ * When the source ws is closed, we need to close the target websocket.
+ * If the source ws is normally closed, that is, the code is reserved, we need to transfrom them
+ * @param {object} event CloseEvent
+ */
+const getCloseFromOriginEvent = (closeEvent) => {
+  const code = closeEvent.code || '';
+  const reason = closeEvent.reason || '';
+  let targetCode = '';
+  let targetReason = '';
+  if (code >= 1004 && code <= 1006) {
+    targetCode = 1000; // normal closure
+    targetReason = `Normally closed. The origin ws is closed at code: ${code} and reason: ${reason}`;
+  } else {
+    targetCode = code;
+    targetReason = reason;
+  }
+
+  return {
+    code: targetCode,
+    reason: targetReason
+  };
+}
+
+/**
+ * get a websocket event handler
+ * @param @required {object} wsClient
+ */
+function handleWs(userRule, recorder, wsClient, wsReq) {
+  const self = this;
+  let resourceInfoId = -1;
+  const resourceInfo = {
+    wsMessages: [] // all ws messages go through AnyProxy
+  };
+  const clientMsgQueue = [];
+  const serverInfo = getWsReqInfo(wsReq);
+  // proxy-layer websocket client
+  const proxyWs = new WebSocket(serverInfo.url, '', {
+    rejectUnauthorized: !self.dangerouslyIgnoreUnauthorized,
+    headers: serverInfo.noWsHeaders
+  });
+
+  if (recorder) {
+    Object.assign(resourceInfo, {
+      host: serverInfo.hostname,
+      method: 'WebSocket',
+      path: serverInfo.path,
+      url: serverInfo.url,
+      req: wsReq,
+      startTime: new Date().getTime()
+    });
+    resourceInfoId = recorder.appendRecord(resourceInfo);
+  }
+
+  /**
+   * store the messages before the proxy ws is ready
+   */
+  const sendProxyMessage = (finalMsg) => {
+    const message = finalMsg.data;
+    if (proxyWs.readyState === 1) {
+      // if there still are msg queue consuming, keep it going
+      if (clientMsgQueue.length > 0) {
+        clientMsgQueue.push(message);
+      } else {
+        proxyWs.send(message);
+      }
+    } else {
+      clientMsgQueue.push(message);
+    }
+  };
+
+  /**
+   * consume the message in queue when the proxy ws is not ready yet
+   * will handle them from the first one-by-one
+   */
+  const consumeMsgQueue = () => {
+    while (clientMsgQueue.length > 0) {
+      const message = clientMsgQueue.shift();
+      proxyWs.send(message);
+    }
+  };
+
+  /**
+   * consruct a message Record from message event
+   * @param @required {object} finalMsg based on the MessageEvent from websockt.onmessage
+   * @param @required {boolean} isToServer whether the message is to or from server
+   */
+  const recordMessage = (finalMsg, isToServer) => {
+    const message = {
+      time: Date.now(),
+      message: finalMsg.data,
+      isToServer: isToServer
+    };
+
+    // resourceInfo.wsMessages.push(message);
+    recorder && recorder.updateRecordWsMessage(resourceInfoId, message);
+  };
+
+  /**
+   * prepare messageDetail object for intercept hooks
+   * @param {object} messageEvent
+   * @returns {object}
+   */
+  const prepareMessageDetail = (messageEvent) => {
+    return {
+      requestOptions: {
+        port: serverInfo.port,
+        hostname: serverInfo.hostname,
+        path: serverInfo.path,
+        secure: serverInfo.secure,
+      },
+      url: serverInfo.url,
+      data: messageEvent.data,
+    };
+  };
+
+  proxyWs.onopen = () => {
+    consumeMsgQueue();
+  };
+
+  // this event is fired when the connection is build and headers is returned
+  proxyWs.on('upgrade', (response) => {
+    resourceInfo.endTime = new Date().getTime();
+    const headers = response.headers;
+    resourceInfo.res = { //construct a self-defined res object
+      statusCode: response.statusCode,
+      headers: headers,
+    };
+
+    resourceInfo.statusCode = response.statusCode;
+    resourceInfo.resHeader = headers;
+    resourceInfo.resBody = '';
+    resourceInfo.length = resourceInfo.resBody.length;
+
+    recorder && recorder.updateRecord(resourceInfoId, resourceInfo);
+  });
+
+  proxyWs.onerror = (e) => {
+    // https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent#Status_codes
+    wsClient.close(1001, e.message);
+    proxyWs.close(1001);
+  };
+
+  proxyWs.onmessage = (event) => {
+    co(function *() {
+      const modifiedMsg = (yield userRule.beforeSendWsMessageToClient(prepareMessageDetail(event))) || {};
+      const finalMsg = {
+        data: modifiedMsg.data || event.data,
+      };
+      recordMessage(finalMsg, false);
+      wsClient.readyState === 1 && wsClient.send(finalMsg.data);
+    });
+  };
+
+  proxyWs.onclose = (event) => {
+    logUtil.debug(`proxy ws closed with code: ${event.code} and reason: ${event.reason}`);
+    const targetCloseInfo = getCloseFromOriginEvent(event);
+    wsClient.readyState !== 3 && wsClient.close(targetCloseInfo.code, targetCloseInfo.reason);
+  };
+
+  wsClient.onmessage = (event) => {
+    co(function *() {
+      const modifiedMsg = (yield userRule.beforeSendWsMessageToServer(prepareMessageDetail(event))) || {};
+      const finalMsg = {
+        data: modifiedMsg.data || event.data,
+      };
+      recordMessage(finalMsg, true);
+      sendProxyMessage(finalMsg);
+    });
+  };
+
+  wsClient.onclose = (event) => {
+    logUtil.debug(`original ws closed with code: ${event.code} and reason: ${event.reason}`);
+    const targetCloseInfo = getCloseFromOriginEvent(event);
+    proxyWs.readyState !== 3 && proxyWs.close(targetCloseInfo.code, targetCloseInfo.reason);
+  };
+}
+
+module.exports = function getWsHandler(userRule, recorder, wsClient, wsReq) {
+  try {
+    handleWs.call(this, userRule, recorder, wsClient, wsReq);
+  } catch (e) {
+    logUtil.debug('WebSocket Proxy Error:' + e.message);
+    logUtil.debug(e.stack);
+    console.error(e);
+  }
+}