react-relay-network-layer/es/middleware/auth.js

Network Layer for React Relay and Express (Batch Queries, AuthToken, Logging, Retry)

/* eslint-disable no-param-reassign, arrow-body-style, dot-notation */
import { isFunction } from '../utils';

class WrongTokenError extends Error {
  constructor(msg, res) {
    super(msg);
    this.res = res;
    this.name = 'WrongTokenError';
  }

}

export default function authMiddleware(opts) {
  const {
    token: tokenOrThunk,
    tokenRefreshPromise,
    allowEmptyToken = false,
    prefix = 'Bearer ',
    header = 'Authorization'
  } = opts || {};
  let tokenRefreshInProgress = null;
  return next => req => {
    return new Promise((resolve, reject) => {
      // $FlowFixMe
      const token = isFunction(tokenOrThunk) ? tokenOrThunk(req) : tokenOrThunk;

      if (!token && tokenRefreshPromise && !allowEmptyToken) {
        reject(new WrongTokenError('Empty token'));
      }

      resolve(token);
    }).then(token => {
      if (token) {
        req.headers[header] = `${prefix}${token}`;
      }

      return next(req);
    }).catch(e => {
      if (e && tokenRefreshPromise) {
        if (e.message === 'Empty token' || e.fetchResponse && e.fetchResponse.status === 401) {
          if (tokenRefreshPromise) {
            if (!tokenRefreshInProgress) {
              tokenRefreshInProgress = Promise.resolve(tokenRefreshPromise(req, e.fetchResponse)).then(newToken => {
                tokenRefreshInProgress = null;
                return newToken;
              });
            }

            return tokenRefreshInProgress.then(newToken => {
              req.headers[header] = `${prefix}${newToken}`;
              return next(req); // re-run query with new token
            });
          }
        }
      }

      throw e;
    });
  };
}