dbartholomae
middy-middleware-jwt-auth
A middy JSON web token authorization middleware inspired by express-jwt.
Installation
Download node at nodejs.org and install it, if you haven't already.
npm install middy-middleware-jwt-auth --saveDocumentation
There is additional documentation.
Usage
import createHttpError from "http-errors";
import middy from "@middy/core";
import httpErrorHandler from "@middy/http-error-handler";
import httpHeaderNormalizer from "@middy/http-header-normalizer";
import JWTAuthMiddleware, {
EncryptionAlgorithms,
IAuthorizedEvent,
} from "middy-middleware-jwt-auth";
// Optionally define the token payload you expect to receive
interface ITokenPayload {
permissions: string[];
}
// Optionally define a type guard for the token payload
function isTokenPayload(token: any): token is ITokenPayload {
return (
token != null &&
Array.isArray(token.permissions) &&
token.permissions.every((permission: any) => typeof permission === "string")
);
}
// This is your AWS handler
const helloWorld = async (event: IAuthorizedEvent<ITokenPayload>) => {
// The middleware adds auth information if a valid token was added
// If no auth was found and credentialsRequired is set to true, a 401 will be thrown. If auth exists you
// have to check that it has the expected form.
if (event.auth!.payload.permissions.indexOf("helloWorld") === -1) {
throw createHttpError(
403,
`User not authorized for helloWorld, only found permissions [${event.auth!.permissions.join(", ")}]`,
{
type: "NotAuthorized",
},
);
}
return {
body: JSON.stringify({
data: `Hello world! Here's your token: ${event.auth!.token}`,
}),
statusCode: 200,
};
};
// Let's "middyfy" our handler, then we will be able to attach middlewares to it
export const handler = middy(helloWorld)
.use(httpHeaderNormalizer()) // Make sure authorization header is saved in lower case
.use(httpErrorHandler()) // This middleware is needed do handle the errors thrown by the JWTAuthMiddleware
.use(
JWTAuthMiddleware({
/** Algorithm to verify JSON web token signature */
algorithm: EncryptionAlgorithms.HS256,
/** An optional boolean that enables making authorization mandatory */
credentialsRequired: true,
/** An optional function that checks whether the token payload is formatted correctly */
isPayload: isTokenPayload,
/** A string or buffer containing either the secret for HMAC algorithms, or the PEM encoded public key for RSA and ECDSA */
secretOrPublicKey: "secret",
/**
* An optional function used to search for a token e. g. in a query string. By default, and as a fall back,
* event.headers.authorization and event.headers.Authorization are used.
*/
tokenSource: (event: any) => event.queryStringParameters.token,
}),
);