如何在過期後自動創建jwt令牌

Question

一旦創建了jwt訪問令牌，我就將它存儲在localstorage中，然後在任何地方使用它。在這裏，我面臨的問題，一旦jwt令牌過期，我無法搜索。所以我想要一旦jwt令牌失效，它應該自動創建。應該如何做到這一點。謝謝

Answer 1

下面是一個可能的解決方案 - 一個簡單的redux中間件，它將刷新即將到期的現有未過期令牌。

它使用jwt-decode函數庫，並假定存在實際更新的renewToken函數。

有關更多詳細信息，請參閱代碼中的註釋。

import jwtDecode from 'jwt-decode' 
import { renewToken } from authManager 

// If less than this time in seconds to expiry - renew the token 
const EXPIRY_THRESHOLD = 600 

// Milli seconds between expiry checks 
// Should be longer than the time it takes for a request for new token to succeed/fail 
// This is how we avoid multiple token requests 
const CHECK_INTERVAL = 10000 

// Timestamp of last time we checked the token for expiry 
let lastCheckTs = -CHECK_INTERVAL 


/** 
* Get time in seconds until the id_token expires. 
* A negative value means it has already expired (or doesn't exist) 
*/ 
function getTimeToExpiry(key) { 
    let jwt = localStorage.getItem(key) 
    if(jwt) { 
     let jwtExp = jwtDecode(jwt).exp 
     let expiryDate = new Date(0) 
     expiryDate.setUTCSeconds(jwtExp) 

     return Math.floor((expiryDate.getTime() - Date.now())/1000) 
    } 
    return -1 
} 

export default store => next => action => { 
    const now = Date.now() 
    if (now - lastCheckTs < CHECK_INTERVAL) { 
     // We checked recently, just continue 
     return next(action) 
    } 
    lastCheckTs = now 

    const timeToExpire = getTimeToExpiry('id_token') 


    // This middleware is only concerned with keeping a valid session alive. 

    // If the existing token is stale or non-existent - 
    // do nothing and let other parts of the app take care of 
    // getting a completely new valid token (EG by prompting the user to login) 

    // If the existing token has a long time to expiry - do nothing until the next check 

    // However, if the existing token is valid but will expire soon - try to renew it. 
    if (timeToExpire > 0 && timeToExpire < EXPIRY_THRESHOLD) { 
     // Try to renew the token 
     const current_id_token = localStorage.getItem('id_token') 
     renewToken(current_id_token, function (err, result) { 
      if (err) { 
       // Do nothing - 
       // If we got here it means that the current token is still fresh, 
       // so we'll just try again in the next expiry check 
      } else { 
       // Store the new token 
       localStorage.setItem('id_token', result.id_token) 
      } 
     }); 
    } 

    return next(action) 
}