Question

我在node.js中使用ES6。长话短说，我现在才谈到回调，并想用Promise代替它们。

我进行了一个测试项目，以从api /端点获取oauth2令牌，对其进行刷新并最终将其撤销。目标是将上一个请求的响应传递给下一个。我的代码如下：

const oauth2Adapter = require('./api/adapter/oauth2Adapter')

function test () {
oauth2Adapter.RequestNewAccessToken()
.then(function (response) {
  console.log(response)
  return oauth2Adapter.RefreshAccessToken(response.body)
})
.then(function (response) {
  return oauth2Adapter.RevokeAccessToken(response.body)
})
.then(console.log)
.catch(console.log)
}

test()

第一个承诺返回其响应。现在的下一步是将其作为第二个承诺。但是第二个Promise只收到一个未定义的对象。

我是CS的第二年学徒，任何评论家都会帮助我，并受到赞赏。

编辑：添加'return'关键字并没有改变情况。问题是'RefreshAccessToken''未定义'收到。另外我也不知道这是否有帮助，但这是“ oauth2Adapter.js”代码：

const Promise = require('promise')
const rp = require('request-promise')
const credentials = require('../../misc/credentials/Staging')

function RequestNewAccessToken () {
  try {
    const response = rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/token`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        username: credentials.username,
        password: credentials.password,
        grant_type: credentials.grantType
      },
      json: true
    })
    return Promise.resolve(response)
  } catch (error) {
    return Promise.reject(error)
  }
}

function RefreshAccessToken (token) {
  try {
    const response = rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/token`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        grant_type: 'refresh_token',
        refresh_token: token.refresh_token
      },
      json: true
    })
    return Promise.resolve(response)
  } catch (error) {
    return Promise.reject(error)
  }
}

function RevokeAccessToken (token) {
  try {
    const response = rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/revoke`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        token: token.access_token
      },
      json: true
    })
    return Promise.resolve(response)
  } catch (error) {
    return Promise.reject(error)
  }
}

module.exports = { RequestNewAccessToken, RefreshAccessToken, RevokeAccessToken }

如果执行代码，我将通过stdout得到以下文本：

Debugger attached.

    { access_token: '31744bf03a2fb92edb67fcbeead14f4ed8c540843c2439179a54b6439dc94c0e',
      token_type: 'Bearer',
      expires_in: 660,
      refresh_token: 'e53642c69bd0ad954d886dad7a437f88c8c269ecacf2cdcfebc8af1a2d0d9b1e',
      created_at: 1538471914 }
    TypeError: Cannot read property 'refresh_token' of undefined
        at Object.RefreshAccessToken (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/api/adapter/oauth2Adapter.js:28:28)
        at /Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/Main.js:7:28
        at tryCatcher (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/util.js:16:23)
        at Promise._settlePromiseFromHandler (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/promise.js:512:31)
        at Promise._settlePromise (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/promise.js:569:18)
        at Promise._settlePromise0 (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/promise.js:614:10)
        at Promise._settlePromises (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/promise.js:694:18)
        at _drainQueueStep (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/async.js:138:12)
        at _drainQueue (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/async.js:131:9)
        at Async._drainQueues (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/async.js:147:5)
        at Immediate.Async.drainQueues (/Users/quest1onmark/coding_stuff/nodejs/EdgeDeviceAdministration/node_modules/bluebird/js/release/async.js:17:14)
        at runCallback (timers.js:810:20)
        at tryOnImmediate (timers.js:768:5)
        at processImmediate [as _immediateCallback] (timers.js:745:5)
    Waiting for the debugger to disconnect...

    Process finished with exit code 0

Answer 1

通过在then块末尾返回另一个Promise来链接Promise。您似乎在第一个return块中没有正确调用then。您应按以下步骤进行更正：

oauth2Adapter.RequestNewAccessToken()
.then(function (requestReponse) {
  console.log(response)
  return oauth2Adapter.RefreshAccessToken()
})
.then(function (refreshResponse) {
  return oauth2Adapter.RevokeAccessToken(JSON.parse(refreshResponse.body))
})

作为一个旁注，我希望在每次Promise返回中为回调args取不同的名称，这将有助于保持环境清洁！

Answer 2

承诺应正确地链接。这意味着then和catch回调应返回承诺链，以防万一。

此外，使用response时，json: true参数是解析的响应正文。如果服务器以令牌对象作为响应，则应将其作为参数传递给期望它的函数：

...
.then(function (response) {
  console.log(response)
  return oauth2Adapter.RefreshAccessToken(response)
})
...

Answer 3

Your second code block is not using promises at all well

try the following instead

const Promise = require('promise')
const rp = require('request-promise')
const credentials = require('../../misc/credentials/Staging')

function RequestNewAccessToken () {
    return rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/token`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        username: credentials.username,
        password: credentials.password,
        grant_type: credentials.grantType
      },
      json: true
    });
}

function RefreshAccessToken (token) {
    return rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/token`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        grant_type: 'refresh_token',
        refresh_token: token.refresh_token
      },
      json: true
    });
}

function RevokeAccessToken (token) {
    return rp({
      method: 'POST',
      url: `${credentials.baseUrl}/oauth/revoke`,
      form: {
        client_id: credentials.apiKey,
        client_secret: credentials.apiSecret,
        token: token.access_token
      },
      json: true
    });
}

module.exports = { RequestNewAccessToken, RefreshAccessToken, RevokeAccessToken }

As for your code that USES this - you console.log(response) which has the required format, but then you oauth2Adapter.RefreshAccessToken(response.body) ... response has no body!

So, simply do:

const oauth2Adapter = require('./api/adapter/oauth2Adapter')
function test () {
    return oauth2Adapter.RequestNewAccessToken()
    .then(response => oauth2Adapter.RefreshAccessToken(response))
    .then(response => oauth2Adapter.RevokeAccessToken(response))
    .then(console.log)
    .catch(console.log)
}
test()

but, since you pass response straight to the next function without any processing, you can also do

const oauth2Adapter = require('./api/adapter/oauth2Adapter')
function test () {
    return oauth2Adapter.RequestNewAccessToken()
    .then(oauth2Adapter.RefreshAccessToken)
    .then(oauth2Adapter.RevokeAccessToken)
    .then(console.log)
    .catch(console.log)
}
test()

承诺链接，将请求结果用于另一个

3 个答案: