josephdpurcell · June 18, 2025 06:36 · Nov 19, 2021 · Nov 19, 2021 · Nov 19, 2021 · Nov 19, 2021
diff --git a/README.md b/README.md
@@ -39,7 +39,7 @@ Then, you need to build another custom decorator that composes that with a valid
 ```ts
 export const ValidBody = () =>
   RawBody(
-    new MyValidationPipe({
+    new ValidationPipe({
       validateCustomDecorators: true,
       whitelist: true,
       forbidNonWhitelisted: true,
@@ -62,7 +62,7 @@ Here is an example of the decorator:
 ```ts
 export const ValidBody = () =>
   Body(
-    new MyValidationPipe({
+    new ValidationPipe({
       whitelist: true,
       forbidNonWhitelisted: true,
       transform: true,

diff --git a/README.md b/README.md
@@ -21,7 +21,7 @@ https://github.com/nestjs/nest/blob/master/packages/common/pipes/validation.pipe
 # Are there alternative approaches?
 
 
-## Alternate 1: Override global ValidationPipe
+## Alternate 1: Use @ValidBody with custom overrides to the global ValidationPipe
 
 You could just change the behavior of the global validation pipe. This is a bit tricky and it only works on the param decorator level. First, you need a custom decorator:
 

diff --git a/README.md b/README.md
@@ -2,6 +2,8 @@
 
 This is an example of how to ignore a global validation pipe for a specific parameter, e.g. a request body. In fact, this example just shows a request body but you could apply this principle to other decorators.
 
+This approach assumes `validateCustomDecorators: false` in the global validation pipe. If `validateCustomDecorators` is true in the global pipe I think you're out of luck. If that is your situation, consider refactoring so that `validateCustomDecorators` is false in the global pipe and then have each custom decorator add validation if it needs it.
+
 # How does this work?
 
 The NestJS `ValidationPipe` does not validate custom decorators. So, in this above example we just make a `@RawBody()` param decorator, and NestJS will skip validating it.
@@ -18,10 +20,61 @@ https://github.com/nestjs/nest/blob/master/packages/common/pipes/validation.pipe
 
 # Are there alternative approaches?
 
-I haven't thoroughly researched this, but here are a few that come to mind:
 
-* Instead of applying a global validator, write a custom `@Body` decorator (e.g. `@ValidBody`) and have that decorator just use a validation pipe; see https://stackoverflow.com/a/56748392/990642
-* Write your own custom `ValidationPipe` class, use that globally, and do some checking logic there?
+## Alternate 1: Override global ValidationPipe
+
+You could just change the behavior of the global validation pipe. This is a bit tricky and it only works on the param decorator level. First, you need a custom decorator:
+
+```ts
+export const RawBody = createParamDecorator(
+  (data: unknown, ctx: ExecutionContext): any => {
+    const request = ctx.switchToHttp().getRequest();
+    return request.body;
+  }
+);
+```
+
+Then, you need to build another custom decorator that composes that with a validation pipe like so:
+
+```ts
+export const ValidBody = () =>
+  RawBody(
+    new MyValidationPipe({
+      validateCustomDecorators: true,
+      whitelist: true,
+      forbidNonWhitelisted: true,
+      transform: true,
+    })
+  );
+```
+
+Note the use of `validateCustomDecorators: true` here! This is important. The validation pipe will not work unless this is true here. (But, remember, `validateCustomDecorators` should be false in the global validation pipe.)
+
+Then, use `@ValidBody` instead of `@Body` wherever you want to override the global validation pipe with your custom validation pipe rules. This approach will work even if there is a global validation pipe.
+
+
+## Alternate 2: Use @ValidBody instead of global ValidationPipe
+
+Instead of applying a global validator, write a custom `@Body` decorator (e.g. `@ValidBody`) and have that decorator just use a validation pipe; see https://stackoverflow.com/a/56748392/990642. Note: I think `validateCustomDecorators: true` would need to be enabled.
+
+Here is an example of the decorator:
+
+```ts
+export const ValidBody = () =>
+  Body(
+    new MyValidationPipe({
+      whitelist: true,
+      forbidNonWhitelisted: true,
+      transform: true,
+    })
+  );
+```
+
+Then, use `@ValidBody` instead of `@Body`. This approach does not work if there is a global validation pipe.
+
+## Alternate 3: Custom ValidationPipe
+
+Write your own custom `ValidationPipe` class, use that globally, and do some checking logic there?
 
 # Links
 

diff --git a/README.md b/README.md
@@ -1,3 +1,7 @@
+# What is this?
+
+This is an example of how to ignore a global validation pipe for a specific parameter, e.g. a request body. In fact, this example just shows a request body but you could apply this principle to other decorators.
+
 # How does this work?
 
 The NestJS `ValidationPipe` does not validate custom decorators. So, in this above example we just make a `@RawBody()` param decorator, and NestJS will skip validating it.

diff --git a/README.md b/README.md
@@ -12,6 +12,13 @@ Here is where it returns if validation shouldn't apply:
 
 https://github.com/nestjs/nest/blob/master/packages/common/pipes/validation.pipe.ts#L102-L106
 
+# Are there alternative approaches?
+
+I haven't thoroughly researched this, but here are a few that come to mind:
+
+* Instead of applying a global validator, write a custom `@Body` decorator (e.g. `@ValidBody`) and have that decorator just use a validation pipe; see https://stackoverflow.com/a/56748392/990642
+* Write your own custom `ValidationPipe` class, use that globally, and do some checking logic there?
+
 # Links
 
 Here are some links that talk about this issue and some documentation links that are relevant:

diff --git a/my.dto → my.dto.ts b/my.dto → my.dto.ts
diff --git a/README.md b/README.md
@@ -0,0 +1,26 @@
+# How does this work?
+
+The NestJS `ValidationPipe` does not validate custom decorators. So, in this above example we just make a `@RawBody()` param decorator, and NestJS will skip validating it.
+
+Take a look at NestJS' `ValidationPipe` class at the relevant points:
+
+Here is where it checks to see if the decorator type is 'custom':
+
+https://github.com/nestjs/nest/blob/master/packages/common/pipes/validation.pipe.ts#L164-L166
+
+Here is where it returns if validation shouldn't apply:
+
+https://github.com/nestjs/nest/blob/master/packages/common/pipes/validation.pipe.ts#L102-L106
+
+# Links
+
+Here are some links that talk about this issue and some documentation links that are relevant:
+
+* https://docs.nestjs.com/techniques/validation
+* https://docs.nestjs.com/interceptors
+* https://github.com/nestjs/nest/issues/2390
+* https://github.com/nestjs/nest/pull/3354
+* https://stackoverflow.com/questions/58751743/disable-validation-in-nestjs-param-decorator?rq=1
+* https://stackoverflow.com/questions/54471331/how-to-ignore-an-interceptor-for-a-particular-route-in-nestjs
+* https://stackoverflow.com/questions/56273543/how-to-override-global-validationpipe-in-controller
+* https://stackoverflow.com/questions/56583609/how-can-we-override-the-global-validation-pipe-in-nestjs
diff --git a/main.ts b/main.ts
@@ -0,0 +1,11 @@
+import { ValidationPipe } from '@nestjs/common';
+
+// ...
+
+  app.useGlobalPipes(new ValidationPipe({
+    whitelist: true,
+    forbidNonWhitelisted: true,
+    transform: true,
+  }));
+
+// ...
diff --git a/my-controller.ts b/my-controller.ts
@@ -0,0 +1,13 @@
+import { Body, Controller, Post } from '@nestjs/common';
+import { RawBody } from './raw-body.ts';
+import { MyDto } from './my.dto';
+
+@Controller()
+export class MyController {
+  @Post()
+  async post(
+    @RawBody() params: MyDto
+  ): Promise<void> {
+    // params will be a raw un-typed object with no validation having been run on it!
+  }
+}
diff --git a/my.dto b/my.dto
@@ -0,0 +1,6 @@
+import { IsNotEmpty } from "class-validator";
+
+export class MyDto {
+  @IsNotEmpty()
+  field: string;
+}
diff --git a/raw-body.ts b/raw-body.ts
@@ -0,0 +1,8 @@
+import { createParamDecorator, ExecutionContext } from '@nestjs/common';
+
+export const RawBody = createParamDecorator(
+  (data: unknown, ctx: ExecutionContext): any => {
+    const request = ctx.switchToHttp().getRequest();
+    return request.body;
+  }
+);
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