一、Koa的使用:
//1.导入Koa模块. 注Koa2开始, 导入的是一个class
const Koa = require('koa');
//2.创建Koa对象
const app = New Koa();
//3.调用异步执行的方法, 处理网络请求
app.use(async (ctx, next) => {
await next();//执行next则会跳转执行下一个middleware
ctx.response.type = 'text/html';
ctx.response.body = '<h1>Hello, koa2!</h1>';
});
//4.绑定端口监听
app.listen(3000);
console.log('app started at port 3000...');
二、Koa-router处理不同URL
const Koa = require('koa');
const app = new Koa();
const bodyParser = require('koa-bodyparser');//用来处理post请求的json数据,注:在router被注册到app之前执行
//1.引入,引入的接口是一个函数, 下面选择直接执行函数获得router对象
const router = require('koa-router')();
//2.接收网络请求, 执行下一个middleware
app.use(async (ctx, next) => {
console.log(`Process ${ctx.request.method} ${ctx.request.url}...`);
await next();
});
app.use(bodyParser());//注册bodyParser用来处理json解析
//3.使用router匹配url get请求
router.get('/hello/:name', async (ctx, next) => {
var name = ctx.params.name;
ctx.response.body = `<h1>Hello, ${name}!</h1>`;
});
router.get('/',async(ctx, next)=>{
ctx.response.body = '<h1>Index</h1>';
});
//post请求
router.post('/signin', async (ctx, next) => {
var name = ctx.request.body.name || '',
password = ctx.request.body.password || '';
console.log(`signin with name: ${name}, password: ${password}`);
if (name === 'koa' && password === '12345') {
ctx.response.body = `<h1>Welcome, ${name}!</h1>`;
} else {
ctx.response.body = `<h1>Login failed!</h1>
<p><a href="/">Try again</a></p>`;
}
});
//4.把routers添加进middleware
app.use(router.routes());
app.listen(3000);
console.log ('app started at port 3000...')
三、Nunjucks的使用
const nunjucks = require('nunjucks');
//1.定义函数用于使用nunjucks对象创建environment
function createEnv(path, opts) {
var
autoescape = opts.autoescape && true,
noCache = opts.noCache || false,
watch = opts.watch || false,
throwOnUndefined = opts.throwOnUndefined || false,
env = new nunjucks.Environment(
new nunjucks.FileSystemLoader('views', {
noCache: noCache,
watch: watch,
}), {
autoescape: autoescape,
throwOnUndefined: throwOnUndefined
});
if (opts.filters) {
for (var f in opts.filters) {
env.addFilter(f, opts.filters[f]);
}
}
return env;
}
//2.创建environment
var env = createEnv('views', {
watch: true,
filters: {
hex: function (n) {
return '0x' + n.toString(16);
}
}
});
//3.使用environment对象渲染html文件
//注:html文件放在views目录下
var s = env.render('hello.html', { name: '小明' });
console.log(s);
四、Koa-router框架注册url, 以及配合Nunjucks框架的MVC封装
参考:廖雪峰JavaScript教程
Nunjuncks官方文档
