How to use keycloak with NestJS properly

Question

I need to use keycloak with NestJS and GrapphQL (type-graphql). There are some guides for using it with pure Express, but I'd prefer using with NestJS auth pattern. Can someboby give any suggestion?

Answer 1

This is a kind of an old question, but since I just went through implementing it, I would like to point to a great tutorial Protecting your NestJS API with Keycloak. It does not use passport, but is simply call the OpenId Connect UserInfo endpoint on Keycloak: https://openid.net/specs/openid-connect-core-1_0.html#UserInfo.

I find it very easy to add to an application, very easy to follow, and generally very well usable (comparing to an unnamed SaaS application I was using before).

async authenticate(accessToken: string): Promise<User> {
    const url = `${this.baseURL}/realms/${this.realm}/protocol/openid-connect/userinfo`;

    try {
        const response = await this.httpService.get<KeycloakUserInfoResponse>(url, {
            headers: {
                authorization: `Bearer ${accessToken}`,
            },
        }).toPromise();

        return {
            id: response.data.sub,
            username: response.data.preferred_username,
        };
    } catch (e) {
        throw new AuthenticationError(e.message);
    }
}

Answer 2

I never tried it myself, but i guess i will soon. What i would do:

1. Check out the Authentication Technique again, and especially learn how to implement the different strategies of passport in nest: https://docs.nestjs.com/techniques/authentication
2. Take a look at the npm-package and it's documentation. The guys from passport have dedicated a whole section to OpenID: http://www.passportjs.org/docs/openid/
3. Implement the OpenID-Strategy in nestjs - here i would just follow the docs, since they are pretty good

I hope this will maybe help you out. At the end of the day, you will have an OpenID implementation of passport with KeyCloak and can use a guard to protect your Routes / Schemes.