wkr-util/esm/app-auth.js

Utility library for wkr project.

import fetch from 'node-fetch'
import urlJoin from 'url-join'
import jwt from 'jsonwebtoken'
import {get} from '@cullylarson/f'
import {retry, memoizePUntil} from '@cullylarson/p'
import {nowStamp, responseData} from './'
import ResponseError from './errors/ResponseError'

const AppAuth = (authApiUrl, appId, appSecret) => {
    const twoMinutes = 120

    // if there is less than 2 minutes left on the JWT, then it should be renewed
    const shouldRenew = tokenInfo => {
        return !tokenInfo || !tokenInfo.exp || (tokenInfo.exp - nowStamp()) <= twoMinutes
    }

    const tokenInfoFromToken = token => {
        const decoded = jwt.decode(token)

        return {
            token,
            exp: get(['header', 'exp'], undefined, decoded),
        }
    }

    const getTokenInfo = memoizePUntil(shouldRenew, retry(3, () => {
        const query = {
            id: appId,
            secret: appSecret,
        }

        return fetch(urlJoin(authApiUrl, '/api/v1/application/authenticate'), {
            method: 'post',
            body: JSON.stringify(query),
            headers: {
                'Content-Type': 'application/json',
            },
        })
            .then(responseData)
            .then(({response, data}) => {
                if(!response.ok) {
                    throw new ResponseError(response.status, data, `Failed to get token. Got status: ${response.status}`)
                }

                return data.token
            })
            .then(tokenInfoFromToken)
    }))

    return {
        getToken: () => {
            return getTokenInfo()
                .then(tokenInfo => tokenInfo.token)
        },
    }
}

export default AppAuth