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const isomorphicFetch = require('isomorphic-fetch')
const jwt = require('jsonwebtoken')
const jwkRsa = require('jwks-rsa')
const fromEvent = require('graphcool-lib').fromEvent
//Validates the request JWT token
const verifyToken = token =>
new Promise(resolve => {
//Decode the JWT Token
const decoded = jwt.decode(token, { complete: true })
if (!decoded || !decoded.header || !decoded.header.kid) {
throw new Error('Unable to retrieve key identifier from token')
}
if (decoded.header.alg !== 'RS256') {
throw new Error(
`Wrong signature algorithm, expected RS256, got ${decoded.header.alg}`
)
}
const jkwsClient = jwkRsa({
cache: true,
jwksUri: `https://${process.env.AUTH0_DOMAIN}/.well-known/jwks.json`
})
//Retrieve the JKWS's signing key using the decode token's key identifier (kid)
jkwsClient.getSigningKey(decoded.header.kid, (err, key) => {
if (err) throw new Error(err)
const signingKey = key.publicKey || key.rsaPublicKey
//If the JWT Token was valid, verify its validity against the JKWS's signing key
jwt.verify(
token,
signingKey,
{
algorithms: ['RS256'],
audience: process.env.AUTH0_API_IDENTIFIER,
ignoreExpiration: false,
issuer: `https://${process.env.AUTH0_DOMAIN}/`
},
(err, decoded) => {
if (err) throw new Error(err)
return resolve(decoded)
}
)
})
})
//Retrieves the Graphcool user record using the Auth0 user id
const getGraphcoolUser = (auth0UserId, api) =>
api
.request(
`
query getUser($auth0UserId: String!){
User(auth0UserId: $auth0UserId){
id
}
}
`,
{ auth0UserId }
)
.then(queryResult => queryResult.User)
//Creates a new User record.
const createGraphCoolUser = (auth0UserId, email, api) =>
api
.request(
`
mutation createUser($auth0UserId: String!, $email: String) {
createUser(
auth0UserId: $auth0UserId
email: $email
){
id
}
}
`,
{ auth0UserId, email }
)
.then(queryResult => queryResult.createUser)
const fetchAuth0Email = accessToken =>
fetch(
`https://${process.env.AUTH0_DOMAIN}/userinfo?access_token=${accessToken}`
)
.then(response => response.json())
.then(json => json.email)
export default async event => {
try {
if (!process.env.AUTH0_DOMAIN || !process.env.AUTH0_API_IDENTIFIER) {
throw new Error(
'Missing AUTH0_DOMAIN or AUTH0_API_IDENTIFIER environment variable'
)
}
const { accessToken } = event.data
const decodedToken = await verifyToken(accessToken)
const graphcool = fromEvent(event)
const api = graphcool.api('simple/v1')
let graphCoolUser = await getGraphcoolUser(decodedToken.sub, api)
//If the user doesn't exist, a new record is created.
if (graphCoolUser === null) {
// fetch email if scope includes it
let email = null
if (decodedToken.scope.includes('email')) {
email = await fetchAuth0Email(accessToken)
}
graphCoolUser = await createGraphCoolUser(decodedToken.sub, email, api)
}
// custom exp does not work yet, see https://github.com/graphcool/graphcool-lib/issues/19
const token = await graphcool.generateNodeToken(
graphCoolUser.id,
'User',
decodedToken.exp
)
return { data: { id: graphCoolUser.id, token } }
} catch (err) {
console.log(err)
return { error: 'An unexpected error occured' }
}
}
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