如何异步读取模块的文件

Question

我正在尝试加载一个用于koa-jsonwebtoken的秘密。

这是我的KOA服务器的相关内容：

import jwt, { fromAuthorizationHeader } from 'koa-jsonwebtoken';
import {serverCredentials} from './auth'
//...
console.log('loaded serverCredentials' + JSON.stringify(serverCredentials))    
app.use(jwt({ secret: serverCredentials.shared, extractToken: fromAuthorizationHeader }));

我的身份验证是：

import ty from 'then-yield'
import md5 from 'md5'
import Promise from 'bluebird'
const fs = Promise.promisifyAll(require('fs'));
const serverCredentials = ty.spawn(function* () {
  let src
  try {
    console.log('trying')
    src = yield fs.readFileAsync('./serverCredentials.json','utf8')
  } catch(e) {
    console.error('Error when opening serverCredentials file: ' + e.message);
    throw e
  }
  console.log('serverCredentials: ' + src)
  return JSON.parse(src)
})
export {serverCredentials}

但我的日志说：

trying
loaded serverCredentials{"isFulfilled":false,"isRejected":false}

而不是服务器密钥。

Answer 1

serverCredentials是 JSON 解析对象的承诺。您将需要等待它：

import jwt, { fromAuthorizationHeader } from 'koa-jsonwebtoken';
import {serverCredentials as credentialsPromise} from './auth';
credentialsPromise.then(serverCredentials => {
    console.log('loaded serverCredentials' + JSON.stringify(serverCredentials))    
    app.use(jwt({secret: serverCredentials.shared, extractToken: fromAuthorizationHeader}));
});