ca-apm-probe/lib/browser-agent.js

CA APM Node.js Agent monitors real-time health and performance of Node.js applications

/**
 * Copyright (c) 2015 CA. All rights reserved.
 *
 * This software and all information contained therein is confidential and proprietary and
 * shall not be duplicated, used, disclosed or disseminated in any way except as authorized
 * by the applicable license agreement, without the express written permission of CA. All
 * authorized reproductions must be marked with this language.
 *
 * EXCEPT AS SET FORTH IN THE APPLICABLE LICENSE AGREEMENT, TO THE EXTENT
 * PERMITTED BY APPLICABLE LAW, CA PROVIDES THIS SOFTWARE WITHOUT WARRANTY
 * OF ANY KIND, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL CA BE
 * LIABLE TO THE END USER OR ANY THIRD PARTY FOR ANY LOSS OR DAMAGE, DIRECT OR
 * INDIRECT, FROM THE USE OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, LOST
 * PROFITS, BUSINESS INTERRUPTION, GOODWILL, OR LOST DATA, EVEN IF CA IS
 * EXPRESSLY ADVISED OF SUCH LOSS OR DAMAGE.
 */

var agent = require('./agent');
var logger = require("./logger.js");
var config = require('./configdata').getConfigData();
var path = require('path');
var fs = require('fs');
var baSnippet;

module.exports = { initializeBrowserAgentParameters, prepareScript, getBaResponseBt, validateRespIfJson }

function initializeBrowserAgentParameters() {
  isCorGuidEnabled = false;
  maxCookieExpInMs = 3000;
  allowedResContentType = 'text/html';
  isAutoInjectionEnabled = (config.http.browseragent.autoInjectionEnabled == undefined) ? false : config.http.browseragent.autoInjectionEnabled;

  isResponseDecEnabled = (config.http.browseragent.response.decoration.enabled == undefined) ? false : config.http.browseragent.response.decoration.enabled;

  if (isResponseDecEnabled) {
    baSnippet = getSnippet();
    isCorGuidEnabled = (config.http.browseragent.corGuidEnabled == undefined) ? true : config.http.browseragent.corGuidEnabled;
  }
  maxCookieExpInMs = (config.http.browseragent.response.decoration.cookie.expirationTime == undefined) ? 3000 : config.http.browseragent.response.decoration.cookie.expirationTime;

  allowedResContentType = (config.http.browseragent.response.decoration.cookie.contentType == undefined) ? 'text/html' : config.http.browseragent.response.decoration.cookie.contentType;

  return { baSnippet, isAutoInjectionEnabled, isResponseDecEnabled, isCorGuidEnabled, maxCookieExpInMs, allowedResContentType };
}

function updateDefaultSnippet(baSnippet) {
  if (config.http.browseragent.autoInjection.snippetLocation != undefined) {
    var filepath = path.join(__dirname, config.http.browseragent.autoInjection.snippetLocation);
    try {
      fs.writeFileSync(filepath, baSnippet);
      logger.debug('Snippet updated in default.snippet');
    } catch (error) {
      logger.debug(error);
    }
  }
}

function getDefaultSnippet() {
  if (config.http.browseragent.autoInjection.snippetLocation != undefined) {
    var filepath = path.join(__dirname, config.http.browseragent.autoInjection.snippetLocation);
    var buffer = fs.readFileSync(filepath);
    if (buffer != undefined) {
      return buffer.toString();
    }
  }
  else {
    return null;
  }
}

function getSnippet() {
  if (config.http.browseragent.snippetString && config.http.browseragent.snippetString !== '') {
    //This snippet is already gets tranformed in the configdata.js postConfig method
    return config.http.browseragent.snippetString;
  } else {
    return getDefaultSnippet();
  }
}

function validateGraphqlResp(bufString) {
  try {
    JSON.parse(bufString)
    return false;
  } catch (error) {
    return true;
  }

}

function prepareScript(ctx) {
  var baResponseBt = encodeURIComponent(getBaResponseBt(ctx, false));
  var snippetArr = baSnippet.split('script ');
  var finalScript = snippetArr[0] + 'script x-apm-ba-response-bt="' + baResponseBt + '" ' + snippetArr[1];
  return finalScript;
}

function getBaResponseBt(ctx, isGqlUrl) {
  var CorBrowsGUID;
  var serverTime = getDateTimeMilliseconds();
  var startTime = ',startTime=' + serverTime;
  serverTime = 'servertime=' + serverTime;
  var apmAgentProcess = ',apmAgentProcess=nodejs-probes';
  var apmAgentName = ',apmAgentName=' + agent.getProbeName();
  var apmWebAppname = ',apmWebAppname=' + agent.getProbeName();
  var apmServletName = ',apmServletName=' + agent.getProbeName();
  var apmAgentHost = ',apmAgentHost=' + ctx.hostName;
  var endTime = ',endTime=' + getDateTimeMilliseconds();
  if (isCorGuidEnabled) {
    if (ctx.corIdObj) {
      CorBrowsGUID = ',CorBrowsGUID=' + ctx.corIdObj.guid;
    }
    else {
      CorBrowsGUID = ',CorBrowsGUID=' + ctx.corId.substring(0, ctx.corId.indexOf(','));
    }
    var headerVal = serverTime + CorBrowsGUID + startTime + endTime + apmServletName + apmAgentProcess + apmAgentName + apmWebAppname + apmAgentHost;
    if (isGqlUrl) {
      return headerVal + ',isGrpql';
    }
    else {
      return headerVal;
    }
  }
  else {
    return serverTime + startTime + endTime + apmServletName + apmAgentProcess + apmAgentName + apmWebAppname + apmAgentHost;
  }
}

function getDateTimeMilliseconds() {
  return Date.now();
}

function validateRespIfJson(bufString) {
  try {
    JSON.parse(bufString)
    return false;
  } catch (error) {
    return true;
  }

}