feat(Feat/permission decorator): Add permissions for specific GraphQL…

… fields (#36)

* Feat: Implement graphql query guard

- Can add inaccessible field from query to block attack request

* Feat: Remove has count type

* Feat: Add check permission

* Chore: Remove test code

* Chore: Move md explanation

* Chore: Change name of class

* Docs: Readme.md

* Docs: Add note about permission guard

* Fix: typo

README.md

@@ -61,6 +61,11 @@ You can solve them with Sending JWT token in `Http Header` with the `Authorizati
 }
 ```
 
+#### Example of some protected GraphQL
+
+- getMe (must be authenticated)
+- All methods generated by the generator (must be authenticated and must be admin)
+
 ### GraphQL Query To Select and relations
 
 #### Dynamic Query Optimization
@@ -75,10 +80,31 @@ You can solve them with Sending JWT token in `Http Header` with the `Authorizati
 
 - You can find example code in [/src/user/user.resolver.ts](/src/user/user.resolver.ts)
 
-#### Example of some protected GraphQL
+### Permission for specific field
 
-- getMe (must be authenticated)
-- All methods generated by the generator (must be authenticated and must be admin)
+The [permission guard](/src/common/decorators/query-guard.decorator.ts) is used to block access to specific fields in client requests.
+
+#### Why it was created
+
+- In GraphQL, clients can request any field, which could expose sensitive information. This guard ensures that sensitive fields are protected.
+
+- It allows controlling access to specific fields based on the server's permissions.
+
+#### How to use
+
+```ts
+@Query(()=>Some)
+@UseQueryPermissionGuard(Some, { something: true })
+async getManySomeList(){
+  return this.someService.getMany()
+}
+```
+
+With this API, if the client request includes the field "something," a `Forbidden` error will be triggered.
+
+#### Note
+
+There might be duplicate code when using this guard alongside `other interceptors`(name: `UseRepositoryInterceptor`) in this boilerplate. In such cases, you may need to adjust the code to ensure compatibility.
 
 ## License
 

generator/templates/resolver.hbs

@@ -20,7 +20,7 @@ export class {{pascalCase tableName}}Resolver {
   @UseRepositoryInterceptor({{pascalCase tableName}})
   getMany{{pascalCase tableName}}List(
     @Args({ name: 'input', nullable: true }) condition: GetManyInput<{{pascalCase tableName}}>,
-    @GraphQLQueryToOption<{{pascalCase tableName}}>(true)
+    @GraphQLQueryToOption<{{pascalCase tableName}}>()
     option: GetInfoFromQueryProps<{{pascalCase tableName}}>,
   ) {
     return this.{{tableName}}Service.getMany({ ...condition, ...option });

src/common/decorators/option.decorator.ts

@@ -21,12 +21,11 @@ const addKeyValuesInObject = <Entity>({
   relations,
   select,
   expandRelation,
-  hasCountType,
 }: AddKeyValueInObjectProps<Entity>): GetInfoFromQueryProps<Entity> => {
   if (stack.length) {
     let stackToString = stack.join('.');
 
-    if (hasCountType) {
+    if (stack.length && stack[0] === DATA) {
       if (stack[0] !== DATA || (stack.length === 1 && stack[0] === DATA)) {
         return { relations, select };
       }
@@ -46,7 +45,6 @@ const addKeyValuesInObject = <Entity>({
 export function getOptionFromGqlQuery<Entity>(
   this: Repository<Entity>,
   query: string,
-  hasCountType?: boolean,
 ): GetInfoFromQueryProps<Entity> {
   const splitted = query.split('\n');
 
@@ -65,7 +63,7 @@ export function getOptionFromGqlQuery<Entity>(
 
       if (line.includes('{')) {
         stack.push(replacedLine);
-        const isFirstLineDataType = hasCountType && replacedLine === DATA;
+        const isFirstLineDataType = replacedLine === DATA;
 
         if (!isFirstLineDataType) {
           lastMetadata = lastMetadata.relations.find(
@@ -78,11 +76,9 @@ export function getOptionFromGqlQuery<Entity>(
           relations: acc.relations,
           select: acc.select,
           expandRelation: true,
-          hasCountType,
         });
       } else if (line.includes('}')) {
-        const hasDataTypeInStack =
-          hasCountType && stack.length && stack[0] === DATA;
+        const hasDataTypeInStack = stack.length && stack[0] === DATA;
 
         lastMetadata =
           stack.length < (hasDataTypeInStack ? 3 : 2)
@@ -110,7 +106,6 @@ export function getOptionFromGqlQuery<Entity>(
         stack: addedStack,
         relations: acc.relations,
         select: acc.select,
-        hasCountType,
       });
     },
     {
@@ -120,7 +115,7 @@ export function getOptionFromGqlQuery<Entity>(
   );
 }
 
-const getCurrentGraphQLQuery = (ctx: GqlExecutionContext) => {
+export const getCurrentGraphQLQuery = (ctx: GqlExecutionContext) => {
   const { fieldName, path } = ctx.getArgByIndex(3) as {
     fieldName: string;
     path: { key: string };
@@ -159,7 +154,7 @@ const getCurrentGraphQLQuery = (ctx: GqlExecutionContext) => {
   return stack.join('\n');
 };
 
-export const GraphQLQueryToOption = <T>(hasCountType?: boolean) =>
+export const GraphQLQueryToOption = <T>() =>
   createParamDecorator((_: unknown, context: ExecutionContext) => {
     const ctx = GqlExecutionContext.create(context);
     const request = ctx.getContext().req;
@@ -175,7 +170,6 @@ export const GraphQLQueryToOption = <T>(hasCountType?: boolean) =>
     const queryOption: GetInfoFromQueryProps<T> = getOptionFromGqlQuery.call(
       repository,
       query,
-      hasCountType,
     );
 
     return queryOption;

src/common/decorators/query-guard.decorator.ts

@@ -0,0 +1,20 @@
+import { SetMetadata, UseGuards, applyDecorators } from '@nestjs/common';
+
+import { FindOptionsSelect } from 'typeorm';
+
+import { GraphqlQueryPermissionGuard } from '../guards/graphql-query-permission.guard';
+
+export type ClassConstructor<T = unknown> = new (...args: unknown[]) => T;
+
+export const PERMISSION = Symbol('PERMISSION');
+export const INSTANCE = Symbol('INSTANCE');
+
+export const UseQueryPermissionGuard = <T extends ClassConstructor>(
+  instance: T,
+  permission: FindOptionsSelect<InstanceType<T>>,
+) =>
+  applyDecorators(
+    SetMetadata(INSTANCE, instance),
+    SetMetadata(PERMISSION, permission),
+    UseGuards(GraphqlQueryPermissionGuard<T>),
+  );

src/common/graphql/utils/types.ts

@@ -115,5 +115,4 @@ export interface AddKeyValueInObjectProps<Entity>
   extends GetInfoFromQueryProps<Entity> {
   stack: string[];
   expandRelation?: boolean;
-  hasCountType?: boolean;
 }

src/common/guards/graphql-query-permission.guard.ts

@@ -0,0 +1,57 @@
+import { ExecutionContext, Injectable } from '@nestjs/common';
+import { Reflector } from '@nestjs/core';
+import { GqlExecutionContext } from '@nestjs/graphql';
+
+import { DataSource, FindOptionsSelect } from 'typeorm';
+
+import {
+  getCurrentGraphQLQuery,
+  getOptionFromGqlQuery,
+} from '../decorators/option.decorator';
+import {
+  ClassConstructor,
+  INSTANCE,
+  PERMISSION,
+} from '../decorators/query-guard.decorator';
+import { GetInfoFromQueryProps } from '../graphql/utils/types';
+
+const checkPermission = <T extends ClassConstructor>(
+  permission: FindOptionsSelect<InstanceType<T>>,
+  select: FindOptionsSelect<InstanceType<T>>,
+): boolean => {
+  return Object.entries(permission)
+    .filter((v) => !!v[1])
+    .every(([key, value]) => {
+      if (typeof value === 'boolean') {
+        return select[key] ? false : true;
+      }
+
+      return checkPermission(value, select[key]);
+    });
+};
+
+@Injectable()
+export class GraphqlQueryPermissionGuard<T extends ClassConstructor> {
+  constructor(
+    private reflector: Reflector,
+    private readonly dataSource: DataSource,
+  ) {}
+
+  canActivate(context: ExecutionContext): boolean {
+    const permission = this.reflector.get<FindOptionsSelect<InstanceType<T>>>(
+      PERMISSION,
+      context.getHandler(),
+    );
+
+    const entity = this.reflector.get<T>(INSTANCE, context.getHandler());
+    const repository = this.dataSource.getRepository<T>(entity);
+
+    const ctx = GqlExecutionContext.create(context);
+    const query = getCurrentGraphQLQuery(ctx);
+
+    const { select }: GetInfoFromQueryProps<InstanceType<T>> =
+      getOptionFromGqlQuery.call(repository, query);
+
+    return checkPermission<T>(permission, select);
+  }
+}

src/user/user.resolver.ts

@@ -25,7 +25,7 @@ export class UserResolver {
   getManyUserList(
     @Args({ name: 'input', nullable: true })
     condition: GetManyInput<User>,
-    @GraphQLQueryToOption<User>(true)
+    @GraphQLQueryToOption<User>()
     option: GetInfoFromQueryProps<User>,
   ) {
     return this.userService.getMany({ ...condition, ...option });