interceptor.js

// https://stackoverflow.com/questions/33106709/chrome-webrequest-doesnt-see-post-data-in-requestbody
// https://developer.chrome.com/extensions/webRequest
const wsUrl = 'ws://localhost:8192/ws'
const requestFilter = { urls: ['<all_urls>'] }
const requests = new Map()

let ws

// -function connect() {
//   ws = new WebSocket(wsUrl)
//   ws.onopen = () => {
//     console.log('соединение с вебсокет-сервером установлено')
//   }
//   ws.message = e => {
//     // Пока необходимости в получении ответов от сервера нет
//     console.log(e.data)
//   }
//   ws.onclose = () => {
//     console.log('Соединение закрыто')
//     setTimeout(connect, 3000)
//   }
// }()

// bytearray.fromhex('deadbeef')
function bytesToHex(a) {
  return new Uint8Array(a).reduce(
    (acc, v) => acc += v.toString(16).padStart(2, '0'),
    ''
  )
}

chrome.webRequest.onBeforeRequest.addListener(
  ({ requestId, method, url, requestBody, timeStamp }) => {
    console.log('requests.size: ' + requests.size)
    requests.set(requestId, {
      id: requestId,
      startTime: timeStamp,
      method,
      url,
      body: requestBody
    })
  },
  requestFilter,
  ['requestBody']
)

chrome.webRequest.onBeforeSendHeaders.addListener(
  ({ requestId, requestHeaders }) => {
    const request = requests.get(requestId)
    Object.assign(request, { headers: requestHeaders })
  },
  requestFilter,
  ['requestHeaders']
)

chrome.webRequest.onCompleted.addListener(
  ({ requestId, responseHeaders, statusCode, timeStamp }) => {
    const request = requests.get(requestId)
    // удаляем запрос
    requests.delete(requestId)
    const { body } = request
    if (body !== undefined) {
      if ('raw' in body) {
        for (const item of body.raw) {
          if ('bytes' in item) {
            item.bytes = bytesToHex(item.bytes)
          }
        }
      }
    }
    const message = JSON.stringify({
      ...request,
      response: {
        status: statusCode,
        headers: responseHeaders
      },
      endTime: timeStamp
    })
    console.log(message)
    // ws.send(message)
  },
  requestFilter,
  ['responseHeaders']
)

chrome.webRequest.onErrorOccurred.addListener(
  ({ requestId }) => {
    requests.delete(requestId)
  },
  requestFilter
)

manifest.json:

{
  "manifest_version": 2,
  "name": "interceptor",
  "version": "0.1.0",
  "author": "self",
  "background": {
    "persistent": true,
    "scripts": ["background.js"]
  },
  "permissions": [
    "webRequest",
    "<all_urls>"
  ]
}