class-validator
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typestack
fix: stopAtFirstError not working as expected, a custom decorator executes when previous validator fails
Description
I have a custom decorator as the last one that validates a string against my database. It's still being called and executed even if a previous validator has failed.
ValidationPipe configuration
app.useGlobalPipes(
new ValidationPipe({
stopAtFirstError: true, // <- Feature activated.
whitelist: true,
forbidNonWhitelisted: true,
transform: true,
}),
);
Entity DTO
@IsString()
@IsNotEmpty() // <- Seems that not executed, did not throw error to the client.
@Length(11, 11) // <- Executed, If this fails, should stop and return error to the client.
@IsUnique({ table: 'users' }) // <-- Custom, validates against database.
readonly identification: string;
POST Request example
{
"identification": "",
}
Response
{
"statusCode": 400,
"message": [
"identification must be longer than or equal to 11 characters",
"The value of identification already exists." // <- Oops!, should not happen.
],
"error": "Bad Request"
}
My custom validator and decorator
@ValidatorConstraint({
name: 'isUnique',
async: true,
})
@Injectable()
export class IsUniqueValidator implements ValidatorConstraintInterface {
async validate(value: string, validationArgs?: ValidationArguments): Promise<boolean> {
// "value" is empty here... I did this as a workaround.
if (isEmpty(value)) {
return false;
}
const results: any[] = []; // Represents the result of a query against database.
return results.length === 0;
}
defaultMessage(validationArguments?: ValidationArguments): string {
const value = validationArguments?.value;
const property = validationArguments?.property;
return `The value ${value} of ${property} already exists.`;
}
}
export function IsUnique(params: any, validationOptions?: ValidationOptions) {
return function (object: Object, propertyName: string) {
registerDecorator({
target: object.constructor,
propertyName: propertyName,
options: validationOptions,
constraints: [params],
validator: IsUniqueValidator,
});
};
}
Expected behavior
Just the result of a previous validation, example:
{
...
"message": [
"identification must be longer than or equal to 11 characters",
],
..
}
To be more precise, the @IsNotEmpty() should have stop the empty string as shown above, being the only error returned to the client.
Actual behavior
The custom validator, which is the last one, is still being called and executed.
class-validator: 0.13.1
Due to the nature of Typescript decorators, All of the decorators are going to run in reversed order as for: https://www.typescriptlang.org/docs/handbook/decorators.html#decorator-composition
Therefore, it's not really related to your custom rule as you probably thought. Since your custom decorator is the last decorator, it means that it's going to be the first decorator to be executed. That's why you are seeing its error message.
Due to the nature of Typescript decorators, All of the decorators (...)
This is correct, but it will not work in the way you describe (reversed from decoration) with async validators. Async validation will be triggered at the beginning. I described it better under: https://github.com/typestack/class-validator/issues/1688 I would propose to close this ticket and keep only #1688 since stopAtFirstError option has nothing to do with the origin of the problem.
@smentek @RRGT19 @secmohammed @thiennhan2310 @feRpicoral Can any of you help me understand y this one passes when I send a req without this optional param (someString) ?
If it runs in the reversed order so I would expect it to fail on the IsNotEmpty decorator.
export class SomeDto {
@IsOptional()
@IsString()
@IsNotEmpty()
public someString?: string
.
.
.
}
Thanks a lot ! 🙏
Is stopAtFirstError really working for someone, I am trying to configure it as below and its not working at all. Is there something I am missing in configuration.
app.useGlobalPipes( new ValidationPipe({ transform: true, stopAtFirstError: true, }), );
