Local Middleware

Create Middleware

For example, we create a Local Middleware logger in the module demo-student

1. Cli command

$ vona :create:bean middleware logger --module=demo-student

2. Menu command

TIP

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

Middleware Definition

export interface IMiddlewareOptionsLogger extends IDecoratorMiddlewareOptions {}

@Middleware<IMiddlewareOptionsLogger>()
class MiddlewareLogger {
  async execute(_options: IMiddlewareOptionsLogger, next: Next) {
    const timeBegin = Date.now();
    const res = await next();
    const timeEnd = Date.now();
    console.log('time: ', timeEnd - timeBegin);
    return res;
  }
}

• IMiddlewareOptionsLogger: Defines middleware parameters
• execute: Outputs execution time

Using Middleware

1. Annotating controller actions

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

@Controller()
class ControllerStudent {
  @Web.get()
+ @Aspect.middleware('demo-student:logger')
  async findMany() {}
}

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

2. Annotating controller class

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

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

@Controller()
+ @Aspect.middleware('demo-student:logger')
class ControllerStudent {
  @Web.get()
  async findMany() {}
}

Middleware Parameters

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

For example, define the prefix parameter for the logger middleware to control the output format

1. Defining parameter types

export interface IMiddlewareOptionsLogger extends IDecoratorMiddlewareOptions {
+ prefix: string;
}

2. Providing default values ​​for parameters

@Middleware<IMiddlewareOptionsLogger>({
+ prefix: 'time',
})

3. Using Parameters

export interface IMiddlewareOptionsLogger extends IDecoratorMiddlewareOptions {
  prefix: string;
}

@Middleware<IMiddlewareOptionsLogger>({
  prefix: 'time',
})
class MiddlewareLogger {
  async execute(options: IMiddlewareOptionsLogger, next: Next) {
    const timeBegin = Date.now();
    const res = await next();
    const timeEnd = Date.now();
-   console.log('time: ', timeEnd - timeBegin);
+   console.log(`${options.prefix}: `, timeEnd - timeBegin);
    return res;
  }
}

4. Specify parameters when using

class ControllerStudent {
  @Web.get()
+ @Aspect.middleware('demo-student:logger', { prefix: 'elapsed' })
  async findMany() {}
}

• When using middleware, just provide the parameter value directly

5. App config

Middleware parameters can be configured in App config

src/backend/config/config/config.ts

// onions
config.onions = {
  middleware: {
    'demo-student:logger': {
      prefix: 'elapsed',
    },
  },
};

6. Parameter precedence

Specify parameters when using > App config > Default values