svk-keycloak

svk-keycloak is a Sveltekit handle for authenticating with keycloak using OIDC authorization code flow. It does not create any session and supports both using and not using cookie to store credential information (i.e. access token).

Install

npm install svk-keycloak

API

import auth, {getSA_access_token} from 'svk-keycloak'

• auth({...}) // return SvelteKit hooks' handle.
• getSA_access_token(...) // return an access token of a service account.

handle function

In hooks.server.js

import auth from 'svk-keycloak'

export const handle = auth({
  realm: 'my_realm',
  client_id : 'test-svk-keycloak',
  client_secret : 'b16fa85f0916e1625c0d6f499a82be0f',
  keycloak_server: 'https://keycloak.example.com:8443',
  //use_cookie: false,
  //cookie_name: 'e17c17164bf9d72b565f62738bd5426f',
  //login_path: '/',
  unprotected_paths : [ '/public/*' ],
  //scopes: ''
})

Call the imported function (auth in this example) with an options obect to get a handle function.

options

realm, client_id and client_secret are mandatory.

keycloak_server is mandatory. There is no default value.

use_cookie is optional. Default is false. When true, the middleware will store access token in browser cookie. The cookie will be encrypted.

cookie_name is optional. Default is 'e17c17164bf9d72b565f62738bd5426f'. This is the name of an access token cookie.

login_path is optional. The default is '/'. This is a path that when users navigate to, they will be redirect to a login page.

unprotected_paths is optional. It is an array of wildcard matching paths that users are allowed to browse without logging in. The default value is an empty array, i.e. all paths are protected (required login). For details on matching syntax see https://www.npmjs.com/package/wildcard-match.

scopes is optional. The default is ''. Use to add client scope to the client i.e. "address phone" (separate scope with blank space).

login procedure

While users have not logged in, event.locals.auth will contain one key - login_path where user can navigate to for redirecting to a login page.

Once a user has sucessfully logged in, event.locals.auth will contain the following keys:

• access_token is user's access token to be used in Authorizatoin header of all futher (API) requests.
• claims is the payload part of the access_token.
• logout_url is a url that user can navigate to a logout page.

A +layout.server.js file should load event.locals.auth so that it will be available to the frontend (SvelteKit's pages). See the demo application below for how this can be done.

On subsequence server requests, if use_cookie is not true, the front-end may send an access token via an authorization header in the form 'baerer <access_token>'. However, on these requests, event.locals.auth.logout_url will be undefined. So, front-end should save logout_url from first successful login request for later use.

Apart from using authorization header, the middleware also supports sending an access token in a form (POST request) using field name authorization.

getSA_access_token

In +server.js of an API route:

import { getSA_access_token } from 'svk-auth'

export async function GET({ url, locals }) {
  const SA_access_token = await getSA_access_token({
    realm: 'my_realm',
    client_id : 'my_client',
    client_secret : '8a7090e35b9bce3f9cc113a54be346e8'
  })
  return new Response(SA_access_token)
}

In the above example, an API use getSA_access_token to return an access token for the service account of this client (application). Note that if the client does not have a service account enabled in keycloak, this will cause an exception.

Debugging

The package uses loglevel for error logging/debugging. Set loglevel environment variable to one of the five levels - error, warn, info, debug, trace. The default level is error. See loglevel's README for details.

Demo applicaiton

git clone https://github.com/kitinon/test-svk-keycloak.git

Source repository

git clone https://github.com/kitinon/svk-keycloak.git