Authorization - Nestjs-query

The following section assumes you are familiar with authentication in nestjs.

nestjs-query provides authorization helpers out of the box to reduce the amount of boilerplate typically required. The nestjs-query graphql package exposes decorators and options to allow the following

Additional filtering for objects based on the graphql context.
Filtering relations based on the graphql context.
Low level authorization service support when your authorizer needs to use other services or additional information that is not in the graphql context.

If you are looking to modify incoming requests based on the context, take a look at the hooks documentation

Authorization is invoked as the last step before calling the QueryService.

Getting Started

All examples assume you have a guard that adds a user to the req on the context.

type AuthenticatedUser = {
  id: number
  username: string
}
type UserContext = {
  req: {
    user: AuthenticatedUser
  }
}

For the sake of this example we’ll use a JWTAuthGuard described in implementing passport jwt nestjs docs. To enable the guard on your resolver endpoints you use the guards option when setting up your resolver. The guards option will ensure that all queries and mutations will have the guard added so the user is added to the request. todo-item/todo-item.module.ts

import { NestjsQueryGraphQLModule } from '@ptc-org/nestjs-query-graphql'
import { NestjsQueryTypeOrmModule } from '@ptc-org/nestjs-query-typeorm'
import { Module } from '@nestjs/common'
import { TodoItemInputDTO } from './dto/todo-item-input.dto'
import { TodoItemUpdateDTO } from './dto/todo-item-update.dto'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'
import { JwtAuthGuard } from '../auth/jwt-auth.guard'

@Module({
  imports: [
    NestjsQueryGraphQLModule.forFeature({
      imports: [NestjsQueryTypeOrmModule.forFeature([TodoItemEntity])],
      resolvers: [
        {
          DTOClass: TodoItemDTO,
          CreateDTOClass: TodoItemInputDTO,
          UpdateDTOClass: TodoItemUpdateDTO,
          guards: [JwtAuthGuard]
        }
      ]
    })
  ]
})
export class TodoItemModule {}

@Authorize Decorator

The @ptc-org/nestjs-query-graphql package includes an @Authorize decorator that allows you to add additional filter criteria to authorize an incoming request. The @Authorize decorator accepts the following types.

An object that has an authorize method that returns a Filter for the DTO.
An instance of an Authorizer that implements the authorize and authorizeRelation methods.
An Authorizer class reference that implements the Authorizer interface. The Authorizer class will be instantiated using the nestjs’s dependency injection.

The @Authorize decorator does not return an unauthorized error instead the following will occur:

queryMany results will not include any DTOs that do not match the filter criteria.
findOne will return a not found for a DTO that cannot be found for the id and auth filter.
updateOne will return a not found error if the DTO to update cannot be found for the id and auth filter.
updateMany will exclude any records that do not match the user provided filter and the auth filter from being updated.
deleteOne will return a not found error if the DTO to delete cannot be found for the id and auth filter.
deleteMany will exclude any records that do not match the user provided filter and the auth filter from being deleted.

You can throw an UnauthorizedException or return a rejected promise with an UnauthorizedException in your authorize function, if you can determine at that point that the user should not be able to access the endpoint.

In the following example the authorize function returns a Filter that includes the ownerId to ensure that only TodoItems that belong to the authenticated user are returned. todo-item/dto/todo-item.dto.ts

import { FilterableField, IDField, FilterableConnection, FilterableRelation, Authorize } from '@ptc-org/nestjs-query-graphql'
import { ObjectType, ID, GraphQLISODateTime, Field } from '@nestjs/graphql'
import { SubTaskDTO } from '../../sub-task/dto/sub-task.dto'
import { TagDTO } from '../../tag/dto/tag.dto'
import { UserDTO } from '../../user/user.dto'
import { UserContext } from '../../auth/auth.interfaces'

@ObjectType('TodoItem')
@Authorize({ authorize: (context: UserContext) => ({ ownerId: { eq: context.req.user.id } }) })
@FilterableRelation('owner', () => UserDTO)
@FilterableConnection('subTasks', () => SubTaskDTO, { update: { enabled: true } })
@FilterableConnection('tags', () => TagDTO)
export class TodoItemDTO {

  @IDField(() => ID)
  id!: number

  @FilterableField()
  title!: string

  @FilterableField({ nullable: true })
  description?: string

  @FilterableField()
  completed!: boolean

  @FilterableField(() => GraphQLISODateTime)
  created!: Date

  @FilterableField(() => GraphQLISODateTime)
  updated!: Date

  @Field()
  age!: number

  @FilterableField()
  priority!: number

  @FilterableField({ nullable: true })
  createdBy?: string

  @FilterableField({ nullable: true })
  updatedBy?: string

  @FilterableField()
  ownerId!: number
}

The above example is pretty straight forward, however your authorize function can be as complex as you need it to be based on information in the context.

Relation Filtering

By default when relations are queried any additional filters defined using the @Authorize decorator on the relation DTO will also be included. When mutating relations

If the DTO that is having a relation(s) added or removed cannot be found for the id and auth filter a not found error will be returned.
When adding or removing a single relation if the relation cannot be found for the id and auth filter a not found error will be returned.
When adding or removing multiple relations if all relations cannot be found a not found error will be throw.

For example given the following SubTaskDTO definition whenever the subTasks connection is queried through a todoItem, only subTasks that belong to the user will be returned. sub-task/dto/sub-task.dto.ts

import { FilterableField, IDField, FilterableRelation, Authorize } from '@ptc-org/nestjs-query-graphql'
import { ObjectType, ID, GraphQLISODateTime } from '@nestjs/graphql'
import { TodoItemDTO } from '../../todo-item/dto/todo-item.dto'
import { UserContext } from '../../auth/auth.interfaces'

@ObjectType('SubTask')
@Authorize({ authorize: (context: UserContext) => ({ ownerId: { eq: context.req.user.id } }) })
@FilterableRelation('todoItem', () => TodoItemDTO, { update: { enabled: true } })
export class SubTaskDTO {

  @IDField(() => ID)
  id!: number

  @FilterableField()
  title!: string

  @FilterableField({ nullable: true })
  description?: string

  @FilterableField()
  completed!: boolean

  @FilterableField(() => GraphQLISODateTime)
  created!: Date

  @FilterableField(() => GraphQLISODateTime)
  updated!: Date

  @FilterableField()
  todoItemId!: string

  @FilterableField({ nullable: true })
  createdBy?: string

  @FilterableField({ nullable: true })
  updatedBy?: string
}

Customizing Relation Authorization

If you run into a case where you need to handle authorization for a relation differently from the @Authorize decorator on the relation DTO you can specify the auth option in your relation/connection decorator.

The auth option will take precedence over the @Authorize decorator on the relation DTO.

For example you could define the subtasks with the auth option, only allowing completed subtasks to be returned.

@FilterableConnection('subTasks', () => SubTaskDTO, {
  update: { enabled: true },
  auth: {
    authorize: (context: UserContext) => ({ ownerId: { eq: context.req.user.id }, completed: { is: true }}),
  },
})

Custom Authorizer

When you need more control over authorization you can create a CustomAuthorizer. You may want to use a CustomAuthorizer if you need to use additional services to do authorization for a DTO. The CustomAuthorizer interface ensures two methods:

authorize - Should return a filter that should be used for all queries and mutations for the DTO.
authorizeRelation - Optionally modify the filter for the relation that will be used when querying the relation or adding/removing relations to/from the DTO. If undefined is returned, the authorization filter of the relation DTO will be used instead.

In this example we’ll create a simple authorizer for SubTasks. You can use this as a base to create a more complex authorizers that depends on other services. sub-task/sub-task.authorizer.ts

import { Injectable } from '@nestjs/common'
import { Authorizer } from '@ptc-org/nestjs-query-graphql'
import { Filter } from '@ptc-org/nestjs-query-core'
import { UserContext } from '../auth/auth.interfaces'
import { SubTaskDTO } from './dto/sub-task.dto'

@Injectable()
export class SubTaskAuthorizer implements CustomAuthorizer<SubTaskDTO> {

  authorize(context: UserContext): Promise<Filter<SubTaskDTO>> {
    return Promise.resolve({ ownerId: { eq: context.req.user.id } })
  }
  authorizeRelation(relationName: string, context: UserContext): Promise<Filter<unknown> | undefined> {
    if (relationName === 'todoItem') {
      return Promise.resolve({ ownerId: { eq: context.req.user.id } })
    }
    return Promise.resolve(undefined)
  }
}

To use the SubTaskAuthorizer you only need to provide it as an argument to the @Authorize decorator sub-task/sub-task.dto.ts

import { Authorize, FilterableField, IDField, FilterableRelation } from '@ptc-org/nestjs-query-graphql'
import { ObjectType, ID, GraphQLISODateTime } from '@nestjs/graphql'
import { TodoItemDTO } from '../../todo-item/dto/todo-item.dto'
import { UserDTO } from '../../user/user.dto'
import { SubTaskAuthorizer } from '../sub-task.authorizer'

@ObjectType('SubTask')
@Authorize(SubTaskAuthorizer)
@FilterableRelation('owner', () => UserDTO)
@FilterableRelation('todoItem', () => TodoItemDTO, { update: { enabled: true } })
export class SubTaskDTO {

  @IDField(() => ID)
  id!: number

  @FilterableField()
  title!: string

  @FilterableField({ nullable: true })
  description?: string

  @FilterableField()
  completed!: boolean

  @FilterableField(() => GraphQLISODateTime)
  created!: Date

  @FilterableField(() => GraphQLISODateTime)
  updated!: Date

  @FilterableField()
  todoItemId!: string

  @FilterableField({ nullable: true })
  createdBy?: string

  @FilterableField({ nullable: true })
  updatedBy?: string
  ownerId!: number
}

Using Authorizers In Your Resolver

The easiest way to leverage Authorizers in a custom resolver is to use the AuthorizerInterceptor and AuthorizerFilter param decorator. In this example there are two important additions:

The AuthorizerInterceptor is added to the TodoItemResolver as an interceptor, this interceptor will add the authorizer to the context so it can be used down stream
The AuthorizerFilter param decorator uses the authorizer added by the interceptor to create an authorizer filter.

todo-item/todo-item.resolver.ts

import { Filter, InjectQueryService, mergeFilter, mergeQuery, QueryService } from '@ptc-org/nestjs-query-core'
import { AuthorizerInterceptor, AuthorizerFilter, ConnectionType } from '@ptc-org/nestjs-query-graphql'
import { Args, Query, Resolver } from '@nestjs/graphql'
import { UseInterceptors } from '@nestjs/common'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemConnection, TodoItemQuery } from './types'

@Resolver(() => TodoItemDTO)
@UseInterceptors(AuthorizerInterceptor(TodoItemDTO))
export class TodoItemResolver {

  constructor(@InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemEntity>) {}
  // Set the return type to the TodoItemConnection

  @Query(() => TodoItemConnection)
  async uncompletedTodoItems(
    @Args() query: TodoItemQuery,
    @AuthorizerFilter() authFilter: Filter<TodoItemDTO>
  ): Promise<ConnectionType<TodoItemDTO>> {
    // add the completed filter the user provided filter
    const filter: Filter<TodoItemDTO> = mergeFilter(query.filter ?? {}, { completed: { is: false } })
    const uncompletedQuery = mergeQuery(query, { filter: mergeFilter(filter, authFilter) })
    return TodoItemConnection.createFromPromise(
      (q) => this.service.query(q),
      uncompletedQuery,
      (q) => this.service.count(q)
    )
  }
}

@InjectAuthorizer Decorator

If you need access to an authorizer for a DTO you can use the @InjectAuthorizer decorator. The most common use case for using the @InjectAuthorizer decorator is when you are not using the autogenerated resolvers provided by nestjs-query. In this example the Authorizer is injected as a readonly property you can then use it for any custom methods. todo-item/todo-item.resolver.ts

import { QueryService, InjectQueryService } from '@ptc-org/nestjs-query-core'
import { CRUDResolver, InjectAuthorizer } from '@ptc-org/nestjs-query-graphql'
import { Resolver, Query, Args } from '@nestjs/graphql'
import { TodoItemDTO } from './dto/todo-item.dto'
import { TodoItemEntity } from './todo-item.entity'

@Resolver(() => TodoItemDTO)
export class TodoItemResolver extends CRUDResolver(TodoItemDTO) {

  constructor(
    @InjectQueryService(TodoItemEntity) readonly service: QueryService<TodoItemEntity>,
    @InjectAuthorizer(TodoItemDTO) readonly authorizer: Authorizer<TodoItemDTO>
  ) {
    super(service)
  }
}

If you are extending the CRUDResolver directly be sure to register your DTOs with the NestjsQueryGraphQLModule

When using @InjectAuthorizer, the injected Authorizer is not the CustomAuthorizer, but the DefaultCRUDAuthorizer that internally uses the CustomAuthorizer. If you want to use the CustomAuthorizer directly, inject it with @InjectCustomAuthorizer instead.

Authorize depending on operation

Sometimes it might be necessary to perform different authorization based on the kind of operation an user wants to execute. E.g. some users could be allowed to read all todo items but only update/delete their own. In this case we can make use of the second parameter of the authorize function in our CustomAuthorizer or the one passed to the @Authorizer decorator which gets passed additional AuthorizationContext such as the name of the operation that should be authorized: sub-task/sub-task.authorizer.ts

import { Injectable } from '@nestjs/common'
import { CustomAuthorizer } from '@ptc-org/nestjs-query-graphql'
import { Filter } from '@ptc-org/nestjs-query-core'
import { UserContext } from '../auth/auth.interfaces'
import { SubTaskDTO } from './dto/sub-task.dto'

@Injectable()
export class SubTaskAuthorizer implements CustomAuthorizer<SubTaskDTO> {

  authorize(context: UserContext, authorizationContext?: AuthorizationContext): Promise<Filter<SubTaskDTO>> {
    if (authorizationContext?.readonly) {
      return Promise.resolve({})
    }
    return Promise.resolve({ ownerId: { eq: context.req.user.id } })
  }
  authorizeRelation(relationName: string, context: UserContext): Promise<Filter<unknown>> {
    if (relationName === 'todoItem') {
      return Promise.resolve({ ownerId: { eq: context.req.user.id } })
    }
    return Promise.resolve({})
  }
}

The AuthorizationContext has the following shape: authorizer.ts

export enum OperationGroup {

  READ = 'read',
  AGGREGATE = 'aggregate',
  CREATE = 'create',
  UPDATE = 'update',
  DELETE = 'delete'
}
interface AuthorizationContext {

  /** The name of the method that uses the @AuthorizeFilter decorator */
  operationName: string
  /** The group this operation belongs to */
  operationGroup: OperationGroup
  /** If the operation does not modify any entities */
  readonly: boolean
  /** If the operation can affect multiple entities */
  many: boolean
}

This context is automatically created for you when using the built-in resolvers. If you authorize custom methods by using the @AuthorizerFilter(), you should pass the context as argument to the decorator:

@AuthorizerFilter({
  operationName: 'completedTodoItems',
  operationGroup: OperationGroup.READ,
  readonly: true,
  many: true
})

You can leave out the operationName to let the context use the name of the decorated Method. If you leave out the readonly property, it’s inferred from the operationGroup. The operationNames of the generated CRUD resolver methods are similar to the ones of the QueryService:

queryMany
findById
aggregate
createOne
createMany
updateOne
updateMany
deleteOne
deleteMany

Relations

query{PluralRelationName} (e.g. querySubTasks)
find{SingularRelationName} (e.g. findTodoItem)
aggregate{PluralRelationName} (e.g. aggregateSubTasks)
remove{SingularRelationName}from{SingularParentName} (e.g. removeSubTaskFromTodoItem)
remove{PluralRelationName}from{SingularParentName} (e.g. removeSubTasksFromTodoItem)
set{SingularRelationName}On{SingularParentName} (e.g. setSubTaskOnTodoItem)
add{PluralRelationName}On{SingularParentName} (e.g. addSubTasksOnTodoItem)

Complete Example

You can find a complete example in ../../../examples/auth Edit this page

​Getting Started​

​@Authorize Decorator​

​Relation Filtering​

​Customizing Relation Authorization​

​Custom Authorizer​

​Using Authorizers In Your Resolver​

​@InjectAuthorizer Decorator​

​Authorize depending on operation​

​Complete Example​

Getting Started

@Authorize Decorator

Relation Filtering

Customizing Relation Authorization

Custom Authorizer

Using Authorizers In Your Resolver

@InjectAuthorizer Decorator

Authorize depending on operation

Complete Example