Create WebRequestMonitor class to monitor network traffic to game domain

src/webRequestMonitor.js

@@ -0,0 +1,88 @@
+/* exported WebRequestMonitor */
+/* global NexusData, NexusDataQueue, NexusDataSender */
+'use strict'
+
+class WebRequestMonitor {
+  constructor(sessionId, nexusDataQueue, nexusDataSender) {
+    if (!(nexusDataQueue instanceof NexusDataQueue)) {
+      window.console.error('[NexusDataSender] constructor: argument is not an instance of NexusDataQueue!')
+    }
+    if (!(nexusDataSender instanceof NexusDataSender)) {
+      window.console.error('[NexusDataSender] constructor: argument is not an instance of NexusDataSender!')
+    }
+    this._sessionId = sessionId
+    this._nexusDataQueue = nexusDataQueue
+    this._nexusDataSender = nexusDataSender
+  }
+
+  _attachResponseDataFilter(nexusData) {
+    const decoder = new TextDecoder('utf-8')
+    const encoder = new TextEncoder()
+    const responseDataFilter = browser.webRequest.filterResponseData(nexusData.requestId)
+    responseDataFilter.ondata = event => {
+      const bodyPart = decoder.decode(event.data, {stream: true})
+      responseDataFilter.write(encoder.encode(bodyPart))
+      nexusData.appendResponseBodyPart(bodyPart)
+    }
+    responseDataFilter.onstop = event => {
+      const bodyPart = decoder.decode(event.data, {stream: false})
+      responseDataFilter.write(encoder.encode(bodyPart))
+      responseDataFilter.close()
+      nexusData.appendResponseBodyPart(bodyPart)
+    }
+  }
+
+  _onBeforeRequest(details) {
+    const nexusData = new NexusData()
+    nexusData.sessionId = this._sessionId
+    nexusData.requestId = details.requestId
+    nexusData.requestStartedAt = details.timeStamp
+    nexusData.method = details.method
+    nexusData.url = details.url
+    if (
+      null !== details.requestBody &&
+      Object.prototype.hasOwnProperty.call(details.requestBody, 'formData')
+    ) {
+      nexusData.formData = details.requestBody.formData
+    }
+    this._nexusDataQueue.push(nexusData)
+    this._attachResponseDataFilter(nexusData)
+  }
+
+  _onCompleted(details) {
+    const requestId = details.requestId
+    if (false !== this._nexusDataQueue.has(requestId)) {
+      const nexusData = this._nexusDataQueue.get(requestId)
+      nexusData.responseCompletedAt = details.timeStamp
+      this._nexusDataQueue.delete(requestId)
+      this._nexusDataSender.send(nexusData)
+    }
+  }
+
+  _onErrorOccurred(details) {
+    this._nexusDataQueue.delete(details.requestId)
+    window.console.error('[WebRequestMonitor] Error has occurred: ' + details.error)
+  }
+
+  addListeners() {
+    const requestFilters = {
+      types: ['main_frame'],
+      urls: [
+        '*://*.nexusclash.com/*'
+      ]
+    }
+    browser.webRequest.onBeforeRequest.addListener(
+      this._onBeforeRequest.bind(this),
+      requestFilters,
+      ['blocking', 'requestBody']
+    )
+    browser.webRequest.onCompleted.addListener(
+      this._onCompleted.bind(this),
+      requestFilters
+    )
+    browser.webRequest.onErrorOccurred.addListener(
+      this._onErrorOccurred.bind(this),
+      requestFilters
+    )
+  }
+}