npm package: @ifjkt/nest-oidc
Description: An OIDC authentication module for NestJS APIs
Author: Tamas Kiss
Latest version: 10.4.0

# NestJS OIDC

![npm](https://img.shields.io/npm/v/@ifjkt/nest-oidc.svg)
![NPM](https://img.shields.io/npm/l/@ifjkt/nest-oidc.svg)

A configurable OIDC library for NestJS and GraphQL or REST.

- [Install](#install)
- [Basic Setup & Usage](#basic-setup--usage)
- [Guards](#guards)
  - [REST](#rest-guard)
  - [GraphQL](#graphql-guard)
- [Current User](#current-user)
  - [REST](#rest-user)
  - [GraphQL](#graphql-user)
- [Roles](#roles)
- [Role Evaluators](#role-evaluators)
- [JWT Mapping](#jwt-mapping)
- [Advanced](#advanced)
  - [Authenticating GraphQL Subscriptions](#authenticating-graphql-subscriptions)
  - [Optional Authentication](#optional-authentication)
- [Release](#release)

## Install

Install `nest-oidc`:

```sh
npm i @ifjkt/nest-oidc
```

Install it's peer dependencies:

```sh
npm i @nestjs/jwt @nestjs/passport passport passport-jwt
```

:warning: Note: If you're using this package for GraphQL you'll need the
corresponding GQL libraries installed.
[Please follow the NestJS documentation first.](https://docs.nestjs.com/graphql/quick-start)

## Basic Setup & Usage

You'll need to import and configure the `AuthModule` in your application. This
package contains a JWT authentication strategy which will validate a JWT against
the issuer's public key. You must pass configure a value for the `oidcAuthority`.

```ts
import { Module } from '@nestjs/common';
import { AuthModule } from '@5stones/nest-oidc';

@Module({
  imports: [
    ...AuthModule.forRoot({
      oidcAuthority: 'http://iam.app.com/auth/realms/app',
    }),
  ],
})
export class AppModule {}
```

This will add the JWT validation strategy, and will verify any incoming JWT's
against the OIDC authorities public keys.

Finally, you should decorate your endpoints with the provided guards.

## Guards

This package exports two basic guards:

- `JwtAuthGuard` - for use in REST contexts.
- `JwtAuthGuardGraphQL` - for use in GQL contexts.

#### REST Guard

Applying the guard will require a valid JWT to be passed in order to access any
of the controller endpoints:

```ts
import { Controller, Get, UseGuards } from '@nestjs/common';
import { Roles, JwtAuthGuard } from '@5stones/nest-oidc';

@UseGuards(JwtAuthGuard)
@Controller('cats')
export class CatsController {
  @Get()
  findAll(): string {
    return 'This action returns all cats';
  }
}
```

You can also use it on specific endpoints:

```ts
import { Controller, Get, Post, UseGuards } from '@nestjs/common';
import { Roles, JwtAuthGuard } from '@5stones/nest-oidc';

@Controller('cats')
export class CatsController {
  @UseGuards(JwtAuthGuard)
  @Post()
  create(): string {
    return 'This action adds a new cat';
  }

  @Get()
  findAll(): string {
    return 'This action returns all cats';
  }
}
```

#### GraphQL Guard

Applying the guard will require a valid JWT to be passed in order to access any
of the controller endpoints:

```ts
import { UseGuards } from '@nestjs/common';
import { Resolver } from '@nestjs/graphql';
import { JwtAuthGuardGraphQL } from '@5stones/nest-oidc';

@UseGuards(JwtAuthGuardGraphQL)
@Resolver(() => Cat)
export class CatResolver {
  ...
}
```

You can also use it on specific endpoints:

```ts
import { UseGuards } from '@nestjs/common';
import { Resolver, Query, Mutation } from '@nestjs/graphql';
import { JwtAuthGuardGraphQL } from '@5stones/nest-oidc';

@Resolver(() => Cat)
export class CatResolver {

  @Query(() => [Cat], { name: 'allCats' })
  async findAll() {
    ...
  }

  @UseGuards(JwtAuthGuardGraphQL)
  @Mutation(() => Cat, { name: 'createCat' })
  async create() {
    ...
  }
}
```

## Current User

This package exports two basic user decorators:

- `CurrentUser` - for use in REST contexts.
- `CurrentUserGraphQL` - for use in GQL contexts.

#### REST User

```ts
import { Controller, Get, UseGuards } from '@nestjs/common';
import { Roles, JwtAuthGuard, CurrentUser } from '@5stones/nest-oidc';

@UseGuards(JwtAuthGuard)
@Controller('cats')
export class CatsController {
  @Get()
  findAll(@CurrentUser() user: any): string {
    return 'This action returns all cats';
  }
}
```

#### GraphQL User

```ts
import { UseGuards } from '@nestjs/common';
import { Resolver, Query } from '@nestjs/graphql';
import { JwtAuthGuardGraphQL, CurrentUserGraphQL } from '@5stones/nest-oidc';

@UseGuards(JwtAuthGuardGraphQL)
@Resolver(() => Cat)
export class CatResolver {

  @Query(() => [Cat], { name: 'allCats' })
  async findAll(@CurrentUserGraphQL() user: any) {
    ...
  }
}
```

## Roles

If you want to permission different endpoints based on properties of the JWT you
can do so using the `Roles` decorator in conjunction with the Auth Guards (both
REST & GQL). The `Roles` decorator will accept a list of `string`s and will
check if the user object accessing that endpoint has any of those strings in the
`user.roles` property. It expects the `user.roles` property to be a flat array
of strings.

#### Example

```ts
import { UseGuards } from '@nestjs/common';
import { Resolver, Query, Mutation, Args, ID } from '@nestjs/graphql';
import { JwtAuthGuardGraphQL, Roles } from '@5stones/nest-oidc';

@UseGuards(JwtAuthGuardGraphQL)
@Resolver(() => Cat)
export class CatResolver {

  @Query(() => [Cat], { name: 'allCats' })
  async findAll(): Promise<Cat[]> {
    ...
  }

  @Roles()
  @Query(() => Cat, { name: 'Cat' })
  async findOne(@Args('id', { type: () => ID }) id: number): Promise<Cat> {
    ...
  }

  @Roles('ADMIN', 'SUPER_ADMIN')
  @Mutation(() => Cat, { name: 'createCat' })
  async create(): Promise<Cat> {
    ...
  }
}
```

In this scenario, the mutation can only be executed by an `ADMIN` or `SUPER_ADMIN`
but the query can be executed by any user with a valid JWT.

:warning: Note: if you do not pass _any_ roles parameters to the `Roles`
decorator (i.e. `@Roles()`) it is the same as not adding the decorator at all.
That is to say, any scenario above the `findAll` and the `findOne` queries
behave identically.

## Roles

You can define your own set of roles based on either the JWT payload and or other logic.
You can also use forRootAsync() to inject services to determine the role of the user.

You can simply decorate your endpoint with the `@Roles('ADMIN')`
annotation in order to lock it down to users of that role.

## JWT Mapper

By default, the JWT payload is passed as the user into the application. However,
if you need to map the JWT payload to different structure you can pass the
`jwtMapper` option:

```ts
import { Module } from '@nestjs/common';
import { AuthModule } from '@5stones/nest-oidc';

@Module({
  imports: [
    ...
    AuthModule.forRoot({
      oidcAuthority: 'http://iam.app.com/auth/realms/app',
      jwtMapper: async (payload: any) => ({
        id: payload.sub,
        email: payload.email,
        ...
      }),
    }),
  ],
})
export class AppModule {}
```

## Advanced

#### Authenticating GraphQL Subscriptions

The websocket spec doesn't support headers, so if you want to authenticate a
GraphQL Subscription via the standard Guard & Role decorators you can do so, but
you'll need to modify your `GraphQLModule` configuration. The below example will
walk you through how to do it with the `graphql-ws` library.

The first step is to make sure that you're passing the Auth token as a parameter
through your websocket request. [Read more in the `graphql-ws` docs](https://github.com/enisdenjo/graphql-ws#user-content-apollo-client)

Next you'll need to modify the `GraphQLModule`'s `onConnect` and `context`
functions to map the token and the request. You [can read the NestJS documentation](https://docs.nestjs.com/graphql/subscriptions#authentication-over-websocket)
on generally how to do this, but that documentation only deals with the validation
of the token directly in the `onConnect` function. However to allow it to be
done by the Guards you'll need to map the token into a header on a request object
and then ensure that you're always returning a request to be processed by the
`JwtStrategy`. See the example below:

```ts
// app.module.ts
...
import type { Context } from 'graphql-ws';

...
@Module({
  imports: [
    GraphQLModule.forRoot({
      ...
      subscriptions: {
        'graphql-ws': {
          onConnect: (context: Context<any>) => {
            const { connectionParams, extra } = context;
            const authToken = connectionParams?.Authorization;

            if (authToken) {
              // Add the auth token to the request object provided by `graphql-ws`
              // NOTE: headers are lowercased in express. Using `Authorization`
              // will result in a failure to authenticate.
              extra.request.headers.authorization = authToken;
            }
          },
        }
      },
      context: (context) => {
        if (context?.req === undefined) {
          // The jwt strategy requires a request with headers to perform jwt
          // validation. If no request exists in the context object then we're
          // dealing with a websocket connection. In that case pass along the
          // request object provided by the `graphql-ws` context for validation.
          context.req = context.extra.request;
        }

        // return the context object.
        return context;
      },
    }),
    ...
  ],
})
export class AppModule implements NestModule {
  ...
}
```

Once this has been configured you'll be able to apply the `JwtAuthGuardGraphQL`
and `Roles` decorators as you would on any other resolver, query, or mutation.

#### Optional Authentication

You can use the `IsAuthenticationOptional` decorator on an endpoint or resolver
in conjunction with an auth guard. If this is done so, then JWTs will populate
`user` object as expected. If an invalid JWT is passed or no JWT is passed at
all, then no user will be populated on the request.

## Release

The standard release command for this project is:

```
npm version [<newversion> | major | minor | patch | premajor | preminor | prepatch | prerelease | from-git]
```

This command will:

1. Generate/update the Changelog
1. Bump the package version
1. Tag & pushing the commit

e.g.

```
npm version 1.2.17
npm version patch // 1.2.17 -> 1.2.18
```

## Additional information
Based on: https://github.com/5-stones/nest-oidc