Authentication Backend
Provides minimal backend functionality for integrating with external
authentication providers.
Currently supports Google, GitHub and GitLab.
Install dependency
npm install --save authentication-backend
Usage
import express from 'express';
import { buildAuthenticationBackend } from 'authentication-backend';
const config = {
google: {
clientId: 'my-google-client-id',
authUrl: 'https://accounts.google.com/o/oauth2/auth',
tokenInfoUrl: 'https://oauth2.googleapis.com/tokeninfo',
},
github: {
clientId: 'my-github-client-id',
clientSecret: 'my-github-client-secret',
authUrl: 'https://github.com/login/oauth/authorize',
accessTokenUrl: 'https://github.com/login/oauth/access_token',
userUrl: 'https://api.github.com/user',
},
gitlab: {
clientId: 'my-gitlab-client-id',
authUrl: 'https://gitlab.com/oauth/authorize',
tokenInfoUrl: 'https://gitlab.com/oauth/token/info',
},
};
function tokenGranter(userId, service, externalId) {
const myUserSessionToken = uuidv4();
myDatabase.recordUserSession(myUserSessionToken, userId);
return myUserSessionToken;
}
const auth = buildAuthenticationBackend(config, tokenGranter);
express()
.use('/my-prefix', auth.router)
.listen(8080);
You will need to do some work for each service on the client-side too.
See the source in /example/static
for a reference implementation.
Mock SSO server
This package also contains a mock SSO server, which can be run alongside your app
(this is useful for local development and testing):
import express from 'express';
import { buildAuthenticationBackend, buildMockSsoApp } from 'authentication-backend';
buildMockSsoApp().listen(9000);
const config =
google: {
clientId: 'my-google-client-id',
authUrl: 'http://localhost:9000/auth',
tokenInfoUrl: 'http://localhost:9000/tokeninfo',
},
};
const auth = buildAuthenticationBackend(config, tokenGranter);
express()
.use('/my-prefix', auth.router)
.listen(8080);
Authentication Providers
Google sign in
You will need a Google client ID:
- Go to https://console.developers.google.com/apis
- Create a new project (if necessary)
- In the "Credentials" screen, find the auto-generated OAuth client
entry (if it was not created automatically, create one manually with
"Create credentials" → "OAuth client ID")
- Record the client ID (you will not need the client secret)
- Update the authorised JavaScript origins to match your deployment.
e.g. for local testing, this could be
http://localhost:8080
- Update the authorised redirect URIs to the same value, with
/<my-prefix>/google
appended to the end. - You may want to change the "Support email" listed under
"OAuth consent screen", as this will be visible to users of your
deployed app.
You can now configure the client ID in your app:
const config =
google: {
clientId: 'something.apps.googleusercontent.com',
authUrl: 'https://accounts.google.com/o/oauth2/auth',
tokenInfoUrl: 'https://oauth2.googleapis.com/tokeninfo',
},
};
GitHub sign in
You will need a GitHub client ID:
- Go to https://github.com/settings/applications/new
- Set the "Homepage URL" to match your deployment. e.g. for local
testing, this could be
http://localhost:8080
- Set the "Authorization callback URL" to the same value, with
/<my-prefix>/github
appended to the end. - Record the client ID and client secret.
You can now configure the client ID and secret in your app:
const config =
github: {
clientId: 'my-github-client-id',
clientSecret: 'my-github-client-secret',
authUrl: 'https://github.com/login/oauth/authorize',
accessTokenUrl: 'https://github.com/login/oauth/access_token',
userUrl: 'https://api.github.com/user',
},
};
GitLab sign in
You will need a GitLab client ID:
- Go to https://gitlab.com/profile/applications
- Set the "Redirect URI" to match your deployment with
/<my-prefix>/gitlab
appended to the end. e.g. for local
testing, this could be http://localhost:8080/<my-prefix>/gitlab
- Untick the "confidential" option. You do not need to enable
any scopes.
- Record the application ID (you will not need the secret).
You can now configure the application ID in your app:
const config =
gitlab: {
clientId: 'my-gitlab-application-id',
authUrl: 'https://gitlab.com/oauth/authorize',
tokenInfoUrl: 'https://gitlab.com/oauth/token/info',
},
};
API
This expects you to create a frontend which handles the user interaction and propagates returned data to the API.
GET /
This will return the public parts of your config (i.e. clientId
and authUrl
for each service).
Example:
{
"google": {
"clientId": "my-google-client-id",
"authUrl": "https://accounts.google.com/o/oauth2/auth"
},
"github": {
"clientId": "my-github-client-id",
"authUrl": "https://github.com/login/oauth/authorize"
},
"gitlab": {
"clientId": "my-gitlab-client-id",
"authUrl": "https://gitlab.com/oauth/authorize"
}
}
Any services which have not been configured will be omitted from the response.
POST /<service-name>
Where <service-name>
is google
, github
or gitlab
.
This expects to receive JSON-encoded data:
{
"externalToken": "token-returned-by-service"
}
It will check the token with the service, and if successful, will invoke the configured
tokenGranter
function with a user ID, service name, and service user ID. The string
returned by tokenGranter
will be sent to the user in a JSON response:
{
"userToken": "returned-token-granter-value"
}
If the check fails, an error will be returned instead, with a status code of 4xx or 5xx:
{
"error": "an error message"
}