http://www.liaoxuefeng.com/wiki/001434446689867b27157e896e74d51a89c25cc8b43bdb3000/0014735914606943e2866257aa644b4bdfe01d26d29960b000

package.json

{
    "name": "rest-koa",
    "version": "1.0.0",
    "description": "koa 2 example with rest api",
    "main": "app.js",
    "scripts": {
        "start": "node --use_strict app.js"
    },
    "keywords": [
        "koa",
        "rest",
        "api"
    ],
    "author": "Michael Liao",
    "license": "Apache-2.0",
    "repository": {
        "type": "git",
        "url": "https://github.com/michaelliao/learn-javascript.git"
    },
    "dependencies": {
        "koa": "2.0.0",
        "koa-bodyparser": "3.2.0",
        "koa-router": "7.0.0"
    }
}

controller.js

const fs = require('fs');

// add url-route in /controllers:

function addMapping(router, mapping) {
    for (var url in mapping) {
        if (url.startsWith('GET ')) {
            var path = url.substring(4);
            router.get(path, mapping[url]);
            console.log(`register URL mapping: GET ${path}`);
        } else if (url.startsWith('POST ')) {
            var path = url.substring(5);
            router.post(path, mapping[url]);
            console.log(`register URL mapping: POST ${path}`);
        } else if (url.startsWith('PUT ')) {
            var path = url.substring(4);
            router.put(path, mapping[url]);
            console.log(`register URL mapping: PUT ${path}`);
        } else if (url.startsWith('DELETE ')) {
            var path = url.substring(7);
            router.del(path, mapping[url]);
            console.log(`register URL mapping: DELETE ${path}`);
        } else {
            console.log(`invalid URL: ${url}`);
        }
    }
}

function addControllers(router, dir) {
    fs.readdirSync(__dirname + '/' + dir).filter((f) => {
        return f.endsWith('.js');
    }).forEach((f) => {
        console.log(`process controller: ${f}...`);
        let mapping = require(__dirname + '/' + dir + '/' + f);
        addMapping(router, mapping);
    });
}

module.exports = function (dir) {
    let
        controllers_dir = dir || 'controllers',
        router = require('koa-router')();
    addControllers(router, controllers_dir);
    return router.routes();
};

controllers目錄

api.js

var products = [{
    name: 'iPhone',
    price: 6999
}, {
    name: 'Kindle',
    price: 999
}];

module.exports = {
    'GET /api/products': async (ctx, next) => {
        ctx.response.type = 'application/json';
        ctx.response.body = {
            products: products
        };
    },

    'POST /api/products': async (ctx, next) => {
        var p = {
            name: ctx.request.body.name,
            price: ctx.request.body.price
        };
        products.push(p);
        ctx.response.type = 'application/json';
        ctx.response.body = p;
    }
};

app.js

const Koa = require('koa');

const bodyParser = require('koa-bodyparser');

const controller = require('./controller');

const app = new Koa();

// log request URL:
app.use(async (ctx, next) => {
    console.log(`Process ${ctx.request.method} ${ctx.request.url}...`);
    await next();
});

// parse request body:
app.use(bodyParser());

// add controller:
app.use(controller());

app.listen(3000);
console.log('app started at port 3000...');