Web Middleware

Midway Hooks supports defining Web middleware through function + useContext().

Grammar

The middleware has only one parameter next. ctx needs to be obtained by useContext. You can also use any Hooks in the middleware.

Basic example

Take recording request logs as an example:

import { Context } from '@midwayjs/koa';
import { useContext } from '@midwayjs/hooks';

const logger = async (next: any) => {
  const ctx = useContext<Context>();

  console.log (
    '<-- [${ctx.method}] ${ctx.url}'
  );

  const start = Date.now();
  await next();
  const cost = Date.now() - start;

  console.log (
    '--> [${ctx.method}] ${ctx.url} ${cost}ms'
  );
};

Global middleware

Global middleware is defined in configuration.ts, and the middleware defined here takes effect for all interfaces.

import {
  hooks
  createConfiguration
} from '@midwayjs/hooks';
import logger from './logger';

// Global Middleware
export default createConfiguration({
  imports: [
    hooks({
      middleware: [logger],
    }),
  ],
});

File-level middleware

File-level middleware is defined in the Api file. Through the exported config.middleware, the middleware takes effect on all Api functions in the file.

import {
  ApiConfig
  Api
  Get
} from '@midwayjs/hooks';
import logger from './logger';

// File Level Middleware
export const config: ApiConfig = {
  middleware: [logger]
};

export default Api(Get(), async () => {
  return 'Hello World!';
});

Single function middleware

Middleware defined by Middleware(... Middlewares: HooksMiddleware[]) takes effect only for a single function

import {
  Api
  Get
  Middleware
} from '@midwayjs/hooks';
import logger from './logger';

export default Api (
  Get()
  Middleware(logger)
  async () => {
    return 'Hello World!';
  }
);

Using Koa middleware

You can pass in the Koa middleware directly in the above example.

Take @koa/cors as an example.

Global Enabled:

import {
  hooks
  createConfiguration
} from '@midwayjs/hooks';
import logger from './logger';
import cors from '@koa/cors';

// Global Middleware
export default createConfiguration({
  imports: [
    hooks({
      middleware: [logger, cors()]
    }),
  ],
});

File level enabled:

import {
  ApiConfig
  Api
  Get
} from '@midwayjs/hooks';
import logger from './logger';
import cors from '@koa/cors';

// File Level Middleware
export const config: ApiConfig = {
  middleware: [logger, cors]
};

export default Api(Get(), async () => {
  return 'Hello World!';
});

Function level enabled:

import {
  Api
  Get
  Middleware
} from '@midwayjs/hooks';
import logger from './logger';
import cors from '@koa/cors';

export default Api (
  Get()
  Middleware(logger, cors)
  async () => {
    return 'Hello World!';
  }
);