alexmngn alexmngn - 2 months ago 13
Javascript Question

React Native + Redux basic authentication

I'm looking for a way to create a basic authentication for my react-native app.
I couldn't find any good example for react-native app.


  • To login, the app sends the email/password + clientSecret to my server

  • If OK, the server returns accessToken + refreshToken

  • The user is logged in, all other requests include the bearer with the accessToken.

  • If the accessToken expires, the app requests a new one with the refreshToken automatically.

  • The user stays logged in all the time, the states should be saved in the phone.



What would be the best approach for this?

Thanks.

Answer

When an app communicates with a HTTP API which enforces some form of authentication, the app typically follows these steps:

  1. The app is not authenticated, so we prompt the user to log in.
  2. The user enters their credentials (username and password), and taps submit.
  3. We send these credentials to the API, and inspect the response:
    • On success (200 - OK): We cache the authentication token/ hash, because we're going to use this token/ hash in every subsequent request.
      • If the token/ hash does not work during any of the subsequent API requests (401 - Unauthorized), we'll need to invalidate the hash/ token and prompt the user to log in again.
    • Or, on failure (401 - Unauthorized): We display an error message to the user, prompting them re-enter their credentials.

Logging In

Based on the work flow defined above our app starts by displaying a login form, step 2 kicks in when the user taps the login button which dispatches the login action creator below:

/// actions/user.js

export function login(username, password) {
  return (dispatch) => {

    // We use this to update the store state of `isLoggingIn`          
    // which can be used to display an activity indicator on the login
    // view.
    dispatch(loginRequest())

    // Note: This base64 encode method only works in NodeJS, so use an
    // implementation that works for your platform:
    // `base64-js` for React Native,
    // `btoa()` for browsers, etc...
    const hash = new Buffer(`${username}:${password}`).toString('base64')
    return fetch('https://httpbin.org/basic-auth/admin/secret', {
      headers: {
        'Authorization': `Basic ${hash}`
      }
    })
    .then(response => response.json().then(json => ({ json, response })))
    .then(({json, response}) => {
      if (response.ok === false) {
        return Promise.reject(json)
      }
      return json
    })
    .then(
      data => {
        // data = { authenticated: true, user: 'admin' }
        // We pass the `authentication hash` down to the reducer so that it
        // can be used in subsequent API requests.

        dispatch(loginSuccess(hash, data.user))
      },
      (data) => dispatch(loginFailure(data.error || 'Log in failed'))
    )
  }
}

There's a lot of code in the function above, but take comfort in the fact that the majority of the code is sanitising the response and can be abstracted away.

The first thing we do is dispatch an action LOGIN_REQUEST which updates our store and lets us know that the user isLoggingIn.

dispatch(loginRequest())

We use this to display an activity indicator (spinning wheel, "Loading...", etc.), and to disable the log in button in our log in view.

Next we base64 encode the user's username and password for http basic auth, and pass it to the request's headers.

const hash = new Buffer(`${username}:${password}`).toString('base64')
return fetch('https://httpbin.org/basic-auth/admin/secret', {
  headers: {
    'Authorization': `Basic ${hash}`
  }
/* ... */

If everything went well, we'll dispatch a LOGIN_SUCCESS action, which results in us having an authentication hash in our store, which we'll use in subsequent requests.

dispatch(loginSuccess(hash, data.user))

On the flip side, if something went wrong then we also want to let the user know:

dispatch(loginFailure(data.error || 'Log in failed')

The loginSuccess, loginFailure, and loginRequest action creators are fairly generic and don't really warrant code samples. See: https://github.com/peterp/redux-http-basic-auth-example/blob/master/actions/user.js)

Reducer

Our reducer is also typical:

/// reducers/user.js
function user(state = {
  isLoggingIn: false,
  isAuthenticated: false
}, action) {
  switch(action.type) {
    case LOGIN_REQUEST:
      return {
        isLoggingIn: true, // Show a loading indicator.
        isAuthenticated: false
      }
    case LOGIN_FAILURE:
      return {
        isLoggingIn: false,
        isAuthenticated: false,
        error: action.error
      }
    case LOGIN_SUCCESS:
      return {
        isLoggingIn: false,
        isAuthenticated: true, // Dismiss the login view.
        hash: action.hash, // Used in subsequent API requests.
        user: action.user
      }
    default:
      return state
  }
}

Subsequent API requests

Now that we have an authentication hash in our store we can pass it into subsequent request's headers.

In our example below we're fetching a list of friends for our authenticated user:

/// actions/friends.js
export function fetchFriends() {
  return (dispatch, getState) => {

    dispatch(friendsRequest())

    // Notice how we grab the hash from the store:
    const hash = getState().user.hash
    return fetch(`https://httpbin.org/get/friends/`, {
      headers: {
        'Authorization': `Basic ${hash}`
      }
    })
    .then(response => response.json().then(json => ({ json, response })))
    .then(({json, response}) => {
      if (response.ok === false) {
        return Promise.reject({response, json})
      }
      return json
    })
    .then(
      data => {
        // data = { friends: [ {}, {}, ... ] }
        dispatch(friendsSuccess(data.friends))
      },
      ({response, data}) => {
        dispatch(friendsFailure(data.error))

        // did our request fail because our auth credentials aren't working?
        if (response.status == 401) {
          dispatch(loginFailure(data.error))
        }
      }
    )
  }
}

You may find that most API requests typically dispatch the same 3 actions as above: API_REQUEST, API_SUCCESS, and API_FAILURE, and as such the majority of the request/ response code can be pushed into Redux middleware.

We fetch the hash authentication token from the store and setup the request.

const hash = getState().user.hash
return fetch(`https://httpbin.org/get/friends/`, {
  headers: {
    'Authorization': `Basic ${hash}`
  }
})
/* ... */

If the API response with a 401 status code then we've got to remove our hash from the store, and present the user with a log in view again.

if (response.status == 401) {
  dispatch(loginFailure(data.error))
}

I've answered the question generically and only dealing with http-basic-auth.

I think that the concept may remain the same, you'll push the accessToken and refreshToken in the store, and extract it in subsequent requests.

If the request fails then you'll have to dispatch another action which updates the accessToken, and then recalls the original request.