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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: $auth0UserId){
id
}
}
`,
{ auth0UserId }
)
.then(queryResult => queryResult.User);
// Creates a new User record.
const createGraphCoolUser = ({ sub }, api) =>
api
.request(
`
mutation createUser($auth0UserId: String!) {
createUser(
auth0UserId: $auth0UserId
){
id
}
}
`,
{ auth0UserId: sub }
)
.then(queryResult => queryResult.createUser);
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 = null;
graphCoolUser = await getGraphcoolUser(decodedToken.sub, api);
// If the user doesn't exist. a new record is created.
if (graphCoolUser === null) {
graphCoolUser = await createGraphCoolUser(decodedToken, api);
}
const token = await graphcool.generateAuthToken(graphCoolUser.id, 'User');
return { data: { id: graphCoolUser.id, token } };
} catch (err) {
console.log(err);
return { error: 'An unexpected error occured' };
}
};
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