bugfix(core) fix interceptors execution flow

Author: kamilmysliwiec

packages/common/cache/interceptors/cache.interceptor.ts

@@ -2,6 +2,7 @@ import { Observable, of } from 'rxjs';
 import { tap } from 'rxjs/operators';
 import { Inject, Injectable, Optional } from '../../decorators';
 import {
+  CallHandler,
   ExecutionContext,
   HttpServer,
   NestInterceptor,
@@ -30,20 +31,22 @@ export class CacheInterceptor implements NestInterceptor {
 
   async intercept(
     context: ExecutionContext,
-    call$: Observable<any>,
+    next: CallHandler,
   ): Promise<Observable<any>> {
     const key = this.trackBy(context);
     if (!key) {
-      return call$;
+      return next.handle();
     }
     try {
       const value = await this.cacheManager.get(key);
       if (value) {
         return of(value);
       }
-      return call$.pipe(tap(response => this.cacheManager.set(key, response)));
+      return next
+        .handle()
+        .pipe(tap(response => this.cacheManager.set(key, response)));
     } catch {
-      return call$;
+      return next.handle();
     }
   }
 

packages/common/files/interceptors/file-fields.interceptor.ts

@@ -7,7 +7,10 @@ import {
   MulterField,
   MulterOptions,
 } from '../../interfaces/external/multer-options.interface';
-import { NestInterceptor } from '../../interfaces/features/nest-interceptor.interface';
+import {
+  CallHandler,
+  NestInterceptor,
+} from '../../interfaces/features/nest-interceptor.interface';
 import { MULTER_MODULE_OPTIONS } from '../files.constants';
 import { MulterModuleOptions } from '../interfaces';
 import { transformException } from '../multer/multer.utils';
@@ -34,7 +37,7 @@ export function FileFieldsInterceptor(
 
     async intercept(
       context: ExecutionContext,
-      call$: Observable<any>,
+      next: CallHandler,
     ): Promise<Observable<any>> {
       const ctx = context.switchToHttp();
 
@@ -51,7 +54,7 @@ export function FileFieldsInterceptor(
           },
         ),
       );
-      return call$;
+      return next.handle();
     }
   }
   const Interceptor = mixin(MixinInterceptor);

packages/common/files/interceptors/file.interceptor.ts

@@ -4,7 +4,10 @@ import { Inject, Optional } from '../../decorators';
 import { mixin } from '../../decorators/core/component.decorator';
 import { ExecutionContext } from '../../interfaces';
 import { MulterOptions } from '../../interfaces/external/multer-options.interface';
-import { NestInterceptor } from '../../interfaces/features/nest-interceptor.interface';
+import {
+  CallHandler,
+  NestInterceptor,
+} from '../../interfaces/features/nest-interceptor.interface';
 import { MULTER_MODULE_OPTIONS } from '../files.constants';
 import { MulterModuleOptions } from '../interfaces';
 import { transformException } from '../multer/multer.utils';
@@ -31,7 +34,7 @@ export function FileInterceptor(
 
     async intercept(
       context: ExecutionContext,
-      call$: Observable<any>,
+      next: CallHandler,
     ): Promise<Observable<any>> {
       const ctx = context.switchToHttp();
 
@@ -48,7 +51,7 @@ export function FileInterceptor(
           },
         ),
       );
-      return call$;
+      return next.handle();
     }
   }
   const Interceptor = mixin(MixinInterceptor);

packages/common/files/interceptors/files.interceptor.ts

@@ -4,7 +4,10 @@ import { Inject, Optional } from '../../decorators';
 import { mixin } from '../../decorators/core/component.decorator';
 import { ExecutionContext } from '../../interfaces';
 import { MulterOptions } from '../../interfaces/external/multer-options.interface';
-import { NestInterceptor } from '../../interfaces/features/nest-interceptor.interface';
+import {
+  CallHandler,
+  NestInterceptor,
+} from '../../interfaces/features/nest-interceptor.interface';
 import { MULTER_MODULE_OPTIONS } from '../files.constants';
 import { MulterModuleOptions } from '../interfaces';
 import { transformException } from '../multer/multer.utils';
@@ -32,7 +35,7 @@ export function FilesInterceptor(
 
     async intercept(
       context: ExecutionContext,
-      call$: Observable<any>,
+      next: CallHandler,
     ): Promise<Observable<any>> {
       const ctx = context.switchToHttp();
 
@@ -49,7 +52,7 @@ export function FilesInterceptor(
           },
         ),
       );
-      return call$;
+      return next.handle();
     }
   }
   const Interceptor = mixin(MixinInterceptor);

packages/common/index.ts

@@ -15,6 +15,7 @@ export * from './http';
 export {
   ArgumentMetadata,
   ArgumentsHost,
+  CallHandler,
   CanActivate,
   DynamicModule,
   ExceptionFilter,

packages/common/interfaces/features/nest-interceptor.interface.ts

@@ -1,9 +1,13 @@
 import { Observable } from 'rxjs';
 import { ExecutionContext } from './execution-context.interface';
 
+export interface CallHandler<T = any> {
+  handle(): Observable<T>;
+}
+
 export interface NestInterceptor<T = any, R = any> {
   intercept(
     context: ExecutionContext,
-    call$: Observable<T>,
+    next: CallHandler<T>,
   ): Observable<R> | Promise<Observable<R>>;
 }

packages/common/serializer/class-serializer.interceptor.ts

@@ -4,7 +4,11 @@ import { Inject, Injectable } from '../decorators/core';
 import { ClassTransformOptions } from '../interfaces/external/class-transform-options.interface';
 import { loadPackage } from '../utils/load-package.util';
 import { isObject } from '../utils/shared.utils';
-import { ExecutionContext, NestInterceptor } from './../interfaces';
+import {
+  CallHandler,
+  ExecutionContext,
+  NestInterceptor,
+} from './../interfaces';
 import { CLASS_SERIALIZER_OPTIONS } from './class-serializer.constants';
 
 let classTransformer: any = {};
@@ -25,16 +29,15 @@ export class ClassSerializerInterceptor implements NestInterceptor {
     classTransformer = loadPkg('class-transformer');
   }
 
-  intercept(
-    context: ExecutionContext,
-    call$: Observable<any>,
-  ): Observable<any> {
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
     const options = this.getContextOptions(context);
-    return call$.pipe(
-      map((res: PlainLiteralObject | Array<PlainLiteralObject>) =>
-        this.serialize(res, options),
-      ),
-    );
+    return next
+      .handle()
+      .pipe(
+        map((res: PlainLiteralObject | Array<PlainLiteralObject>) =>
+          this.serialize(res, options),
+        ),
+      );
   }
 
   serialize(

packages/core/interceptors/interceptors-consumer.ts

@@ -18,18 +18,14 @@ export class InterceptorsConsumer {
     }
     const context = this.createContext(args, instance, callback);
     const start$ = defer(() => this.transformDeffered(next));
-    /***
-      const nextFn =  (i: number) => async () => {
+
+    const nextFn = (i = 0) => async () => {
       if (i <= interceptors.length) {
         return start$;
       }
-      return await interceptors[i].intercept(context, nextFn(i + 1) as any);
+      return interceptors[i].intercept(context, nextFn(i + 1) as any);
     };
-    */
-    const result$ = await interceptors.reduce(
-      async (stream$, interceptor) => interceptor.intercept(context, await stream$),
-      Promise.resolve(start$),
-    );
+    const result$ = await nextFn()();
     return result$.toPromise();
   }