feat: new and guard (#32)

With the new`AndGuard`, devs can now set up cases where they want to use
an `OrGuard` to handle an `(A && B) || C` kind of condition, or any
other complex logical approach they'd like. Devs are also now able to
correctly pass injection tokens to the `AndGuard` and `OrGuard` and use
custom providers for their guards that are registered as providers

.changeset/tame-eels-impress.md

@@ -0,0 +1,9 @@
+---
+'@nest-lab/or-guard': minor
+---
+
+Add a new AndGuard to handle complex logical cases
+
+With the new `AndGuard` it is now possible to create logical cases like
+`(A && B) || C` using the `OrGuard` and a composite guard approach. Check out
+the docs for more info

.prettierrc

@@ -1,3 +1,5 @@
 {
-  "singleQuote": true
-}
+  "printWidth": 80,
+  "singleQuote": true,
+  "proseWrap": "always"
+}

packages/or-guard/README.md

@@ -1,6 +1,8 @@
-# or-guard
+# @nest-lab/or-guard
 
-This library contains a single guard that allows for checking multiple guards and if **any one of them passes** the entire request will be considered authenticated.
+This library contains a two guards that allows for checking multiple guards and
+creating complex logical statements based on the results of those guards for if
+the request should be completed or not.
 
 ## Installation
 
@@ -12,39 +14,104 @@ yarn add @nest-lab/or-guard
 pnpm i @nest-lab/or-guard
 ```
 
-## Usage
+## OrGuard
 
-To use the `OrGuard`, there are a couple of things that need to happen, due to how the guard resolves the guards it's going to be using.
+To use the `OrGuard`, there are a couple of things that need to happen, due to
+how the guard resolves the guards it's going to be using.
 
-First, make sure to add all the guards the `OrGuard` will be using to the current module's `providers` array. Enhancer in Nest are just specialized providers after all. This will allow the `OrGuard` to use a `ModuleRef` to get these guards.
+First, make sure to add all the guards the `OrGuard` will be using to the
+current module's `providers` array. Enhancer in Nest are just specialized
+providers after all. This will allow the `OrGuard` to use a `ModuleRef` to get
+these guards. The guards can either be registered directly as providers, or set
+up as custom providers and you may use an injection token reference. Make sure,
+that if you use a custom provider, the _instance_ of the guard is what is tied
+to the token, not the reference to the class.
 
-Second, make sure **none** of these guards are `REQUEST` or `TRANSIENT` scoped, as this **will** make the `OrGuard` throw an error.
+Second, make sure **none** of these guards are `REQUEST` or `TRANSIENT` scoped,
+as this **will** make the `OrGuard` throw an error.
 
-Third, make use of it! The `OrGuard` takes in an array of guard to use for the first parameter, and an optional second parameter for options as described below.
+Third, make use of it! The `OrGuard` takes in an array of guard to use for the
+first parameter, and an optional second parameter for options as described
+below.
 
-> **important**: for Nest v7, use `@nest-lab/or-guard@1.0.0`, for Nest v8, please use v2
+> **important**: for Nest v7, use `@nest-lab/or-guard@1.0.0`, for Nest v8,
+> please use v2
 
 ```ts
-OrGuard(guards: CanActivate[], orGuardOptions?: OrGuardOptions): CanActivate
+OrGuard(guards: Array<Type<CanActivate> | InjectionToken>, orGuardOptions?: OrGuardOptions): CanActivate
 ```
 
-- `guards`: an array of guards for the `OrGuard` to resolve and test
-- `orGuardOptions`: an optional object with properties to modify how the `OrGuard` functions
+- `guards`: an array of guards or injection tokens for the `OrGuard` to resolve
+  and test
+- `orGuardOptions`: an optional object with properties to modify how the
+  `OrGuard` functions
 
 ```ts
 interface OrGuardOptions {
   throwOnFirstError?: boolean;
 }
 ```
 
-- `throwOnFirstError`: a boolean to tell the `OrGuard` whether to throw if an error is encountered or if the error should be considered a `return false`. The default value is `false`. If this is set to `true`, the **first** error encountered will lead to the same error being thrown.
+- `throwOnFirstError`: a boolean to tell the `OrGuard` whether to throw if an
+  error is encountered or if the error should be considered a `return false`.
+  The default value is `false`. If this is set to `true`, the **first** error
+  encountered will lead to the same error being thrown.
+
+> **Note**: guards are ran in a non-deterministic order. All guard returns are
+> transformed into Observables and ran concurrently to ensure the fastest
+> response time possible.
+
+## AndGuard
+
+Just like the `OrGuard`, you can create a logic grouping of situations that
+should pass. This is Nest's default when there are multiple guards passed to the
+`@UseGuards()` decorator; however, there are situations where it would be useful
+to use an `AndGuard` inside of an `OrGuard` to be able to create logic like
+`(A && B) || C`. With using an `AndGuard` inside of an `OrGuard`, you'll most
+likely want to create a dedicated [custom provider][customprov] for the guard
+like so:
+
+```typescript
+{
+  provide: AndGuardToken,
+  useClass: AndGuard([GuardA, GuardB])
+}
+```
+
+With this added to the module's providers where you plan to use the related
+`OrGuard` you can use the following in a controller or resolve:
+
+```typescript
+@UseGuards(OrGuard([AndGuardToken, GuardC]))
+```
+
+And this library will set up the handling of the logic for
+`(GuardA && GuardB) || GuardC` without having to worry about the complexities
+under the hood.
+
+```ts
+AndGuard(guards: Array<Type<CanActivate> | InjectionToken>, orGuardOptions?: OrGuardOptions): CanActivate
+```
+
+- `guards`: an array of guards or injection tokens for the `AndGuard` to resolve
+  and test
+- `orGuardOptions`: an optional object with properties to modify how the
+  `OrGuard` functions
 
-> **Note**: guards are ran in a non-deterministic order. All guard returns are transformed into Observables and ran concurrently to ensure the fastest response time possible.
+```ts
+interface OrGuardOptions {
+  throwOnFirstError?: boolean;
+}
+```
 
 ## Local Development
 
-Feel free to pull down the repository and work locally. If any changes are made, please make sure tests are added to ensure the functionality works and nothing is broken.
+Feel free to pull down the repository and work locally. If any changes are made,
+please make sure tests are added to ensure the functionality works and nothing
+is broken.
 
 ### Running unit tests
 
 Run `nx test or-guard` to execute the unit tests via [Jest](https://jestjs.io).
+
+[customprov]: https://docs.nestjs.com/fundamentals/custom-providers

packages/or-guard/package.json

@@ -11,6 +11,10 @@
   "publishConfig": {
     "access": "public"
   },
+  "main": "src/index.js",
+  "files": [
+    "src"
+  ],
   "repository": {
     "type": "github",
     "url": "https://github.com/jmcdo29/nest-lab",

packages/or-guard/src/index.ts

@@ -1 +1,2 @@
+export * from './lib/and.guard';
 export * from './lib/or.guard';

packages/or-guard/src/lib/and.guard.ts

@@ -0,0 +1,85 @@
+import {
+  CanActivate,
+  ExecutionContext,
+  Inject,
+  InjectionToken,
+  mixin,
+  Type,
+} from '@nestjs/common';
+import { ModuleRef } from '@nestjs/core';
+import {
+  defer,
+  from,
+  Observable,
+  of,
+  OperatorFunction,
+  throwError,
+} from 'rxjs';
+import { catchError, last, mergeMap, every } from 'rxjs/operators';
+
+interface OrGuardOptions {
+  throwOnFirstError?: boolean;
+}
+
+export function AndGuard(
+  guards: Array<Type<CanActivate> | InjectionToken>,
+  orGuardOptions?: OrGuardOptions
+) {
+  class AndMixinGuard implements CanActivate {
+    private guards: CanActivate[] = [];
+    constructor(@Inject(ModuleRef) private readonly modRef: ModuleRef) {}
+    canActivate(context: ExecutionContext): Observable<boolean> {
+      this.guards = guards.map((guard) => this.modRef.get(guard));
+      const canActivateReturns: Array<Observable<boolean>> = this.guards.map(
+        (guard) => this.deferGuard(guard, context)
+      );
+      return from(canActivateReturns).pipe(
+        mergeMap((obs) => {
+          return obs.pipe(this.handleError());
+        }),
+        every((val) => val === true),
+        last()
+      );
+    }
+
+    private deferGuard(
+      guard: CanActivate,
+      context: ExecutionContext
+    ): Observable<boolean> {
+      return defer(() => {
+        const guardVal = guard.canActivate(context);
+        if (this.guardIsPromise(guardVal)) {
+          return from(guardVal);
+        }
+        if (this.guardIsObservable(guardVal)) {
+          return guardVal;
+        }
+        return of(guardVal);
+      });
+    }
+
+    private handleError(): OperatorFunction<boolean, boolean> {
+      return catchError((err) => {
+        if (orGuardOptions?.throwOnFirstError) {
+          return throwError(() => err);
+        }
+        return of(false);
+      });
+    }
+
+    private guardIsPromise(
+      guard: boolean | Promise<boolean> | Observable<boolean>
+    ): guard is Promise<boolean> {
+      return !!(guard as Promise<boolean>).then;
+    }
+
+    private guardIsObservable(
+      guard: boolean | Observable<boolean>
+    ): guard is Observable<boolean> {
+      return !!(guard as Observable<boolean>).pipe;
+    }
+  }
+
+  const Guard = mixin(AndMixinGuard);
+  return Guard as Type<CanActivate>;
+}

packages/or-guard/src/lib/or.guard.ts

@@ -2,6 +2,7 @@ import {
   CanActivate,
   ExecutionContext,
   Inject,
+  InjectionToken,
   mixin,
   Type,
 } from '@nestjs/common';
@@ -14,14 +15,14 @@ import {
   OperatorFunction,
   throwError,
 } from 'rxjs';
-import { catchError, last, mergeMap, takeWhile} from 'rxjs/operators';
+import { catchError, last, mergeMap, takeWhile } from 'rxjs/operators';
 
 interface OrGuardOptions {
   throwOnFirstError?: boolean;
 }
 
 export function OrGuard(
-  guards: Type<CanActivate>[],
+  guards: Array<Type<CanActivate> | InjectionToken>,
   orGuardOptions?: OrGuardOptions
 ) {
   class OrMixinGuard implements CanActivate {
@@ -60,7 +61,7 @@ export function OrGuard(
     private handleError(): OperatorFunction<boolean, boolean> {
       return catchError((err) => {
         if (orGuardOptions?.throwOnFirstError) {
-          return throwError(err);
+          return throwError(() => err);
         }
         return of(false);
       });

packages/or-guard/test/app.controller.ts

@@ -26,4 +26,10 @@ export class AppController {
   getThrowGuardThrow() {
     return this.message;
   }
+
+  @UseGuards(OrGuard(['SyncAndProm', ObsGuard]))
+  @Get('logical-and')
+  getLogicalAnd() {
+    return this.message;
+  }
 }

packages/or-guard/test/app.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 
+import { AndGuard } from '../src/';
 import { AppController } from './app.controller';
 import { ObsGuard } from './obs.guard';
 import { PromGuard } from './prom.guard';
@@ -8,6 +9,15 @@ import { ThrowGuard } from './throw.guard';
 
 @Module({
   controllers: [AppController],
-  providers: [ObsGuard, SyncGuard, PromGuard, ThrowGuard],
+  providers: [
+    ObsGuard,
+    SyncGuard,
+    PromGuard,
+    ThrowGuard,
+    {
+      provide: 'SyncAndProm',
+      useClass: AndGuard([SyncGuard, PromGuard]),
+    },
+  ],
 })
 export class AppModule {}

packages/or-guard/test/or.guard.spec.ts

@@ -24,6 +24,61 @@ describe('Or Guard Integration Test', () => {
   `(
     'sync val $sync syncExpect $syncExpect',
     ({ sync, syncExpect }: { sync: boolean; syncExpect: boolean }) => {
+      describe.each`
+        prom     | promExpect
+        ${true}  | ${true}
+        ${false} | ${false}
+      `(
+        'prom val $prom promExpect $promExpect',
+        ({ prom, promExpect }: { prom: boolean; promExpect: boolean }) => {
+          describe.each`
+            obs      | obsExpect
+            ${true}  | ${true}
+            ${false} | ${syncExpect && promExpect}
+          `(
+            'obs val $obs final expect $obsExpect',
+            ({ obs, obsExpect }: { obs: boolean; obsExpect: boolean }) => {
+              let app: INestApplication;
+              beforeEach(async () => {
+                const testMod = await moduleConfig
+                  .overrideProvider(SyncGuard)
+                  .useValue({ canActivate: () => sync })
+                  .overrideProvider(PromGuard)
+                  .useValue({ canActivate: async () => prom })
+                  .overrideProvider(ObsGuard)
+                  .useValue({ canActivate: () => of(obs) })
+                  .compile();
+                app = testMod.createNestApplication();
+                await app.init();
+              });
+              afterEach(async () => {
+                await app.close();
+              });
+              /**
+               * OrGuard([SyncGuard, PromGuard, ObsGuard])
+               *
+               * | Sync | Prom | Obs | Final |
+               * |  - | - | - | - |
+               * | true | true | true | true |
+               * | true | true | false | true |
+               * | true | false | true | true |
+               * | true | false | false | false |
+               * | false | true | true | true |
+               * | false | true | false | false |
+               * | false | false | true | true |
+               * | false  | false | false | false |
+               */
+              it(`should make a request to the server and${
+                obsExpect ? ' ' : ' not '
+              }succeed`, async () => {
+                return supertest(app.getHttpServer())
+                  .get('/logical-and')
+                  .expect(obsExpect ? 200 : 403);
+              });
+            }
+          );
+        }
+      );
       describe.each`
         prom     | promExpect
         ${true}  | ${true}

packages/or-guard/tsconfig.lib.json

@@ -8,5 +8,5 @@
     "target": "es2021"
   },
   "exclude": ["**/*.spec.ts", "jest.config.ts"],
-  "include": ["**/*.ts"]
+  "include": ["src/**/*.ts"]
 }