Local Pipe

Create Pipe

For example, create a local pipe number in the module demo-student to convert the request parameter to number type

1. Cli command

$ vona :create:bean pipe number --module=demo-student

2. Menu command

TIP

Context Menu - [Module Path]: Vona Aspect/Pipe

Pipe Definition

export type TypePipeNumberData = unknown;

export type TypePipeNumberResult = number;

export interface IPipeOptionsNumber extends IDecoratorPipeOptions {}

@Pipe<IPipeOptionsNumber>()
class PipeNumber {
  async transform(value: TypePipeNumberData, _metadata: RouteHandlerArgumentMeta, _options: IPipeOptionsNumber): Promise<TypePipeNumberResult> {
    const valueNew = Number(value);
    if (Number.isNaN(valueNew)) this.app.throw(400);
    return valueNew;
  }
}

• TypePipeNumberData: Input parameter type
• TypePipeNumberResult: Result type
• IPipeOptionsNumber: Defines pipe parameters
• transform: Parameter evaluation and conversion

Using Pipe

1. Annotating controller actions

import { Aspect } from 'vona-module-a-aspect';

@Controller()
class ControllerStudent {
  @Web.get(':id')
+ @Aspect.pipe('demo-student:number')
  async findOne(id: number) {}
}

• @Aspect.pipe: This decorator is used to use local pipe. Simply pass the pipe name
  • The number pipe belongs to the demo-student module, so the full name is demo-student:number

2. Annotating controller class

You can use pipe for controller classes so that all actions in the class will apply this pipe

import { Aspect } from 'vona-module-a-aspect';

@Controller()
+ @Aspect.pipe('demo-student:number')
class ControllerStudent {
  @Web.get(':id')
  async findOne(id: number) {}
}

Pipe Parameters

You can define parameters for pipe, allowing for more flexible configuration of pipe logic

For example, define the errorCode parameter for the number pipe. If the incoming request parameter is not of type number, an exception is thrown with the error code errorCode

1. Defining parameter types

export interface IPipeOptionsNumber extends IDecoratorPipeOptions {
+ errorCode: number;
}

2. Providing default values ​​for parameters

@Pipe<IPipeOptionsNumber>({
+ errorCode: 400,
})

3. Using Parameters

export interface IPipeOptionsNumber extends IDecoratorPipeOptions {
  errorCode: number;
}

@Pipe<IPipeOptionsNumber>({
  errorCode: 400,
})
export class PipeNumber extends BeanBase implements IPipeTransform<TypePipeNumberData, TypePipeNumberResult> {
  async transform(value: TypePipeNumberData, _metadata: RouteHandlerArgumentMeta, options: IPipeOptionsNumber): Promise<TypePipeNumberResult> {
    const valueNew = Number(value);
-    if (Number.isNaN(valueNew)) this.app.throw(400);
+    if (Number.isNaN(valueNew)) this.app.throw(options.errorCode);
    return valueNew;
  }
}

4. Specify parameters when using

You can specify local pipe parameters for a specific API

class ControllerStudent {
  @Web.get(':id')
+ @Aspect.pipe('demo-student:number', { errorCode: 500 })
  async findOne(id: number) {}
}

• When using pipe, just provide the parameter value directly

5. App config

Pipe parameters can be configured in App config

src/backend/config/config/config.ts

// onions
config.onions = {
  pipe: {
    'demo-student:number': {
      errorCode: 500,
    },
  },
};

6. Parameter precedence

Specify parameters when using > App config > Default values