如何使用Redux刷新JWT令牌？

Question

componentDidMount() {
    dispath(loadProfile());
    dispatch(loadAssets());
    ...
}

// jwt-middleware.js

export function refreshJWTToken({ dispatch, getState }) {

  return (next) => (action) => {
    if (isExpired(getState().auth.token)) {
      return dispatch(refreshToken())
          .then(() => next(action))
          .catch(e => console.log('error refreshing token', e));
    }
    return next(action);
};

我遇到的问题是，LoadProfile和LoadAssets操作都将刷新令牌，因为在分派时，令牌将过期。理想情况下，我希望“暂停”需要身份验证的操作，直到令牌刷新。有没有一种方法可以用中间件做到这一点？

Answer 1

我找到了解决这个的办法。我不确定这是否是最佳实践方法，可能会有一些改进。

我最初的想法是：JWT刷新在中间件中。如果使用thunk，则必须在thunk之前提供该中间件。

...
const createStoreWithMiddleware = applyMiddleware(jwt, thunk)(createStore);

然后在中间件代码中，我们在任何异步操作之前检查token是否过期。如果它过期了，我们还检查我们是否已经刷新了令牌--为了能够进行这样的检查，我们在状态中添加了fresh令牌的promise。

import { refreshToken } from '../actions/auth';

export function jwt({ dispatch, getState }) {

    return (next) => (action) => {

        // only worry about expiring token for async actions
        if (typeof action === 'function') {

            if (getState().auth && getState().auth.token) {

                // decode jwt so that we know if and when it expires
                var tokenExpiration = jwtDecode(getState().auth.token).<your field for expiration>;

                if (tokenExpiration && (moment(tokenExpiration) - moment(Date.now()) < 5000)) {

                    // make sure we are not already refreshing the token
                    if (!getState().auth.freshTokenPromise) {
                        return refreshToken(dispatch).then(() => next(action));
                    } else {
                        return getState().auth.freshTokenPromise.then(() => next(action));
                    }
                }
            }
        }
        return next(action);
    };
}

export function refreshToken(dispatch) {

    var freshTokenPromise = fetchJWTToken()
        .then(t => {
            dispatch({
                type: DONE_REFRESHING_TOKEN
            });

            dispatch(saveAppToken(t.token));

            return t.token ? Promise.resolve(t.token) : Promise.reject({
                message: 'could not refresh token'
            });
        })
        .catch(e => {

            console.log('error refreshing token', e);

            dispatch({
                type: DONE_REFRESHING_TOKEN
            });
            return Promise.reject(e);
        });



    dispatch({
        type: REFRESHING_TOKEN,

        // we want to keep track of token promise in the state so that we don't try to refresh
        // the token again while refreshing is in process
        freshTokenPromise
    });

    return freshTokenPromise;
}